Comparison of biodegradable materials PLA, PBAT, PHA and PBS

2020.12.29

Biodegradable plastics include starch blends made of thermo-plastically modified starch and other biodegradable polymers as well as polyesters such as polylactic acid (PLA), polyhydroxyalkanoate (PHA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS) and so on. What are their strengths and weaknesses? Let’s compare their performances of different biodegradable materials.

PLA is chemically converted and polymerized with lactic acid which is produced from various starches, sugars, and other biomass materials through biological fermentation. The bio-based PLA can be thermo-plastically processed into highly transparent products to replace the conventional disposable products and inhibit the increasing scarcity of petroleum resources.

PLA is the first commodity polymer produced from annually renewable resources. It is classified as generally recognized as safe (GRAS) by the United State Food and Drug Administration (FDA) and is safe for all food packaging applications. PLA is non-toxic, non-irritating, high strength, easy processing and molding as well as excellent biocompatibility. The melting point of PLA is 160-180 degrees, and its heat-resistant temperature can reach 150 degrees. With the best mechanical properties and best thermostability, PLA can be injection molding, foaming, and also can blow molding, but the toughness is not enough.

PBAT is produced by polycondensation of terephthalic acid, adipic acid and butanediol. With aliphatic and aromatic segments, it contains a flexible fatty chain, which give it good flexibility of molecular chain. Due to the flexibility and high elongation at break, PBAT and its composite are widely used as biodegradable blown film products. The melting point is 110-130 degrees, which is suitable for all kinds of film bag products, including shopping bags, express delivery bags, plastic wrap, etc. But because of low melting point and poor heat resistance, PBAT is not suitable for injection molding materials.

PHA is a polyhydroxyalkanoate synthesized by microbial fermentation and synthesized from microbial plasmid. Most of its monomers are 3-hydroxy fatty acids with a chain length of 3 to 14 carbons. It has biocompatibility, biodegradability, piezoelectricity and good use and processing performance. Its basic properties are similar to polypropylene. Compared with other biodegradable materials such as polylactic acid (PLA), the structure of PHA is diversified. The composition of PHA can be easily changed by changing the strain, feed, and fermentation process, which makes it have obvious advantages in applications. PHA can be widely used in agriculture, environmental protection, biochemical industry, microelectronics Materials, energy, medicine, medical materials and other fields.

PBS is polyglycol succinate. Its strength is between PLA and PBAT. It has good heat resistance, with a melting point of 110 degrees. The performance is close to polypropylene.

	Starch blends	PLA	PHA	PBS/PBSA	PBAT
Thermostability	o	++	+++	+++	+++
Film-forming	++	--	++	++	++
Hardness	o	+++	-	o	-
Mechanical strength	+	++	+++	+++	+++
Hydrolysis resistance	+	-	+++	+++	+++
Transmittance	-	+++	-	-	-
Production cost	lowest	lower	highest	higher	higher

+++ best, ++ better, + medium, o not good, - bad, --worse

Compared to other biodegradable materials, PLA has advantages in hardness and transmittance, as well as production cost. The performances of PHA, PBS/PBSA and PBAT are similar because monomer molecular structure of their upstream materials are similar, with advantages of thermostability, strength and hydrolysis resistance. Therefore many products are produced by these composite material.

The table of physical properties

Comparison of hear resistance

Comparison of Elongation(%)

The applications of different biodegradable materials

Material	Daily plastic			High performance plastics		High-end biomedical materials
Material	Garbage bag	Disposable meal box	Fiber	Agricultural film	High air resistance packaging	Surgical Suture	Drug carrier
PLA	√	√	√
PBAT	√	√		√
PCL						√	√
PHA						√	√
PGA					√	√

OKCHEM PLA, PBAT and PBS Distribution Project

OKCHEM is the strategic partner of Anhui BBCA (the largest PLA producer in China) and Xinjiang Blue Ridge Tunhe (the largest PBAT producer in China) to look for buyers and partners globally. If you want to join us in this project, please contact us at info@okchem.com. You may also make the application online at: https://www.okchem.com/agent/detail/degradableplastics/oem