讲解生物降解的机理方式.doc

讲解生物降解的机理方式生物可降解高分子材料是指在一定的时间和一定的条件下，能被微生物或其分泌物在酶或化学分解作用下发生降解的高分子材料。Biodegradable polymer materials is to point to in a certain time and certain conditions, can be microbes or their secretions in enzymatic or chemical decomposition under the action of degradable polymer materials. 生物可降解的机理大致有以下3种方式：生物的细胞增长使物质发生机械性破坏；微生物对聚合物作用产生新的物质；酶的直接作用，即微生物侵蚀高聚物从而导致裂解。一般认为，高分子材料的生物可降解是经过两个过程进行的。首先，微生物向体外分泌水解酶和材料表面结合，通过水解切断高分子链，生成分子量小于500的小分子量的化合物；然后，降解的生成物被微生物摄入人体内，经过种种的代谢路线，合成为微生物体物或转化为微生物活动的能量，最终都转化为水和二氧化碳。Biodegradable generally has the following three ways: the mechanism of biological cell growth makes material mechanical damage; Microbial effect on polymer produce new substances; Direct effect of enzymes, namely microbial erosion polymer which can lead to cracking. It is generally believed that of biodegradable polymer materials is carried out through two processes. First, the microbes to secretion in vitro hydrolysis enzyme and combination of materials and through hydrolysis to cut off the polymer chain, generated molecular weight smaller than 500 compound of small molecular weight; Then, degradation products by microbial intake of the body, through a variety of metabolic route, synthesis of microorganisms or energy into microbial activity, eventually into water and carbon dioxide. 因此，生物可降解并非单一机理，而是一个复杂的生物物理、生物化学协同作用，相互促进的物理化学过程。到目前为止，有关生物可降解的机理尚未完全阐述清楚。除了生物可降解外，高分子材料在机体内的降解还被描述为生物吸收、生物侵蚀及生物劣化等。生物可降解高分子材料的降解除与材料本身性能有关外，还与材料温度、酶、PH值、微生物等外部环境有关。Therefore, biodegradable mechanism is not single, but a complex biophysical, biochemical synergies and mutual promotion of the physical and chemical process. So far, about the biodegradable mechanism has not yet completely clear. Besides biodegradable, the degradation of polymer materials in the body has also been described as a biological absorption and biological degradation, biological erosion, etc. Of biodegradable polymer materials had lifted related material itself performance, but also with material, such as temperature, PH, microbial and enzyme is related to the external environment. 2、生物可降解高分子材料的类型2, the type of biodegradable polymer materials 按来源，生物可降解高分子材料可分为天然高分子和人工合成高分子两大类。按用途分类，有医用和非医用生物钢塑土工格栅可降羟丙基甲基纤维素解高分子材料两大类。按合成方法可分为如下几种类型。According to sources, biodegradable polymer materials can be divided into two types: natural polymers and synthetic polymers. Classification according to the use, there are medical and non medical biodegradable high polymer material two kinds big. According to the synthetic methods can be divided into the following several types. 2.1微生物生产型2.1 microbial production 通过微生物合成的高分子物质。这类高分子主要有微生物聚酯和微生物多糖，无纺布水性油墨具有生物可降解性，可用于制造不污染环境的生物可降解塑料。By microbial synthesis of polymer material. Such polymers are mainly polyester and microbial polysaccharide, is biodegradable, can be used in the manufacture of polluting the environment of biodegradable plastics. 2.2合成高分子型2.2 synthetic polymer type 脂肪族聚酯具有较好的生物可降解性。但其熔点低，强度及耐热性差，无法应用。芳香族聚酯(PET) 和聚酰胺的熔点较高，强度好，是应用价值很高的工程塑料，小型升降机但没有生物可降解性。将脂肪族和芳香族聚酯(或聚酰胺) 制成一定结构的共聚物，这种共聚物具有良好的性能，又有一定的生物可降解性。Aliphatic polyester has good biodegradable properties. But the low melting point, strength and heat resistance is poor, cannot be applied. Aromatic polyester (PET) and polyamide high melting point, good strength, is the very high application value engineering plastics, but is not biodegradable. Aliphatic and aromatic polyester or polyamide made a certain structure of copolymer, the copolymer has good performance, and is biodegradable.