s:Hydrolysis kinetics and thermal stability of Ethylene-vinyl acetate copolymers(EVA) and Polyvinyl acetate(PVAc) have been studied comparatively. by using thermal hydrolysis

chemical titration

infrared spectrum

thermogravimetry analysis and Differential scanning calorimetry(DSC). The result shows that the hydrolysis rates of PVAc is about 25~30 times faster than EVA

it is due to the introduction of vinyl chain in the molecular structure of EVA reduces the acetoxy density

and space effect of double bond adjacent to the acetoxy group

making EVA get good hydrolysis stability. At the same time

greatly increasing the thermal stability of the molecular structure. Therefore

PVAc is peculiarly prone to degraded during the long storage process. However

EVA could dramatically improve the long term storage failure of the cartridge.