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Studies on the Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate): I. Catalytic Activity of Metal Acetate in Transesterification of Ethylene Carbonate with Dimethyl Terephthalate 被引量:4
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作者 Dan ZHANG Shu Yong JLA +3 位作者 Yue WANG Jie YAO Yi ZENG Gong Ying WANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第12期1607-1610,共4页
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
关键词 Metal acetate ethylene carbonate dimethyl terephthalate dimethyl Carbonate polyethylene terephthalate).
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Characterization and Properties of Electroless Nickel Plated Poly (ethylene terephthalate) Nonwoven Fabric Enhanced by Dielectric Barrier Discharge Plasma Pretreatment 被引量:4
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作者 耿亚敏 卢灿辉 +1 位作者 梁梅 张伟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第6期715-722,共8页
In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge (DBD) plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of po... In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge (DBD) plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly (ethylene terephthalate) (PET) nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity (WA), aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference (EMI)- shielding effectiveness (SE) were studied. The liquid absorptive capacity (WA) increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction (XRD) measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value (38.2 dB to 37.3 dB) in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties. 展开更多
关键词 dielectric barrier discharge plasma electroless nickel plating polyethylene terephthalate) (PET) surface properties
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In-situ Polymerization-modification Process and Foaming of Poly(ethylene terephthalate) 被引量:4
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作者 仲华 奚桢浩 +1 位作者 刘涛 赵玲 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第12期1410-1418,共9页
Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support... Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support and keep cells.An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride(PMDA)or pentaerythritol(PENTA)as modifying monomers to obtain PETs with high melt strength.The influence of amounts of modifying monomers on the properties of modified PET was investigated.It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength.With increasing the amount of the modifying monomer,the melt strength of the modified PET increased.But when the amount of PENTA reached 0.35%or PMDA reached 0.9%,crosslinking phenomenon was observed in the modified PET.Supercritical carbon dioxide(ScCO2)was employed as physical foaming agent to evaluate the foaming ability of modified PETs.The modified PETs had good foaming properties at 14 MPa of CO2pressure with foaming temperature ranging from 265°C to 280°C.SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures,with cell diameter ranging from 35μm to 49μm for PENTA modified PETs and38μm to 57μm for PMDA modified ones.Correspondingly,the cell density had a range of 3.5×107cells·cm 3to 7×106cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter. 展开更多
关键词 polyethylene terephthalate) in-situ polymerization-modification supercritical carbon dioxide molten-state foaming
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Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate) Using Alkali Metals as Catalysts 被引量:2
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作者 张丹 王庆印 +3 位作者 姚洁 王越 曾毅 王公应 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第5期772-774,共3页
Dimethyl carbonate (DMC) and poly(ethylene terephthalate) was simultaneously synthesized by the transesterification of ethylene carbonate (EC) with dimethyl terephthalate (DMT) in this paper. This reaction is ... Dimethyl carbonate (DMC) and poly(ethylene terephthalate) was simultaneously synthesized by the transesterification of ethylene carbonate (EC) with dimethyl terephthalate (DMT) in this paper. This reaction is an excellent green chemical process without poisonous substance. Various alkali metals were used as the catalysts. The results showed alkali metals had catalytic activity in a certain extent. The effect of reaction condition was also studied. When the reaction was carded out under the following conditions: the reaction temperature 250℃, molar ratio of EC to DMT 3 : 1, reaction time 3h, and catalyst amount 0.004 (molar ratio to DMT), the yield of DMC was 68.9%. 展开更多
关键词 ethylene carbonate dimethyl terephthalate dimethyl carbonate poly ethylene terephthalate) TRANSESTERIFICATION CATALYST
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Flame Retardancy and Thermal Property of Poly (ethylene terephthalate)/Modified Cyclotriphosphazene Composites 被引量:2
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作者 汪娇宁 苏兴勇 +4 位作者 雅兰 陈雯婷 陈飞 陈樱 毛志平 《Journal of Donghua University(English Edition)》 EI CAS 2015年第3期384-389,共6页
In this study,hexachlorocyclotriphosphazene( HCCP)modified by boric acid and 3-aminopropyltriethoxysilane( KH-550)in solvent diglyme( FR-HCCP) was used as the flame retardant for poly( ethylene terephthalate)( PET) co... In this study,hexachlorocyclotriphosphazene( HCCP)modified by boric acid and 3-aminopropyltriethoxysilane( KH-550)in solvent diglyme( FR-HCCP) was used as the flame retardant for poly( ethylene terephthalate)( PET) composites. The flame retardancy and thermal property of pure PET and flame-retarded PET composites were mainly investigated. The flame retardancy was investigated by limited oxygen index( LOI) and UL-94 vertical burning test. The results showed that the composites could achieved an increased UL-94 V-0 rating and LOI value 30. 2, when the content of FR-HCCP was just 1%. The pyrolysis-gas chromatography-mass spectrometry( Py-GC / MS) study demonstrated that introducing FR-HCCP into PET would prevent the polymer pyrolysis during heating. TGA analysis showed that the addition of FR-HCCP could improve the char formation of the system. Roman spectra showed the order degree of residue was increasing by adding the additive. The morphology and the chemical structure of the charred residue were detected by SEMand FTIR,respectively. Results demonstrated that a good barrier was formed by the char of the composite,which protected the inside of the composite during burning. 展开更多
关键词 boron-silicon polyPHOSPHAZENE flame retardant poly(ethylene terephthalate)(PET)
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FOURIER TRANSFORM INFRARED STUDIES OF POLY (ETHYLENE TEREPHTHALATE) FILM IN THE GLASS TRANSITION REGION 被引量:1
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作者 钱人元 沈德言 李惠鸣 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1989年第2期150-158,共9页
Three specimens from a solution-cast poly (ethylene terephthalate) (PET) film, one being liquid-N_2 quenched from 92℃(Q), one being slowly cooled from 92℃(SC) and one being quenched and sub-T_g annealed at 67℃(AN),... Three specimens from a solution-cast poly (ethylene terephthalate) (PET) film, one being liquid-N_2 quenched from 92℃(Q), one being slowly cooled from 92℃(SC) and one being quenched and sub-T_g annealed at 67℃(AN), have been studied by specimen difference spectra Q-SC and AN-Q and temperature difference spectra T-70 and T_2-T_1 for every 2℃ steps on heating to 90℃ at 2℃ /min. SC and AN showed more gauche conformers than Q. That means that the PET chain has more trans conformers at higher temperatures and some of these are frozen during quenching through T_g. A band at 1340 cm^(-1) has been found to be complex containing overlapping bands reflecting trans in crystalline regions and trans in amorphous regions. The temperature difference spectra on heating through T_g showed that the spectral changes in Q are gradual while a rather abrupt change occurs in AN at 80—82℃ for the bands at 1340, 1042 and 1020 cm^(-1). No new conformational structure or new vibrational mode is involved. A kind of locking mechanism is suggested which hinders the molecular vibrational changes in AN below T_g until a sudden release occurs at T_g. These locking sites can be nothing else than sites of tighter local packing of chain segments. Consequently it is believed that inter-chain van der Waals attraction energy plays a dominating role in the volume relaxation and sub-T_g annealing of quenched amorphous polymers. 展开更多
关键词 Infrared spectra Glass transition poly ( ethylene terephthalate ) CONFORMATION Enthalpy relaxation.
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High-efficiency acetaldehyde removal during solid-state polycondensation of poly(ethylene terephthalate) assisted by supercritical carbon dioxide 被引量:2
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作者 Zhenhao Xi Tian Liu +3 位作者 Wei Si Fenglei Bi Zhimei Xu Ling Zhao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第6期1285-1291,共7页
The concentration of acetaldehyde(AA) is the main quality index of poly(ethylene terephthalate)(PET) used in food and drink packaging.A new method for AA removal has been developed by using supercritical carbon dioxid... The concentration of acetaldehyde(AA) is the main quality index of poly(ethylene terephthalate)(PET) used in food and drink packaging.A new method for AA removal has been developed by using supercritical carbon dioxide(sc CO2) during the solid-state polycondensation of PET.The influence factors of AA removal including the temperature,pressure,reaction time and the size of pre-polymer particles are systematically studied in this work.The results indicate that it is a highly efficient way to obtain high molecular weight PET with relative low concentration of AA.Correspondingly,the polymerization degree of PET could increase from 27.9 to 85.6 while the concentration of AA reduces from 0.229 × 10^(-6) to 0.055 × 10^(-6) under the optimal operation conditions of 230 °C,8 MPa and size of 0.30–0.45 mm.Thermodynamic performance tests show the increasing extent of PET crystallinity due to the fact that the plasticization of sc CO_2 is not obvious with extended reaction time,therefore the increasing crystallinity has no significant influence on AA removal.SEM observations reveal that the effects of sc CO_(2-) induced plasticization and swelling on PET increase significantly with the decrease of prepolymer size,and the surface of PET becomes more loose and porous in favor of the AA removal. 展开更多
关键词 Supercritical CO2 Solid-state polycondensation polyethylene terephthalate) Removal of acetaldehyde
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Isothermal Crystallization Behavior of Poly (ethylene terephthalate)/Carbon Black Masterbatch 被引量:1
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作者 姜兆辉 金剑 +1 位作者 肖长发 李鑫 《Journal of Donghua University(English Edition)》 EI CAS 2012年第2期123-128,共6页
Poly(ethylene terephthalate) (PET)/carbon black (CB) masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron micros... Poly(ethylene terephthalate) (PET)/carbon black (CB) masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron microscope (TEM). The Avrami and Hoffman-Lauritzen secondary nucleation theories were employed to analyze the effect of high CB content on crystallization kinetics of PET, providing theoretical support for the development of masterbatch with high content of functional components. The Avrami exponents,average values of n,for PET and PET/CB masterbatch are both greater than 3, which indicates three-dimensional growth of crystals. In addition,no significant evidence for regime transition of PET is found applying Hoffman-Lauritzen secondary nucleation theory,though such observations have been reported previously in the literature. Furthermore,appropriate U* value for PET is determined to be 12 800 J/mol. For PET/CB masterbatch,a transition from regime I to regime II around 225℃ is observed with appropriate U* value (12 800 J/mol) . This phenomenon is consistent with a transition point in plot of G versus Tc . The fold surface free energy σe (100. 3 mJ/m 2) of PET is much greater than that of PET/CB masterbatch (48. 3 mJ/m 2) ,which indicates heterogeneous nucleation effect of CB particles. 展开更多
关键词 thermal properties poly(ethylene terephthalate) (PET) carbon black (CB) MASTERBATCH crystallization kinetics
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Enzymatic Modification of Poly (ethylene terephthalate) Fiber with Lipase from Aspergillus oryzae 被引量:1
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作者 王小花 陆大年 +1 位作者 邵志宇 洪枫 《Journal of Donghua University(English Edition)》 EI CAS 2007年第3期357-361,共5页
Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly (ethylene terephthalate) fibers and a possible hydrolytic product mono (2-hydroxyethyl) terephthalate was released. After ... Lipase preparation from Aspergillus oryzae could act on ester bonds on the surface of poly (ethylene terephthalate) fibers and a possible hydrolytic product mono (2-hydroxyethyl) terephthalate was released. After the iipase modification, there were more carboxyi groups on the treated poly (ethylene terephthalate) fabric surface that resulted in binding with more cationic dyes. Increased hydrophilicity and antistatic ability of poly (ethylene terephthalate) samples were found based on moisture regain, water contact angle and static half decay time. 展开更多
关键词 Aspergillus oryzae polyethylene terephthalate)fiber enzymatic modification LIPASE antistatic ability HYDROPHILICITY
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Synthesis and characterization of copolymers of poly(m-xylylene adipamide) and poly(ethylene terephthalate) oligomers by melt copolycondensation 被引量:2
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作者 Fenglei Bi Jianqiang Shao +2 位作者 Zhenhao Xi Ling Zhao Di Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第9期1290-1297,共8页
Poly(m-xylylene adipamide)/poly(ethylene terephthalate)(MXD6/PET) copolymers are synthesized by melt copolycondensation with 1–5 wt% low molecular weight PET oligomers into the MXD6 oligomers at 260 ℃.FR-IR an... Poly(m-xylylene adipamide)/poly(ethylene terephthalate)(MXD6/PET) copolymers are synthesized by melt copolycondensation with 1–5 wt% low molecular weight PET oligomers into the MXD6 oligomers at 260 ℃.FR-IR and1 H NMR analysis results indicate that the interchange reaction has occurred between MXD6 oligomers and PET oligomers. The thermal behavior of copolymers shows that the melting temperature of MXD6/PET copolymers decreases with the increasing of amount of PET oligomers, while the crystallization temperature accordingly increases. And the equilibrium temperature Tm0 is evaluated to be 251.8 ℃ for the copolymers with5 wt% PET oligomer adding, which is very close to that of neat MXD6. The tensile and impact strength of MXD6/PET copolymers are significantly improved than that of pure MXD6 by mechanical properties test, and the microfibril structure in the impact fracture sample's surface reveals the feature of ductile fracture. 展开更多
关键词 polymerization poly(m-xylylene adipamide) polyethylene terephthalate) Crystallization Mechanical properties
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TRANSESTERIFICATION OF POLY(ETHYLENE TEREPHTHALATE) WITH POLY(ε-CAPROLACTONE)
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作者 Zheng-ping Zhang Xiao-lie Luo +1 位作者 Yu-chen Lu De-zhu Ma Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2000年第5期405-412,共8页
Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and ph... Transesterification of poly(ethylene terephthalate) (PET) with poly(ε-caprolactone) (PCL) was investigated bymeans of NMR spectroscopy, extraction experiments, differential scanning calorimetry (DSC) and phase contrast microscopy(PCM). The;H-NMR results show that transesterification takes place in the melt blends and leads to the formation of thePET-PCL copolyester with a chemical structure similar to ethylene terephthalate-ε-caprolactonc copolycster (TCL)synthesized directly from monomers. However, even in the blend that has been transesterified for 8 h, the random PET-PCLcopolyester, PET-PCL copolyester with long PET or long PCL segments and the unreacted PET and PCL homopolymersmay coexist. Due to the low mobility of PET and PCL chains and the high viscosity of the two macromolecules, thetransesterification proceeds with difficulty. Furthermore, PET is incompatible with PCL, the transesterification can onlyoccur at the interface or in the interfacial region between two phases, and finally the reaction can only reach a localequilibrium. These results indicate that in fact the transesterification in the melt blend between two incompatiblehomopolymers could not lead to the formation of completely random or typical block copolyesters. 展开更多
关键词 TRANSESTERIFICATION poly(ethylene terephthalate) poly(ε-caprolactone) CRYSTALLIZATION Phase structure
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EFFECT 0F INTERFACIAL ADHESION ON CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE)/GLASS BEAD COMPOSITES
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作者 欧玉春 于中振 +2 位作者 朱进 李革 祝善广 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1996年第2期172-182,共11页
The interfacial adhesion between poly (ethylene terephthalate) (PET) and glass beadwas investigated by scanning electron microscope and parallel-plate rheometer. Effect ofinterfacial adhesion on the crystallization an... The interfacial adhesion between poly (ethylene terephthalate) (PET) and glass beadwas investigated by scanning electron microscope and parallel-plate rheometer. Effect ofinterfacial adhesion on the crystallization and mechenical properties of PET/glass beadcomposites was also studied by differential scanning calorimeter and mechanical testers.The results obtained indicate that the glass bead has a heterogeneous nucleation effecton the PET crystallization. Although better interfacial adhesion is advantageous to theincrease of the tensile strength of the composite, yet it is unfavorable to the crystallizationof PET. It should be pointed out that the crystallization rate of filled PET is always higherthan that of pure PET, regardless of the state of interfacial adhesion. 展开更多
关键词 poly(ethylene terephthalate) Glass bead INTERFACE CRYSTALLIZATION Mechanical properties
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CRYSTALLIZATION BEHAVIOR OF PURE AND ADDITIVE-CONTAINING POLY (ETHYLENE TEREPHTHALATE)
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作者 卜海山 金毅敏 +1 位作者 胡家伦 于同隐 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1992年第3期242-249,共8页
The isothermal crystallization of poly (ethylene terephthalate ) (PET),which is free of catalyst, stabilizer, oligomer and diethylene glycol (DEG), was studied by DSC. The crystallization behaviour of pure PET is diff... The isothermal crystallization of poly (ethylene terephthalate ) (PET),which is free of catalyst, stabilizer, oligomer and diethylene glycol (DEG), was studied by DSC. The crystallization behaviour of pure PET is different from commercial PET and a reasonable explanation is presented. The influences of catalyst, stabilizer, oligomer and DEG on the crystallization of pure PET were examined. It is shown that catalyst (Manganese acetate)and stabilizer (Triphenyl phosphite) result in an increase of the crystallization rate of PET; on the contrary, DEG and oligomer (cyclotetramer) result in a reduction of the crystallization rate. When catalyst and stabilizer coexist together, both of them promote the crystallization at lower temperature ,only a smaller effect was found at higher temperature, it is evident that metal phosphite is formed between the catalyst and stabilizer at higher temperature. 展开更多
关键词 poly (ethylene terephthalate) ADDITIVE Isothermal crystallization NUCLEATION Nucleating agent
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RECOVERY OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)FILM UNIAXIALLY DRAWN JUST BELOW THE GLASS TRANSITION TEMPERATURE
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作者 Nan-jian Sun Juan Yang +1 位作者 De-yan Shen Ren-yuan Qian Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2000年第1期69-75,共7页
Isothermal recovery in the macroscopic length of homogeneously deformed specimens of amorphous poly(ethylene terephthalate) (PET) film sample uniaxially drawn at 69 degrees C to the draw ratios lambda(0) = 1.26-2.20 w... Isothermal recovery in the macroscopic length of homogeneously deformed specimens of amorphous poly(ethylene terephthalate) (PET) film sample uniaxially drawn at 69 degrees C to the draw ratios lambda(0) = 1.26-2.20 were studied at temperatures around the glass transition temperature (T-g = 73 degrees C). Experimental results indicate that the length recovery look place in two distinct steps: a fast first step (fast relaxation) followed by a slow second step (slow relaxation). The relaxation processes were accompanied by the reversion of trans-conformers (1340 cm(-1)) to gauche, and the dichroic function of the 1340 cm(-1) band characterizing the segmental orientation along the chain direction decreased to a very low value at the end of the fast relaxation. This fact led us to assign the fast relaxation as the segmental orientation while the slow relaxation as relaxation of the global chain orientation. It was found that the slow relaxation follows a single exponential function, with relaxation times strongly dependent on the temperature resembling the glass transition process. The fast relaxation does not follow a single exponential decay, presumably a distribution of relaxation times is involved. 展开更多
关键词 poly(ethylene terephthalate) uniaxial drawing RECOVERY orientation
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Surface Characterization and in Vitro Blood Compatibility of Poly (Ethylene Terephthalate) Immobilized with Hirudin
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作者 李方 王进 +1 位作者 孙鸿 黄楠 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第2期235-239,共5页
Poly (ethylene terephthalate)(dacron, PET) films were exposed under argon plasma glow discharge with different glows and induced polymerization of acrylic acid(AA) in order to in- troduce carboxylic acid group o... Poly (ethylene terephthalate)(dacron, PET) films were exposed under argon plasma glow discharge with different glows and induced polymerization of acrylic acid(AA) in order to in- troduce carboxylic acid group onto PET (PET-AA) assisted by ultraviolet radiation(UV). Hirudin- immobilized PET (PET-HRD) films were prepared by the grafting of PET-AA, followed by chem- ical reaction with hirudin. The surface structure of the treated PET was determined by X-ray photoelectron spectroscopy (XPS). The wettability, surface free energy, and interface free energy of the films were investigated by contact angle measurement. The blood compatibility of the films was assessed by platelet-adhesion test and fibrinogen conformational change measurements to eval- uate the viability of the materials in biomedical engineering. Measurement by scanning electron microscopy (SEM) revealed that the amounts of adhered, aggregated and morphologically changed platelets were reduced on the hirudin-immobilized PET films. Enzyme-linked-immunoassay mea- surements that disclosed fibrinogen conformational changes showed results consistent with the platelets' behavior. 展开更多
关键词 HIRUDIN blood compatibility poly ethylene terephthalate) interface energy surface energy
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In vitro Blood Compatibility of Polyethylene Terephthalate with Covalently Bounded Hirudin on Surface
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作者 李方 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第5期950-954,共5页
Polyethylene terephthalate (PET,Dacron) was modified by surface immobilization of hirudin with glutaraldehyde(GA) as coupling reagent to improve the blood compatibility.Hirudin-immobilized PETs were characterized ... Polyethylene terephthalate (PET,Dacron) was modified by surface immobilization of hirudin with glutaraldehyde(GA) as coupling reagent to improve the blood compatibility.Hirudin-immobilized PETs were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements.The blood compatibility of the PETs was evaluated by platelet adhesion evaluation and fibrinogen conformational change measurements in vitro.The results showed the decrease of platelet adhesion and activation on hirudin-immobilized PET with increasing of glutaraldehyde concentration.Fibrinogen experiment showed that fibrinogen adherence and conformational changes of PET-HRD were less than those of untreated PET,which made the materials difficult to form thrombus.The proper reason of blood compatibility improvement was low interface tension between hirudin-immobilized PETs and blood,as well as blood proteins,and low ratio of dispersive/polar component of the surface energy(γsd/γsp) and high hydrophilicity. 展开更多
关键词 HIRUDIN blood compatibility polyethylene terephthalate) (PET) interface tension surface energy
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LARGELY IMPROVED TENSILE PROPERTIES OF POLY(ETHYLENE TEREPHTHALATE) BY USING GLYCERIN
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作者 张琴 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第3期319-324,共6页
In order to improve the tensile properties of poly(ethylene terephthalate)(PET), we used the direct esterification method to synthesize PET in a home-made facility, and a certain amount of ethylene glycol (EG), ... In order to improve the tensile properties of poly(ethylene terephthalate)(PET), we used the direct esterification method to synthesize PET in a home-made facility, and a certain amount of ethylene glycol (EG), one of the two starting monomers, was substituted by glycerin (GE). Four PETs with different GE contents were prepared to investigate the effect of GE on the crystallization and tensile properties of the prepared copolyester. The results showed largely improved tensile properties and increased crystallization temperature due to the possible crosslinking structure in PET by using a small amount of GE. 展开更多
关键词 polyethylene terephthalate) Tensile strength GLYCERIN
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Non-isothermal Crystallization Kinetics of Modified Poly(ethylene terephthalate) with Ultraviolet Protection
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作者 滕翠青 《Journal of Donghua University(English Edition)》 EI CAS 2002年第1期56-59,共4页
The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of th... The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer under non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system. 展开更多
关键词 poly(ethylene terephthalate) NON-ISOTHERMAL crystallization kinetics ultraviolet-resistant fibers.
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SYNTHESIS OF POLY(ETHYLENE TEREPHTHALATE)-POLYCAPROLACTONE BLOCK COPOLYMER BY DIRECT COPOLYMERIZATION
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作者 Shen-guo Wang Kai Tang Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第3期231-235,共5页
Po ly(ethylene terephthalate)-polycaprolactone block copolymer (PCL-b-PET) is a polyester with improved biodegradability. In the present paper, a new direct copolymerization method of epsilon-caprolactone (epsilon-CL)... Po ly(ethylene terephthalate)-polycaprolactone block copolymer (PCL-b-PET) is a polyester with improved biodegradability. In the present paper, a new direct copolymerization method of epsilon-caprolactone (epsilon-CL) and bishydroxyethylene terephthalate (BHET) in the presence of Ti(OBu)(4) was proposed for the synthesis of PCL-b-PET. The PCL-b-PET copolymer was characterized by IR, GPC and H-1-NMR techniques, and the effects of synthesis conditions, such as temperature, reaction time and concentration of catalyst on the copolymerization were discussed. 展开更多
关键词 poly(ethylene terephthalate)-polycaprolactone block copolymer direct copolymerization biodegradable polymer
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KINETICS OF NON-ISOTHERMAL CRYSTALLIZATION OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY POLY (ETHYLENE GLYCOL)
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作者 张志英 吴世臻 +1 位作者 杜莹华 曹振林 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1991年第4期318-325,共8页
The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship... The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m^0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed. 展开更多
关键词 poly (ethylene glycol)/poly (ethylene terephthalate) copolyester Non-isothermal crystallization Crystallization kinetics Differential scanning calorimetry (DSC)
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