有机玻璃在盐水条件下老化性能的研究

Study on Brine Ageing Property of Perspex

在盐水(50℃温度,3%NaCl溶液)条件下对有机玻璃做了70d左右的人工加速老化试验,对不同老化时间的有机玻璃试样进行了宏观力学性能测试,并进一步利用凝胶渗透色谱法(GPC)、示差扫描量热法(DSC)等手段分析了老化前后有机玻璃试样的结构和组成差异,结合老化前后有机玻璃力学性能的变化,揭示了有机玻璃在盐水条件下的老化规律和老化机理。实验表明,有机玻璃在温度为50℃,盐质量分数为3%的盐水条件下老化66d,拉伸强度、弯曲强度、弯曲模量都呈现下降趋势。有机玻璃在盐水条件下老化的主要机理是水对有机玻璃的化学作用和物理作用,有机玻璃由于水分渗入的结果影响,降低了分子间的相互作用力(范德华力)从而使材料机械性能下降;同时水对有机玻璃的化学作用没有引起力学性能的变化。

The accelerated aging experiments for PMMA specimens were conducted for 70 d at 50 ℃ in NaC1 solution of 3% concentration）, and the macro-mechanical characteristics of PMMA were tested at different time during the experiments, the structure and composition difference of the samples before and after aging were analyzed by means of GPC and DSC. Combined with the mechanical data, the aging rule and aging mechanisms for PMMA in brine were clarified qualitatively. The results showed the tensile strength, bending strength and bending modulus of PMMA tended to degrade after the brine ageing for 66 d at 50 ℃ in NaC1 solution of 3% concentration. The brine ageing mechanism of PMMA was mainly the chemical and physical actions on PMMA by water. Owing to the permeation of water molecule, the intermolecular force of PMMA decreased, which made the mechanical properties of PMMA degraded; the chemical action on PMMA by water did not change the mechanical properties of PMMA.