Optimization of Flexural Strength of Recycled Polyethylene-terephthalate (PET) Eco-Composite using Response Surface Methodology

Abstract

Recycling and reuse of plastic waste by blending with virgin polymer has been affirmed to be the best way of managing the waste. Equally, agro-waste are best recycled than being burnt off. In the development of stronger and cheaper ecoefficient recycled PET composite for food packaging, this study focused on reinforcement of the blend of 20 wt. % recycled PET (rPET) and 80 wt. % virgin PET (vPET) with snail shell particulate and kenaf fiber via compression moulding process. The process parameters are fiber dosage, particulate dosage, moulding pressure and temperature. Box-Behnken design was engaged in the design of experiment and the samples were produced according to the experimental runs. Result of analysis of variance pinpointed the process factors as significant contributors to the flexural strength response. The model developed was validated to be significant and statistically fit. Interactions between the process variables as revealed by the response surface plots indicated the response was dependent on the interactive pattern between the variables. Response surface optimization showed an optimum flexural strength of 57.16 MPa was attainable at process parameters of 27.27 wt. %, 4.18 wt. %, 3.95 MPa, and 160 ˚C for fiber proportion, particulate proportion, moulding pressure and temperature respectively yielding 34.2 % improvement over the reference 80/20-vPET/rPET matrix. Model validation experiment undergone with the combined parameters and deviation of +0.036 was noted. Since the deviation is insignificant, the model is concluded to be statistically fit for predicting the flexural strength of the developed eco-composite.