Husken D, Gaymans R J
Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands.
J Mater Sci. 2009;44(10):2656-2664. doi: 10.1007/s10853-009-3348-4. Epub 2009 May 1.
The tensile properties of poly(ethylene oxide)-based segmented block copolymers were studied in the dry and wet state. The hard segments were made up of monodisperse crystallisable tetra-amide segments (T6T6T) comprising terephthalate (T) and hexamethylenediamine (6) groups. The length of the segments making up the soft phase was varied from 600 to 10,000 g/mol. The water absorption of the PEO-based copolymers was found to increase exponentially with the PEO concentration. The modulus and yield strength decreased with water absorption and this effect seemed to be mainly the result of a lowering hard segment content caused by their swelling with water. Upon wetting, the copolymers demonstrated an increased yield strain. Furthermore, the ultimate properties were sensitive to the hard segment content, the molecular weight of the copolymer and whether or not strain-hardening could take place. Upon wetting, the fracture stresses decreased whereas the fracture strains increased. The true fracture stresses of the wet samples were as high as those of the dry samples for reasonable amounts of absorbed water.
研究了聚环氧乙烷基嵌段共聚物在干燥和潮湿状态下的拉伸性能。硬段由包含对苯二甲酸（T）和六亚甲基二胺（6）基团的单分散可结晶四酰胺段（T6T6T）组成。构成软相的链段长度在600至10,000 g/mol之间变化。发现聚环氧乙烷基共聚物的吸水率随聚环氧乙烷浓度呈指数增加。模量和屈服强度随吸水率降低，这种影响似乎主要是由于硬段因吸水膨胀导致其含量降低的结果。润湿后，共聚物的屈服应变增加。此外，极限性能对硬段含量、共聚物的分子量以及是否能发生应变硬化敏感。润湿后，断裂应力降低而断裂应变增加。对于适量吸收的水分，湿样品的真实断裂应力与干样品的一样高。
