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morphology and melting behavior of isothermally crystallized composites of short carbon fiber and poly(trimethyleneterephthalate)

Mingtao RUN, Hongzan SONG, Yanping HAO

《化学科学与工程前沿（英文）》 2009年第3卷第3期页码 255-264 doi: 10.1007/s11705-009-0008-9

摘要： The spherulites of the short carbon fiber(SCF)/poly (trimethylene terephthalate) (PTT) composites formed in limited space at designed temperatures, and their melting behaviors were studied by the polarized optical microscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively. The results suggest that SCF content, isothermal crystallization temperatures, and the film thicknesses influence the crystal morphology of the composites. The dimension of the spherulites is decreased with increasing SCF content, but whether banded or nonbanded spherulites will form in the composites is not dependent on SCF content. However, the crystal morphology of the composites depends strongly on the temperature. When the isothermal crystallization temperatures increase from 180°C to 230°C, the crystal morphology of SCF/PTT composites continuously changes in the following order: nonbanded → banded → nonbanded spherulites. Discontinuous circle lines form in the film when the film thickness increases from 30 to 60 μm. Basing on the SEM observation, it is found that these circle lines are cracks formed due to the constriction difference of the different parts of the spherulites. These cracks are formed when the film is cooled from the isothermal crystallization temperature to the room temperature at a slow cooling rate; while they will disappear gradually at different temperatures in the heating process. The crack will appear/disappear first around the center of the spherulite when the film was cooled/heated. The nontwisted or slightly twisted lamellas will reorganize to form highly twisted lamellas inducing apparent banded texture of the spherulites.

关键词： poly(trimethylene terephthalate) short carbon fiber banded spherulites crack

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Studies on the rheological, phase morphologic, thermal and mechanical properties of poly(trimethyleneterephthalate)/ethylene propylene diene monomer copolymer grafted with maleic anhydride/metallocene

RUN Mingtao, SONG Hongzan, WANG Yingjin, YAO Chenguang, GAO Jungang

《化学科学与工程前沿（英文）》 2007年第1卷第3期页码 238-245 doi: 10.1007/s11705-007-0043-3

摘要： The rheological, phase morphologic, thermal and mechanical properties of poly(trimethylene terephthalate)/metallocene polyethylene (PTT/mPE) blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride (EPDM--MAH) as compatibilizer are studied by means of a capillary rheometer, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). Results suggest that the compatibility of PTT/mPE blends is improved greatly after the addition of a compatibilizer. The radius of the dispersed phase in the system decreases greatly when the compatibilizer is added into the blend. When the amount of compatibilizer exceeds 8 wt-%, the size of dispersed phase becomes larger again. This phenomena could be attributed to the higher viscosity of the EPDM--MAH phase, which is dispersed more difficulty in the PTT phase of lower viscosity, thus the mixing efficiency is apparently decreased during the melt blending process. Moreover, the melt viscosity of the blend reaches the maximal value in case of 4 wt-% compatibilizer content, above which it would decrease again. This result is associated with the generation of more and bigger dispersed phase inside the bulk phase, thus the grafting efficiency at the interface is decreased, which could result in lower viscosity. The DSC results suggest that the mPE component shows a nucleating effect, and could increase the overall degree and rate of PTT crystallization, while the addition of a compatibilizer might slightly diminish these effects. In addition, the blend with 4 wt-% compatibilizer shows the best thermal stability. Furthermore, the Izod impact strength and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4 8 wt-% compatibilizer.

关键词： /metallocene polyethylene presence rheological phenomena trimethylene terephthalate

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Influence of recycled polyethylene terephthalate fibres on plastic shrinkage and mechanical properties

Necat ÖZAŞIK; Özgür EREN

《结构与土木工程前沿（英文）》 2022年第16卷第6期页码 792-802 doi: 10.1007/s11709-022-0849-6

摘要： Polyethylene terephthalate bottles production has drastically increased year after year due to high versatility of polyethylene terephthalate plastics and considerable consumption of beverages. In tandem with that increase, the major concern of society has been the improper disposal of this non-biodegradable material to the environment. To deal with this concern, recycled polyethylene terephthalate bottles were incorporated in concrete as fibre reinforcements in this study. The objective of this research is to evaluate the mechanical properties of recycled polyethylene terephthalate fibre reinforced concrete (RPFRC) in comparison with control concrete without fibres. polyethylene terephthalate fibres with three different diameters (0.45, 0.65, and 1.0 mm) and two lengths (20 and 30 mm) were added at various proportions (0.5%, 1.0%, 1.5% and 2.0%) by volume of concrete in order to determine the effect of fibres initially on compressive, flexural and splitting tensile strengths of concrete. The results revealed that none of the fibres have detrimental effects up to 1% volume fraction, however further addition caused slight reductions on mechanical properties in some conditions. Plastic shrinkage resistance and impact resistance tests were also performed according to related standards. Polyethylene terephthalate fibres were observed to have marked improvements on those properties. Such a good performance could be attributed primarily to the bridging effect of fibres.

关键词： recycled PET fibre-reinforced concrete mechanical properties plastic shrinkage impact energy

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Thermal decomposition of poly(ethylene terephthalate)/mesoporous molecular sieve composites

RUN Mingtao, ZHANG Dayu, WU Sizhu, WU Gang

《化学科学与工程前沿（英文）》 2007年第1卷第1期页码 50-54 doi: 10.1007/s11705-007-0010-z

摘要： The nonisothermal and isothermal degradation processes of poly (ethylene terephthalate)/mesoporous molecular sieve (PET/MMS) composites synthesized by in-situ polymerization were studied by using thermogravimetric analysis in nitrogen. The nonisothermal degradation of the composite is found to be the first-order reaction. An iso-conversional procedure developed by Ozawa is used to calculate the apparent activation energy (), which is an average value of about 260 kJ/mol with the weight conversion from 0% to 30%, and is higher than that of neat PET. Isothermal degradation results are confirmed with the nonisothermal process, in which PET/MMS showed higher thermal stability than neat PET. The polymer in mesoporous channels has more stability due to the protection of the inorganic pore-wall. These results indicate that mesoporous MMS in PET/MMS composites improve the stability of the polymer.

关键词： polymerization isothermal degradation conversion nonisothermal degradation activation

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通过蛋白质工程提高聚酯水解酶对PET 塑料的降解效率 Article

马渊, 姚明东, 李炳志, 丁明珠, 何博, 陈思, 周晓, 元英进

《工程（英文）》 2018年第4卷第6期页码 888-893 doi: 10.1016/j.eng.2018.09.007

摘要：

来自Ideonella sakaiensis 的聚对苯二甲酸乙二醇酯水解酶（PETase）在室温下具有很强的降解聚对苯二甲酸乙二醇酯（PET）的能力，因此被认为是解决聚酯塑料污染问题的潜在工具。在本研究中，基于PETase 和底物2PET 结合时的相互作用模型，分析了PETase 与底物2PET 之间的相互作用，从而对底物结合沟壑周围的六个关键残基进行改造。为了更加快速地筛选突变体酶的活性，本研究利用无细胞蛋白表达体系对设计的PETase 突变体进行高通量的表达和验证。最终发现三种突变体（R61A、L88F 和I179F）的酶活性相比野生型分别提高了1.4 倍、2.1 倍和2.5 倍。其中，I179F突变体的酶活性最高，降解效率为22.5 mg·μmol^–1·d^–1。因此，本研究通过蛋白质工程对PETase 的关键疏水位点进行设计和改造，获得了降解效果提高的酶突变体，并进一步证实了其生物降解塑料的潜力。

关键词：聚酯酶 PET降解无细胞蛋白质合成聚酯 PET酶

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废弃塑料和废弃胎胶的增值综合回收及其在路面工程中的可持续性实践 Article

徐雄, 冷真, 兰景婷, 王伟, 虞将苗, 白雅伟, Anand Sreerama, 胡静

《工程（英文）》 2021年第7卷第6期页码 857-867 doi: 10.1016/j.eng.2020.08.020

摘要：

废弃聚对苯二甲酸乙二醇酯（PET）饮料瓶等废弃塑料和废弃橡胶轮胎为主要的城市固体废弃物，如不进行合理回收，可能会引发各种环境问题。本研究对这两种废弃物经综合处理后用作沥青路面性能增强改性剂的可行性进行了分析。通过采用三乙烯四胺（TETA）和乙醇胺（EA）对废弃PET进行处理，分析废弃PET经处理获得添加剂的回收机理，同时表征这两种添加剂在改性橡胶沥青过程中的表现。鉴于此，本文采用红外光谱和热分析法对PET添加剂（PET-TETA和PET-EA）进行了研究，进而通过红外光谱、黏度、动态剪切流变和多次应力蠕变恢复等试验对这两种PET添加剂改性的橡胶沥青进行了分析。结果表明：通过化学处理后，废弃PET可被增值回收为功能性添加剂，以提高橡胶沥青的整体性能。本研究所开发的回收方法不仅有助于缓解废弃PET塑料和废弃轮胎的填埋问题，而且可将这些废弃物转变为耐久性路面建设的高附加值新材料。

关键词：废弃PET 废弃轮胎橡胶橡胶沥青回收机理可持续性