What is the raw material for PLA granules?


PLA (polylactic acid) granules are becoming increasingly popular in various industries due to their eco-friendly nature. These granules are derived from a renewable raw material known as plant-based biomass. In this article, we will delve deeper into the sources and production process of PLA granules.

The primary raw material for PLA granules is starch, which is extracted from various plant sources such as corn, wheat, sugarcane, and tapioca. Starch is a complex carbohydrate that consists of glucose molecules linked together. It serves as an energy reserve in plants and is abundant in many agricultural products.

To obtain PLA granules, the raw starch is first subjected to a process called hydrolysis, which breaks down complex carbohydrates into simple sugars. This hydrolysis process involves using enzymes or acids to break the starch molecules into glucose units. Enzymatic hydrolysis is the preferred method, as it is more environmentally friendly and produces higher quality PLA.

After the hydrolysis step, the glucose molecules are fermented using specific strains of bacteria, such as Lactobacillus or Bacillus. During fermentation, the bacteria consume the glucose, producing lactic acid as a by-product. Lactic acid is a key intermediate in the production of PLA. The fermentation process can take several days to convert a significant amount of glucose into lactic acid.

Once the fermentation is complete, the lactic acid produced undergoes further processing to form polylactic acid. It involves a two-step process called polymerization. In the first step, lactic acid molecules are heated and distilled to remove any impurities. Then, the purified lactic acid is subjected to condensation polymerization, where the molecules are linked together, forming long chains known as polylactic acid.

The polylactic acid is subsequently cooled, crushed, and granulated into PLA granules of various sizes for different applications. These granules are then ready to be used in a wide range of industries, including packaging, textiles, 3D printing, and biomedical applications.

It is important to note that PLA granules derived from different plant sources may exhibit slight variations in their properties. For example, PLA made from corn starch generally has excellent transparency and heat-resistant properties, making it suitable for applications like clear packaging films or disposable cutlery. On the other hand, PLA made from sugarcane or tapioca starch may have a slightly lower heat resistance but offer improved flexibility and compostability, making them ideal for products like compostable food containers or biodegradable bags.

The use of plant-based biomass as a raw material for PLA granules offers significant environmental benefits. Unlike traditional petroleum-based plastics, PLA is biodegradable, meaning it can be broken down by natural processes into environmentally safe substances. Furthermore, since the raw material is derived from renewable sources, PLA contributes to reducing greenhouse gas emissions and dependence on fossil fuels.

In conclusion, PLA granules are derived from starch obtained from plant-based biomass such as corn, wheat, sugarcane, or tapioca. The raw starch undergoes hydrolysis and fermentation processes to convert it into lactic acid, which is subsequently polymerized into polylactic acid. These polylactic acid chains are then granulated to form PLA granules, which find numerous applications across various industries. The utilization of renewable raw materials and the biodegradability of PLA make it an eco-friendly alternative to traditional plastics, contributing to a more sustainable future.