Squash (Cucurbita maxima D.) Seed Oil as Thermal Stabilizer for Polyvinyl Chloride (PVC)

Thermal stabilizers such as lead, a toxic heavy metal, are incorporated in polyvinyl chloride (PVC) which is thermally unstable. Due to environmental concerns, organic thermal stabilizers like squash seed oil were used in the study. Squash seed oil was extracted using improvised distillation. Two PVC flat sheet samples, with and without thermal stabilizers, were fabricated through incorporation of squash seed oil. Physical characterization, lead content determination, and thermal characterization were performed. Physical characterizations on the PVC samples were done by exposing the two samples in high temperatures. Yellowish brown stains formed in both PVC samples indicated that certain areas degraded due to long heat exposures. Absence of lead in the degraded samples was confirmed through US EPA Method 3050B, thus indicating nontoxicity of both the thermally stabilized and unstabilized PVCs. Thermal characterization was done through the improvisation of Differential Scanning Calorimeter. Results showed that the fabricated PVC was able to resist heat significantly longer by 168 seconds, compared to the unstabilized PVC by 81 seconds. Squash seed oil improved the thermal stability of PVC, therefore having the ability to replace the toxic thermal stabilizers.