pCBT: A New Material for High Performance Composites in Automotive Applications

Abstract

Cyclic oligomers of butylene terephthalate (CBT®) represent a new chemical route to semicrystalline thermoplastic polybutylene terephthalate (PBT). The oligomers of interest melt completely at about 150°C to produce a low-viscosity fluid that is ideal for wetting and dispersing fibrous fillers and reinforcements, thereby enabling the development of composites that were previously not possible when working with high-viscosity commercial PBT. Introduction of catalyst to undiluted molten cyclic oligomer leads to rapid ring opening polymerization and the formation of high-molecular-weight thermoplastic PBT without the generation of volatile organic compounds. The polymer resulting from this polymerization will be hereafter referred to as pCBT. Treatment of cyclic oligomers in this fashion results in pCBT thermoplastic resin with a high melting point (230°C) and physical performance similar to that of other commercially available PBT resins. The low viscosity of these oligomers enables the selection of processing technologies that are typically reserved for thermosetting systems and that work in conjunction with easy flowing monomers or pre-polymers. The combination of excellent mechanical performance and the ability to utilize processing techniques typically reserved for thermosets enables broad uses for these oligomers in a range of applications including interior, exterior and structural automotive components. Additionally, the thermoplastic nature of pCBT holds promise to provide a low-capital route to a new family of pCBT-based recyclable materials made using a range of plastic processing technologies.

Reactive Processing of Acrylic-Based Thermoplastic Composites: A Mini-Review

“…During the last two decades, a number of precursors for reactive thermoplastics have been developed. In the beginning, some precursors of reactive thermoplastic materials have been developed to obtain thermoplastic polymers via in-situ polymerization such as cyclic butylene terephthalate (Bank et al, 2004;Parton and Verpoest, 2005), caprolactam (van Rijswijk et al, 2009), and laurolactam (Mairtin et al, 2001;Zingraff et al, 2005), and more recently L-lactide (Louisy et al, 2019;Miranda Campos et al, 2022). Representative polymers for reactive processing are Polybutyleneteraphthalate (PBT), thermoplastic polyurethanes (TPU), polyamides including Polyamide-6 (PA-6) and Polyamide-12 (PA-12) (van Rijswijk and Bersee, 2007).…”