Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polyme...Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.展开更多
It is well known that cationic polymers have excellent antimicrobial capacity accompanied with high biotoxicity,to reduce biotoxicity needs to decrease the number of cationic groups on polymers,which will influence an...It is well known that cationic polymers have excellent antimicrobial capacity accompanied with high biotoxicity,to reduce biotoxicity needs to decrease the number of cationic groups on polymers,which will influence antimicrobial activity.It is necessary to design a cationic polymer mimic natural antimicrobial peptide with excellent antibacterial activity and low toxicity to solve the above dilemma.Here,we designed and prepared a series of cationic poly(β-amino ester)s(PBAEs)with different cationic contents,and introducing hydrophobic alkyl chain to adjust the balance between antimicrobial activity and biotoxicity to obtain an ideal antimicrobial polymer.The optimum one of synthesized PBAE(hydrophilic cationic monomer:hydrophobic monomer=5:5)was screened by testing cytotoxicity and minimum inhibitory concentration(MIC),which can effectively kill S.aureus and E.coli with PBAE concentration of15μg/m L by a spread plate bacteriostatic method and dead and alive staining test.The way of PBAE killing bacterial was destroying the membrane like natural antimicrobial peptide observed by scanning electron microscopy(SEM).In addition,PBAE did not exhibit hemolysis and cytotoxicity.In particular,from the result of animal tests,the PBAE was able to promote healing of infected wounds from removing mature S.aureus and E.coli on the surface of infected wound.As a result,our work offers a viable approach for designing antimicrobial materials,highlighting the significant potential of PBAE polymers in the field of biomedical materials.展开更多
Poly(butylene succinate-co-furandicarboxylate)(PBSF)and poly(butylene adipateco-furandicarboxylate)(PBAF)are novel furandicarboxylic acid-based biodegradable copolyesters with great potential to replace fossil-derived...Poly(butylene succinate-co-furandicarboxylate)(PBSF)and poly(butylene adipateco-furandicarboxylate)(PBAF)are novel furandicarboxylic acid-based biodegradable copolyesters with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene succinate-co-terephthalate)(PBST)and poly(butylene adipate-co-terephthalate)(PBAT).In this study,quantum chemistry techniques after molecular dynamics simulations are employed to investigate the degradationmechanism of PBSF and PBAF catalyzed by Candida antarctica lipase B(CALB).Computational analysis indicates that the catalytic reaction follows a four-step mechanism resembling the ping-pong bibi mechanism,with the initial two steps being acylation reactions and the subsequent two being hydrolysis reactions.Notably,the first step of the hydrolysis is identified as the rate-determining step.Moreover,by introducing single-point mutations to expand the substrate entrance tunnel,the catalytic distance of the first acylation step decreases.Additionally,energy barrier of the rate-determining step is decreased in the PBSF system by site-directed mutations on key residues increasing hydrophobicity of the enzyme’s active site.This study unprecedently show the substrate binding pocket and hydrophobicity of the enzyme’s active site have the potential to be engineered to enhance the degradation of copolyesters catalyzed by CALB.展开更多
It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation...It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation but can also track the fouling process during operation.Herein,an aggregation-induced emission(AIE)-active polymer membrane was prepared by the interfacial polymerization of a cyclodextrin-based glycocluster(CD@Glucose)and a tetraphenylethylene derivative modified with boronic acid groups(TPEDB)on the surface of a polyacrylonitrile(PAN)ultrafiltration membrane.This interfacial polymerization method can be stacked layer-by-layer to regulate the hydrophilicity and pore structure of the membrane.With the increase in the number of polymer layers,the separation and antifouling properties of the membrane gradually improved.Owing to the AIE property of the crosslinking agent TPEDB,the occurrence of interfacial polymerization and the degree of fouling during membrane operation can be monitored by the fluorescence distribution and intensity.With the aggravation of membrane fouling,the fluorescence decreased gradually,but recovered after cleaning.Therefore,this AIE effect can be used for real-time monitoring of interfacial polymerization as well as membrane fouling.展开更多
Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The misc...Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The miscibility, mechanical properties, phase morphology and toughening mechanism of the blend were investigated. Both DSC and DMTA results manifested that the addition of TPU elastomer not only accelerated the crystallization rate, but also increased the final degree of crystallinity, which proved that TPU has limited miscibility with PLA and has functioned as a plasticizer. All the blend samples showed distinct phase separation phenomenon with sea-island structure under SEM observation and the rubber particle size in the PLA matrix increased with the increased contents of TPU. The mechanical property variation of PLA/TPU blends could be quantitatively explained by Wu＇s model. With the variation of TPU, a brittle-ductile transition has been observed for the TPU/PLA blends. When these blends were under tensile stress conditions, the TPU particles could be debonded from the PLA matrix and the blends showed a high ability to induce large area plastic deformation before break, which was important for the dissipation of the breaking energy. Such mechanism was demonstrated by tensile tests and scanning electron microcopy （SEM） observations.展开更多
The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples wer...The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples were collected in June 2010.Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry.Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L,respectively.Fluoranthene,naphthalene,pyrene,phenanthrene,di-2ethylhexyl phthalate,and di-n-butyl phthalate were the most abundant compounds in the samples.The water samples were moderately polluted with benzo[a]pyrene according to China＇s environmental quality standard for surface water.The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake,Wuxi City and the western section of Yangchenghu Lake.Potential sources of pollution at S7 were petroleum combustion and the plastics industry,and at Yangchenghu Lake were petroleum combustion and domestic waste.Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines.There were no obvious sources of pollution for the other water samples.These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.展开更多
Electrospun nanofibrous mats represent a new generation of medical textiles with promising applications in heart valve tissue reconstruction. It is important for biomaterials to mimic the biological and mechanical mic...Electrospun nanofibrous mats represent a new generation of medical textiles with promising applications in heart valve tissue reconstruction. It is important for biomaterials to mimic the biological and mechanical microenvironment of native extracellular matrix(ECM). However, the major challenges are still remaining for current biomedical materials, including appropriate mechanical properties,biocompatibility, and hemocompatibility. In the present work, the novel composite nanofibrous mats of poly(p-dioxanone)(PDO) and poly(ester-urethane)ureas(PEUU) are fabricated by electrospinning system. The optimal combination ratio of PDO to PEUU may balance the mechanical properties and cellular compatibility to match the newly formed tissue. In PDO/PEUU composite nanofibrous mats, PEUU can provide the biomimetic elastomeric behavior, and PDO could endow the excellent biocompatibility. In comparison to nanofibrous mat of neat PDO, the composite showed significantly improved mechanical properties, with 5-fold higher initial elongation at break.Furthermore, human umbilical vein endothelial cells(HUVECs) were cultured on the composite to evaluate its ability to rapidly endothelialize as heart valve tissue engineering. The results revealed that PDO/PEUU composite nanofibrous mats could promote cell adhesion and proliferation, especially for the ratio of 60/40. Overall, PDO/PEUU composite nanofibrous mats(60/40) show the excellent mechanical properties, appropriate biocompatibility and hemocompatibility which meet the necessary norm for tissue engineering and may be suitable for potential heart valve tissue reconstruction.展开更多
A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitroben...A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.展开更多
A series of non-isocyanate linear high molecular weight poly(ester urethane)s(PETUs)were prepared through an environmentallyfriendly route based on dimethyl carbonate,1,6-hexanediol and 1,6-hexanediamine.In this route...A series of non-isocyanate linear high molecular weight poly(ester urethane)s(PETUs)were prepared through an environmentallyfriendly route based on dimethyl carbonate,1,6-hexanediol and 1,6-hexanediamine.In this route,the polyurethane diol was first prepared by the reaction between bis-1,6-hexamethylencarbamate(BHC)and 1,6-hexanediol.A series of polyester soft segments of polyurethane have been synthesized from the polycondensation of adipic acid and different diols,including butanediol,hexanediol,octanediol and decanediol.The subsequent polycondensation of polyurethane diol and polyester diol led to linear PETUs.The resultant polymers were characterized by GPC,FTIR,^(1)H-NMR,^(13)C-NMR,DSC,WAXD,TGA and tensile test.The results indicated that PETUs possess weight-average molecular weights higher than 1×10^(5) and the tensile strength as high as 10 MPa.The thermal properties,crystallization behavior,microphase separation behavior and morphology were studied by DSC and AFM,and the results indicated that the degree of phase separation was affected by two factors,the crystallization and hydrogen bonding interaction between soft segment and hard segment.展开更多
Poly[（alanino ethyl ester）0.67 （glycino ethyl ester）0.33 phosphazene] （PAGP） was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field em...Poly[（alanino ethyl ester）0.67 （glycino ethyl ester）0.33 phosphazene] （PAGP） was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field emission scanning electron microscope （SEM） with changing the important processing variables such as applied voltage, polymeric concentration, and ambient temperature. The average diameter of PAGP nanofibers was inversely proportional to the applied voltage, but increased with the increase of solution concentration. Lower environmental temperature was unfavorable due to the nanofibers conglutination.展开更多
A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis...A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis（hydroxyethyloxycarbonylamino） hexane （BHCH）, i.e. PrePBHCHs, were prepared through the self-transurethane polycondensation of BHCH. A poly（butylene adipate） prepolymer （PrePBA） with terminal HO-- groups was prepared and used as a polyester glycol. A series of TPEURs were prepared by the co-polycondensation of the PrePBHCHs with PrePBA at 170 ℃under a reduced pressure of 399 Pa. The TPEURs were characterized by gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile test. The TPEURs exhibited Mn up to 23300 g/mol, Mw up to 51100 g/mol, Tg ranging from -33.8 ℃ to -3.1 ℃, Tm from 94.3 ℃ to 111.9 ℃, initial decomposition temperature over 274.7℃, tensile strength up to18.8 MPa with a strain at break of 450.0%, and resilience up to 77.5%. TPU elastomers with good crystallization and mechanical properties were obtained through a non-isocyanate route.展开更多
Gene-based therapeutics has emerged as a promising approach for human cancer therapy. Among a variety of non-viral vectors, polymer vectors are particularly attractive due to their safety and multivalent groups on the...Gene-based therapeutics has emerged as a promising approach for human cancer therapy. Among a variety of non-viral vectors, polymer vectors are particularly attractive due to their safety and multivalent groups on their surface. This study focuses on guanidinylated O-carboxymethyl chitosan(GOCMCS) along with poly-β-amino ester(PBAE) for si RNA delivery. Binding efficiency of PBAE/si RNA/GOCMCS nanoparticles were characterized by gel electrophoresis. The si RNA-loaded nanoparticles were found to be stable in the presence of RNase A, serum and BALF respectively. Fine particle fraction(FPF) which was determined by a two-stage impinger(TSI) was 57.8% ± 2.6%. The particle size and zeta potential of the nanoparticles were 153.8 ± 12.54 nm and + 12.2 ± 4.94 m V. In vitro cell transfection studies were carried out with A549 cells. The cellular uptake was significantly increased. When the cells were incubated with si Survivin-loaded nanoparticles, it could induce 26.83% ± 0.59% apoptosis of A549 cells and the gene silencing level of survivin expression in A549 cells were 30.93% ± 2.27%. The results suggested that PBAE/GOCMCS nanoparticle was a very promising gene delivery carrier.展开更多
A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/P...A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/PDLA-CHOL） and poly（β-cyclodextrin） （PCD） with the molar ratios of CHOL/β-CD at 1：0.5, 1 ：l, and 1：2 in an aqueous environment. The hydrodynamic diameters of the micelles ranged from 84.1 nm to 107 nm depending on the molar ratio of CHOL/β-CD. It was shown that the micelle with the largest proportion of PCD possessed excellent abilities in drug release, cell internalization as well as proliferation inhibitory effect toward human A549 lung cancer cells. The results demonstrated that the stereocomplex and host-vip interactions-mediated PLA micelles exhibited great potential in sustained drug delivery.展开更多
Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols), polytetrahydrofuran diol (PTMG diols), 4,4'-dicyclohexylmethane diisocyanate (HMDI), and 1,4-butanediol (BDO) by ...Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols), polytetrahydrofuran diol (PTMG diols), 4,4'-dicyclohexylmethane diisocyanate (HMDI), and 1,4-butanediol (BDO) by a two-step reaction, and the morphology and property of the resultant TPU could be adjusted by varying the PLLA contents. The soft segment was composed of PLLA and PTMG diols. By controlling the percentage of PLLA in the soft segment, the glass transition temperature and mechanical properties of the polyurethanes could be regulated. Based on the FTIR spectrum, we found that two kinds of hydrogen bonding existed individually in soft matrix and hard domain. The hydrogen bonding in soft matrix was unstable, which could be destroyed during elongation. With in situ stretching WAXS and SAXS experiments, we found that the PLLA crystal was destroyed and the PLLA domain oriented along the stretch direction. Finally, we proposed a schematic model to illustrate the microstructures of these elastomers before and after stretch.展开更多
Supramolecular structures have received growing attention and been widely applied in many fields.Herein, we synthesized hydrophobic β-cyclodextrin-contained poly(β-amino ester)(PAE-β-CD) and hydrophilic adamantyl-t...Supramolecular structures have received growing attention and been widely applied in many fields.Herein, we synthesized hydrophobic β-cyclodextrin-contained poly(β-amino ester)(PAE-β-CD) and hydrophilic adamantyl-terminated poly(ethylene glycol)(PEG-AD) to form a supramolecular micelle via the host-vip interaction. The micelle displayed pH responsive structure change due to the transform of hydrophobic PAE core to hydrophilic form in weakly acid condition. After the anticancer drug curcumin(Cur) was loaded into the micelle, the drug release behavior of the Cur-loaded micelle was studied, and it turned out that the Cur-loaded supramolecular micelle could effectively unload the drug at pH 5.5.Furthermore, the antitumor efficiency of the Cur-loaded micelle was also examined both in vitro and in vivo, indicating considerable inhibition ratio as high as 62.14% against mouse sarcoma 180.展开更多
Amphiphilic hydroxyl functioned polyester（HFP） can be used as compatibilizers for blends of starch and resins.We developed a synthetic method for effective preparation of HFPs.Water was removed by high flow rate N_2...Amphiphilic hydroxyl functioned polyester（HFP） can be used as compatibilizers for blends of starch and resins.We developed a synthetic method for effective preparation of HFPs.Water was removed by high flow rate N_2 rather than high vacuum during polycondensation of sebacic acid with xylitol,sorbitol,or mannitol in the presence of dehydrative condensation catalyst and the product is with[η]of 27.2 mL/g,M_n of 1903,M_w of 167,693,T_g of -30.5℃,T_m of 44.0℃.Weight loss is 1.73%under 200℃. The integral distributions of molecular weight are 43.6 wt%and 63.8 wt%over 10,000 and 3000,respectively.The results indicated that higher molecular weight HFP was economically synthesized.展开更多
Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The compos...Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.展开更多
A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithi...A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.展开更多
Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct poly...Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis（imide-carboxylic acid）s （1）, such as 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole （lo） and 2-[3,5-bis（N- trimellitimidoyl）phenyl]benzothiazole （Is） and two bis（imide-ether-carboxylic acid）s （2）, such as 2-[3,5-bis（4- trimellitimidophenoxy）-phenyl]benzoxazole （2o）, and 2-[3,5-bis（4-trimellitimidophenoxy）-phenyl]benzothiazole （2s） with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and IH-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl·g^-1 Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.展开更多
Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic aci...Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic acid catalyst. Some physicochemicalconstants of the compounds, such as density and refractive index, aredetermined. The complexes are hydrolabll in aqueous solutions andthe bond of Sb-S is weaker than that of Sb-o. The forming bondproperty of antimony tris (mercaptoacid ester ) has been elucidatedby measurement of infrared spectra in comparison with mercaptocarboxylic acid esters. The polyvinyl chloride resins containing antimony mercaptide heat stabilizers, do not darken at elevated temperatures and exhibit a high degree of stability. It is proposed that mercaptocarboxylic acid ester freeradicals can esterify PVC microradicals at carbon atoms with upaired electrons.展开更多
基金supported by the National Key R&D Program of China(No.2023YFA1506804)the National Natural Science Foundation of China(Nos.22471110,22171111,22131007 and 22071093)+1 种基金the Science Foundation of Gansu Province of China(No.22JR5RA406)the Fundamental Research Funds for the Central Universities(No.lzujbky-2023-15)。
文摘Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.
基金financially supported by the Natural Science Foundation of Jilin Province Science and Technology Department(No.20230101221JC)the National Natural Science Foundation of China(Nos.52173115,52073278,52203189)the Research Foundation for Advanced Talents of Xiamen University of Technology(Nos.5010423019,YKJ22052R)。
文摘It is well known that cationic polymers have excellent antimicrobial capacity accompanied with high biotoxicity,to reduce biotoxicity needs to decrease the number of cationic groups on polymers,which will influence antimicrobial activity.It is necessary to design a cationic polymer mimic natural antimicrobial peptide with excellent antibacterial activity and low toxicity to solve the above dilemma.Here,we designed and prepared a series of cationic poly(β-amino ester)s(PBAEs)with different cationic contents,and introducing hydrophobic alkyl chain to adjust the balance between antimicrobial activity and biotoxicity to obtain an ideal antimicrobial polymer.The optimum one of synthesized PBAE(hydrophilic cationic monomer:hydrophobic monomer=5:5)was screened by testing cytotoxicity and minimum inhibitory concentration(MIC),which can effectively kill S.aureus and E.coli with PBAE concentration of15μg/m L by a spread plate bacteriostatic method and dead and alive staining test.The way of PBAE killing bacterial was destroying the membrane like natural antimicrobial peptide observed by scanning electron microscopy(SEM).In addition,PBAE did not exhibit hemolysis and cytotoxicity.In particular,from the result of animal tests,the PBAE was able to promote healing of infected wounds from removing mature S.aureus and E.coli on the surface of infected wound.As a result,our work offers a viable approach for designing antimicrobial materials,highlighting the significant potential of PBAE polymers in the field of biomedical materials.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.U21A20320)the National Natural Science Foundation of China(No.22106102)was also sponsored by the special fund of State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants(No.SEPKLEHIAEC-202203).
文摘Poly(butylene succinate-co-furandicarboxylate)(PBSF)and poly(butylene adipateco-furandicarboxylate)(PBAF)are novel furandicarboxylic acid-based biodegradable copolyesters with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene succinate-co-terephthalate)(PBST)and poly(butylene adipate-co-terephthalate)(PBAT).In this study,quantum chemistry techniques after molecular dynamics simulations are employed to investigate the degradationmechanism of PBSF and PBAF catalyzed by Candida antarctica lipase B(CALB).Computational analysis indicates that the catalytic reaction follows a four-step mechanism resembling the ping-pong bibi mechanism,with the initial two steps being acylation reactions and the subsequent two being hydrolysis reactions.Notably,the first step of the hydrolysis is identified as the rate-determining step.Moreover,by introducing single-point mutations to expand the substrate entrance tunnel,the catalytic distance of the first acylation step decreases.Additionally,energy barrier of the rate-determining step is decreased in the PBSF system by site-directed mutations on key residues increasing hydrophobicity of the enzyme’s active site.This study unprecedently show the substrate binding pocket and hydrophobicity of the enzyme’s active site have the potential to be engineered to enhance the degradation of copolyesters catalyzed by CALB.
基金supported by the Fundamental Research Funds for Central Universities(No.30922010811).
文摘It is important to understand the evolution of the matter on the polymer membrane surface.The in situ and real-time monitoring of the membrane surface will not only favor the investigation of selective layer formation but can also track the fouling process during operation.Herein,an aggregation-induced emission(AIE)-active polymer membrane was prepared by the interfacial polymerization of a cyclodextrin-based glycocluster(CD@Glucose)and a tetraphenylethylene derivative modified with boronic acid groups(TPEDB)on the surface of a polyacrylonitrile(PAN)ultrafiltration membrane.This interfacial polymerization method can be stacked layer-by-layer to regulate the hydrophilicity and pore structure of the membrane.With the increase in the number of polymer layers,the separation and antifouling properties of the membrane gradually improved.Owing to the AIE property of the crosslinking agent TPEDB,the occurrence of interfacial polymerization and the degree of fouling during membrane operation can be monitored by the fluorescence distribution and intensity.With the aggravation of membrane fouling,the fluorescence decreased gradually,but recovered after cleaning.Therefore,this AIE effect can be used for real-time monitoring of interfacial polymerization as well as membrane fouling.
文摘Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The miscibility, mechanical properties, phase morphology and toughening mechanism of the blend were investigated. Both DSC and DMTA results manifested that the addition of TPU elastomer not only accelerated the crystallization rate, but also increased the final degree of crystallinity, which proved that TPU has limited miscibility with PLA and has functioned as a plasticizer. All the blend samples showed distinct phase separation phenomenon with sea-island structure under SEM observation and the rubber particle size in the PLA matrix increased with the increased contents of TPU. The mechanical property variation of PLA/TPU blends could be quantitatively explained by Wu＇s model. With the variation of TPU, a brittle-ductile transition has been observed for the TPU/PLA blends. When these blends were under tensile stress conditions, the TPU particles could be debonded from the PLA matrix and the blends showed a high ability to induce large area plastic deformation before break, which was important for the dissipation of the breaking energy. Such mechanism was demonstrated by tensile tests and scanning electron microcopy （SEM） observations.
基金supported by the National Basic Research Program of China (No. 2009CB421602)the Water Pollution Control and Treatment Special Project (No.2009ZX07527-001)+1 种基金the State Key Laboratory of Environmental Chemistry and Ecotoxicology (No. KF2010-20)the Special Fund for Public Welfare Industry on Environmental Protection (No. 2009467109)
文摘The pollution from polycyclic aromatic hydrocarbons（PAHs） and phthalic acid esters（PAEs） in the surface water of the rapidly urbanized Yangtze River Delta region was investigated.Fourteen surface water samples were collected in June 2010.Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry.Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L,respectively.Fluoranthene,naphthalene,pyrene,phenanthrene,di-2ethylhexyl phthalate,and di-n-butyl phthalate were the most abundant compounds in the samples.The water samples were moderately polluted with benzo[a]pyrene according to China＇s environmental quality standard for surface water.The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake,Wuxi City and the western section of Yangchenghu Lake.Potential sources of pollution at S7 were petroleum combustion and the plastics industry,and at Yangchenghu Lake were petroleum combustion and domestic waste.Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines.There were no obvious sources of pollution for the other water samples.These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.
基金financially supported by the Capacity Building Project of Some Local Colleges and Universities in Shanghai (No. 17030501200)the National Natural Science Foundation of China (No. 81501595)+2 种基金Youth Foundation of Zhongshan Hospital (No. 2015ZSQN09)Talent Training Program Foundation for the Excellent Youth Supported by Zhongshan Hospital (No. 2017ZSYQ24)Innovation Fund of Zhongshan Hospital (No. 2017ZSCX05)
文摘Electrospun nanofibrous mats represent a new generation of medical textiles with promising applications in heart valve tissue reconstruction. It is important for biomaterials to mimic the biological and mechanical microenvironment of native extracellular matrix(ECM). However, the major challenges are still remaining for current biomedical materials, including appropriate mechanical properties,biocompatibility, and hemocompatibility. In the present work, the novel composite nanofibrous mats of poly(p-dioxanone)(PDO) and poly(ester-urethane)ureas(PEUU) are fabricated by electrospinning system. The optimal combination ratio of PDO to PEUU may balance the mechanical properties and cellular compatibility to match the newly formed tissue. In PDO/PEUU composite nanofibrous mats, PEUU can provide the biomimetic elastomeric behavior, and PDO could endow the excellent biocompatibility. In comparison to nanofibrous mat of neat PDO, the composite showed significantly improved mechanical properties, with 5-fold higher initial elongation at break.Furthermore, human umbilical vein endothelial cells(HUVECs) were cultured on the composite to evaluate its ability to rapidly endothelialize as heart valve tissue engineering. The results revealed that PDO/PEUU composite nanofibrous mats could promote cell adhesion and proliferation, especially for the ratio of 60/40. Overall, PDO/PEUU composite nanofibrous mats(60/40) show the excellent mechanical properties, appropriate biocompatibility and hemocompatibility which meet the necessary norm for tissue engineering and may be suitable for potential heart valve tissue reconstruction.
文摘A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.
基金the National Natural Science Foundation of China(Nos.52173009,81971711,21574137,51373186)Beijing Natural Science Foundation(No.2192065)National Key R&D Program of China(No.2016YFB1100800)。
文摘A series of non-isocyanate linear high molecular weight poly(ester urethane)s(PETUs)were prepared through an environmentallyfriendly route based on dimethyl carbonate,1,6-hexanediol and 1,6-hexanediamine.In this route,the polyurethane diol was first prepared by the reaction between bis-1,6-hexamethylencarbamate(BHC)and 1,6-hexanediol.A series of polyester soft segments of polyurethane have been synthesized from the polycondensation of adipic acid and different diols,including butanediol,hexanediol,octanediol and decanediol.The subsequent polycondensation of polyurethane diol and polyester diol led to linear PETUs.The resultant polymers were characterized by GPC,FTIR,^(1)H-NMR,^(13)C-NMR,DSC,WAXD,TGA and tensile test.The results indicated that PETUs possess weight-average molecular weights higher than 1×10^(5) and the tensile strength as high as 10 MPa.The thermal properties,crystallization behavior,microphase separation behavior and morphology were studied by DSC and AFM,and the results indicated that the degree of phase separation was affected by two factors,the crystallization and hydrogen bonding interaction between soft segment and hard segment.
基金Funded by the National Natural Science Foundation of China (No.50873012)
文摘Poly[（alanino ethyl ester）0.67 （glycino ethyl ester）0.33 phosphazene] （PAGP） was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field emission scanning electron microscope （SEM） with changing the important processing variables such as applied voltage, polymeric concentration, and ambient temperature. The average diameter of PAGP nanofibers was inversely proportional to the applied voltage, but increased with the increase of solution concentration. Lower environmental temperature was unfavorable due to the nanofibers conglutination.
基金financially supported by the National Natural Science Foundation of China(Nos.21244006 and 50873013)
文摘A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis（hydroxyethyloxycarbonylamino） hexane （BHCH）, i.e. PrePBHCHs, were prepared through the self-transurethane polycondensation of BHCH. A poly（butylene adipate） prepolymer （PrePBA） with terminal HO-- groups was prepared and used as a polyester glycol. A series of TPEURs were prepared by the co-polycondensation of the PrePBHCHs with PrePBA at 170 ℃under a reduced pressure of 399 Pa. The TPEURs were characterized by gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile test. The TPEURs exhibited Mn up to 23300 g/mol, Mw up to 51100 g/mol, Tg ranging from -33.8 ℃ to -3.1 ℃, Tm from 94.3 ℃ to 111.9 ℃, initial decomposition temperature over 274.7℃, tensile strength up to18.8 MPa with a strain at break of 450.0%, and resilience up to 77.5%. TPU elastomers with good crystallization and mechanical properties were obtained through a non-isocyanate route.
基金This work was supported by the 3rd Jiangsu Overseas Research&Training Program for University Prominent Young&Middleaged Teachers and Presidentsthe College Students Innovation Project for the R&D of Novel Drugs[No.J1310032]And we would like to thank cell and molecular biology experiment platform of China Pharmaceutical University for the assistance with relevant test items.
文摘Gene-based therapeutics has emerged as a promising approach for human cancer therapy. Among a variety of non-viral vectors, polymer vectors are particularly attractive due to their safety and multivalent groups on their surface. This study focuses on guanidinylated O-carboxymethyl chitosan(GOCMCS) along with poly-β-amino ester(PBAE) for si RNA delivery. Binding efficiency of PBAE/si RNA/GOCMCS nanoparticles were characterized by gel electrophoresis. The si RNA-loaded nanoparticles were found to be stable in the presence of RNase A, serum and BALF respectively. Fine particle fraction(FPF) which was determined by a two-stage impinger(TSI) was 57.8% ± 2.6%. The particle size and zeta potential of the nanoparticles were 153.8 ± 12.54 nm and + 12.2 ± 4.94 m V. In vitro cell transfection studies were carried out with A549 cells. The cellular uptake was significantly increased. When the cells were incubated with si Survivin-loaded nanoparticles, it could induce 26.83% ± 0.59% apoptosis of A549 cells and the gene silencing level of survivin expression in A549 cells were 30.93% ± 2.27%. The results suggested that PBAE/GOCMCS nanoparticle was a very promising gene delivery carrier.
基金financially supported by the National Natural Science Foundation of China(Nos.51673190,51303174,51603204 and 51390484)
文摘A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/PDLA-CHOL） and poly（β-cyclodextrin） （PCD） with the molar ratios of CHOL/β-CD at 1：0.5, 1 ：l, and 1：2 in an aqueous environment. The hydrodynamic diameters of the micelles ranged from 84.1 nm to 107 nm depending on the molar ratio of CHOL/β-CD. It was shown that the micelle with the largest proportion of PCD possessed excellent abilities in drug release, cell internalization as well as proliferation inhibitory effect toward human A549 lung cancer cells. The results demonstrated that the stereocomplex and host-vip interactions-mediated PLA micelles exhibited great potential in sustained drug delivery.
基金financially supported by the National Key Research and Development Program of China (No. 2017YFB0309300)the National Natural Science Foundation of China (No. 51773218)+1 种基金Youth Innovation Promotion Association of CAS (No. 2018338)Ningbo Natural Science Foundation (No.2018A610109)
文摘Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols), polytetrahydrofuran diol (PTMG diols), 4,4'-dicyclohexylmethane diisocyanate (HMDI), and 1,4-butanediol (BDO) by a two-step reaction, and the morphology and property of the resultant TPU could be adjusted by varying the PLLA contents. The soft segment was composed of PLLA and PTMG diols. By controlling the percentage of PLLA in the soft segment, the glass transition temperature and mechanical properties of the polyurethanes could be regulated. Based on the FTIR spectrum, we found that two kinds of hydrogen bonding existed individually in soft matrix and hard domain. The hydrogen bonding in soft matrix was unstable, which could be destroyed during elongation. With in situ stretching WAXS and SAXS experiments, we found that the PLLA crystal was destroyed and the PLLA domain oriented along the stretch direction. Finally, we proposed a schematic model to illustrate the microstructures of these elastomers before and after stretch.
基金supported by the National Natural Science Foundation of China(No.81473173)
文摘Supramolecular structures have received growing attention and been widely applied in many fields.Herein, we synthesized hydrophobic β-cyclodextrin-contained poly(β-amino ester)(PAE-β-CD) and hydrophilic adamantyl-terminated poly(ethylene glycol)(PEG-AD) to form a supramolecular micelle via the host-vip interaction. The micelle displayed pH responsive structure change due to the transform of hydrophobic PAE core to hydrophilic form in weakly acid condition. After the anticancer drug curcumin(Cur) was loaded into the micelle, the drug release behavior of the Cur-loaded micelle was studied, and it turned out that the Cur-loaded supramolecular micelle could effectively unload the drug at pH 5.5.Furthermore, the antitumor efficiency of the Cur-loaded micelle was also examined both in vitro and in vivo, indicating considerable inhibition ratio as high as 62.14% against mouse sarcoma 180.
基金the financial support of National Key Technology R&D Program(No.2006BAD07A06)National"863"Program Project of China(No.2006AA100216)
文摘Amphiphilic hydroxyl functioned polyester（HFP） can be used as compatibilizers for blends of starch and resins.We developed a synthetic method for effective preparation of HFPs.Water was removed by high flow rate N_2 rather than high vacuum during polycondensation of sebacic acid with xylitol,sorbitol,or mannitol in the presence of dehydrative condensation catalyst and the product is with[η]of 27.2 mL/g,M_n of 1903,M_w of 167,693,T_g of -30.5℃,T_m of 44.0℃.Weight loss is 1.73%under 200℃. The integral distributions of molecular weight are 43.6 wt%and 63.8 wt%over 10,000 and 3000,respectively.The results indicated that higher molecular weight HFP was economically synthesized.
基金Sponsored by the Ministerial Level Advanced Research Foundation (120701BQ0126)
文摘Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.
文摘A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.
文摘Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis（imide-carboxylic acid）s （1）, such as 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole （lo） and 2-[3,5-bis（N- trimellitimidoyl）phenyl]benzothiazole （Is） and two bis（imide-ether-carboxylic acid）s （2）, such as 2-[3,5-bis（4- trimellitimidophenoxy）-phenyl]benzoxazole （2o）, and 2-[3,5-bis（4-trimellitimidophenoxy）-phenyl]benzothiazole （2s） with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and IH-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl·g^-1 Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.
文摘Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic acid catalyst. Some physicochemicalconstants of the compounds, such as density and refractive index, aredetermined. The complexes are hydrolabll in aqueous solutions andthe bond of Sb-S is weaker than that of Sb-o. The forming bondproperty of antimony tris (mercaptoacid ester ) has been elucidatedby measurement of infrared spectra in comparison with mercaptocarboxylic acid esters. The polyvinyl chloride resins containing antimony mercaptide heat stabilizers, do not darken at elevated temperatures and exhibit a high degree of stability. It is proposed that mercaptocarboxylic acid ester freeradicals can esterify PVC microradicals at carbon atoms with upaired electrons.
