What makes PLA bio-polymers in general different than most commodity thermoplastics like polystyrene?
NatureWorks PLA is derived from organic plant materials, which serve as an alternative source of carbon & hydrogen. These plant products are fermented and then polymerized in such a manner that the end result is a viable substitute for petroleum based commodity thermoplastics. PLA resin has many different properties requiring new processing hardware and methods for commercial success. These new bio-polymers can not be expected to process like something they’re not. Generally, bio-polymers like PLA start with a relatively low molecular weight, and are long & narrow molecules that require processing aids and additives to make them work successfully in plastic extrusion processes, especially for foaming. For extrusion foaming, PLA bio-polymer must be processed in what is known as a reactive extrusion process. In this case, the new foam extrusion process involves combining PLA resin with various additives to enhance process-ability. A chemical reaction is then initiated inside the extruder
