Enhancement of thermal characteristics of flexible poly(vinyl chloride) for automotive applications by using environmentally friendly heavy metal-free modifier

Abstract

This work intends to develop an effective heavy metal-free modifier having properties comparable to traditional stabilizers and flame retardants, simultaneously being environmentally friendly and may be superior in many aspects. The important requirement focused on is: how to increase thermal stability and flame retardancy of flexible poly(vinyl chloride). Due to the typical materials now used with poly(vinyl chloride), which increases health and environmental concerns, utilizing a novel heavy metal-free additive will make poly(vinyl chloride) substantially safer. We have used an artificial silicate for this aim, which proved to be an efficient flame retardant and surprisingly showed excellent heat stabilizing effect. Thermal stability of flexible poly(vinyl chloride) was tested by both discoloration and hydrochloric-acid release methods. Fire properties were tested by limiting oxygen index (L.O.I) method. And penetration resistance of poly(vinyl chloride) has been tested by vicat test. The improvement rate in the thermal stability time during the dehydrochlorination test was 110.7% at 160°C and 90.1% at 180°C. Also, the improvement rate in the L.O.I test was 22.2%, which increased from 21.6% for the poly(vinyl chloride) to 26.4% when 5wt.% of artificial silicate was added. The artificial silicate also increases the thermal stability of the poly(vinyl chloride) and maintains its appearance of more saturated chromatic saturated (brighter). In addition, artificial silicate increases the resistance to hot penetration of poly(vinyl chloride). Where the resistance of poly(vinyl chloride) increased by 8.9% after adding 5wt.% of artificial silicate.