Biodegradable materials include natural polymer cellulose, synthetic polycaprolactone, polyvinyl alcohol and so on. After being used and discarded, the materials can be degraded by enzymes of natural microorganisms, and the degradation products can be absorbed and metabolized by microorganisms as carbon sources. According to the varieties of biodegradable materials, this paper introduces their properties
Polycaprolactone (PCL) is a low-cost biodegradable synthetic polymer. The polycaprolactone used is a cyclic monomer - caprolactone. Caprolactone is an aliphatic polyester prepared by ring opening polymerization of organometallic compounds. The main properties are as follows: the melting point and glass transition temperature are low, only 60 ℃ - 60 ℃, and the crystallization temperature is 22 ℃; the fiber strength is almost the same as that of polyamide 6 fiber, the tensile strength can reach more than 70.56cn/tex, the nodule strength is more than 44.1cn/tex, and the strength loss in wet state is very small; the biodegradability is similar to that of man-made fiber, and its product is about one week Degradation into thin sections that are impossible to test.
Polyvinyl alcohol is a biodegradable resin, so starch based polyvinyl alcohol plastics can be completely biodegradable. The copolymer of ethylene and modified starch has good processability, secondary processing, mechanical properties and excellent biodegradability. The poly (vinyl alcohol) resin with thermoplastic, water-soluble and biodegradable properties has been developed by Japan synthetic chemical industry company. The melting point of the resin is 199 ℃. It can be molded by extrusion, blow molding and injection molding at 214 ℃ - 230 ℃. The transparency, water solubility and drug resistance of the products are excellent, which can be used for coating composite containers and packaging materials.
Polylactic acid (PLA) was jointly developed by Shimadzu company and Zhongfang company of Japan in the early stage. Lactic acid is a kind of natural compound which is common in animals, plants and microorganisms. It is easy to decompose naturally. Its fiber has excellent performance, which is between synthetic fiber and natural fiber. Hydrophilicity is better than polyester fiber, specific gravity is lower than polyester fiber, has excellent handle, drape and appearance, good resilience, excellent crimp and crimp retention, controllable shrinkage, strength up to 62cn / tex, not affected by ultraviolet light, can be dyed with various dyes, excellent processability, controllable thermal bonding temperature, crystal melting temperature up to 120 ℃ - 230 ℃, low flammability Sex.
The main characteristic of lactic acid monomer is that it exists in two forms of optical activity. Polylactic acid technology uses the unique polymer properties to control the crystallization melting point of the product by controlling the proportion and distribution of D and l isomers in the polymer chain.
Poly (L-lactic acid) (PLLC) is a kind of polymer material which is produced by fermentation of starch, molasses and other biological resources, and then synthesized by chemical methods. PLLC is a thermoplastic material, its plasticity is similar to polystyrene and polyester, its crystallinity and rigidity are relatively high, tensile strength is excellent.