History of Sustainable Bio-based Polymers
Bio-based polymers have played an important role in the development of today's plastics industry. Plastics derived from renewable resources have been around for millennia; they have come and gone, and are slowly making a comeback. After almost disappearing, today, engineering viable bio-based materials may contribute to a more sustainable future economy and advance the field of biomedical engineering. The biodegradability of bio-based plastics, formerly perceived as a problem, is seen by many today as an asset, since it offers an outlet for overflowing solid waste streams. Polylactic acid, soy protein-based plastics, starches and many more are promising renewable, biodegradable materials. Although agriculture-based plastics have been around for centuries, they were largely forgotten after the advent of synthetic, petroleum- based polymers. This chapter reviews the history of the development of what was once a thriving industry, tying it to today's technological and societal needs. Starting with the use of silk as suture material for over 100 years, this chapter revisits the literature left to us by early twentieth century engineers who made protein-based plastics from casein and soy protein on an industrial scale. With advances in tissue engineering and cell culture, biocompatible and biodegradable natural polymers have gained great importance, such as collagen and chitosan. Major progress in genetics and molecular biology has allowed industrial growth of polymers produced from bacteria for a great array of applications. In recent years, there has been a resurgence of interest in green industry and biopolymers; for this reason the history of bio-based plastics can be a starting point to its resurgence.