Performance Analysis of Acrylonitrile–Butadiene–Styrene Copolymer and Its Irradiated Products Under Constant and Cyclic Thermal Processes

This study focuses on using constant and ramp cyclic processes to evaluate the performance of acrylonitrile-butadiene-styrene (ABS) copolymer with electron beam irradiation cross-linking. The main objective of this study is to compare the effects of both constant and ramp cyclic thermal processes on ABS where the results demonstrated degradation effects on ABS and its irradiated products. Under constant thermal ageing at 100 degrees C, the impact strength of the samples decreased drastically with increasing irradiation dosage, reaching a minimum value of 54 J/m2 at 250 kGy. Tensile strength also showed a significant reduction, with values dropping from 49 MPa to 43 MPa for samples aged for 2 and 8 days, respectively, when dosages exceeded 100 kGy. This degradation is attributed to the chain scission process induced by prolonged thermal ageing and heating effects. In the ramp cyclic thermal ageing condition (Ramp-100), the impact strength followed a trend similar to the constant 100 degrees C thermal effect but exhibited less severe degradation. The impact strength decreased from 72 J/m2 to 58 J/m2 for the ramp cyclic effect compared to the greater reduction in the constant 100 degrees C condition (73 J/m2 to 54 J/m2). This difference is likely due to the less harsh, intermittent heating ramp cyclic process compared to the continuous heating, suggesting that intermittent heating mitigated thermal degradation and chain scission mechanisms. Differential Scanning Calorimetry (DSC) analysis verified the effects of irradiation and thermal ageing on thermal properties. For unaged samples, the melting temperature remained low at 106.24 degrees C. With irradiation dosages of 100 and 200 kGy, the melting temperature increased to 107.76 degrees C and 111.43 degrees C, respectively, likely due to enhanced intermolecular bonding from increased cross-linking. Overall, cyclic thermal ageing caused less significant degradation of ABS products compared to constant thermal ageing. This suggests that ABS products have a longer service life in environments with ramp cyclic temperature variations compared to constant temperature conditions, which accelerate degradation.