Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultraf...Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultrafiltration （UF） substrate in dopamine solution. The changes in surface chemical composition and morphology of membranes were determined by Fourier transform infrared spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The experimental results indicated that the self-polymerized dopamine formed an ultrathin and defect-free barrier layer on the PSf UF membrane. The surface hydrophilicity of membranes was evaluated through water contact angle measurements. It was found that membrane hydrophilicity was significantly improved after coating a polydopamine （pDA） layer, especially after double coating. The dyes filtration experiments showed that the double-coated membranes were able to reject completely the dyes of brilliant blue, congo red and methyl orange with a pure water flux of 83.7 L/（mE.h） under 0.6 MPa. The zeta potential determination revealed the positively-charged characteristics of PSf/pDA composite membrane in NF process. The salt rejection of the membranes was characterized by 0.01 mmol/L of salts filtration experiment. It was demonstrated that the salts rejections followed the sequence： NaC1 〈 NaaSO4 〈 MgSO4 〈 MgC12 〈 CaCl2, and the rejection to CaC12 reached 68.7%. Moreover, the composite NF membranes showed a good stability in water-phase filtration process.展开更多
A series of stable waterborne polysiloxaneurethane （WPSUR） dispersions were prepared using amino-terminated polydimethylsiloxane （NS）, dimethylolpropionic acid （DMPA）, castor oil, polypropylene glycol and toluen...A series of stable waterborne polysiloxaneurethane （WPSUR） dispersions were prepared using amino-terminated polydimethylsiloxane （NS）, dimethylolpropionic acid （DMPA）, castor oil, polypropylene glycol and toluene diisocyanate. Meanwhile, NS with different molecular weights was synthesized and used as the soft co-segment. Effects of types and contents of soft co-segments as well as chain extenders on the thermal degradation and stability for WPSUR films were examined. Results reveal that WPSUR films exhibit excellent water resistance and mechanical properties as compared with pure polyurethane （PU） films, and the NS soft co-segment possesses a remarkable effect on the second stage （stage Ⅱ）, while the content of the hard segment is propitious to the initial stage （stage Ⅰ）. Moreover, the highest temperature of stage Ⅱ （T2m） for WPSUR films using NS as soft co-segment is 413℃, approximately being 30℃ higher than that of those typical PUs using HDA and APDMS as the chain extenders, respectively.展开更多
Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (e...Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.展开更多
The influences of shearing conducted by a Brabender behavior of a commercial impact polypropylene copolymer （IPC） rheometer on phase morphology, thermal and rheological were studied. The crystallization and melting ...The influences of shearing conducted by a Brabender behavior of a commercial impact polypropylene copolymer （IPC） rheometer on phase morphology, thermal and rheological were studied. The crystallization and melting traces show that short-time annealing at 210℃ is unable to completely erase the influence of shearing on the samples. When the samples which were treated at a rotation speed of 80 r/rnin crystallize at a cooling rate of 10 K/min, their Tcs and corresponding Tms obviously rise with the increase of shearing time. Furthermore, the POM results reveal that the shearing can lead to the formation of shish-kebab and the shish-kebab amount is proportional to shearing time. The rheological measurement results show that the treated samples exhibit different G＇-ω dependences. The ＇second plateau＇ appears when the sample is treated at a rotation speed of 60 r/min or 80 r/min for 10 min, and linear G＇-ω dependence is observed at other rotation speeds. In addition, it is found that the appearance of the ＇second plateau＇ depends on the shearing time when the rotation speed is fixed. According to SEM observations, it is proposed that the ＇second plateau＇ of IPC samples should be ascribed to the aggregation of dispersion particles.展开更多
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxid...Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.展开更多
Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and...Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and three maleic-anhydride-grafted polypropylenes （PP-g-MA） with different melt flow indexes （MFI）, were used to improve the dispersion of organic clay in matrix. On the other hand, the effects of organic montmorillonite （OMMT） content on the nanocomposite structure in terms of clay dispersion in PPR matrix, thermal behavior and tensile properties were also studied. The X-ray diffraction （XRD） and transmission electron microscopy （TEM） results show that the organic clay layers are mainly intercalated and partially exfoliated in the nanocomposites. Moreover, a PP-g-MA compatibilizer （compatibilizer B） having high MFI can greatly increase the interlayer spacing of the clay as compared with other compatibilizers. With the introduction of compatibilizer D （POE-g-MA）, most of the clays are dispersed into the POE phase, and the shape of the dispersed OMMT appears elliptic, which differs from the strip of PP-g-MA. Compared with virgin PPR, the Young＇s modulus of the nanocomposite evidently increases when a compatibilizer C （PP-g-MA） with medium MFI is used. For the nanocomposites with compatibilizer B and C, their crystallinities （Xc） increase as compared with that of the virgin PPR. Furthermore, the increase of OMMT loadings presents little effect on the melt temperature （Tc） of the PPR/OMMT nanocomposites, and slight effect on their crystallization temperature （Tc）. Only compatibilizer B can lead to a marked increases in crystallinity and Tc of the nanocomposite when the OMMT content is 2 wt%.展开更多
The excellent drug encapsulation,prolonged in vivo circulation time,enhanced pharmacokinetics,and reduced adverse effects make the polymeric assemblies ideal carriers in nanomedicine,and become an emerging research fi...The excellent drug encapsulation,prolonged in vivo circulation time,enhanced pharmacokinetics,and reduced adverse effects make the polymeric assemblies ideal carriers in nanomedicine,and become an emerging research field with rapid development.In vivo,the polymer nanoassemblies will experience five steps,including circulation in the blood,accumulation in the tumoral site,penetration into the deep tumor tissue to reach cancer cells,internalization into cancer cells,and intracellular drug release.However,although tremendous efforts have been made to the material design,currently available carriers still have difficulties in fulfilling all of the requirements.Moreover,the long-standing dilemma of the synchronized stability and permeability of vesicles is still a big challenge,which confused researchers for a long time.This feature article tbcuses on the recent progress of single-or multi-stimuli triggered theranostic platforms,and the extracellularly reengineered shell-sheddable polymeric nanocarriers are systematically discussed.The perspectives for future developments in the nanocarriers functioned with artificial helical polymers(the potential cell-penetrating peptides mimics)are also proposed.We speculate that this feature article can fit the interesting of diverse readers and a guideline for the design of next generation of drug nanocarriers.展开更多
A novel graft copolymer consisting of polyisoprene backbone and hydrophilic side chain with carbamic acid ester functional group was prepared via thiol-ene＂click＂reaction and alcohol-isocyanate reactions.Polyisopren...A novel graft copolymer consisting of polyisoprene backbone and hydrophilic side chain with carbamic acid ester functional group was prepared via thiol-ene＂click＂reaction and alcohol-isocyanate reactions.Polyisoprene was synthesized by anionic polymerization using n-butyl lithium as initiator,and the pendant hydroxyl groups were introduced by the thiol-ene reaction of mercaptoethanol with the double bond of 1,2-addition units of PI backbone in the presence of radical initiator azobisisobutyronitrile. Isocyanate end group capped poly（ethylene glycol）（mPEG-NCO） was grafted onto the PI backbone through alcoholisocyanate reaction between the pendant hydroxyl groups and isocyanate group of mPEG-NCO.The structure of the graft copolymer were characterized and confirmed by means of size-exclusion chromatography,~1H NMR and FTIR spectroscopy.展开更多
Consisting of natural histidine residues,polyhistidine(PHis)simulates functional proteins.Traditional approaches towards PHis require the protection of imidazole groups before monomer synthesis and polymerization to p...Consisting of natural histidine residues,polyhistidine(PHis)simulates functional proteins.Traditional approaches towards PHis require the protection of imidazole groups before monomer synthesis and polymerization to prevent degradation and side reactions.In the contribution,histidine N-thiocarboxyanhydride(His-NTA)is directly synthesized in aqueous solution without protection.With the self-catalysis of the imidazole side group,the ring-closing reaction to form His-NTA does not require any activating reagent(e.g.,phosphorus tribromide),which is elucidated by density functional theory(DFT)calculations.His-NTA directly polymerizes into PHis bearing unprotected imidazole groups with designable molecular weights(4.2-7.7 kg/mol)and low dispersities(1.10-1.19).Kinetic experiments and Monte Carlo simulations reveal the elementary reactions and the relationship between the conversion of His-NTA and time during polymerization.Block copolymerization of His-NTA with sarcosine N-thiocarboxyanhydride(Sar-NTA)demonstrate versatile construction of functional polypept(o)ides.The triblock copoly(amino acid)PHis-b-PSar-b-PHis is capable to reversibly coordinate with transition metal ions(Fe^(2+),Co^(2+),Ni^(2+),Cu^(2+)and Zn^(2+))to form pH-sensitive hydrogels.展开更多
High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercia...High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercially available polylactide(PLA)is limited by their inherent brittleness and high cost.Unfortunately,toughening PLA-based materials via cost-effective blending strategies without sacrificing transparency remains a challenge.Herein,we report a novel strategy involving active refractive index matching for creation of highly transparent and tough PLA blends.Specifically,we engineered the refractive index of a promising renewable poly(epichlorohydrin-co-ethylene oxide)elastomer by introducing polar ionic moieties via a simple chemical method,and we blended the resulting ionomers with PLA.The best blend showed an impact strength of>80 kJ/m2,an elongation at break of 400%,and high transparency(90%).These characteristics are of great importance for potential applications such as packaging.Our strategy offers a versatile new way to prepare high-performance sustainable polymer materials with excellent transparency.展开更多
High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as d...High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.展开更多
Dielectric polymer nanocomposites are considered as one of the most promising candidates for high-power-density electrical energy storage applications.Inorganic nanofillers with high insulation property are frequently...Dielectric polymer nanocomposites are considered as one of the most promising candidates for high-power-density electrical energy storage applications.Inorganic nanofillers with high insulation property are frequently introduced into fluoropolymer to improve its breakdown strength and energy storage capability.Normally,inorganic nanofillers are thought to introducing traps into polymer matrix to suppress leakage current.However,how these nanofillers effect the leakage current is still unclear.Meanwhile,high dopant(>5 vol%)is prerequisite for distinctly improved energy storage performance,which severely deteriorates the processing and mechanical property of polymer nanocomposites,hence brings high technical complication and cost.Herein,boron nitride nanosheet(BNNS)layers are utilized for substantially improving the electrical energy storage capability of polyvinylidene fluoride(PVDF)nanocomposite.Results reveal that the high conduction band minimum of BNNS produces energy barrier at the interface of adjacent layers,preventing the electron in PVDF from passing through inorganic layers,leading to suppressed leakage current and superior breakdown strength.Accompanied by improved Young’s modulus(from 1.2 GPa of PVDF to 1.6 GPa of nanocomposite),significantly boosted discharged energy density(14.3 J cm^(-3)) and charge-discharge efficiency(75%)are realized in multilayered nanocomposites,which are 340 and 300% of PVDF(4.2 J cm^(-3),25%).More importantly,thus remarkably boosted energy storage performance is accomplished by marginal BNNS.This work offers a new paradigm for developing dielectric nanocomposites with advanced energy storage performance.展开更多
Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-...Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-NTA)initiated by amino-terminated PEG.The self-assemblies of three PEG-b-PMeSPG copolymers with different PMeSPG block lengths were first prepared by nanoprecipitation method using THF and DMF,respectively,as the organic solvent,and their morphologies were studied by Cryo-EM and DLS.To prepare polymersomes loaded with glucose oxidase(GOx),double emulsion method followed by extrusion treatment was employed.The oxidation-responsive disruption of polymersomes was achieved upon the introduction of glucose because of the oxidants generated insitu by GOx/glucose.展开更多
The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fo...The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fourier transform infrared spectroscopy （FT-IR） and scanning electron microscopy （SEM）. The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC, FT-IR, and SEM in order to make clear the reason of that phenomenon. Finally, the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight, orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight, orientation degree and crystallinity increase under shear field, but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight, the shear field has little effect on the morphology and mechanical properties.展开更多
Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethy...Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethylphosphate （TEP） as solvent. P（MMA-r-PEGMA） was synthesized by radical polymerization in TEP. Then the obtained amphiphilic copolymer solution was mixed with PVDF and TEP to prepare the dope solution. The effects of P（MMA-r-PEGMA） content and coagulation composition on membrane morphologies were investigated using scanning electron microscopy （SEM）. The results demonstrated that, even blended with amphiphilic copolymers, a symmetric structure can be formed. Hollow fiber membranes with a mainly symmetric structure were also fabricated. The dry hollow fiber membranes showed good hydrophilicity, high flux and good rejection performance because of their hydrophilic surface and pores wall.展开更多
Rheological measurement has been a preferred approach to the characterization of the structure and phase behaviors for multi-component/multi-phase polymer systems, due to its sensitive response to the changes of struc...Rheological measurement has been a preferred approach to the characterization of the structure and phase behaviors for multi-component/multi-phase polymer systems, due to its sensitive response to the changes of structure for these heterogeneous polymers. In the present article, recent progresses in the studies on rheology for heterogeneous polymer systems including phase-separated polymeric blends and block copolymers are reviewed, mainly depending on the results by the authors＇ research group. By means of rheological measurements, not only some new fingerprints responsible for the evolution of morphology and structure concerning these polymer systems are obtained, also the corresponding results are significant for design and preparation of novel polymeric structural materials and functional materials.展开更多
Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively...Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively）, were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly（BAPNPGCP） were 8 ℃ and 7% higher than those of poly（BAPBACP）. Meanwhile, the total heat release of poly（BAPNPGCP） was less than half of that for poly（BAPBACP）, indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly（BAPNCP） gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.展开更多
H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene ox...H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.展开更多
A novel star-comb styrene/butadiene copolymer（SC-SBC） was synthesized by anionic polymerization and grafting reaction with epoxidized star liquid polybutadiene（ESPB） as coupling agent.The overall shape of the star...A novel star-comb styrene/butadiene copolymer（SC-SBC） was synthesized by anionic polymerization and grafting reaction with epoxidized star liquid polybutadiene（ESPB） as coupling agent.The overall shape of the star-comb macromolecules can be altered by changing the molecular weight and number of the side chain.The molecular parameters and mechanical properties of the SC-SBC resins were investigated.The notched izod impact strength of the SC-SBC resins are excellent and reach as high as to 239 J/m.展开更多
A series of double-hydrophilic double-grafted PMA-g-PEG/PDMA copolymers, which contained poly（methacrylate） （PMA） as backbone, poly（ethylene glycol） （PEG） and poly（N,N-dimethylacrylamide） （PDMA） as side ch...A series of double-hydrophilic double-grafted PMA-g-PEG/PDMA copolymers, which contained poly（methacrylate） （PMA） as backbone, poly（ethylene glycol） （PEG） and poly（N,N-dimethylacrylamide） （PDMA） as side chains synthesized successfully by using reversible addition-fragmentation chain transfer （RAFT） polymerization and atom transfer radical polymerization （ATRP）, were used as physical coatings for the evaluation of protein-resistant properties by capillary electrophoresis （CE）. Electroosmotic flow （EOF） measurement results showed that the PMA-g-PEG/PDMA copolymer coated capillaries could suppress electroosmotic mobility in a wide pH range （pH = 2.8-9.8） and EOF mobility decreased with the increase of copolymer molecular mass and PDMA content. At the same time, protein recovery, theoretical plate number of separation and repeatability of migration time demonstrated that antifouling efficiency was improved with the increase of molecular mass and PEG content.展开更多
基金financially supported by the National Natural Science Foundation of China(No.50803054)Zhejiang Provincial Nature Science Foundation of China(No.Y4100204)
文摘Inspired by the self-polymerization and strong adhesion characteristics of dopamine in aqueous conditions, a novel hydrophilic nanofiltration （NF） membrane was fabricated by simply dipping polysulfone （PSf） ultrafiltration （UF） substrate in dopamine solution. The changes in surface chemical composition and morphology of membranes were determined by Fourier transform infrared spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM） and atomic force microscopy （AFM）. The experimental results indicated that the self-polymerized dopamine formed an ultrathin and defect-free barrier layer on the PSf UF membrane. The surface hydrophilicity of membranes was evaluated through water contact angle measurements. It was found that membrane hydrophilicity was significantly improved after coating a polydopamine （pDA） layer, especially after double coating. The dyes filtration experiments showed that the double-coated membranes were able to reject completely the dyes of brilliant blue, congo red and methyl orange with a pure water flux of 83.7 L/（mE.h） under 0.6 MPa. The zeta potential determination revealed the positively-charged characteristics of PSf/pDA composite membrane in NF process. The salt rejection of the membranes was characterized by 0.01 mmol/L of salts filtration experiment. It was demonstrated that the salts rejections followed the sequence： NaC1 〈 NaaSO4 〈 MgSO4 〈 MgC12 〈 CaCl2, and the rejection to CaC12 reached 68.7%. Moreover, the composite NF membranes showed a good stability in water-phase filtration process.
基金supported by the Science and Technology Department of Zhejiang Province(No.2006C11050)
文摘A series of stable waterborne polysiloxaneurethane （WPSUR） dispersions were prepared using amino-terminated polydimethylsiloxane （NS）, dimethylolpropionic acid （DMPA）, castor oil, polypropylene glycol and toluene diisocyanate. Meanwhile, NS with different molecular weights was synthesized and used as the soft co-segment. Effects of types and contents of soft co-segments as well as chain extenders on the thermal degradation and stability for WPSUR films were examined. Results reveal that WPSUR films exhibit excellent water resistance and mechanical properties as compared with pure polyurethane （PU） films, and the NS soft co-segment possesses a remarkable effect on the second stage （stage Ⅱ）, while the content of the hard segment is propitious to the initial stage （stage Ⅰ）. Moreover, the highest temperature of stage Ⅱ （T2m） for WPSUR films using NS as soft co-segment is 413℃, approximately being 30℃ higher than that of those typical PUs using HDA and APDMS as the chain extenders, respectively.
基金Supported by the National Natural Science Foundation of China and the State Education Committee of China
文摘Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.
基金financially supported by the National Natural Science Foundation of China(No.51173157),National Basic Research Program of China(No.2005CB623800) and Natural Science Foundation of Zhejiang Province(No.Y4100314).
文摘The influences of shearing conducted by a Brabender behavior of a commercial impact polypropylene copolymer （IPC） rheometer on phase morphology, thermal and rheological were studied. The crystallization and melting traces show that short-time annealing at 210℃ is unable to completely erase the influence of shearing on the samples. When the samples which were treated at a rotation speed of 80 r/rnin crystallize at a cooling rate of 10 K/min, their Tcs and corresponding Tms obviously rise with the increase of shearing time. Furthermore, the POM results reveal that the shearing can lead to the formation of shish-kebab and the shish-kebab amount is proportional to shearing time. The rheological measurement results show that the treated samples exhibit different G＇-ω dependences. The ＇second plateau＇ appears when the sample is treated at a rotation speed of 60 r/min or 80 r/min for 10 min, and linear G＇-ω dependence is observed at other rotation speeds. In addition, it is found that the appearance of the ＇second plateau＇ depends on the shearing time when the rotation speed is fixed. According to SEM observations, it is proposed that the ＇second plateau＇ of IPC samples should be ascribed to the aggregation of dispersion particles.
基金financially supported by the National Natural Science Foundation of China (No. 21871232)the Zhejiang Provincial Natural Science Foundation of China (No. LR15B040001)
文摘Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.
基金supported by the National Basic Research Program of China(No.2005CB623800)Joint Research Fund for Overseas Chinese Young Scholars(No.50728302)the Program for Zhejiang Provincial Innovative Research Team (No.2009R50004)
文摘Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and three maleic-anhydride-grafted polypropylenes （PP-g-MA） with different melt flow indexes （MFI）, were used to improve the dispersion of organic clay in matrix. On the other hand, the effects of organic montmorillonite （OMMT） content on the nanocomposite structure in terms of clay dispersion in PPR matrix, thermal behavior and tensile properties were also studied. The X-ray diffraction （XRD） and transmission electron microscopy （TEM） results show that the organic clay layers are mainly intercalated and partially exfoliated in the nanocomposites. Moreover, a PP-g-MA compatibilizer （compatibilizer B） having high MFI can greatly increase the interlayer spacing of the clay as compared with other compatibilizers. With the introduction of compatibilizer D （POE-g-MA）, most of the clays are dispersed into the POE phase, and the shape of the dispersed OMMT appears elliptic, which differs from the strip of PP-g-MA. Compared with virgin PPR, the Young＇s modulus of the nanocomposite evidently increases when a compatibilizer C （PP-g-MA） with medium MFI is used. For the nanocomposites with compatibilizer B and C, their crystallinities （Xc） increase as compared with that of the virgin PPR. Furthermore, the increase of OMMT loadings presents little effect on the melt temperature （Tc） of the PPR/OMMT nanocomposites, and slight effect on their crystallization temperature （Tc）. Only compatibilizer B can lead to a marked increases in crystallinity and Tc of the nanocomposite when the OMMT content is 2 wt%.
基金financially supported by the National Natural Science Foundation of China(No.51673058)
文摘The excellent drug encapsulation,prolonged in vivo circulation time,enhanced pharmacokinetics,and reduced adverse effects make the polymeric assemblies ideal carriers in nanomedicine,and become an emerging research field with rapid development.In vivo,the polymer nanoassemblies will experience five steps,including circulation in the blood,accumulation in the tumoral site,penetration into the deep tumor tissue to reach cancer cells,internalization into cancer cells,and intracellular drug release.However,although tremendous efforts have been made to the material design,currently available carriers still have difficulties in fulfilling all of the requirements.Moreover,the long-standing dilemma of the synchronized stability and permeability of vesicles is still a big challenge,which confused researchers for a long time.This feature article tbcuses on the recent progress of single-or multi-stimuli triggered theranostic platforms,and the extracellularly reengineered shell-sheddable polymeric nanocarriers are systematically discussed.The perspectives for future developments in the nanocarriers functioned with artificial helical polymers(the potential cell-penetrating peptides mimics)are also proposed.We speculate that this feature article can fit the interesting of diverse readers and a guideline for the design of next generation of drug nanocarriers.
基金supports of the Special Funds for Major Basic Research Projects (NoG2011CB606001)Zhejiang Provincial Top Key Discipline of New Materials and Process Engineering(No 20110926)
文摘A novel graft copolymer consisting of polyisoprene backbone and hydrophilic side chain with carbamic acid ester functional group was prepared via thiol-ene＂click＂reaction and alcohol-isocyanate reactions.Polyisoprene was synthesized by anionic polymerization using n-butyl lithium as initiator,and the pendant hydroxyl groups were introduced by the thiol-ene reaction of mercaptoethanol with the double bond of 1,2-addition units of PI backbone in the presence of radical initiator azobisisobutyronitrile. Isocyanate end group capped poly（ethylene glycol）（mPEG-NCO） was grafted onto the PI backbone through alcoholisocyanate reaction between the pendant hydroxyl groups and isocyanate group of mPEG-NCO.The structure of the graft copolymer were characterized and confirmed by means of size-exclusion chromatography,~1H NMR and FTIR spectroscopy.
基金financially supported by the National Natural Science Foundation of China(Nos.22271252 and 22201105)。
文摘Consisting of natural histidine residues,polyhistidine(PHis)simulates functional proteins.Traditional approaches towards PHis require the protection of imidazole groups before monomer synthesis and polymerization to prevent degradation and side reactions.In the contribution,histidine N-thiocarboxyanhydride(His-NTA)is directly synthesized in aqueous solution without protection.With the self-catalysis of the imidazole side group,the ring-closing reaction to form His-NTA does not require any activating reagent(e.g.,phosphorus tribromide),which is elucidated by density functional theory(DFT)calculations.His-NTA directly polymerizes into PHis bearing unprotected imidazole groups with designable molecular weights(4.2-7.7 kg/mol)and low dispersities(1.10-1.19).Kinetic experiments and Monte Carlo simulations reveal the elementary reactions and the relationship between the conversion of His-NTA and time during polymerization.Block copolymerization of His-NTA with sarcosine N-thiocarboxyanhydride(Sar-NTA)demonstrate versatile construction of functional polypept(o)ides.The triblock copoly(amino acid)PHis-b-PSar-b-PHis is capable to reversibly coordinate with transition metal ions(Fe^(2+),Co^(2+),Ni^(2+),Cu^(2+)and Zn^(2+))to form pH-sensitive hydrogels.
基金supported by the National Natural Science Foundation of China(No.51573130)。
文摘High transparency and toughness are prerequisites for sustainable polymers if they are to find wide application as alternatives to petroleum-based polymers.However,the utility of sustainable polymers such as commercially available polylactide(PLA)is limited by their inherent brittleness and high cost.Unfortunately,toughening PLA-based materials via cost-effective blending strategies without sacrificing transparency remains a challenge.Herein,we report a novel strategy involving active refractive index matching for creation of highly transparent and tough PLA blends.Specifically,we engineered the refractive index of a promising renewable poly(epichlorohydrin-co-ethylene oxide)elastomer by introducing polar ionic moieties via a simple chemical method,and we blended the resulting ionomers with PLA.The best blend showed an impact strength of>80 kJ/m2,an elongation at break of 400%,and high transparency(90%).These characteristics are of great importance for potential applications such as packaging.Our strategy offers a versatile new way to prepare high-performance sustainable polymer materials with excellent transparency.
基金supported by the 863 program(No.2006AA03Z233)973 program(No.2009CB623402) of China
文摘High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.
基金supported by China Postdoctoral Science Foundation(2021M690103)National Natural Science Foundation of China(52003153,51877132,and 52002300)+2 种基金Program of Shanghai Academic Research Leader(21XD1401600)State Key Laboratory of Electrical Insulation and Power Equipment(EIPE20203,EIPE21206)the Major Research Plan of National Natural Science Foundation of China(92066103)。
文摘Dielectric polymer nanocomposites are considered as one of the most promising candidates for high-power-density electrical energy storage applications.Inorganic nanofillers with high insulation property are frequently introduced into fluoropolymer to improve its breakdown strength and energy storage capability.Normally,inorganic nanofillers are thought to introducing traps into polymer matrix to suppress leakage current.However,how these nanofillers effect the leakage current is still unclear.Meanwhile,high dopant(>5 vol%)is prerequisite for distinctly improved energy storage performance,which severely deteriorates the processing and mechanical property of polymer nanocomposites,hence brings high technical complication and cost.Herein,boron nitride nanosheet(BNNS)layers are utilized for substantially improving the electrical energy storage capability of polyvinylidene fluoride(PVDF)nanocomposite.Results reveal that the high conduction band minimum of BNNS produces energy barrier at the interface of adjacent layers,preventing the electron in PVDF from passing through inorganic layers,leading to suppressed leakage current and superior breakdown strength.Accompanied by improved Young’s modulus(from 1.2 GPa of PVDF to 1.6 GPa of nanocomposite),significantly boosted discharged energy density(14.3 J cm^(-3)) and charge-discharge efficiency(75%)are realized in multilayered nanocomposites,which are 340 and 300% of PVDF(4.2 J cm^(-3),25%).More importantly,thus remarkably boosted energy storage performance is accomplished by marginal BNNS.This work offers a new paradigm for developing dielectric nanocomposites with advanced energy storage performance.
基金the French National Research Agency(No.ANR16-CE29-0028)the National Natural Science Foundation of China(No.21674091)+2 种基金the Joint Foundation of Shaanxi Province Natural Science Basic Research ProgramShaanxi Coal Chemical Group Co.,Ltd.(No.2019JLM-46)for financial supportthe China Scholarship Council for funding his Ph.D.scholarship in France。
文摘Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-NTA)initiated by amino-terminated PEG.The self-assemblies of three PEG-b-PMeSPG copolymers with different PMeSPG block lengths were first prepared by nanoprecipitation method using THF and DMF,respectively,as the organic solvent,and their morphologies were studied by Cryo-EM and DLS.To prepare polymersomes loaded with glucose oxidase(GOx),double emulsion method followed by extrusion treatment was employed.The oxidation-responsive disruption of polymersomes was achieved upon the introduction of glucose because of the oxidants generated insitu by GOx/glucose.
基金supported by the special funds for Major State Basic Research Projects of China (No.2011CB606006)Program for the New-Century Excellent Talents of Ministry of Education of China(NCET-10- 0580)
文摘The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fourier transform infrared spectroscopy （FT-IR） and scanning electron microscopy （SEM）. The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC, FT-IR, and SEM in order to make clear the reason of that phenomenon. Finally, the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight, orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight, orientation degree and crystallinity increase under shear field, but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight, the shear field has little effect on the morphology and mechanical properties.
基金financially supported by the National Natural Science Foundation of China(No.20974094)National 973 Program(No.2009CB623402)+1 种基金Key Innovation Team for Science and Technology of Zhejiang Province,China(No.2009R50047)Postdoctoral Science Foundation funded project of Zhejiang Province,China(No.Bsh1202045)
文摘Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethylphosphate （TEP） as solvent. P（MMA-r-PEGMA） was synthesized by radical polymerization in TEP. Then the obtained amphiphilic copolymer solution was mixed with PVDF and TEP to prepare the dope solution. The effects of P（MMA-r-PEGMA） content and coagulation composition on membrane morphologies were investigated using scanning electron microscopy （SEM）. The results demonstrated that, even blended with amphiphilic copolymers, a symmetric structure can be formed. Hollow fiber membranes with a mainly symmetric structure were also fabricated. The dry hollow fiber membranes showed good hydrophilicity, high flux and good rejection performance because of their hydrophilic surface and pores wall.
基金This work was supported by the Special Funds for Major Stale Basic Research Projects (No. 2005CB623802) National Natural Science Foundation of China (No. 50373037).
文摘Rheological measurement has been a preferred approach to the characterization of the structure and phase behaviors for multi-component/multi-phase polymer systems, due to its sensitive response to the changes of structure for these heterogeneous polymers. In the present article, recent progresses in the studies on rheology for heterogeneous polymer systems including phase-separated polymeric blends and block copolymers are reviewed, mainly depending on the results by the authors＇ research group. By means of rheological measurements, not only some new fingerprints responsible for the evolution of morphology and structure concerning these polymer systems are obtained, also the corresponding results are significant for design and preparation of novel polymeric structural materials and functional materials.
基金supported by the National Natural Science Foundation of China(No.51103129)the National Basic Research Program of China("973 Program",No.2010CB631105)+1 种基金the Ningbo Natural Science Foundation(No.2012A610084)the Open Fund of Zhejiang Provincial Top Key Discipline of New Materials and Process Engineering(No.20110939)
文摘Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively）, were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly（BAPNPGCP） were 8 ℃ and 7% higher than those of poly（BAPBACP）. Meanwhile, the total heat release of poly（BAPNPGCP） was less than half of that for poly（BAPBACP）, indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly（BAPNCP） gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.
基金financial support from the National Natural Science Foundation of China(No.20134020)the Science Research Fund of the Chinese Ministry of Education(No.104005)the Science Research Fund of Shandong Provincial Education Department of China(No.105D11).
文摘H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.
基金financially supported by the National High Technology Research and Development Program of China(No.2007AA03Z532)the National Natural Science Foundation of China(No.20774015)the China National Petroleum Corporation Innovation Fund(No.07E1034)
文摘A novel star-comb styrene/butadiene copolymer（SC-SBC） was synthesized by anionic polymerization and grafting reaction with epoxidized star liquid polybutadiene（ESPB） as coupling agent.The overall shape of the star-comb macromolecules can be altered by changing the molecular weight and number of the side chain.The molecular parameters and mechanical properties of the SC-SBC resins were investigated.The notched izod impact strength of the SC-SBC resins are excellent and reach as high as to 239 J/m.
基金supported by the National Natural Science Foundation of China (No. 21074124)Ministry of Science and Technology of China (No. 2012CB933802)
文摘A series of double-hydrophilic double-grafted PMA-g-PEG/PDMA copolymers, which contained poly（methacrylate） （PMA） as backbone, poly（ethylene glycol） （PEG） and poly（N,N-dimethylacrylamide） （PDMA） as side chains synthesized successfully by using reversible addition-fragmentation chain transfer （RAFT） polymerization and atom transfer radical polymerization （ATRP）, were used as physical coatings for the evaluation of protein-resistant properties by capillary electrophoresis （CE）. Electroosmotic flow （EOF） measurement results showed that the PMA-g-PEG/PDMA copolymer coated capillaries could suppress electroosmotic mobility in a wide pH range （pH = 2.8-9.8） and EOF mobility decreased with the increase of copolymer molecular mass and PDMA content. At the same time, protein recovery, theoretical plate number of separation and repeatability of migration time demonstrated that antifouling efficiency was improved with the increase of molecular mass and PEG content.
