Thermal and mechanical behavior of ethylene-vinyl alcohol copolymer and amorphous nylon blends

Blends of ethylene-vinyl alcohol (EVOH) copolymers with different contents of amorphous copolyamide were studied. Blends films were prepared by various way as melt mixing and cast by dissolving both polymers in a common solvent. The techniques applied on blends films were isothermal and dynamic thermogravimetric (TGA), infrared spectroscopy analysis (FTIR) and dynamic mechanical analysis. The effects on thermal stability and degradation reaction were studied. Weight loss of blends were studied as a function of time under isothermal conditions. Moreover, dynamic TGA tests were used as a qualitative measure of thermal stability by comparing the temperature at which samples degradation begin. Test were performed isothermally at temperatures ranging from 170oC to 220oC. Dynamic test were also performed at rates from 10oC/min at temperatures ranging from 25oC to 550oC. Preliminary studies of EVOH copolymer thermal degradation were performed for 215oC exposure temperature by means of FTIR analysis. Results demonstrated that increasing the content of amorphous polyamide the thermal stability was increased. The dynamic mechanical analysis of blends showed that the polyamide content increases in the blend acts as stiffener of the EVOH copolymer.