Poly (butylene succinate): a promising biopolymer
Since 1976, plastics play a major role in everyday life and they have been the most used material in the world. Plastics are often selected over traditional materials because of their superior properties and lower cost. Their versatility enables their use in applications ranging from clothing and packaging to high-tech composites. Currently manufacturers and researchers are targeting in new bio based products able to be used in several applications with packaging in first position. Owing to its biodegradability, wide processing window, and balanced mechanical properties, poly(butylene succinate) (PBS) and its copolymers have attracted much interest. This paper deals with PBS, this fairly new but a lot promising biopolymer. PBS synthesized from succinic acid and 1,4-butanediol exhibits balanced performance in thermal and mechanical properties as well as thermoplastic process ability compared with other common plastics. In this paper, synthesis, process ability, properties, biodegradability and recycling of PBS and its copolymers will be outlined. In addition, industrial production and applications will be briefly summarized. In Chapter 1 PBS monomers are presented. The synthesis of succinic acid and butanediol, are briefly reviewed, focusing on bio based production methods. Moreover we present the manufactures of these building blocks worldwide. In Chapter 2 PBS preparation processes are described. Two-step trans esterification polymerization, direct polymerization, condensation polymerization followed by chain extension, enzymatic polymerization and direct polyesterification under microwave irradiation are the ones we lay out about. Except of PBS homopolymer, we also introduce the copolymers' and branched PBS preparation processes. Industrial production is also reviewed. In Chapter 3, characterization and critical properties of the biopolymer are presented, focusing on molecular weight determination, gel permeation chromatography, end group analysis, viscosity, melt flow index, thermal /mechanical properties and transition, melting and thermal degradation and crystallization. In Chapter 4, processing and applications of PBS are briefly described. Several types of additives and processing methods such as extrusion, injection molding and thermoforming are defined. Moreover there is a review on all possible application fields of PBS. In Chapter 5, we get through degradability and recycling of PBS. Non enzymatic and enzymatic hydrolytic degradation, environmental biodegradation and thermal degradation are presented. PBS possible recycling techniques reviewed are mechanical recycling, chemical recycling and incineration.