Hydrothermal aging of an epoxy-anhydride network has been studied by means of gravimetric analysis, Fourier transform infrared spectroscopy (FTIR) and modulated differential scanning calorimetry (MDSC). The long-term aging results revealed a fourth stage mechanism in which an initial short diffusional period is followed by the hydrolysis of the ester groups. Degraded materials showed two values of glass transition temperature suggesting a heterogeneous process. Hydrolysis undergoes in preferential sites due to the catalytic effect of the carboxyl acids formed during the chemical degradation. Domains with low crosslinking density and high mobility are formed. At long degradation time, samples presented a unique glass transition temperature around 50 °C. The lixiviation of low molecular weight species formed by the hydrolytic scissions was confirmed by FTIR and pH variations.

已经通过重量分析，傅立叶变换红外光谱（FTIR）和调制差示扫描量热法（MDSC）研究了环氧酸酐网络的水热老化。长期老化结果揭示了第四阶段机理，其中最初的短扩散期随后是酯基团的水解。降解的材料显示出两个玻璃化转变温度值，表明该过程是不均匀的。由于在化学降解过程中形成的羧酸的催化作用，水解发生在优先位置。形成具有低交联密度和高迁移率的域。在较长的降解时间下，样品呈现出约50°C的独特玻璃化转变温度。