Water diffusion in a crosslinked polyether-based polyurethane adhesive
Water diffusion in a crosslinked polyether-based polyurethane adhesive
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DOI：
10.1016/j.ijadhadh.2016.01.005
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发表时间：
2016-04-01
影响因子：
3.4
通讯作者：
Possart, W.
中科院分区：
文献类型：
--
作者：
Huacuja-Sanchez, J. E.;Mueller, K.;Possart, W.
交联聚氨酯（PU）被用作结构胶粘剂。关于水与热塑性聚氨酯的相互作用已经进行了广泛的研究，但在聚氨酯网络方面很大程度上仍未被探索。这里使用一种化学结构简单但定义明确的聚氨酯作为起点，以了解水在这类聚合物中的影响。在水中浸泡长达15天，红外光谱中未观察到聚氨酯化学成分的变化。根据温度的不同，水使聚氨酯样品饱和的时间要早得多。增塑是其结果，表现为聚合物的机械模量显著降低以及玻璃化转变温度向低温移动。有趣的是，仅约70%的水饱和度就足以实现最大程度的增塑。从红外光谱可以得出结论，水削弱了网络内聚合物链之间的相互作用。原本至少一部分通过氢键连接的氨基甲酸酯基团的桥连被水和氨基甲酸酯部分之间的氢键所取代。（C）2016爱思唯尔有限公司。保留所有权利。
Crosslinlced polyurethanes (PU) are employed as structural adhesives. Research has been done extensively on the interaction of water with thermoplastic PU but is still largely unexplored in the case of PU networks. A chemically simple but well-defined PU is utilized here as a starting point to understand the influence of water in this kind of polymer. For up to 15 days of immersion in water, no changes in the chemical composition of the PU were observed in the IR spectra. Depending on temperature, water saturates the PU samples much earlier. Plasticization is the result as a significant decrease of the mechanical modulus and a glass transition shift to lower temperature is observed in the polymer. Interestingly, only some 70% of the water saturation is sufficient for maximum plasticization. It is concluded from the IR spectra that water debilitates the interactions between polymer chains within the network. The bridging of at least a part of the originally hydrogen-bonded urethane groups is substituted by hydrogen bonds between water and the urethane moieties. (C)2016 Elsevier Ltd. All rights reserved.