Stretch film has an irreplaceable existence in people's daily life and industrial production. From food preservation to product packaging, to packaging of goods. All processes are inseparable from it. However, the existing PE stretch film is non-degradable, and the stretch film after use is generally disposed of in two ways: incineration and landfill. With the continuous increase of usage, its impact on the environment is becoming more and more obvious. Is there a stretch film that can be degraded? Today we will introduce the PLA biodegradable stretch film.
Polylactic acid (polylactide, polylactic acid, referred to as PLA), also known as polylactide, is made from corn, wheat, cassava and other starch-containing organisms as the initial raw material, which is decomposed by enzymes to obtain glucose, and then fermented by soft acid bacteria to become lactic acid , and finally get biodegradable thermoplastic polyester after compounding. Polylactic acid has good biocompatibility, environmental safety, non-toxicity, good mechanical properties and light transparency, and good processing performance. It can be used for plastic film, food packaging bags, medicines, etc. Various packaging materials.
Polylactic acid can be processed by common plastic molding methods such as injection molding, extrusion, blow molding, stretching and other processes. The melt viscosity of polylactic acid is mainly related to the weight average molecular chain, L/D type unit ratio, plasticizer content, shear rate and temperature.
Polylactic acid has relatively good mechanical properties, and its tensile strength can reach up to about 60MPa. Its performance is rigid and brittle, which is a major problem for polylactic acid to require more flexible molded products for daily packaging applications. Like other materials, the mechanical properties of PLA depend on molecular characteristics, ordered structures such as crystallinity, crystal thickness, spherulite size, and degree of molecular chain oirentation.
The full degradation of PLA polylactic acid is a relatively advanced environmental protection product, which uses starch as the main raw material. Since starch is a biodegradable natural polymer, it is decomposed into glucose under the action of microorganisms, and finally decomposed into water and carbon dioxide. In addition, the material blended with it is also a fully degradable material, so it can be said that it has no impact on the environment. At present, the degradation pathways of polylactic acid are mainly hydrolysis and composting.
