大豆蛋白复合材料的研究进展

对国外近十年来大豆蛋白与聚磷酸盐、玻璃纤维、麦草、苎麻、淀粉、聚乙烯醇、聚己内酯、聚羟基酯醚等的复合材料的制备方法，材料性能特点进行了总结。分析了大豆蛋白复合材料作为可生物降解材料替代某些通用塑料和工程塑料的应用前景，并提出了近期的发展方向。     

苎麻织物增强PLA-PCL复合材料的制备及其性能研究

采用原位聚合法制备了聚乳酸-聚己内酯（PLA—PCL）／苎麻复合材料。研究了硅烷偶联剂（KH550）预处理、纤维含量以及成型工艺对PLA—PCL／苎麻复合材料力学性能的影响。结果表明,经KH550处理后,复合材料的力学性能有不同程度的提高,拉伸强度由49．84MPa到68．95MPa,弯曲强度由34．84MPa提高到65．06MPa,冲击强度由30．13J／m^2提高到53．54J／m^2。在纤维的质量分数为45％,成型温度为170℃,复合材料具有最优性能;采用原位聚合法制备PLA-PCL／苎麻复合材料,复合材料的界面性能较好。     

明胶蛋白质基可降解塑料薄膜的研究

将分散均匀的明胶、无机填料和复合增塑剂的水溶液用流延法成膜,制得了蛋白质基可降解塑料薄膜。用拉伸实验、吸水实验和降解实验表征了蛋白质基可降解塑料薄膜的性能。结果表明:薄膜的拉伸强度和断裂伸长率随增塑剂用量的增加而增加,随无机填料用量的增加而减小;薄膜的耐水性随增塑剂用量的增加而变差;蛋白质基塑料薄膜具有生物降解性,在20天内降解度为10%左右。     

我国生物基及可降解塑料发展研究

在国家环保压力及国际国内双循环背景下,由于生物基及可降解塑料的优良特性,采用生物基塑料及可降解塑料制品是当前解决塑料污染问题的办法之一.目前我国生物基及可降解塑料存在回收体系不健全、与现有的循环再利用体系不兼容及生产成本较高的问题,需要从加强监管、正面引导及加快回收再利用技术的研发着手,加快我国生物基及可降解塑料的使用...     

LLDPE/淀粉共混体系的生物降解特性

介绍生物降解性检测的土埋法和微生物生长法,研究了ＬＬＤＰＥ／ 淀粉生物降解塑料的生物降解性能。结果表明,当淀粉含量比２０ ％ ～４０ ％ 时,材料降解十分明显,加入玉米油,当加入量为淀粉含量的２ ％ 时,可使伸长率降低明显加快。由微生物生长法可证实ＬＬＤＰＥ／ 淀粉不但可以直接作为碳源供微生物利用,并能为微生物的次生代谢物葡萄糖所腐蚀。     

60Co-γ射线改性淀粉制备可降解材料及热压工艺的研究

研究了60Co-γ射线对玉米淀粉进行的辐射改性处理.研究了辐照剂量、热压温度、热压时间、热压压力对所得材料的力学性能、透光率、吸水率的影响规律,制备出较好的可生物降解材料.结果表明:选用辐照剂量30kGy、热压温度125℃、热压时间12 min、热压压力12 MPa,制备材料的断裂伸长率153.9％,拉伸强度4.28 MPa,透光率48.6％,吸水率61.26％.     

Efficient Gene Transfection into Mammalian Cells Mediated by Cross-linked Polyethylenimine

25 kDa branched polyethylenimine (PEI) has successfully been used for in vitro and in vivo gene delivery approaches, but it is cytotoxic. Smaller PEIs are usually non-cytotoxic but less efficient. In order to enhance the gene delivery efficiency and minimize cytotoxicity of PEI, we explored to synthesize cross-linked PEIs with degradable bonds by reacting amines of small branched 2000 Da PEI with small diacrylate (1,4-butanediol diacrylate or ethyleneglycol dimethacrylate) for 2–6 hours. The efficiency of the cross-linked PEIs during in vitro delivering plasmid containing enhanced green fluorescent protein (EGFP) gene reporter and their cytotoxicity were assessed in melanoma B16F10 cell and other cell lines. In vivo gene delivery efficiency was evaluated by direct injection delivery of the EGFP plasmid/cross-linked PEI complexes into mice and by estimating the EGFP expression in animal muscles. Compared to commercially available 25-kDa branched PEI, the cross-linked PEIs reported here could mediate more efficient expression of reporter gene than the 25-kDa PEI control, 19-fold more efficiently in B16F10 cells, 17-fold in 293T cells, 2.3-fold in 3T3 cells, and they exhibited essentially nontoxic at their optimized condition for gene delivery. Furthermore the transfection activity of polyplexs was preserved in the presence of serum proteins. The muscle transfected with the cross-linked PEI prepared here exhibited normal morphology and excellent gene expression. The cross-linked PEIs reported here were evidently more efficient than the commercial 25-kD PEI control and had less cytotoxicity in gene delivery in vitro and in vivo.     

PHB在生产可降解塑料方面的应用及其微生物累积的研究进展

着重介绍了聚β-羟基丁酸（PHB）的一些性质、用途以及在生产可降解塑料方面的应用情况，同时也介绍了微生物累积PHB的情况，并对微生物累积PHB以及PHB的研究发展提出了一点建议。     

Degradable blends of semi-crystalline and amorphous branched poly(caprolactone): Effect of microstructure on blend properties

The blend properties of semi-crystalline and amorphous polycaprolactone (PCL) are shown here for the first time. The amorphous polycaprolactone (PCLB) having 20% branches was made by radical-ring-opening polymerization of 2-methylene-1,3-dioxepane. The presence of branches led to non-crystallinity in PCLB. The blends were made in solution in entire concentration range and showed some very interesting properties in terms of synergistic effect on crystallinity leading to the increased crystallinity of PCL and induced crystallinity of amorphous PCLB, minima in the % elongation and maxima in spherulite size depending upon the ratio of amorphous and crystalline part. There was a drastic increase in the compostability as compared to pure PCL on adding even low % of amorphous PCLB in the blends without affecting the thermal stability. The addition of PCLB also affected the transparency and it increased exponentially from about 8% at 650 nm for PCL to about 45% for a blend with composition PCL:PCLB 30:70.     

Thermo-Mechanical Properties of Semi-Degradable Poly(β-amino ester)-co-Methyl Methacrylate Networks under Simulated Physiological Conditions

Poly(β-amino ester) networks are being explored for biomedical applications, but they may lack the mechanical properties necessary for long term implantation. The objective of this study is to evaluate the effect of adding methyl methacrylate on networks’ mechanical properties under simulated physiological conditions. The networks were synthesized in two parts: (1) a biodegradable crosslinker was formed from a diacrylate and amine, (2) and then varying concentrations of methyl methacrylate were added prior to photopolymerizing the network. Degradation rate, mechanical properties, and glass transition temperature were studied as a function of methyl methacrylate composition. The crosslinking density played a limited role on mechanical properties for these networks, but increasing methyl methacrylate concentration improved the toughness by several orders of magnitude. Under simulated physiological conditions, networks showed increasing toughness or sustained toughness as degradation occurred. This work establishes a method of creating degradable networks with tailorable toughness while undergoing partial degradation.