Comparison of toughening effects of several common toughening agents and polycarbonate-polydimethylsiloxane block copolymer on polyvinyl chloride

In this work, different toughening agents such as chlorinated polyethylene (CPE), acrylonitrile–styrene-acrylate (ASA) terpolymer, acrylic modifier (ACR, the main component is poly(methyl methacrylate-butyl acrylate)) and polycarbonate-polydimethylsiloxane block copolymer (PC-b-PDMS) were used to toughen polyvinyl chloride (PVC). Different content toughening agents (10 and 20 phr) were added into PVC and their properties were tested. The results exhibited that ACR, ASA, and PC-b-PDMS-40 (40% PDMS content) had high impact strength (more than 100 kJ m⁻²) at room temperature. With the decrease of temperature, the toughening effect of ACR and ASA dropped significantly (7.30 and 3.69 kJ m⁻² at −30°C respectively), while PC-b-PDMS-40 still had certain toughening effect (19.66 kJ m⁻² at −30°C). The tensile and flexural strength of blends decreased with the addition of toughening agents, while due to strong interactions between PC and PVC, elongation at break of PVC/PC-b-PDMS also have obvious drop. Heat distortion temperature results showed that the heat resistance of PVC was not reduced by toughening agents except CPE. The DMTA curves of blends revealed the reason why PVC/PC-b-PDMS-40 had good toughness at low temperature that the glass transition temperature of PDMS is very low (−123°C), which makes it flexible at low temperature.