Cellular PVC-U: current technology and future challenges

This study discusses the formulation technology involved in the production of rigid PVC foams, and typical formulations for rigid foam sheet and profile are presented. Particular reference is given to acrylic processing aids and their effect on melt extensibility and strength. Measurements carried out using an elongational rheometer have confirmed that melt extensibility and rupture stress are increased with increasing addition level and/or molecular weight of the processing aid used. The challenges faced by the PVC foam industry are also addressed. These include environmental issues, such as the need to develop formulations with sustainable additives and to increase recycling of PVC products. Future developments include the use of organic-based stabilizers (OBS) and the use of nanofillers.