A Comprehensive Study on Bakelite Valves in Diaphragm Gas Meters and Improvement of their Physical and Mechanical Properties by Electron Beam Irradiation

The present study investigates the effects of electron beam irradiation on the physical and mechanical properties of Bakelite valves used in diaphragm gas meters. The irradiation is performed under vacuum at ambient temperature. Various analytical techniques, including FTIR, SEM, EDX, XRD, AFM, and TGA, are employed to monitor the physical characteristics of the samples before and after the treatment. In addition, mechanical properties, specifically impact and tensile behaviors, are assessed using an Izod impact tester and a universal testing machine (UTM). A ۱۲ MeV electron beam is utilized at two doses: ۶۰ kGy and ۸۰ kGy. The results demonstrate that irradiation at ۶۰ kGy results in significant enhancements in both physical and mechanical properties. In contrast, at ۸۰ kGy, while some properties exhibit slight improvements, others show deterioration. Moreover, FTIR analysis reveals the elimination of hydroxyl groups at both irradiation doses. In addition, SEM and AFM analyses confirm that the surface properties of samples irradiated at ۶۰ kGy are improved. Furthermore, XRD shows a decrease in crystallinity at this dose. Also, TGA results indicate that samples irradiated at ۶۰ kGy possess higher thermal stability. Specifically, samples irradiated at ۶۰ kGy show a ۱۸۰% increase in impact strength, whereas those at ۸۰ kGy show a ۵۵% increase. Moreover, the Tensile strength increases by ۲% for samples treated at ۶۰ kGy, whereas it decreases by ۳۴% for those treated at ۸۰ kGy. Ultimately, the results confirm that upon electron beam irradiation of Bakelite valves, crosslinking dominates over degradation at ۶۰ kGy, while degradation becomes dominant at ۸۰ kGy.

کلیدواژه ها:

Bakelite valves ، Diaphragm Gas meters ، Electron beam irradiation ، Phenol formaldehyde