玉米淀粉颗粒材料聚乳酸的使用

玉米淀粉材料是生物降解塑料聚乳酸（PLA）的一种，聚乳酸是以乳酸为主要原料聚合得到的聚合物，主要以玉米、木薯等为原料。聚乳酸的生产过程，而且产品可以生物降解，实现在自然界中的循环，因此是理想的绿色高分子材料。

Corn starch material is a kind of biodegradable plastic polylactic acid (PLA). PLA is a polymer polymerized with lactic acid as the main raw material, mainly corn, cassava, etc. Polylactic acid is an ideal green polymer material because of its production process and its biodegradation to realize its circulation in nature.

聚乳酸（PLA）是一种新型的生物降解材料，使用可再的植物资源（如玉米）所提出的淀粉原料制成。淀粉原料经由糖化得到葡萄糖，再由葡萄糖及一定的菌种制成纯度高的乳酸，再通过化学合成方法合成一定分子量的聚乳酸。其具有良好的生物可降解性，使用后能被自然界中微生物完全降解，生成二氧化碳和水，不污染环境，这对保护环境非常有利。

Polylactic acid (PLA) is a new type of biodegradable material, which is made of starch from renewable plant resources (such as corn). Glucose is obtained from starch raw material through saccharification, then lactic acid with high purity is made from glucose and certain bacteria, and polylactic acid with certain molecular weight is synthesized through chemical synthesis. It has good biodegradability. After use, it can be completely degraded by microorganisms in nature to generate carbon dioxide and water. It does not pollute the environment, which is very beneficial to environmental protection.

聚乳酸适用于吸塑、注塑等各种加工方法，加工方便，应用十分广泛。可用于加工从工业到民用的各种食品容器、包装食品、快餐饭盒、无纺布、工业及民用布。进而加工成农用织物、抹布、卫生用品、帐篷布、地垫面等等，市场前景十分看好。可见其机械性能及物理性能良好。

Polylactic acid is suitable for various processing methods such as blister and injection molding. It is easy to process and widely used. It can be used to process all kinds of food containers, packaged food, fast food lunch boxes, non-woven fabrics, industrial and civil fabrics from industry to civil use. And then processed into agricultural fabrics, rags, sanitary products, tent cloth, floor mats and so on. The market prospect is very promising. It can be seen that its mechanical and physical properties are good.

相容性与可降解性良好。聚乳酸在医药领域应用也非常广泛，如可生产一次性输液用具、免拆型缝合线等，低分子聚乳酸作药缓释包装剂等。

Good compatibility and degradability. Polylactic acid is also widely used in the pharmaceutical field, such as the production of disposable infusion equipment, non detachable suture, low molecular polylactic acid as drug release packaging agent, etc.

当焚化聚乳酸（PLA）时，其燃烧热值与焚化纸类相同，是焚化传统塑料（如聚乙烯）的一半，而且焚化聚乳酸不会释放出氮化物、硫化物等有毒气体。人体也含有以单体形态存在的乳酸。

When polylactic acid (PLA) is incinerated, its combustion calorific value is the same as that of incinerated paper, half of that of incinerated traditional plastics (such as polyethylene), and the incinerated PLA will not release toxic gases such as nitrides and sulfides. The human body also contains lactic acid in monomer form.

玉米淀粉颗粒之聚乳酸的优点主要有：一是原材料易得可再生，适合大规模集约化生产；二是透气性能、透明度光泽和硬度、拉伸和弯曲均可与传统的塑料树脂相媲美；三是更好的生物相容性。其单体原料L-乳酸是人体内源性活物质，因此聚乳酸制品对人体不排斥，并可被人体吸收，能制成医用组织骨架材料和医药载体用于人体内，并获得美国FDA认证；四是完全可降解性。埋入土壤中6～12个月即可降解成二氧化碳和水。

The advantages of PLA with corn starch granules are as follows: first, raw materials are easily available and renewable, which is suitable for large-scale intensive production; Second, the air permeability, transparency, gloss, hardness, stretching and bending can be comparable with the traditional plastic resin; Third, better biocompatibility. Its monomer L-lactic acid is an endogenous living substance in human body. Therefore, polylactic acid products are not exclusive to human body and can be absorbed by human body. They can be made into medical tissue skeleton materials and medical carriers for use in human body, and have been certified by FDA; Fourth, complete degradability. It can be degraded into carbon dioxide and water after being buried in soil for 6 ~ 12 months.

聚乳酸的制备方法

Preparation of polylactic acid

1）直接缩聚法

1) Direct polycondensation

缩聚法就是把乳酸单体进行直接缩合，也称一步聚合法。在脱水剂的存在下，乳酸分子中的羟基和羧基受热脱水，直接缩聚合成低聚物。加入催化剂，继续升温，低相对分子质量的聚乳酸聚合成更高相对分子量的聚乳酸。

Polycondensation is the direct condensation of lactic acid monomer, also known as one-step polymerization. In the presence of dehydrating agent, hydroxyl and carboxyl groups in lactic acid molecules are dehydrated by heating, and oligomers are synthesized by direct polycondensation. Add catalyst and continue to heat up, and poly (lactic acid) with low relative molecular weight can be polymerized to poly (lactic acid) with higher relative molecular weight.

2）二步法

2) Two step method

使乳酸生成环状二聚体丙交酯，再开环缩聚成聚乳酸。这一技术较为成熟，美国NatureWorks公司生产聚乳酸工艺的工艺即为该工艺。的海正与中科院共同研制的聚乳酸生产技术也与此相似，主要过程是原料经微生物发酵制得乳酸后，再经过精制、脱水低聚、高温裂解，聚合成聚乳酸。

Lactic acid is made into a cyclic dimer lactide, and then ring opening polycondensation is carried out to form polylactic acid. This technology is relatively mature, which is the process of producing polylactic acid by NatureWorks in the United States. The polylactic acid production technology jointly developed by Haizheng and Chinese Academy of Sciences is similar to this. The main process is that the raw materials are fermented by microorganisms to produce lactic acid, then refined, dehydrated and oligomerized, high-temperature pyrolysis, and finally polymerized into polylactic acid.

3）反应挤出制备高分子量聚乳酸

3) Preparation of high molecular weight polylactic acid by reactive extrusion

用间歇式搅拌反应器和双螺杆挤出机组合，进行连续的熔融聚合实验，可获得由乳酸通过连续熔融缩聚制得的分子量达150000的聚乳酸。利用双螺杆挤出机将低摩尔质量的乳酸预聚物在挤出机上进一步缩聚，制备出较高摩尔质量的聚乳酸。在反应温度为150℃、催化剂用量为0.5%、螺杆转速为75r/min时可通过双螺杆反应挤出缩聚法快速有效地提高聚乳酸的摩尔质量，而且反应挤出产物分散系数减小，均匀性变好。通过DSC曲线的比较发现，通过反应挤出缩聚法制得的聚乳酸的结晶度有所降低，这对改善聚乳酸材料在使用过程中表现出较大的脆性是有益的。

The continuous melt polymerization experiment was carried out in a batch stirred reactor and a twin-screw extruder. The polylactic acid with molecular weight up to 150000 was prepared from lactic acid by continuous melt polycondensation. The low molar mass of lactic acid prepolymer was further polycondensated on the twin-screw extruder to prepare high molar mass of polylactic acid. When the reaction temperature is 150 ℃, the amount of catalyst is 0.5% and the screw speed is 75r/min, the molar mass of polylactic acid can be rapidly and effectively increased by twin-screw reactive extrusion polycondensation, and the dispersion coefficient of reactive extrusion products is reduced and the uniformity is improved. Through the comparison of DSC curves, it was found that the crystallinity of polylactic acid prepared by reactive extrusion polycondensation decreased, which was beneficial to improve the brittleness of polylactic acid materials in the process of use.

玉米淀粉颗粒材料聚乳酸的使用相关内容便是如此了，您可以关注我们的网站www.qiluxinke.com咨询更为详细的信息。

This is the case with the use of corn starch granule material polylactic acid. You can follow our website www.qiluxinke Com for more detailed information.