Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by...Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.展开更多
Solid-state lithium batteries are constrained by sluggish ion kinetics and poor interfacial stability.Herein,a quasi-solid polymer electrolyte was designed via an in-situ copolymerization strategy with 1,3-dioxolane(D...Solid-state lithium batteries are constrained by sluggish ion kinetics and poor interfacial stability.Herein,a quasi-solid polymer electrolyte was designed via an in-situ copolymerization strategy with 1,3-dioxolane(DOL)and 1,3,5-trioxane(TXE).The incorporation of TXE modulates the regularity and motility of the polymer segment and then enhances the Li^(+)transport kinetics.Moreover,fluorothylene carbonate and tris(trimethylsilyl)borate are conducive to constructing a stable and inorganic-rich electrodeelectrolyte interface,which can effectively prevent electrolyte decomposition and inhibit lithium dendrite growth.The two additives can also participate in solvation to form a loose solvated sheath that accelerates Li^(+)coupling-decoupling behaviors.When applied in Li‖LiFePO_(4)(LFP)battery,an initial capacity of 157.8 mAh g^(-1)and a capacity retention of 88.7%after 800 cycles at 1 C were obtained,along with an exceptional rate performance(114.3 mAh g^(-1),5 C).Even at-20℃,a remarkable capacity of103.7 mAh g^(-1)was still obtained.The synergetic strategy of ether-oxygen segment design and solvation structure regulation paves the way for high-performance quasi-solid lithium metal batteries.展开更多
A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units in...A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units into the polycarbonate(PC)chain.In addition to high transparency,the resultant copolymers(SS-co-PC5,SS-co-PC9,SS-co-PC14,and SS-co-PC20)exhibited remarkable improvements in fire safety and mechanical performance.Compared to pure PC,these copolymers demonstrated significantly enhanced limiting oxygen index(LOI,up to 34.5%)and a UL-94 V-0 rating under a thickness of only 1.6 mm.The incorporation of the polysiloxane blocks not only improved flame retardancy but also enhanced the impact strength,with SS-co-PC9 showing a 48%increase in elongation at break and a 38%rise in impact toughness compared to pure PC.In addition,SS-co-PC9 presented high mechanical strength.The synergistic effects between the naphthalene-sulfonate and polysiloxane blocks,along with the well-controlled polysiloxane phase separation(sulfonate units enabled lower processing viscosity of copolymers),led to superior comprehensive performance.These findings provide a promising pathway to create high-performance copolycarbonates for real-world applications.展开更多
Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor sol...Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor solutions and other fabrication processes utilized in the production of organic ferroelectric transistors. In this study, an organic ferroelectric field effect transistor(OFeFET) with the 6,13-Bis(triisopropylsilylethynyl) pentacene(TIPS-pentacene) channel is fabricated, in which the aluminum oxide(Al_(2)O_(3)) interlayer is used to improve compatibility. The device displays polymorphic memory and synaptic plasticity of long-term potentiation and depression. Furthermore, an artificial neural network constructed using our devices is simulated to succeed in recognizing the MNIST handwritten digit database with a high accuracy of 92.8%. This research offers a viable approach to enhance the compatibility of the organic ferroelectric polymer P(VDF-TrFE) with organic semiconductors.展开更多
The ring-opening alternating copolymerization(ROAC)of 3,4-dihydrocoumarin(DHC)/epoxides has been successfully developed using an imidazolium salt of 1-ethyl-3-methylimidazolium chloride(EMIMCl)as a catalyst.The result...The ring-opening alternating copolymerization(ROAC)of 3,4-dihydrocoumarin(DHC)/epoxides has been successfully developed using an imidazolium salt of 1-ethyl-3-methylimidazolium chloride(EMIMCl)as a catalyst.The resulting copolymer has a molecular weight of 13.7kg·mol^(-1),a narrow molecular weight distribution of 1.03 and a strictly alternating structure.The MALDI-TOF MS characterization and DFT calculations including electrostatic potential(ESP),hydrogen-atom abstraction(HAA),independent gradient model based on hirshfeld partition(IGMH)and atoms-in-molecules(AIM)analysis were used to investigate the metal-free catalytic process.The synergistic effect of anions and cations of EMIMCl for ROAC of DHC and epoxides was demonstrated.This study provides a metal-free catalytic system for the facile synthesis of alternating polyesters from DHC.展开更多
The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development ...The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications.Besides its biodegradability,PBS can be derived from petroleum and biobased monomers.At the same time,the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products.The processes and techniques presented herein,are based on the production of biobased succinic acid monomer to PBS.However,the counterpart biobased monomer 1,4-butanediol(1,4-BDO)production has not been commercially demonstrated.This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS,its copolymers,and composites with the view to improve molecular weight,thermal,and mechanical properties.It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical,thermal,stability and mechanical structural properties.Importantly,the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films,biomedical and drug release,fire retardants,and agricultural products.The structure-functional performance characteristics of these developments in the PBS,copolymers,and composites are highlighted to provide baseline insights for future developments in engineering the specific applications,and structural interface PBS composites with enhanced structure-functional performance properties.展开更多
High-voltage LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathodes are critical for enhancing the energy density of lithium-ion batteries(LIBs).The development of binders compatible with high-voltage NCM811 cathode material...High-voltage LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathodes are critical for enhancing the energy density of lithium-ion batteries(LIBs).The development of binders compatible with high-voltage NCM811 cathode materials is crucial to enhance the electrochemical performance of LIBs.However,the traditional fluoropolymer binder,poly(vinylidene difluoride)(PVDF),can potentially leach components or break down into poly(fluoroalkyl substances)(PFAS)chemicals,thereby contributing to PFAS contamination.A novel fluorine-free polymer,polysulfone-polyamide-polyimide(SPIO),was designed and synthesized as a binder for NCM811 cathodes.The SPIO binder exhibits exceptional mechanical properties and superior electrochemical characteristics.The cathode film fabricated with SPIO demonstrated a remarkable delamination force of 8 N(390 N·m^(-1)),indicating robust adhesion.The Li‖NCM811 cell incorporating the SPIO binder retained 80%of its initial capacity after 300 cycles at a current density of 0.2 C.In comparison,the control cells assem bled with the PVDF binder retained only 52%of their capacities under the same cycling conditions.Furthermore,the SPIO binder exhibited improved compatibility with the electrolyte.Transmission electron microscopy analysis of the cathode films after 100 cycles revealed the formation of a unifo rm,dense,and continuous chemical-electrochemical interface(CEI)by the SPIO binder on the surface of the NCM811 particles,which significantly contributed to the enhancement of the electrochemical performance.These results highlight the potential of SPIO as an advanced binder material for high-perfo rmance lithium-ion batteries.展开更多
As one of the most promising metal-free photocatalysts for renewable H_(2) evolution,graphitic carbon nitride(g-C_(3)N_(4))has attracted notable attention.Regulating its morphology and electronic structure is crucial ...As one of the most promising metal-free photocatalysts for renewable H_(2) evolution,graphitic carbon nitride(g-C_(3)N_(4))has attracted notable attention.Regulating its morphology and electronic structure is crucial for enhancing its performance.In this work,aromatic small molecules and melamine were hydrothermally cotreated to form a novel supramolecular precur-sor,which was subsequently calcined to obtain aπ-πconjugated structure of g-C_(3)N_(4) photocatalyst.The introduction of benzene-ring structures expanded the conjugated system and promoted the excitation ofπelectrons,thereby broadening the light-absorption range of g-C_(3)N_(4).The synergism of bromine and chlorine provided abundant active sites for g-C_(3)N_(4),greatly promoted the migration of photogenerated charge carriers,and reduced the recombination probability,thus improving in photocatalytic performance.Therefore,the g-C_(3)N_(4) photocatalyst obtained from 2-bromo-5-chlorobenzoic acid-derived supramolecular precursor exhibited a visible-light(λ≥400 nm)photocatalytic H_(2) evolution activity of 839.8μmol/(h g),which was about three times that of the unmodifi ed g-C_(3)N_(4).This work off ers a novel perspective for g-C_(3)N_(4) application in the fi eld of photocatalysis and expands the utilization of aromatic small molecules in photocatalysts modifi cation.展开更多
Using molecular dynamics modeling,the change in the shape and density of the macromolecular corona consisting of two oppositely charged polyelectrolytes,including those combined into one block copolymer,on the surface...Using molecular dynamics modeling,the change in the shape and density of the macromolecular corona consisting of two oppositely charged polyelectrolytes,including those combined into one block copolymer,on the surface of a polarized spherical metal nanoparticle was studied.A mathematical model of the structure of the block copolymer chain adsorbed on a polarized spherical nanoparticle is presented for the cases of polyelectrolyte blocks of large and small length.Based on the modeling results,radial and angular distributions of the density of atoms of polyelectrolyte polypeptides adsorbed on the surface of a spherical nanoparticle were calculated depending on its dipole moment.As the dipole moment of the nanoparticle increased,the dense macromolecular shell was destroyed,forming caps of polyelectrolyte macro molecules or fragments of block copolymer of different types on the poles of the polarized nanoparticle.In this case,the macromolecular corona in the region of the poles of the polarized nanoparticle swelled the more strongly,the greater the distance between the charged links in the polymer.展开更多
A series of imido-vanadium(Ⅴ)complexes bearing bidentate phenoxy-phosphine ligands were synthesized and characterized by NMR,elemental analysis,and single-crystal X-ray diffraction.These complexes demonstrated excell...A series of imido-vanadium(Ⅴ)complexes bearing bidentate phenoxy-phosphine ligands were synthesized and characterized by NMR,elemental analysis,and single-crystal X-ray diffraction.These complexes demonstrated excellent catalytic performance in ethylene/1-hexene copolymerization,achieving high activities of 12.0×10~6–49.0×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1)and affording random copolymers with tunable 1-hexene incorporations.These catalysts also exhibited ultrahigh activity,up to 112.2×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1),in ethylene/norbornene(NB)copolymerization,yielding cyclic olefin copolymers with adjustable NB incorporations.Remarkably,these catalysts demonstrated exceptional tolerance toward polar functional groups,enabling efficient copolymerization of ethylene with both 10-undecen-1-ol(U-OH)and 5-norbornene-2-methanol(NB-OH),incorporating about 2 mol%polar comonomers with high efficiency.Different with the catalytic behaviors in copolymerization of ethylene with nonpolar comonomers,the catalytic activities in E/U-OH copolymerization(25.7×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1))were much higher than those in E/NB-OH copolymerization(8.6×10^(6) g_(polymer)·(mol_(V))^(-1)·h^(-1)).DFT calculations revealed that the catalytic performance is governed by synergistic electronic and steric effects.For E/NB copolymerization,strong preference for cyclic olefins was attributed to favorable transition state stabilization.In polar comonomer systems,steric effects were predominant,with NB-OH exhibiting a larger buried volume around vanadium center upon coordination compared to U-OH.Overall,this work provides fundamental insights into vanadium-catalyzed(co)polymerization and offers new strategies for tailored polyolefin design.展开更多
Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a n...Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a new way to access degradable polyethylene materials with a low content of in-chain ester units via mechanochemical backbone editing.Initially,ester groups are incorporated as side groups through catalytic copolymerization of ethylene with a cyclobutene-fused lactone monomer(CBL),yielding polyethylene materials with high molecular weights and adjustable thermomechanical properties.Subsequent solid-state ball-milling treatment selectively introduces side-chain ester groups into the main chain of the polyethylene materials via force-induced cycloreversion of the cyclobutane units.Under acidic conditions,hydrolysis of the resultant polyethylene materials with in-chain ester units facilitates further degradation into oligomers.展开更多
The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast com...The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast combinatorial phase space defined by components,se-quences,and topologies,and is often computationally intractable due to its NP-hard nature.At the core of this challenge lies the need to evalu-ate complex correlations among structural variables,a classical problem in both statistical physics and combinatorial optimization.To address this,we adopt a mean-field approach that decouples direct variable-variable interactions into effective interactions between each variable and an auxiliary field.The simulated bifurcation(SB)algorithm is employed as a mean-field-based optimization framework.It constructs a Hamiltonian dynamical system by introducing generalized momentum fields,enabling efficient decoupling and dynamic evolution of strongly coupled struc-tural variables.Using the sequence optimization of a linear copolymer adsorbing on a solid surface as a case study,we demonstrate the applica-bility of the SB algorithm to high-dimensional,non-differentiable combinatorial optimization problems.Our results show that SB can efficiently discover polymer sequences with excellent adsorption performance within a reasonable computational time.Furthermore,it exhibits robust con-vergence and high parallel scalability across large design spaces.The approach developed in this work offers a new computational pathway for polymer structure optimization.It also lays a theoretical foundation for future extensions to topological design problems,such as optimizing the number and placement of side chains,as well as the co-optimization of sequence and topology.展开更多
A series of divinylphenyl-acryloyl chloride copolymers(PDVB-co-PACl)is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers.PDVB-co-PACl is utilized to graf...A series of divinylphenyl-acryloyl chloride copolymers(PDVB-co-PACl)is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers.PDVB-co-PACl is utilized to graft on the surface of spherical aluminum nitride(AlN)to prepare functionalized AlN(AlN@PDVB-co-PACl).Polymethylhydrosiloxane(PMHS)is then used as the matrix to prepare thermally conductive AlN@PDVB-co-PACl/PMHS composites with AlN@PDVB-co-PACl as fillers through blending and curing.The grafting of PDVB-co-PACl synchronously enhances the hydrolysis resistance of AlN and its interfacial compatibility with PMHS matrix.When the molecular weight of PDVB-co-PACl is 5100 g mol^(-1)and the grafting density is 0.8 wt%,the composites containing 75 wt%of AlN@PDVB-co-PACl exhibit the optimal comprehensive performance.The thermal conductivity(λ)of the composite is 1.14 W m^(-1)K^(-1),which enhances by 20%and 420%compared to theλof simply physically blended AlN/PMHS composite and pure PMHS,respectively.Meanwhile,AlN@PDVB-co-PACl/PMHS composites display remarkable hydrothermal aging resistance by retaining 99.1%of itsλafter soaking in 90°C deionized water for 80 h,whereas theλof the blended AlN/PMHS composites decreases sharply to 93.7%.展开更多
Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In t...Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.展开更多
The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from ep...The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from epoxide building block,the chirality from anhydride and the configurational match with epoxide remain elusive.Herein,we discover that the bimetallic chromium catalysts have led to an obvious enhancement in terms of reactivity and enantioselectivity for the asymmetric copolymerization of meso-epoxide with various non-symmetric chiral anhydrides.Up to 97%ee was obtained during the asymmetric copolymerization of cyclohexene oxide(CHO)with(R)-methylsuccinic anhydride(R-MSA),and three-or four-carbon chiral centers were simultaneously installed in the aliphatic polyester backbone.In particular,the different combinations of stereochemistry in epoxide and anhydride building blocks considerably affect the thermal properties and crystalline behaviors of the resulting polyesters.This study uncovers an interesting method for regulating polymer crystallinity via matching the chirality of different monomers.展开更多
As a naturally occurring terpenoid that is abundant in essential oils,citronellal remains largely unexplored in polymer science.Herein,we present a novel strategy for converting bio-based citronellal into the diene mo...As a naturally occurring terpenoid that is abundant in essential oils,citronellal remains largely unexplored in polymer science.Herein,we present a novel strategy for converting bio-based citronellal into the diene monomer 6,10-dimethyl-1,3,9-undecatriene(DMUT),which under-goes neodymium-catalyzed coordination polymerization to yield poly(6,10-dimethyl-1,3,9-undecatriene)(PDMUT),a bio-derived polydiene poly-mer.This provides a facile and sustainable route for transforming renewable citronellal into functional polymers.The effects of polymerization conditions on the catalytic performance and polymer characteristics,including molecular weight,polydispersity,and microstructure,were sys-tematically investigated.In addition,DMUT was successfully copolymerized with isoprene(IP)and 1,3-butadiene(BD),yielding copolymers with tunable compositions and microstructures.These results demonstrate the versatility of DMUT as a renewable building block for both homopoly-mers and copolymers,paving the way toward bio-based elastomeric materials with customizable properties.展开更多
The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydr...The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydride copolymer,characterized by its amphiphilic nature,shows potential applications in adhesives,emulsifiers,etc.However,the Diels-Alder(DA)reaction of butadiene and maleic anhydride competes with the polymerization,limiting the copolymer yield.In this study,the kinetics of the DA reaction and copolymerization between butadiene and maleic anhydride were examined,and the influence of various reaction conditions on the copolymer yield was investigated.We found that the DA reaction in the induction period of the radical polymerization was the critical factor in limiting copolymer yield.Therefore,we proposed the two-step method to suppress the DA reaction and achieve high-yield production(~85%)of cross-linked microspheres with controllable particle size(175-800 nm)by self-stabilized precipitation polymerization.This work enables an efficient synthesis of conjugated diolefin-maleic anhydride cross-linked microspheres,offering a novel approach to address the issue of butadiene overcapacity.展开更多
Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the sel...Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the self-assembly of AB di-block copolymers(di-BCPs)confined in Janus spherical nanocavities using simulations,and explained the structure formation mechanisms.In the case of a strongly selective cavity wall,all the lamella-forming,gyroid-forming,and cylinder-forming di-BCPs can form interfacial frustration-induced Janus concentric perforated lamellar nanoparticles,whose outermost is a Janus spherical shell and the internal is a sphere with concentric perforated lamellar structure.In particular,Janus concentric perforated lamellar nanoparticles with holes distributed only near the equatorial plane were obtained in both lamella-forming and gyroid-forming di-BCPs,directly reflecting the effect of interfacial frustration.The minority-block domain of the cylider-forming di-BCPs may form hemispherical perforated lamellar structures with holes distributed in parallel layers with a specific orientation.For symmetric di-BCPs,both the A and B domains in each nanoparticle are continuous,interchangeable,and have rotational symmetry.While for gyroid-forming and cylinder-forming di-BCPs,only the majority-block domains are continuous in each nanoparticle,and holes in the minority-block domains usually have rotational symmetry.In the case of a weakly selective cavity wall,the inhomogeneity of the cavity wall results in structures having a specific orientation(such as flower-like and branched structures in gyroid-forming and cylinder-forming di-BCPs)and a perforated wetting layer with uniformly distributed holes.The novel nanoparticles obtained may have potential applications in nanotechnology as functional nanostructures or nanoparticles.展开更多
Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To...Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To achieve the desired properties of PI,the monomers 2,6-diaminopyrimidin-4-ol(DAPD)and 6-(2,3,5,6-tetrafluoro-4-vinylphenoxy)pyrimidin-2,4-diamine(DAFPD),which contains crosslinkable functional groups,were designed and synthesized successfully and copolymerized with 4,4'-oxydianiline(ODA)and 4,4-hexafluoroisopropylphthalic anhydride(6FDA).The prepared PI film(PI-3),with rigid backbones and loose packing had excellent heat resistance(Td5%=489℃)and optical properties(T450=82%).Furthermore,a crosslinked PI film(c-PI-3)with more heat-resistant(Td5%=524℃)and better mechanical properties(σ=125.46MPa),can be obtained through thermal crosslinking of tetrafluorostyrene.In addition,the changes in the properties caused by the proportion of DAFPD added during copolymerization are discussed comprehensively.This study provides a promising candidate for heat-resistant PI materials.展开更多
As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of t...As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.展开更多
基金Supported by the Basic Research Program of the State Key Laboratory of Heavy Oil Processing (200310) China University of Petroleum,Beijing,China
文摘Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.
基金supported by the Fundamental Research Funds for the Central Universities(JD2311)the National Natural Science Foundation of China(Grant No.51572012)。
文摘Solid-state lithium batteries are constrained by sluggish ion kinetics and poor interfacial stability.Herein,a quasi-solid polymer electrolyte was designed via an in-situ copolymerization strategy with 1,3-dioxolane(DOL)and 1,3,5-trioxane(TXE).The incorporation of TXE modulates the regularity and motility of the polymer segment and then enhances the Li^(+)transport kinetics.Moreover,fluorothylene carbonate and tris(trimethylsilyl)borate are conducive to constructing a stable and inorganic-rich electrodeelectrolyte interface,which can effectively prevent electrolyte decomposition and inhibit lithium dendrite growth.The two additives can also participate in solvation to form a loose solvated sheath that accelerates Li^(+)coupling-decoupling behaviors.When applied in Li‖LiFePO_(4)(LFP)battery,an initial capacity of 157.8 mAh g^(-1)and a capacity retention of 88.7%after 800 cycles at 1 C were obtained,along with an exceptional rate performance(114.3 mAh g^(-1),5 C).Even at-20℃,a remarkable capacity of103.7 mAh g^(-1)was still obtained.The synergetic strategy of ether-oxygen segment design and solvation structure regulation paves the way for high-performance quasi-solid lithium metal batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.52403117,52173083,51991355,and 52173082)the 2024 Ningbo Yongjiang Talent Programme,the Natural Science Foundation of Zhejiang Province(No.LY24E030007)the Australian Research Council(No.DE230100616).
文摘A series of transparent,intrinsically flame-retardant,and impact-resistant poly(carbonates-b-siloxanes)were synthesized by incorporating Schiff-base modified polysiloxanes(DMS-Schiff)and naphthalene-sulfonate units into the polycarbonate(PC)chain.In addition to high transparency,the resultant copolymers(SS-co-PC5,SS-co-PC9,SS-co-PC14,and SS-co-PC20)exhibited remarkable improvements in fire safety and mechanical performance.Compared to pure PC,these copolymers demonstrated significantly enhanced limiting oxygen index(LOI,up to 34.5%)and a UL-94 V-0 rating under a thickness of only 1.6 mm.The incorporation of the polysiloxane blocks not only improved flame retardancy but also enhanced the impact strength,with SS-co-PC9 showing a 48%increase in elongation at break and a 38%rise in impact toughness compared to pure PC.In addition,SS-co-PC9 presented high mechanical strength.The synergistic effects between the naphthalene-sulfonate and polysiloxane blocks,along with the well-controlled polysiloxane phase separation(sulfonate units enabled lower processing viscosity of copolymers),led to superior comprehensive performance.These findings provide a promising pathway to create high-performance copolycarbonates for real-world applications.
基金supported by the National Key Research and Development program of China (Nos. 2024YFA1410700 and 2021YFA1200700)the National Natural Science Foundation of China (Nos. T2222025, 62174053, 62474065 and 52372120)+3 种基金the Natural Science Foundation of Chongqing (CSTB2024NSCQ-JQX0005)the Shanghai Science and Technology Innovation Action Plan (Nos. 24QA2702300 and 24YF2710400)the National Postdoctoral Program (GZB20240225)the Fundamental Research Funds for the Central Universities。
文摘Poly(vinylidene-trifluoroethylene) [P(VDF-TrFE)] copolymer films generally demonstrate limited compatibility with organic semiconductors. The material is frequently compromised by exposure to organic semiconductor solutions and other fabrication processes utilized in the production of organic ferroelectric transistors. In this study, an organic ferroelectric field effect transistor(OFeFET) with the 6,13-Bis(triisopropylsilylethynyl) pentacene(TIPS-pentacene) channel is fabricated, in which the aluminum oxide(Al_(2)O_(3)) interlayer is used to improve compatibility. The device displays polymorphic memory and synaptic plasticity of long-term potentiation and depression. Furthermore, an artificial neural network constructed using our devices is simulated to succeed in recognizing the MNIST handwritten digit database with a high accuracy of 92.8%. This research offers a viable approach to enhance the compatibility of the organic ferroelectric polymer P(VDF-TrFE) with organic semiconductors.
基金financially supported by the National Natural Science Foundation of China(No.22161040)Natural Science Foundation of Gansu(No.24JRRA125)Science Research Project of Northwest Normal University(No.NWNU-LKZD2021-3)。
文摘The ring-opening alternating copolymerization(ROAC)of 3,4-dihydrocoumarin(DHC)/epoxides has been successfully developed using an imidazolium salt of 1-ethyl-3-methylimidazolium chloride(EMIMCl)as a catalyst.The resulting copolymer has a molecular weight of 13.7kg·mol^(-1),a narrow molecular weight distribution of 1.03 and a strictly alternating structure.The MALDI-TOF MS characterization and DFT calculations including electrostatic potential(ESP),hydrogen-atom abstraction(HAA),independent gradient model based on hirshfeld partition(IGMH)and atoms-in-molecules(AIM)analysis were used to investigate the metal-free catalytic process.The synergistic effect of anions and cations of EMIMCl for ROAC of DHC and epoxides was demonstrated.This study provides a metal-free catalytic system for the facile synthesis of alternating polyesters from DHC.
文摘The materialization of polybutylene succinate(PBS)belongs to the family of polyesters which are degrad-able and biodegradable,their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications.Besides its biodegradability,PBS can be derived from petroleum and biobased monomers.At the same time,the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products.The processes and techniques presented herein,are based on the production of biobased succinic acid monomer to PBS.However,the counterpart biobased monomer 1,4-butanediol(1,4-BDO)production has not been commercially demonstrated.This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS,its copolymers,and composites with the view to improve molecular weight,thermal,and mechanical properties.It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical,thermal,stability and mechanical structural properties.Importantly,the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films,biomedical and drug release,fire retardants,and agricultural products.The structure-functional performance characteristics of these developments in the PBS,copolymers,and composites are highlighted to provide baseline insights for future developments in engineering the specific applications,and structural interface PBS composites with enhanced structure-functional performance properties.
基金supported by the Shenzhen Science and Technology Program(No.JCYJ20220818100407016)the National Natural Science Foundation of China(No.22275059)+1 种基金Guangdong Special Support Program(No.2021TX06L775)high-level special funds(No.G03050K002)。
文摘High-voltage LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathodes are critical for enhancing the energy density of lithium-ion batteries(LIBs).The development of binders compatible with high-voltage NCM811 cathode materials is crucial to enhance the electrochemical performance of LIBs.However,the traditional fluoropolymer binder,poly(vinylidene difluoride)(PVDF),can potentially leach components or break down into poly(fluoroalkyl substances)(PFAS)chemicals,thereby contributing to PFAS contamination.A novel fluorine-free polymer,polysulfone-polyamide-polyimide(SPIO),was designed and synthesized as a binder for NCM811 cathodes.The SPIO binder exhibits exceptional mechanical properties and superior electrochemical characteristics.The cathode film fabricated with SPIO demonstrated a remarkable delamination force of 8 N(390 N·m^(-1)),indicating robust adhesion.The Li‖NCM811 cell incorporating the SPIO binder retained 80%of its initial capacity after 300 cycles at a current density of 0.2 C.In comparison,the control cells assem bled with the PVDF binder retained only 52%of their capacities under the same cycling conditions.Furthermore,the SPIO binder exhibited improved compatibility with the electrolyte.Transmission electron microscopy analysis of the cathode films after 100 cycles revealed the formation of a unifo rm,dense,and continuous chemical-electrochemical interface(CEI)by the SPIO binder on the surface of the NCM811 particles,which significantly contributed to the enhancement of the electrochemical performance.These results highlight the potential of SPIO as an advanced binder material for high-perfo rmance lithium-ion batteries.
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.52488201)the National Natural Science Foundation of China(Nos.52276213,52206276 and 52376209)+1 种基金the Key Research and Development Program of Shaanxi Province(No.2024GX-YBXM-459)the Fundamental Research Funds for the Central Universities.
文摘As one of the most promising metal-free photocatalysts for renewable H_(2) evolution,graphitic carbon nitride(g-C_(3)N_(4))has attracted notable attention.Regulating its morphology and electronic structure is crucial for enhancing its performance.In this work,aromatic small molecules and melamine were hydrothermally cotreated to form a novel supramolecular precur-sor,which was subsequently calcined to obtain aπ-πconjugated structure of g-C_(3)N_(4) photocatalyst.The introduction of benzene-ring structures expanded the conjugated system and promoted the excitation ofπelectrons,thereby broadening the light-absorption range of g-C_(3)N_(4).The synergism of bromine and chlorine provided abundant active sites for g-C_(3)N_(4),greatly promoted the migration of photogenerated charge carriers,and reduced the recombination probability,thus improving in photocatalytic performance.Therefore,the g-C_(3)N_(4) photocatalyst obtained from 2-bromo-5-chlorobenzoic acid-derived supramolecular precursor exhibited a visible-light(λ≥400 nm)photocatalytic H_(2) evolution activity of 839.8μmol/(h g),which was about three times that of the unmodifi ed g-C_(3)N_(4).This work off ers a novel perspective for g-C_(3)N_(4) application in the fi eld of photocatalysis and expands the utilization of aromatic small molecules in photocatalysts modifi cation.
基金the financial support of the Ministry of Science and Higher Education of the Russian Federation within the framework of a grant for conducting large scientific projects in priority areas of scientific and technological development 075-15-2024-550。
文摘Using molecular dynamics modeling,the change in the shape and density of the macromolecular corona consisting of two oppositely charged polyelectrolytes,including those combined into one block copolymer,on the surface of a polarized spherical metal nanoparticle was studied.A mathematical model of the structure of the block copolymer chain adsorbed on a polarized spherical nanoparticle is presented for the cases of polyelectrolyte blocks of large and small length.Based on the modeling results,radial and angular distributions of the density of atoms of polyelectrolyte polypeptides adsorbed on the surface of a spherical nanoparticle were calculated depending on its dipole moment.As the dipole moment of the nanoparticle increased,the dense macromolecular shell was destroyed,forming caps of polyelectrolyte macro molecules or fragments of block copolymer of different types on the poles of the polarized nanoparticle.In this case,the macromolecular corona in the region of the poles of the polarized nanoparticle swelled the more strongly,the greater the distance between the charged links in the polymer.
基金financially supported by the National Natural Science Foundation of China(No.52130307)。
文摘A series of imido-vanadium(Ⅴ)complexes bearing bidentate phenoxy-phosphine ligands were synthesized and characterized by NMR,elemental analysis,and single-crystal X-ray diffraction.These complexes demonstrated excellent catalytic performance in ethylene/1-hexene copolymerization,achieving high activities of 12.0×10~6–49.0×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1)and affording random copolymers with tunable 1-hexene incorporations.These catalysts also exhibited ultrahigh activity,up to 112.2×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1),in ethylene/norbornene(NB)copolymerization,yielding cyclic olefin copolymers with adjustable NB incorporations.Remarkably,these catalysts demonstrated exceptional tolerance toward polar functional groups,enabling efficient copolymerization of ethylene with both 10-undecen-1-ol(U-OH)and 5-norbornene-2-methanol(NB-OH),incorporating about 2 mol%polar comonomers with high efficiency.Different with the catalytic behaviors in copolymerization of ethylene with nonpolar comonomers,the catalytic activities in E/U-OH copolymerization(25.7×10~6 g_(polymer)·(mol_(V))^(-1)·h^(-1))were much higher than those in E/NB-OH copolymerization(8.6×10^(6) g_(polymer)·(mol_(V))^(-1)·h^(-1)).DFT calculations revealed that the catalytic performance is governed by synergistic electronic and steric effects.For E/NB copolymerization,strong preference for cyclic olefins was attributed to favorable transition state stabilization.In polar comonomer systems,steric effects were predominant,with NB-OH exhibiting a larger buried volume around vanadium center upon coordination compared to U-OH.Overall,this work provides fundamental insights into vanadium-catalyzed(co)polymerization and offers new strategies for tailored polyolefin design.
基金financially supported by the National Natural Science Foundation of China(No.52473097)the Fundamental Research Funds for the Central Universities(No.24X010301678)Shanghai Jiao Tong University 2030 Initiative(No.WH510363002/002)。
文摘Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a new way to access degradable polyethylene materials with a low content of in-chain ester units via mechanochemical backbone editing.Initially,ester groups are incorporated as side groups through catalytic copolymerization of ethylene with a cyclobutene-fused lactone monomer(CBL),yielding polyethylene materials with high molecular weights and adjustable thermomechanical properties.Subsequent solid-state ball-milling treatment selectively introduces side-chain ester groups into the main chain of the polyethylene materials via force-induced cycloreversion of the cyclobutane units.Under acidic conditions,hydrolysis of the resultant polyethylene materials with in-chain ester units facilitates further degradation into oligomers.
基金supported by the Fundamental Research Funds for the Central Universities(No.2024JBZX029)Shijiazhuang High Level Science and Technology Innovation and Entrepreneurship Talent Project(No.08202307)the National Natural Science Foundation of China(NSFC)(No.22173004).
文摘The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast combinatorial phase space defined by components,se-quences,and topologies,and is often computationally intractable due to its NP-hard nature.At the core of this challenge lies the need to evalu-ate complex correlations among structural variables,a classical problem in both statistical physics and combinatorial optimization.To address this,we adopt a mean-field approach that decouples direct variable-variable interactions into effective interactions between each variable and an auxiliary field.The simulated bifurcation(SB)algorithm is employed as a mean-field-based optimization framework.It constructs a Hamiltonian dynamical system by introducing generalized momentum fields,enabling efficient decoupling and dynamic evolution of strongly coupled struc-tural variables.Using the sequence optimization of a linear copolymer adsorbing on a solid surface as a case study,we demonstrate the applica-bility of the SB algorithm to high-dimensional,non-differentiable combinatorial optimization problems.Our results show that SB can efficiently discover polymer sequences with excellent adsorption performance within a reasonable computational time.Furthermore,it exhibits robust con-vergence and high parallel scalability across large design spaces.The approach developed in this work offers a new computational pathway for polymer structure optimization.It also lays a theoretical foundation for future extensions to topological design problems,such as optimizing the number and placement of side chains,as well as the co-optimization of sequence and topology.
基金support from the National Natural Science Foundation of China(52473083 and 52403112)the Technological Base Scientific Research Projects(Highly Thermal conductivity Nonmetal Materials),the Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)+4 种基金the Shaanxi Province Key Research and Development Plan Project(2023-YBGY-461)the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57),the Natural Science Foundation of Chongqing,China(2023NSCQ-MSX2547)the Fundamental Research Funds for the Central Universities(D5000240077 and D5000240067)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2024094)the Analytical&Testing Center of Northwestern Polytechnical University for FT-IR,XRD and TEM tests performed in this work.
文摘A series of divinylphenyl-acryloyl chloride copolymers(PDVB-co-PACl)is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers.PDVB-co-PACl is utilized to graft on the surface of spherical aluminum nitride(AlN)to prepare functionalized AlN(AlN@PDVB-co-PACl).Polymethylhydrosiloxane(PMHS)is then used as the matrix to prepare thermally conductive AlN@PDVB-co-PACl/PMHS composites with AlN@PDVB-co-PACl as fillers through blending and curing.The grafting of PDVB-co-PACl synchronously enhances the hydrolysis resistance of AlN and its interfacial compatibility with PMHS matrix.When the molecular weight of PDVB-co-PACl is 5100 g mol^(-1)and the grafting density is 0.8 wt%,the composites containing 75 wt%of AlN@PDVB-co-PACl exhibit the optimal comprehensive performance.The thermal conductivity(λ)of the composite is 1.14 W m^(-1)K^(-1),which enhances by 20%and 420%compared to theλof simply physically blended AlN/PMHS composite and pure PMHS,respectively.Meanwhile,AlN@PDVB-co-PACl/PMHS composites display remarkable hydrothermal aging resistance by retaining 99.1%of itsλafter soaking in 90°C deionized water for 80 h,whereas theλof the blended AlN/PMHS composites decreases sharply to 93.7%.
基金financially supported by the National Natural Science Foundation of China(No.21172269)the Fundamental Research Funds for the Central Universities,SouthCentral Minzu University(No.CZH24005)。
文摘Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.
基金financially supported by the National Natural Science Foundation of China(Nos.22071016 and 21920102006)。
文摘The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from epoxide building block,the chirality from anhydride and the configurational match with epoxide remain elusive.Herein,we discover that the bimetallic chromium catalysts have led to an obvious enhancement in terms of reactivity and enantioselectivity for the asymmetric copolymerization of meso-epoxide with various non-symmetric chiral anhydrides.Up to 97%ee was obtained during the asymmetric copolymerization of cyclohexene oxide(CHO)with(R)-methylsuccinic anhydride(R-MSA),and three-or four-carbon chiral centers were simultaneously installed in the aliphatic polyester backbone.In particular,the different combinations of stereochemistry in epoxide and anhydride building blocks considerably affect the thermal properties and crystalline behaviors of the resulting polyesters.This study uncovers an interesting method for regulating polymer crystallinity via matching the chirality of different monomers.
基金supported by the National Key R&D Program of China(No.2022YFC2104702)the National Natural Science Foundation of China(No.22071236)H.L.thanks for the financial support from the Taishan Scholars Program(No.tsqn202211165).
文摘As a naturally occurring terpenoid that is abundant in essential oils,citronellal remains largely unexplored in polymer science.Herein,we present a novel strategy for converting bio-based citronellal into the diene monomer 6,10-dimethyl-1,3,9-undecatriene(DMUT),which under-goes neodymium-catalyzed coordination polymerization to yield poly(6,10-dimethyl-1,3,9-undecatriene)(PDMUT),a bio-derived polydiene poly-mer.This provides a facile and sustainable route for transforming renewable citronellal into functional polymers.The effects of polymerization conditions on the catalytic performance and polymer characteristics,including molecular weight,polydispersity,and microstructure,were sys-tematically investigated.In addition,DMUT was successfully copolymerized with isoprene(IP)and 1,3-butadiene(BD),yielding copolymers with tunable compositions and microstructures.These results demonstrate the versatility of DMUT as a renewable building block for both homopoly-mers and copolymers,paving the way toward bio-based elastomeric materials with customizable properties.
基金financially supported by an internal fund from Tsinghua University。
文摘The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydride copolymer,characterized by its amphiphilic nature,shows potential applications in adhesives,emulsifiers,etc.However,the Diels-Alder(DA)reaction of butadiene and maleic anhydride competes with the polymerization,limiting the copolymer yield.In this study,the kinetics of the DA reaction and copolymerization between butadiene and maleic anhydride were examined,and the influence of various reaction conditions on the copolymer yield was investigated.We found that the DA reaction in the induction period of the radical polymerization was the critical factor in limiting copolymer yield.Therefore,we proposed the two-step method to suppress the DA reaction and achieve high-yield production(~85%)of cross-linked microspheres with controllable particle size(175-800 nm)by self-stabilized precipitation polymerization.This work enables an efficient synthesis of conjugated diolefin-maleic anhydride cross-linked microspheres,offering a novel approach to address the issue of butadiene overcapacity.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22173051,21829301,21774066)College Discipline Innovation and Intelligence Introduction Program(111 Project(B16027)+1 种基金the International Cooperation Base(2016D01025)Tianjin International Joint Research and Development Center。
文摘Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the self-assembly of AB di-block copolymers(di-BCPs)confined in Janus spherical nanocavities using simulations,and explained the structure formation mechanisms.In the case of a strongly selective cavity wall,all the lamella-forming,gyroid-forming,and cylinder-forming di-BCPs can form interfacial frustration-induced Janus concentric perforated lamellar nanoparticles,whose outermost is a Janus spherical shell and the internal is a sphere with concentric perforated lamellar structure.In particular,Janus concentric perforated lamellar nanoparticles with holes distributed only near the equatorial plane were obtained in both lamella-forming and gyroid-forming di-BCPs,directly reflecting the effect of interfacial frustration.The minority-block domain of the cylider-forming di-BCPs may form hemispherical perforated lamellar structures with holes distributed in parallel layers with a specific orientation.For symmetric di-BCPs,both the A and B domains in each nanoparticle are continuous,interchangeable,and have rotational symmetry.While for gyroid-forming and cylinder-forming di-BCPs,only the majority-block domains are continuous in each nanoparticle,and holes in the minority-block domains usually have rotational symmetry.In the case of a weakly selective cavity wall,the inhomogeneity of the cavity wall results in structures having a specific orientation(such as flower-like and branched structures in gyroid-forming and cylinder-forming di-BCPs)and a perforated wetting layer with uniformly distributed holes.The novel nanoparticles obtained may have potential applications in nanotechnology as functional nanostructures or nanoparticles.
基金supported by the National Key Research and Development Program of China(No.2022YFB3603101)。
文摘Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To achieve the desired properties of PI,the monomers 2,6-diaminopyrimidin-4-ol(DAPD)and 6-(2,3,5,6-tetrafluoro-4-vinylphenoxy)pyrimidin-2,4-diamine(DAFPD),which contains crosslinkable functional groups,were designed and synthesized successfully and copolymerized with 4,4'-oxydianiline(ODA)and 4,4-hexafluoroisopropylphthalic anhydride(6FDA).The prepared PI film(PI-3),with rigid backbones and loose packing had excellent heat resistance(Td5%=489℃)and optical properties(T450=82%).Furthermore,a crosslinked PI film(c-PI-3)with more heat-resistant(Td5%=524℃)and better mechanical properties(σ=125.46MPa),can be obtained through thermal crosslinking of tetrafluorostyrene.In addition,the changes in the properties caused by the proportion of DAFPD added during copolymerization are discussed comprehensively.This study provides a promising candidate for heat-resistant PI materials.
基金financially supported by National Key R&D Program of China(No.2021YFA1501700)CAS Project for Young Scientists in Basic Research(No.YSBR-094)+1 种基金Natural Science Foundation of Anhui Province(Nos.2308085Y35 and 2023AH030002)Hefei Natural Science Foundation(No.202304)。
文摘As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.
