This work explores the process of water ageing of high-temperature high-pressure polymerized urethane dimethacrylate (UDMA) networks. UDMA samples polymerized under several pressures (0.1–300 MPa) and differing by the conversion degree of polymerization were aged in water at 37, 50 and 70 °C and followed by gravimetry. Diffusion was observed to obey Fick's law. The diffusion coefficient and water maximal uptake were observed to be almost independent of polymerization pressure, consistently with analysis of Dynamic Vapor Sorption data suggesting that external polymerization pressure has no effect on polymer affinity with water. This was ascribed to the fact that all materials have the same cohesive energy, as confirmed by ultrasonic measurements of elastic moduli. Polymerization pressure (used to improve conversion degree and mechanical properties) would thus have a minor influence on water ageing that is mainly triggered by polymer chemistry. When elevating the polymerization pressure, there is hence no compromise between the optimization of thermo-mechanical properties and the resistance to water ageing.

这项工作探讨了高温高压聚合的氨基甲酸乙酯二甲基丙烯酸酯（UDMA）网络的水老化过程。在几种压力（0.1–300 MPa）下聚合且因聚合转化率而异的UDMA样品在37、50和70°C的水中老化，然后进行重量分析。观察到扩散遵守菲克定律。观察到扩散系数和水的最大吸收率几乎与聚合压力无关，这与动态蒸气吸附数据的分析一致，表明外部聚合压力对聚合物与水的亲和力没有影响。这归因于以下事实：所有材料都具有相同的内聚能，这一点已通过弹性模量的超声测量得到证实。聚合压力（用于提高转化率和机械性能）因此对水的老化影响很小，这主要是由聚合物化学反应引起的。因此，当提高聚合压力时，在热机械性能的优化与耐水老化性之间不会有任何妥协。