Poly(Butylene-Succinate) PBS Polybutylene succinate-co-butylene adipate
Poly(butylene succinate-co-butylene adipate) PBSA Butylene succinate-co-butylene adipate*** polymer
Poly(butylene succinate-co-terephthalate)s PBST Polybutylene succinate/butylene terephthalate
Soft biodegradable material technology Soft biodegradable material technology
Photodegradable PlasticsPhotodegradable Plastics
Disintegradable PlasticsDisintegradable Plastics
Biodegradable MaterialsBiodegradable Materials
Bio-PolymerBio-Polymer
Green Plastics
Green Plastics
Aliphatic-Aromatic Polyester Copolymers Block Polymers of Aliphatic-Aromatic Polyesters
Aliphatic Polyesters
CPLA, Polylactide Aliphatic Polyester Copolymers Block Molecule Polymers of Polylactide-Aliphatic Polyesters
Polycaprolactone PCL Polycaprolactone
Polyhydroxyalkanoates PHA Polyhydroxycarboxylates
Poly-beta-hydroxybutyrate PHB Polyhydroxybutyrate
Polyhydroxybutyrate-valerate PHBV Polyhydroxyvalerate
Polylactide PLA poly(lactic acid)
poly(butylene adipate-co-terephthalate) (PBAT) adipic acid-terephthalic acid-butylene terephthalate***polymer (PBAT)
Poly(butylene Succinate-co- butylene Fumarate) Poly(butylene succinate-***-butylene fumarate)
What other types of biodegradable plastics are currently available besides PLA?
Degradable plastic (degradable plastic) means a plastic that, under specified environmental conditions, over a period of time and consisting of one or more steps, results in a significant change in the chemical structure of the material leading to a loss of certain properties (e.g., integrity, molecular weight, structural or mechanical strength) and/or fragmentation. They should be tested using standardized test methods that reflect the change in properties and are categorized by mode of degradation and life cycle. Degradable plastics are categorized as biodegradable, compostable, photo-degradable, and thermo-oxidative according to the ultimate degradation pathway they are designed to follow.
Biodegradable plastic refers to plastics that are degraded by naturally occurring microorganisms, such as bacteria, molds, and algae, under natural conditions, such as soil and/or sand, and/or specific conditions, such as composting or anaerobic digestion, or aqueous cultures, and ultimately degraded completely to carbon dioxide (CO2) or/and methane (CH4), water (H2O) and mineralized inorganic salts of the elements they contain, as well as new biomass. This is often referred to as biodegradable plastics.
Classification of biodegradable plastics: according to the composition of raw materials and manufacturing process can be divided into the following three kinds: natural polymers and their modified materials, microbial synthesis of polymer materials and chemical synthesis of polymer materials.
The current biodegradable plastics with application prospects are: poly(3-hydroxyalkanoate) (PHA), poly(lactic acid) (PLA), poly(epsilon-caprolactone) (PCL) and poly(butylene succinate) (PBS).
1. Poly(3-hydroxyalkanoate) (PHA)
Polyhydroxy fatty acid esters are aliphatic*** polypolyesters of different structures synthesized by microorganisms through fermentation of various carbon sources. The most common of these are poly(3-hydroxybutyrate) (PHB), polyhydroxyvalerate (PHV), and a ****polymer of PHB and PHV (PHBV).PHB is a thermoplastic polyester that is widely available in nature, and is especially often found in bacterial intercellular compartments.PHB is close to polypropylene plastics in many of its physical and mechanical properties, but is biodegradable and biocompatible, and in the organisms can be completely degraded to β-hydroxybutyric acid, carbon dioxide and water. Materials made from this bioplastic can be used in drug release systems, implants and some devices that decompose harmlessly in the body after healing, but PHB is harder and a bit more brittle compared to polypropylene. The weaknesses of PHB, which is highly crystalline and brittle, can be improved by polymerizing PHB with PHV*** (PHBV), which improves its mechanical properties, heat and water resistance. PHB/PHV*** polymers are already sold under the trade name of Biopol. Biopol is a series of different materials, which are composed of a range of different materials, and when the maximum amount of PHV in the polypropylene is not more than 30%, and the PHB/PHV is 89 /11*** The strength and toughness of the polymer is optimized, and the product is used in food packaging, cosmetics, pharmaceuticals, hygiene and agriculture.
2. Polylactic acid (PLA)
Polylactic acid (PLA) is a microbial fermentation product - lactic acid as a monomer chemically synthesized polyester.
PLA production is based on lactic acid as a raw material. Most of the traditional lactic acid fermentation with starchy raw materials. At present, the United States, France, Japan and other countries have developed the use of corn, sugar cane, sugar beet, potatoes and other agricultural by-products as raw materials for the fermentation production of lactic acid, and thus the production of PLA. Corn is the preferred raw material for biodegradable plastic PLA. The process of manufacturing biodegradable plastic PLA is as follows: first, grind the corn into powder, separate the starch, then extract the original glucose from the starch, and finally use a fermentation process similar to beer to convert the glucose into lactic acid, and then make the extracted lactic acid into the final polymer - PLA.
Polylactic acid (PLA) is a biodegradable polymer produced from renewable resources such as grains. In the PLA production route, lactic acid monomer is first prepared by hydrolyzing grain starch to glucose, which is converted to sodium lactate by a fermentation process. The lactic acid is further concentrated and then polymerized in the sequence of polycondensation (to form pre-polymers), thermal depolymerization (to form dipropylene cross esters), ring opening polymerization and depolymerization. The molecular weight of PLA obtained is as high as 75,000 g/mol.
Lactic acid polycondensation by the usual method yields only lactic acid oligomers. The most researched method to prepare high molecular weight PLA is through the ring-opening polymerization reaction of propylene glycol ester, which is synthesized from lactic acid oligomer by high temperature cracking. The mechanism and reaction conditions of the ring-opening polymerization reaction of propylene glycol ester have been reported in detail. Recently, Mitsui Chemical Company in Japan has proposed a new technology to prepare PLA directly by lactic acid polycondensation reaction without propylene glycol ester. This technology uses a highly active catalyst to obtain high molecular weight PLA by solution polycondensation. Because lactic acid and propyl ester contain asymmetric carbon atoms, the polymerization can be obtained by different structural regularity of PLA, such as L-PLA, D-PLA and DL-PLA.
PLA has a good moisture-proof, grease-resistant and airtight, stable performance at room temperature, but at temperatures higher than 55 ° C or the role of oxygen-enriched and microbial degradation will be automatic. After use, it can be completely degraded by microorganisms in nature, and eventually generate carbon dioxide and water, without polluting the environment, which is very favorable to the protection of the environment.
The degradation of PLA is divided into two stages: 1) firstly, pure chemical hydrolysis into lactic acid monomer; 2) lactic acid monomer is degraded into carbon dioxide and water under the action of microorganisms. The food cups made of PLA can be completely degraded in only 60 days, which really achieves the double effect of ecology and economy.
3. Poly(ε-caprolactone) (PCL)
Poly(ε-caprolactone) (PCL) is a low-melting polymer obtained by ring-opening polymerization of ε-caprolactone, with a melting point of only 62 ° C. Research on the degradation of PCL started in 1976, and PCL can be completely decomposed by microorganisms in both anaerobic and aerobic environments. Compared with PLA, PCL has better hydrophobicity, but slower degradation; at the same time, its synthesis process is simple and low cost.PCL's processing performance is excellent, and it can be made into films and other products with ordinary plastic processing equipment. At the same time, PCL and a variety of polymers have good compatibility, such as PE, PP, PVA, ABS, rubber, cellulose and starch, etc., through the *** mixing, as well as *** polymerization can be obtained with excellent performance of the material. Especially its *** mixing or *** polymerization with starch, both to maintain its biodegradability, but also to reduce costs, and therefore well received. PCL and starch *** mixing can be obtained from the degradation of water-resistant plastics, and its price is similar to paper; the use of in-situ polymerization methods, can be ε-caprolactone grafted with starch, to get the performance of the thermoplastic polymer.
4. Polyester - PBS / PBSA
Compared with similar products, polyester biodegradable plastics advantages:
1) the above biodegradable plastics (polylactic acid, poly ε-caprolactone, polyhydroxyalkanoate) one of the Achilles' heel is the heat resistance is poor, which affects it in the field of food and beverage applications to promote.
2) The above biodegradable plastics (PLA, poly(ε-caprolactone), poly(hydroxyalkyl ester)) are processed under harsh conditions, and there are some impossible difficulties in industrialization.
3) Polylactic acid is a water degradation bioplastics, the preservation process can not accept water molecules, in ordinary storage and normal use of the process of performance can not be guaranteed.
Polybutylene succinate (PBS) is a typical polyester biodegradable plastics, it is because of overcoming the above weaknesses, become the best biodegradable plastic materials, a wide range of uses, can be used for packaging, tableware, cosmetic bottles and medicine bottles, disposable medical supplies, agricultural films, pesticides and fertilizers, slow-release materials, biomedical polymers and other fields. PBS has excellent comprehensive performance, reasonable cost performance, and has good application and promotion prospects. Compared with PCL, PHB, PHA and other degradable plastics, PBS price is basically the same, there is no advantage; compared with other biodegradable plastics, PBS has excellent mechanical properties, close to PP and ABS plastics; it has good heat-resistant properties, heat distortion temperature is close to 100 ℃, and after modification, the use of the temperature can be more than 100 ℃, it can be used for the preparation of hot and cold beverage packaging and lunch boxes, overcoming the shortcomings of other biodegradable plastics in low temperature; processing performance is good, and the processing performance is reasonable, and has good application prospects. Low heat resistance of other biodegradable plastics; processing performance is very good, can be in the existing general plastics processing equipment for all kinds of molding processing, is currently the best performance of degradable plastics processing, at the same time can be **** mixed with a large number of fillers such as calcium carbonate, starch, etc., to get low-priced products; PBS production can be carried out through a slight modification of the existing general-purpose polyester production equipment, at present, there is a serious surplus of domestic polyester equipment, the modification of the production of PBS for the surplus polyester equipment. PBS provides a new opportunity for the surplus polyester equipment.
In addition, PBS is only degraded when exposed to specific microorganisms such as composting, and its performance is very stable during normal storage and use.
PBS with aliphatic butanedioic acid and butanediol as the main raw materials can be produced through petrochemical products to meet the demand, but also through starch, cellulose, glucose and other natural renewable crop products, through the bio-fermentation pathway to produce, thus realizing the green cycle of production from the nature, back to nature. Moreover, the raw materials produced by the biofermentation process can significantly reduce the cost of raw materials, thus further reducing the cost of PBS.
Reference: "PBS News"