There is a trade-off between water resistance and mechanical properties of the waterborne polyurethane film. Aiming to solve this problem, the waterborne polyurethane-acrylate (WPUBH) was prepared by post-chain extension of dithiol instead of diamine, which could improve the storage stability and reduce the water absorption rate due to the absence of urea groups, and by terminating with hydroxyethyl acrylate, which could reduce the water absorption rate and improve the mechanical properties at the same time deriving from the crosslinking of double bonds after heating. The rate of water absorption for WPUBH-2 film decreased down to 2.87%, and the tensile strength reached 8.5 MPa. The water resistance and the mechanical properties of WPUBH obtained a good balance compared with those of the carboxylate-based waterborne polyurethane-acrylate in the previous reports. They had excellent bonding properties for wood joints, and the tensile shear strength was up to 4.53 MPa.

中文翻译：

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基于二硫醇的扩链后，具有出色的耐水性和机械强度的水性聚氨酯-丙烯酸酯

在水性聚氨酯膜的耐水性和机械性能之间需要权衡。为了解决这个问题，通过二硫醇代替二胺的扩链制备水性聚氨酯-丙烯酸酯（WPUBH），由于没有脲基，可以提高储存稳定性并降低吸水率，并通过终止用丙烯酸羟乙酯，可以降低吸水率，同时由于加热后双键的交联而提高机械性能。WPUBH-2薄膜的吸水率降低到2.87％，拉伸强度达到8.5 MPa。与以前的报道中的羧酸盐基水性聚氨酯-丙烯酸酯相比，WPUBH的耐水性和机械性能达到了良好的平衡。它们具有出色的木材接头粘合性能，拉伸剪切强度高达4.53 MPa。