General
Polybutylene succinate (PBS) (sometimes written polytetramethylene succinate) is a thermoplastic polymer resin of the polyester family. PBS is a biodegradable aliphatic polyester with properties that are comparable to polypropylene.
It may also be referred to by the brand names Bionolle (Showa Denko) or GsPLA (Mitsubishi Chemical). PBS consists of polymerized units of butylene succinate, with repeating C8H12O4 units.
Applications
As PBS decomposes naturally into water and CO2, it may be a biodegradable alternative to some common plastics. The scope of PBS application fields is still growing and several areas can be identified but it remains difficult to know precisely in which specific object PBS is actually used. First in the packaging field, PBS could be processed into films, bags, or boxes, for both food and cosmetic packaging.
Other applications of PBS could be found as disposable products such as tableware or medical articles. In agriculture, PBS finds interest in the fabrication of mulching films or delayed release materials for pesticide and fertilizer. PBS is also promise to find market shares in fishery (for fishing nets), forestery, civil engineering or other fields in which recovery and recycling of materials after use is problematic. In the medical field, PBS could be used as biodegradable drug encapsulation systems, and is also investigated for implants.
Industrial production
In industry, the improvement of the PBS synthesis allowed the large scale production of this polymer. The Japanese company Showa High Polymer, built in 1993 a semi-commercial plant able to produce 3,000 tons of polymer per year. Sold under the tradename Bionolle, these polyesters are synthesized via melt condensation polymerization followed by a chain-extension with a diisocyanate. Much later, in April 2003, Mitsubishi Chemicals built a 3,000 tons/year capacity and launched to the market a PBS named GS Pla (Green and Sustainable Plastic). This polymer has high molar masses without the use of a chain extender. Since then, several PBS producers such as Hexing Chemical (Anhui, China); Xinfu Pharmaceutical (Hangzhou, China) or IRe Chemical (South Korea) appeared on the market. In 2010 Hexing Chemical became China’s first large-scale PBS enterprise, with the annual capacity of 10,000 tons.
The same year Xinfu Pharmaceutical announced the building up of the world’s largest continuous PBS production line with an annual capacity of 20,000 tons. At the moment most of these poly(alkylene succinate)s are synthesized from petrochemical precursors. Nevertheless most of the producers are evaluating or developing bio-based succinic acid for the synthesis of these polyesters. In 2016, Showa Denko announced termination of the production and sale of Bionolle, citing delay in permeation of environmental regulations on plastic shopping bags and a fall in market prices of biodegradable plastics.
