【摘 要】
：
Biodegradable aliphatic/aromatic copolyesters, poly(butylene terephthalate-co-lactate) (PBTL) were prepared via direct melt polycondensation of terephthalic aci
【机 构】
：
Institute of Polymer Composites, Lab of Polymer Materials and Engineering
论文部分内容阅读
Biodegradable aliphatic/aromatic copolyesters, poly(butylene terephthalate-co-lactate) (PBTL) were prepared via direct melt polycondensation of terephthalic acid (TPA), 1,4-butanediol (BDO) and poly(L-lactic acid) oligomer (OLLA). The effects of polymerization time and temperature, as well as aliphatic/aromatic moiety ratio on the physical and thermal properties were investigated. The largest molecular weight of the copolyesters was up to 64100 with molecular weight distribution index of 2.09 when the polycondensation was carried out at 230℃ for 6 h. DSC, XRD, DMA and TGA analysis clearly indicated that the degree of crystallinity, glass-transition temperature, melting point, decomposition temperature, tensile strength, elongation and Young's modulus were influenced by the ratio between TPA and OLLA in the final copolyesters. Hydrolytic degradation results demonstrated that the incorporation of biodegradable lactate moieties into the aromatic polyester could efficiently improve hydrolytic degradability of the copolymer even though it still had many aromatic units in the main chains.
其他文献
阅读,作为内潜性的观念活动,学生在理解的时候,不是按读物上的符合规范的语言来理解的,而是用读者自身的符合思维习惯的内潜性的“语言”来理解的。内潜性的“语言”往往是高
Background Ⅲb-T_4 non-small cell lung cancer (NSCLC) is commonly considered a contraindication to surgery, although chemo-radiotherapy also achieves a poor sur
生物工程专业有多门专业基础课需要运用AutoCAD软件来进行实际的制图操作，AutoCAD的课程教学将直接影响到学生们对生物工程专业课程体系的学习质量。根据这些特点，需要在授课过
Poly(α-hydroxy octanoic acid) was first used as an additive for the preparation of electrospun ultra-fine fibers of poly(ethylene glycol)-b-poly(L-lactide) (PE
蜜蜂是人类饲养的社会性昆虫，它同其他动物一样，也会发生各种疾病。比如由蜂球囊菌感染引发的白垩病是目前养蜂最常见而且最普遍的疾病。该病菌潜伏期长、较顽固，即使治愈，一旦条
Anterior urethral strictures, where the length is more than 2 cm, are best treated by substitution urethroplasy with either preputial/penile skin flaps or free
Walled-off pancreatic necrosis (WOPN), formerly known as pancreatic abscess is a late complication of acute pancreatitis. It can be lethal, even though it is ra
AIM: To evaluate the development of diagnostic tools, indications for surgery and treatment modalities concerning diverticular disease (DD) in the Netherlands.
在德国纽伦堡艺术陈列馆里，珍藏着一幅名为《手》的素描画。一双正在祈祷的手，两掌相合，伸向天空。画面上的手并不如想象中那样白皙稚嫩、纤巧漂亮，反倒是皱纹满布、青筋暴起、瘤
宛如中国革命艰难而曲折的发展道路一样，我们的教育事业在探索中不断前行，终于将脚步落到了一个富有希望的基点上。着眼于未来，着眼于世界的发展需要，以新的理念为指导的课程改革