摘要
塑料废弃物的严重污染日益威胁人类赖以生存的环境,研究“绿色高分子”已经得到广泛重视。淀粉作为一种天然高分子化合物,其来源广泛,成本低廉,且能在各种自然环境下完全降解。淀粉基降解塑料已经部分替代了传统石油基塑料,更拓展了淀粉的非食物用途,成为国内外研究开发最多、应用前景最为广阔的一类生物降解塑料。
本文采用硬脂酸铁(FeSt3)为光敏剂,丙烯酸丁酯接枝改性淀粉,制备出一类降解性能好的光/生物双降解聚乙烯薄膜。采用红外光谱、粘度法、DSC热分析和力学性能测试、人工紫外光老化和土埋生物降解等方法,对老化后的LDPE薄膜进行了结构表征和性能测试,并对降解机理进行了初步研究。结果表明:光敏剂FeSt3对LDPE薄膜的光降解具有双重作用,添加量为0.2%为宜;薄膜的羰基指数随着光照时间的延长先降低后增加;随着光照时间的延长,其降解程度增大,结晶度增加。LDPE薄膜的失重率随着淀粉含量的增加而增加;当淀粉含量25%时,薄膜失重率随着土埋时间的延长先上升,然后基本保持不变。
本文将玉米淀粉分别进行了塑化改性、偶联剂改性(硅烷偶联剂KH560和钛酸酯偶联剂NDZ-102)和丙烯酸丁酯接枝改性,并以MDI做为扩链剂,制备出了一类淀粉/聚乳(PLA)酸全降解材料,结果表明以BA-g-Starch的改性方法效果最好,并且能够改善淀粉/PLA共混体系的吸水性。在制备BA-g-Starch/PLA降解材料的基础上,考察了乙烯醋酸乙烯酯共聚物接枝马来酸酐(EVA-g-MAH)加入量对材料的力学性能的影响,研究表明EVA-g-MAH的添加量定为10%左右时材料的综合性能最好。在BA-g-Starch/PLA为10/90的体系中,EOMMT的加入有利于提高体系的热变形温度;通过TGA分析结果表明,淀粉/PLA/EOMMT体系的热稳定性提高,起始分解温度由未添加前250℃上升到275℃。土埋试验表明:组分TPS/PLA为20/80的共混材料在降解初期淀粉首先发生降解,中后期主要是PLA的降解。SEM分析结果表明:对淀粉进行接枝改性后,淀粉粒径和空洞密度明显减小,BA-g-Starch和PLA的相容性得到了很大改善。
The pollution of plastic waste threats human survival environment and the research of "Green Polymers" has received wide attention. Starch is a natural polymer, its wide variety of sources, low cost, and can completely degrade in the natural environment. Starch-based degradable plastics have partially replaced the traditional oil-based plastics and have been studied extensively.
In this paper, a serial of photo/biodegradable LDPE films were prepared by adding ferric stearate (FeSt3), butyl acrylate grafted starch into the LDPE matrix. and film aging artificial UV light and soil Buried biodegradation. Based on the artificial acceleration ultraviolet photo-degradation, biodegradation of soil burial test, the mechanical propertie, FT-IR spectrum, viscosity average molecular weigh and DSC propertie were measured and the degradation mechanism is preliminarily discussed. The results showed that photo sensitizer FeSt3 has a dual role in the LDPE film and the suitable dosage is 0.2%; when starch and photo-sensitizer contents ware fixed, the carbonyl index of LDPE film first induce, then increase, degradability and crystallinity also increase, with the exposure time prolonged. Weight loss of film first increased and then remained unchanged as the soil burial time extended.
In this paper, with starch deal with glycerol, coupling agent (silane coupling agent KH560 and coupling agent NDZ-102) and grafted by butyl acrylate (BA-g-Starch),a class of starch/polylactic acid biodegradable materials hve been prepared, the Mechanical properties also been tested. The results show that it works best when BA-g-Starch is added to PLA matrix and decrease water absorption. SEM analysis showed that the starch particle size and void density was significantly reduced, compatibility has been greatly improved although the starch/PLA blends shows brittle fracture as the BA-g-Starch has been added. EVA-g-MAH could be improved elongation and toughness,its suitable amount is 10%. TGA analysis showed the initial thermal decomposition temperature increased observably by adding EOMMT to the starch/PLA(10/90)system, it increases from 250℃to 275℃with the EOMMT contents changing from 0 to 7 Phr. Soil burial test showed that when component TPS / PLA blends was 20/80,The component mainly eroded by bacteria is starch in the early, then is PLA in the mid-late time. starch; biodegradation
引文
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