The Effect of Di-2-ethylhexyl Phthalate on the Thermo-oxidative Ageing of Poly(vinyl chloride)/Epoxidized Natural Rubber Blends

Abstract

The effect of di‐2‐ethylhexyl phthalate (DOP) plasticizer on the degradation behaviour of 50/50 poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blend was studied by long‐term exposure to ambient conditions (27–30°C) in the laboratory. While the unplasticized blend showed obvious changes in physical properties such as hardening, loss of elasticity and embrittlement, the plasticized blend retained its properties. Thermo‐oxidative ageing studies were carried out by evaluating the mechanical properties before and after ageing in an air oven at 80°C for 168 h. The relatively rapid degradation of PVC/ENR blend has been attributed to the high concentration of epoxy groups and the occurrence of ring‐opening reactions to form ether crosslinks. It was found that the plasticizer confers adequate stabilization upon the addition of a certain threshold amount. The optimum amount of plasticizer required to adequately stabilize the blend is 20 phr. Above this there is a tendency for plasticizer migration to occur. The use of an antioxidant in conjunction with the plasticizer further stabilizes the blend. The general trend is of decrease in mechanical and physical properties with increase in DOP concentration. In addition, ease of processing also increases as indicated by the torque maxima and minima obtained from the Brabender plastograms.

Molecular Structural Changes of Plasticized PVC after UV Light Exposure

“…However, some signals decreased more than others, which can be used to monitor the bulk structural change induced by UV irradiation. Of special interest are the intensity decreases of signals in the lower frequency range, including decreases at 1027 and 1127 cm –1 , which have been previously assigned in the literature to the aromatic OCH 2 group of DEHP, and 1280 cm –1 , which has been assigned to the conjugated aromatic ester COO group of DEHP. In addition, there is a broadening of the 1725 cm –1 CO stretch, which suggests that the neighboring chemical environment around the CO bond changed.…”

Effects of Poly(Vinyl Chloride)-Grafted-Maleic Anhydride on the Poly(Vinyl Chloride)/Epoxidized Natural Rubber/Kenaf Core Powder Composite

“…In the case of the thermo-oxidative ageing, the continuous heating condition can be a factor to the self cross-linking formation although it is below 140 °C. The loss in tensile strength after five days and seven days of ageing are due to the further crosslinking and chain scission which leads to the hardening and embrittlement of the sample [7][8]. Fig.…”

“…In addition, the ENR rubber itself has poor ageing resistance due to the opening of the epoxide group while processing with the existence of sulphur and other additives. [7]. In this research, the studies are focused on the water absorption and thermo-oxidative ageing properties of the PVC/ENR/Kenaf core powder composites with the introduction of Poly (Vinyl Chloride)grafted-Maleic Anhydride (PVC-g-MA).…”

Effects of Sodium Dodecyl Sulfate Filler Treatment and Thermo-Oxidative Ageing on the Properties of Poly(Vinyl Chloride)/Epoxidized Natural Rubber/Kenaf Core Powder Composites

“…Epoxidized natural rubber (ENR) itself has poor ageing resistance due to the opening of the epoxide group during processing with the existence of sulphur and other additives. [6][7]. In this research, the mechanical and morphological properties of the thermo-oxidative aged PVC/ENR/kenaf core powder composites are studied.…”