İsmail Kutlugün Akbay

Optimization of the vulcanization parameters for ethylene–propylene–diene termonomer (EPDM)/ground waste tyre composite using response surface methodology

The utilization of waste tyre in a green way would definitely mitigate the possible risks of the waste tyre accumulation. A green way to solution for the waste tyre problem is recycling. However, it is necessary to optimize the recycling process parameters to come up with the optimum conditions for the effective reuse of the waste tyre. In this study, response surface methodology (RSM) was used to model and optimize the parameters of curing of EPDM and waste tyre composite for the purpose of waste tyre recycling. EPDM with different loadings of ground waste tyre composites were prepared. Mechanical, thermal, and Soxhlet extraction tests were carried out for the samples. RSM was applied and process parameters were optimized. It was seen that the most effective parameter was the curing temperature. The optimal values of the parameters were determined as curing temperature of 172.1xa0°C, curing pressure of 15.0xa0MPa and ground waste tyre content of 14.8% by weight. To test the parameters determined from optimization study, the samples were prepared under optimum conditions, and it was shown that the samples prepared according to the optimum conditions have better thermal, mechanical, and curing properties. The results were heartening to pursue the waste tyre recycling option with a considerable amount of ground waste tyre content within the final composite material.

Monomer migration and degradation of polycarbonate via UV-C irradiation within aquatic and atmospheric environments

ABSTRACT Polycarbonates (PC) are widely used in daily life as commodity plastics and it is a critical material regarding to the public health for the consequences that may arise especially for infants due to usage in baby bottles. Therefore, understanding the behavior of PC within the degradative environment is vital. In this study, degradation of polycarbonate via UV-C irradiation was studied within atmospheric and aquatic environments. Mechanical, morphological, thermal tests NMR, TGA, SEM, DSC, Extensometer, Yellowness Index, FTIR and HPLC tests of samples irradiated with different irradiation periods within these two environments were carried out. The analysis results have shown that for both of aquatic and atmospheric environments, the degradation and morphological changes were occurred. Structure tests results show that the main degradation occurred on the carbonate group of PC. In addition, significant amount of Bisphenol A was detected via HPLC analysis in the aquatic solution after irradiation in aquatic environment that could be hazardous for the public health.