An effective strategy for enhancing the heat resistance of polystyrene(PS)with regard to its glass transition temperature(T_(g))involves the anionic solution copolymerization of a-methylstyrene(AMS)with styrene(St),ty...An effective strategy for enhancing the heat resistance of polystyrene(PS)with regard to its glass transition temperature(T_(g))involves the anionic solution copolymerization of a-methylstyrene(AMS)with styrene(St),typically requires much lower temperature(-25℃)and multistep monomer feeding to achieve higher number-average molecular weight(M_(n))block copolymers.However,the anionic copolymerization of AMS and St under the mild temperature remains largely unexplored.This study systematically investigated the anionic copolymerization of AMS and St using n-BuLi in nonpolar solvent(-25℃ to 25℃)through both one-step and two-step approaches.We demonstrated that one-step copolymerization at 25℃ yielded only 1-3 terminal AMS units,with higher feed ratios(5 wt%-20 wt%)increasing AMS incorporation but reducing the exact molecular weight(MW)due to enhanced depolymerization,as evidenced by MALDI-TOF MS.Temperature-controlled AMS conversion at-15℃ achieved 98%AMS conversion(5 wt% feed)by suppressing side reactions and lowering the[M]_(e),while 50℃(near T_(C))almost prevented incorporation.Despite t-BuOK regulation induced broader PDI(1.24)via reactive[(polymer-Li)OR]K intermediates,while other systems showed narrow distributions,t-BuOK outperformed THF in enhancing AMS incorporation via efficient ion pair dissociation.In comparison,the two-step polymerization approach demonstrated superior performance,achieving both higher AMS conversion efficiency and preferential incorporation at the initiation end.At a 20 wt%AMS feed ratio,this method yielded copolymer chains containing up to 6 AMS units on average.Thermal analysis revealed a composition-dependent single T_(g),which exhibited a systematic increase with higher AMS incorporation content.These results collectively demonstrate the precise control over AMS incorporation and heat resistance achievable through the manipulation of polymerization conditions.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
Introducing functional polar groups into polyolefins can significantly improve the material properties,but there are still challenges in achieving this goal,with the core difficulty being that polar groups are prone t...Introducing functional polar groups into polyolefins can significantly improve the material properties,but there are still challenges in achieving this goal,with the core difficulty being that polar groups are prone to interact with metal active species,affecting the efficiency of the copolymerization.With the rapid advancement in catalyst,a variety of copolymerization strategies are developed aimed at producing more versatile polyolefin materials.Although early transition metal catalysts play an indispensable role in the traditional polyolefin industry,their inherent strong oxophilicity becomes a significant constraint in copolymerization involving polar olefins,limiting their application scope.This review summarizes the progress made in recent years in the efficient copolymerization of non-polar olefins with polar comonomers catalyzed by groups 3 and 4 single-site catalysts.We classify the catalysts into four categories,Sc-,Ti-,Zr-,Hf-,based on the type of metal centers,and provide insights into the influence of catalyst structures and the type of comonomers on the copolymerization behavior.The introduction of polar monomers fundamentally improves the comprehensive performance of the products,greatly broadens the application scope of polyolefin materials,and meets the growing market demand for multifunctional and high-performance materials.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
Cobalt porphyrin complexes （TPPConIX） （TPP = 5,10,15,20-tetraphenyl-porphyrin; X = halide） in combination with bis（triphenylphosphine） iminium chloride （PPNC1） were used for the eopolymerization of cyelohexene...Cobalt porphyrin complexes （TPPConIX） （TPP = 5,10,15,20-tetraphenyl-porphyrin; X = halide） in combination with bis（triphenylphosphine） iminium chloride （PPNC1） were used for the eopolymerization of cyelohexene oxide and CO2. The highest turnover frequency of 67.2 h^-1 was achieved after 13 h at 20℃, and the obtained poly（1,2-cyclohexylene carbonate） （PCHC） showed number average molecular weight （Mn） of 10 × 10^3. Though the obtained PCHC showed atactie structure, the m-centered tetrads content reached 58.1% at CO2 pressure of 1.0 MPa, and decreased to 51.9% at CO2 pressure of 6.0 MPa, indicating that it was inclined to form atactic polymer at high CO2 pressure.展开更多
In view of the phenomenon that the adhesion strength between the surface of polyacrylonitrile-butadiene-styrene-polycarbonate(ABS-PC)copolymer and the electroless copper plating layer is relatively low.To solve the pr...In view of the phenomenon that the adhesion strength between the surface of polyacrylonitrile-butadiene-styrene-polycarbonate(ABS-PC)copolymer and the electroless copper plating layer is relatively low.To solve the problems of poor surface wettability and low surface roughness of the ABS-PC substrate,the N,N-dimethylformamide(DMF)-ethanol(C_(2)H_(5)OH)-water(H_(2)O)system was employed as the swelling system for the ABS-PC substrate.The effects of the DMF volume fraction in the swelling system and the swelling time on the swelling effect of ABS-PC at 35℃ were investigated.KMnO_(4)-H_(2)SO_(4)-H_(2)O system was used as the etching system for ABS-PC substrate under the conditions of the volume ratio of water to sulfuric acid of 1﹕2,with KMnO_(4) content of 30 g/L,etching temperature of 60℃,and etching time of 25 min.The results indicate that dense pores with uniform sized are formed on the surface of the ABS-PC substrate surface after swelling and etching treatments,accompanied by an increase in surface roughness when the swelling temperature is 35℃,the DMF volume fraction in the swelling system is 80%,and the swelling time is 5 min.Furthermore,the content of C element on the surface of the ABS-PC substrate decreased,while that of O element increased,and the surface hydrophilicity is enhanced,which is attributed to two hydrophilic groups,-C=O and-COOH,being generated on the ABS-PC substrate surface,significantly improving the wettability of the ABS-PC substrate surface.Under the combination effects of high surface roughness and strong surface hydrophilicity,the adhesion strength between the ABS-PC substrate surface and the electroless copper plating layer reached to 0.81 kN/m,meeting the adhesion strength requirement of 0.70 kN/m in the industrial production.展开更多
The random copolymer poly （1, 3-pentadiene-co-styrene） formed through cationic copolymerization using the ~ethylamine hydrochloride and hydrous aluminium chloride （Et3NHCl-AlCl3） room temperature ionic liquid as i...The random copolymer poly （1, 3-pentadiene-co-styrene） formed through cationic copolymerization using the ~ethylamine hydrochloride and hydrous aluminium chloride （Et3NHCl-AlCl3） room temperature ionic liquid as initiating agent in toluene was analyzed using IR spectra in conjunction with gel permeation chromatography （GPC）. The room temperature ionic liquid was found to have high initiatic activity for copolymerization.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is...The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is both robust and readily-functionalized through interfacial click polymerization.A water-in-oil emulsion was constructed to act as the reaction medium,the hydrophilic 1,3-butadiene diepoxide(BDE)in water phase reacted with the oleophilic 1,4-dibutanedithiol(BDT)in oil phase at the water-oil interface to form the amphiphilic ACP named poly(2,3-dihydroxy butylene-alt-butylene dithioether)(abbreviated as P(DHB-a-BDT)below),which would deposite in situ to form the micro-sized capsules.Significantly,the dried capsules are robust enough to be rehydrated once the water was added and almost restored their original morphologies.Further elucidation showed that the Young's modulus of these capsules exceeded 1 GPa.As long as we know,it is the first time for the mechanical properties of the ACP-based microstructures being investigated.Besides,functionalization could be achieved simultaneously with the formation process.As a proof of concept,positive-charged capsules were successfully obtained through click copolymerization.Stemming from the unique characteristics of amphiphilic ACPs which combined both merits of click chemistry and interfacial reactions,all these features of the current method as well as the resultant capsules may promote the application of the polymeric capsules.展开更多
Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cat...Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.展开更多
Bonded type RE3+ doped luminescent co-polymer was synthesized by solution free radical copolymerization. The influence of charge sequence, monomers and co-polymerized method on properties and structures of the co-poly...Bonded type RE3+ doped luminescent co-polymer was synthesized by solution free radical copolymerization. The influence of charge sequence, monomers and co-polymerized method on properties and structures of the co-polymers was studied. The emission intensity of the co-polymers at different RE3+ concentrations was tested. The results showed that the co-polymers of Eu-PSt and Eu-PMMA both had wide absorption peak at 200-400 nm and the strongest peak appeared at 235 nm. The fluorescent intensity of Eu3+ doped polystyrene co-polymer was stronger than that of Eu3+ doped PMMA copolymer. The characteristic emission of europium ions was observed in the co-polymers. The copolymer doped with rare earth elements showed the 'sensitization effect' for the central ions. The bonded-type rare earth copolymer not only enhanced the energy transfer efficiency, but also improved the fluorescence intensity by increasing the rigidity of main and side chain.展开更多
Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted ...Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted much attention for enhancing their desirable properties,of which one efficient way is incorporating the aliphatic polyether segment into the main chain of the polyester.However,this approach is of much challenge because the obtained polyesters are problematic in either low alternating degree or low molecular weight.Herein,we describe an efficient strategy to incorporate polyether fragment into polyester by developing a novel Co-Al based heterodinuclear complex for mediating the copolymerization of propylene oxide(PO)withε-caprolactone(CL).The tracking experiments reveal that PO and CL convert into the polymer chain throughout the polymerization process.Especially,the linear increase in the molecular weight with conversion of CL indicates the controllable nature of the copolymerization.The competition polymerization,offering the monomer reactivity ratios of rCL=0.96 and rPO=1.04,suggests that the tendency of self-propagation or incorporation of monomers is nearly identical.interestingly,the obtained polymers with different ether contents exhibit tunable thermal properties with enhanced decomposition temperature for the polymer with higher ether content.The newly developed heterodinuclear complex for new polymerization provides an idea to synthesize new functional polymeric materials.展开更多
In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentratio...In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentrations. It was shown that the grafting capability of Mn(VII)-TU is the highest in these initiating systems. Using Mn (VII-TU as initiator, the effects of various acids (HClO4, H2SO4, HNO3, HCl) on the graft copolymerization of acrylonitrile onto starch were discussed, and the capabilities of graft copolymerization of methyl methacrylate (MMA), acrylamide (AM), acrylic acid (AA) onto starch were investigated. The experimental results show that the order of the influences of different acids is HClO4 > H2SO4 > HNO3 > HCl, and the order of grafting capabilities of different monomers grafted onto starch is MMA > AN > AM > AA. The structure and morphology of graft, copolymers were studied with infrared spectroscopy and scanning electron microscopy. The size, shape and roughness of surface of the grafted starch granules are changed after grafting.展开更多
Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion...Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52373052)Fundamental Research Funds for the Central Universities(No.DUT24MS011)。
文摘An effective strategy for enhancing the heat resistance of polystyrene(PS)with regard to its glass transition temperature(T_(g))involves the anionic solution copolymerization of a-methylstyrene(AMS)with styrene(St),typically requires much lower temperature(-25℃)and multistep monomer feeding to achieve higher number-average molecular weight(M_(n))block copolymers.However,the anionic copolymerization of AMS and St under the mild temperature remains largely unexplored.This study systematically investigated the anionic copolymerization of AMS and St using n-BuLi in nonpolar solvent(-25℃ to 25℃)through both one-step and two-step approaches.We demonstrated that one-step copolymerization at 25℃ yielded only 1-3 terminal AMS units,with higher feed ratios(5 wt%-20 wt%)increasing AMS incorporation but reducing the exact molecular weight(MW)due to enhanced depolymerization,as evidenced by MALDI-TOF MS.Temperature-controlled AMS conversion at-15℃ achieved 98%AMS conversion(5 wt% feed)by suppressing side reactions and lowering the[M]_(e),while 50℃(near T_(C))almost prevented incorporation.Despite t-BuOK regulation induced broader PDI(1.24)via reactive[(polymer-Li)OR]K intermediates,while other systems showed narrow distributions,t-BuOK outperformed THF in enhancing AMS incorporation via efficient ion pair dissociation.In comparison,the two-step polymerization approach demonstrated superior performance,achieving both higher AMS conversion efficiency and preferential incorporation at the initiation end.At a 20 wt%AMS feed ratio,this method yielded copolymer chains containing up to 6 AMS units on average.Thermal analysis revealed a composition-dependent single T_(g),which exhibited a systematic increase with higher AMS incorporation content.These results collectively demonstrate the precise control over AMS incorporation and heat resistance achievable through the manipulation of polymerization conditions.
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.
基金supported by the National Natural Science Foundation of China(No.U23B6011)。
文摘Introducing functional polar groups into polyolefins can significantly improve the material properties,but there are still challenges in achieving this goal,with the core difficulty being that polar groups are prone to interact with metal active species,affecting the efficiency of the copolymerization.With the rapid advancement in catalyst,a variety of copolymerization strategies are developed aimed at producing more versatile polyolefin materials.Although early transition metal catalysts play an indispensable role in the traditional polyolefin industry,their inherent strong oxophilicity becomes a significant constraint in copolymerization involving polar olefins,limiting their application scope.This review summarizes the progress made in recent years in the efficient copolymerization of non-polar olefins with polar comonomers catalyzed by groups 3 and 4 single-site catalysts.We classify the catalysts into four categories,Sc-,Ti-,Zr-,Hf-,based on the type of metal centers,and provide insights into the influence of catalyst structures and the type of comonomers on the copolymerization behavior.The introduction of polar monomers fundamentally improves the comprehensive performance of the products,greatly broadens the application scope of polyolefin materials,and meets the growing market demand for multifunctional and high-performance materials.
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financially supported by the National Natural Science Foundation of China(Nos.20634040 and 50903084)
文摘Cobalt porphyrin complexes （TPPConIX） （TPP = 5,10,15,20-tetraphenyl-porphyrin; X = halide） in combination with bis（triphenylphosphine） iminium chloride （PPNC1） were used for the eopolymerization of cyelohexene oxide and CO2. The highest turnover frequency of 67.2 h^-1 was achieved after 13 h at 20℃, and the obtained poly（1,2-cyclohexylene carbonate） （PCHC） showed number average molecular weight （Mn） of 10 × 10^3. Though the obtained PCHC showed atactie structure, the m-centered tetrads content reached 58.1% at CO2 pressure of 1.0 MPa, and decreased to 51.9% at CO2 pressure of 6.0 MPa, indicating that it was inclined to form atactic polymer at high CO2 pressure.
文摘In view of the phenomenon that the adhesion strength between the surface of polyacrylonitrile-butadiene-styrene-polycarbonate(ABS-PC)copolymer and the electroless copper plating layer is relatively low.To solve the problems of poor surface wettability and low surface roughness of the ABS-PC substrate,the N,N-dimethylformamide(DMF)-ethanol(C_(2)H_(5)OH)-water(H_(2)O)system was employed as the swelling system for the ABS-PC substrate.The effects of the DMF volume fraction in the swelling system and the swelling time on the swelling effect of ABS-PC at 35℃ were investigated.KMnO_(4)-H_(2)SO_(4)-H_(2)O system was used as the etching system for ABS-PC substrate under the conditions of the volume ratio of water to sulfuric acid of 1﹕2,with KMnO_(4) content of 30 g/L,etching temperature of 60℃,and etching time of 25 min.The results indicate that dense pores with uniform sized are formed on the surface of the ABS-PC substrate surface after swelling and etching treatments,accompanied by an increase in surface roughness when the swelling temperature is 35℃,the DMF volume fraction in the swelling system is 80%,and the swelling time is 5 min.Furthermore,the content of C element on the surface of the ABS-PC substrate decreased,while that of O element increased,and the surface hydrophilicity is enhanced,which is attributed to two hydrophilic groups,-C=O and-COOH,being generated on the ABS-PC substrate surface,significantly improving the wettability of the ABS-PC substrate surface.Under the combination effects of high surface roughness and strong surface hydrophilicity,the adhesion strength between the ABS-PC substrate surface and the electroless copper plating layer reached to 0.81 kN/m,meeting the adhesion strength requirement of 0.70 kN/m in the industrial production.
文摘The random copolymer poly （1, 3-pentadiene-co-styrene） formed through cationic copolymerization using the ~ethylamine hydrochloride and hydrous aluminium chloride （Et3NHCl-AlCl3） room temperature ionic liquid as initiating agent in toluene was analyzed using IR spectra in conjunction with gel permeation chromatography （GPC）. The room temperature ionic liquid was found to have high initiatic activity for copolymerization.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金financially supported by the Fundamental Research Funds for Central Universities(No.24D110627)。
文摘The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is both robust and readily-functionalized through interfacial click polymerization.A water-in-oil emulsion was constructed to act as the reaction medium,the hydrophilic 1,3-butadiene diepoxide(BDE)in water phase reacted with the oleophilic 1,4-dibutanedithiol(BDT)in oil phase at the water-oil interface to form the amphiphilic ACP named poly(2,3-dihydroxy butylene-alt-butylene dithioether)(abbreviated as P(DHB-a-BDT)below),which would deposite in situ to form the micro-sized capsules.Significantly,the dried capsules are robust enough to be rehydrated once the water was added and almost restored their original morphologies.Further elucidation showed that the Young's modulus of these capsules exceeded 1 GPa.As long as we know,it is the first time for the mechanical properties of the ACP-based microstructures being investigated.Besides,functionalization could be achieved simultaneously with the formation process.As a proof of concept,positive-charged capsules were successfully obtained through click copolymerization.Stemming from the unique characteristics of amphiphilic ACPs which combined both merits of click chemistry and interfacial reactions,all these features of the current method as well as the resultant capsules may promote the application of the polymeric capsules.
基金financially supported by the Russian Science Foundation(No.23-13-00205)。
文摘Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.
基金Project supported by the Special Funds for Major State Research Projectsthe National Natural Science Foundation of China (50373034)
文摘Bonded type RE3+ doped luminescent co-polymer was synthesized by solution free radical copolymerization. The influence of charge sequence, monomers and co-polymerized method on properties and structures of the co-polymers was studied. The emission intensity of the co-polymers at different RE3+ concentrations was tested. The results showed that the co-polymers of Eu-PSt and Eu-PMMA both had wide absorption peak at 200-400 nm and the strongest peak appeared at 235 nm. The fluorescent intensity of Eu3+ doped polystyrene co-polymer was stronger than that of Eu3+ doped PMMA copolymer. The characteristic emission of europium ions was observed in the co-polymers. The copolymer doped with rare earth elements showed the 'sensitization effect' for the central ions. The bonded-type rare earth copolymer not only enhanced the energy transfer efficiency, but also improved the fluorescence intensity by increasing the rigidity of main and side chain.
基金the National Natural Science Foundation of China(Nos.21722402 and 21674015)the Fundamental Research Funds for the Central Universities(No.DUT18ZD105).
文摘Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted much attention for enhancing their desirable properties,of which one efficient way is incorporating the aliphatic polyether segment into the main chain of the polyester.However,this approach is of much challenge because the obtained polyesters are problematic in either low alternating degree or low molecular weight.Herein,we describe an efficient strategy to incorporate polyether fragment into polyester by developing a novel Co-Al based heterodinuclear complex for mediating the copolymerization of propylene oxide(PO)withε-caprolactone(CL).The tracking experiments reveal that PO and CL convert into the polymer chain throughout the polymerization process.Especially,the linear increase in the molecular weight with conversion of CL indicates the controllable nature of the copolymerization.The competition polymerization,offering the monomer reactivity ratios of rCL=0.96 and rPO=1.04,suggests that the tendency of self-propagation or incorporation of monomers is nearly identical.interestingly,the obtained polymers with different ether contents exhibit tunable thermal properties with enhanced decomposition temperature for the polymer with higher ether content.The newly developed heterodinuclear complex for new polymerization provides an idea to synthesize new functional polymeric materials.
文摘In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentrations. It was shown that the grafting capability of Mn(VII)-TU is the highest in these initiating systems. Using Mn (VII-TU as initiator, the effects of various acids (HClO4, H2SO4, HNO3, HCl) on the graft copolymerization of acrylonitrile onto starch were discussed, and the capabilities of graft copolymerization of methyl methacrylate (MMA), acrylamide (AM), acrylic acid (AA) onto starch were investigated. The experimental results show that the order of the influences of different acids is HClO4 > H2SO4 > HNO3 > HCl, and the order of grafting capabilities of different monomers grafted onto starch is MMA > AN > AM > AA. The structure and morphology of graft, copolymers were studied with infrared spectroscopy and scanning electron microscopy. The size, shape and roughness of surface of the grafted starch granules are changed after grafting.
基金supported by National Natural Science Foundation of China(Nos.20576117 and 20806067)China Postdoctoral Science Foundation(No.20070420230).
文摘Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.
