The Influence of Gamma Irradiation on Repeated Recycling and Accelerated Acrylonitrile Butadiene Styrene Terpolymer Aging

Tostar S Stenvall E

doi:10.4172/2252-5211.1000152

Abstract

Electronic waste also referred to as waste electrical and electronic equipment (WEEE) is the fastest growing waste stream in Europe today. The fast exchange pace of mobile phones, television sets and computers create an important need to develop recycling areas to take care of, reuse and recycle all the materials they contain. One common plastic in WEEE is acrylonitrile butadiene styrene terpolymer (ABS). Repeated recycling of plastic causes it to chemically degrade and one of the unwanted effects is the shortening of the polymer chains. Gamma irradiation is known to be able to crosslink polymers and thus reverse the chain shortening. Therefore, the hypothesis of this study is that gamma irradiation of ABS would have a beneficial effect when recycling plastic. Comparative experiments of gamma irradiation has been done according to two methods: A single gamma irradiation (40 kGy) before the extrusion and aging cycles, and the effect of four 10 kGy doses delivered before each of the re-extrusion steps were completed. The results show that gamma irradiation has an impact on the mechanical and rheological properties of ABS. The yield stress increased with irradiation doses of 0, 10, 50 and 400 kGy. The viscosity also increased in the test samples with irradiation doses of 0, 10, 100 and 200 kGy. In the multi-recycling and accelerated aging test, there was a significant reduction in stiffness for the gamma irradiated samples after the second out of four cycles which cannot be fully explained.

Highlights

Recycling of plastics from electronic waste has become of increased importance since the waste electrical and electronic equipment (WEEE) directive (Directive 2012/19/EU, Annex V) requires increased recycling levels
Effect of the gamma irradiation dose on Acrylonitrile butadiene styrene terpolymer (ABS) Excluding the 10 kGy sample which was not following the pattern, a decrease in stiffness with increasing irradiation dose was observed and illustrated in Figure 1, which is supported by Figure 2
This is contradictory to the results Perraud et al found. They saw an increase in stiffness for the hydrogenated nitrile butadiene rubber (HNBR), an elastomer commonly used in the automotive and printing industries, which includes two components of ABS, A- and B, when it was irradiated with an electron beam [12]

Summary

Introduction

Recycling of plastics from electronic waste has become of increased importance since the WEEE directive (Directive 2012/19/EU, Annex V) requires increased recycling levels. In this work a comparison between gamma irradiated and unirradiated ABS has been done to compare the degradation behavior of both materials after recycling. The standard deviation is calculated on five test specimens per irradiation dose and shown in the figures with ± σ.

Results

Conclusion