Kwon Yong Rok, Park Jun Ho, Kim Hae Chan, Moon Seok Kyu, Kim Dong Hyun
User Convenience Technology R&D Department, Korea Institute of Industrial Technology (KITECH), 143, Hanggaul-ro, Sangnok-gu, Ansan-si 15588, Gyeonggi-do, Republic of Korea.
Department of Material Chemical Engineering, Hanyang University, 55, Hanggaul-ro, Sangnok-gu, Ansan-si 15588, Gyeonggi-do, Republic of Korea.
Polymers (Basel). 2024 Oct 1;16(19):2794. doi: 10.3390/polym16192794.
Waterborne polyurethane (WPU) often suffers from poor water resistance and mechanical properties due to hydrophilic emulsifiers. To address these issues, this study introduces glycidyl carbamate (GC) as a crosslinker to improve WPU performance. Three types of GC were synthesized using aliphatic, cycloaliphatic, and aromatic isocyanates, respectively. The crosslinked network was established through a reaction between the epoxide group of GC and the carboxylic acid and amine groups of WPU. Among these, the WPU film utilizing aromatic isocyanate-based GC exhibited the highest crosslink density, modulus, hardness, and water resistance, due to the rigidity of the aromatic molecular structure. However, the film displayed excessive brittleness, resulting in reduced tensile strength, along with yellowing typically associated with aromatic compounds. The WPU crosslinked with cycloaliphatic GC demonstrated the next best mechanical properties and water resistance, with a 2.7-fold increase in tensile strength, a 1.5-fold increase in hardness, and a 66% reduction in the water swelling ratio compared to neat WPU. This study presents a novel and effective strategy to enhance the water resistance and mechanical properties of WPU films, making them suitable for advanced coating applications.
由于亲水性乳化剂的存在，水性聚氨酯（WPU）通常具有较差的耐水性和机械性能。为了解决这些问题，本研究引入氨基甲酸缩水甘油酯（GC）作为交联剂来改善WPU的性能。分别使用脂肪族、脂环族和芳香族异氰酸酯合成了三种类型的GC。通过GC的环氧基团与WPU的羧酸和胺基团之间的反应建立交联网络。其中，利用基于芳香族异氰酸酯的GC的WPU膜表现出最高的交联密度、模量、硬度和耐水性，这归因于芳香族分子结构的刚性。然而，该膜表现出过度的脆性，导致拉伸强度降低，同时出现了与芳香族化合物相关的泛黄现象。与纯WPU相比，用脂环族GC交联的WPU表现出次优的机械性能和耐水性，其拉伸强度提高了2.7倍，硬度提高了1.5倍，水溶胀率降低了66%。本研究提出了一种新颖有效的策略来提高WPU膜的耐水性和机械性能，使其适用于先进的涂料应用。
