Influence of Temperature on Compression, Impact Strength and Barreling in Recycled Polyvinylchloride
Izod-type impact and compression tests were carried out on virgin and recycled unplasticized polyvinylchloride (uPVC) for different temperatures, T; from 25oC to 130oC at intervals of 15oC, to determine and compare their impact strength and axial compressive stress (σz)a, respectively. Appropriate formulae available in literature were used to determine the barreling correction factor; C, and the effective stress at fracture with respect to C; σeff. Comparison was made between (σz)a and σeff to determine the effect of barreling on (σz)a at fracture for virgin and recycled uPVC. Empirical equations were developed to describe the relationship between T, (σz)a and σeff. The results show that under dynamic loading, recycled uPVC exhibit greater impact strength at 70oC (142.86 and 171.43J/m for virgin and recycled uPVC, respectively) and temperatures above 85oC; while 85oC to 100oC is the transition temperature range for change in appearance of break in specimen. Compression test show that except at 85oC, recycled uPVC show greater (σz)a. Softening temperature (Ts = 85oC) of uPVC was discovered to have significant effect on the impact and compressive behaviour of uPVC. Barreling causes reduction in σeff for virgin and recycled uPVC by a mean C of 1.2474 and 1.7404, respectively. The relevance of the model was discussed.
Keywords: Virgin uPVC, Recycled uPVC, Barreling, Correction factor, Softening temperature