The plastics industry is one of the fastest growing in the world. The global plastics demand in 2015 was over 300 million tons, and this number is growing steadily each year. The low cost of production and the ease with which they are processed combine to make plastics usable in a wide variety of applications, from food packaging to insulation to clothing.
Unfortunately, the source of most commercial plastics is petroleum, and almost half of the total amount of plastics is only used short-term. As Matthew Korey and colleagues point out in their study, published in the Journal of Polymer Science Part A: Polymer Chemistry, this means “that producers are using nonrenewable resources to make a product that will be used once or twice and then put into waste.”
To this end, Korey and team focused on an alternative source for epoxy hardening agents: tannic acid (TA). Tannic acid is a naturally occurring compound found in nuts, seeds, and tree bark that is labeled safe by the FDA. The cost of TA is comparable to the chemical hardeners currently in use, but it has the advantage of being renewable and nontoxic. This study demonstrated that TA was able to react and form an epoxy polymer with high thermal stability analogous to several epoxy thermosets that are currently commercially available.