A large part of the “plastics” around us is made of three-dimensional cross linked networks, so-called “thermoset plastics”. The classic example is Bakelite, the phenol/formaldehyde-based resin invented by the Belgian chemist Baekeland in the early 20th century. Today, formica and medium density fiberboard (MDF) are still made by mixing bakelite with paper pulp or sawdust, with cotton and other fibers also used as fillers.
Resins are also ubiquitous in the construction industry. So-called “betonplex” is an urea/formaldehyde resin applied to plywood used in moulding of concrete and polyurethane-based foams (PUR-foams) are used as isolation materials in construction and in upholstery.
Today’s resins are all based on petrochemical sources. Moreover, their production involves highly toxic ingredients, such as epichlorohydrin, bisphenol-A, melamine, formaldehyde, and phosgene. Such resins are not biodegradable, and cannot be burned safely, because their combustion releases many toxic components. Even the sawdust of coated plywood and MDF is harmful.
Rising to this challenge, UvA-chemists prof. dr. Gadi Rothenberg and dr. Albert H. Alberts of the Heterogeneous Catalysis and Sustainable Chemistry group have developed a range of new thermoset resins starting from 100% non-toxic renewable raw materials derived from biomass. By choosing the appropriate components and conditions for the cross linking/polymerization process, they succeeded in making a variety of bio-plastics, including rigid foams, elastic foams, and rigid and elastic plates. These new materials are fully biodegradable, non-toxic and non-hazardous. Moreover, the starting materials are cheap and readily available worldwide.
The new resins can in principle replace polyurethane and polystyrene in building and packaging applications, as well as epoxy resins in the production of plywood and MDF. The UvA has filed European and US patent applications on the invention and is currently working on developing industrial applications and upscaling of the process.