Shah Rishabh A, Ostertag Thomas W, Tang Shuo, Dziubla Thomas D, Hilt J Zach
Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA.
Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA.
J Appl Polym Sci. 2021 Apr 20;138(16). doi: 10.1002/app.50257. Epub 2020 Nov 6.
Monomers containing biphenyl moieties were employed to create two sets of covalently crosslinked polymers that displayed noncovalent interactions in their 3-dimensional network. The biphenyls (precursors) used were 2-phenylphenol, 4-phenylphenol and 4,4'-dihydroxybiphenyl, and their acrylated forms were synthesized and named as 2-phenylphenolmonoacrylate (2PPMA), 4-phenylphenolmonoacrylate (4PPMA), and 4,4'-dihydroxybiphenyldiacrylate (44BDA), respectively. These were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) to confirm the successful acrylation reaction. Polymers were synthesized via free radical polymerization reactions with varying crosslinker contents, and their network properties were characterized using swelling studies and compressive modulus tests. Interestingly, swelling studies did not show the expected decreasing swelling ratio with increasing crosslinker content, while compression testing indicated the expected trend of increasing modulus with increasing crosslinking density. The unexpected swelling results are hypothesized to result from the intramolecular interactions between the biphenyl side groups that result in noncovalent crosslinks.
含有联苯部分的单体被用于制备两组共价交联聚合物，这些聚合物在其三维网络中表现出非共价相互作用。所使用的联苯（前体）为2-苯基苯酚、4-苯基苯酚和4,4'-二羟基联苯，它们的丙烯酸化形式被合成并分别命名为2-苯基苯酚单丙烯酸酯（2PPMA）、4-苯基苯酚单丙烯酸酯（4PPMA）和4,4'-二羟基联苯二丙烯酸酯（44BDA）。通过差示扫描量热法（DSC）、核磁共振（NMR）和傅里叶变换红外光谱（FTIR）对这些物质进行表征，以确认丙烯酸化反应成功。通过自由基聚合反应合成了具有不同交联剂含量的聚合物，并使用溶胀研究和压缩模量测试对其网络性能进行了表征。有趣的是，溶胀研究并未显示出随着交联剂含量增加，溶胀率按预期降低，而压缩测试则表明随着交联密度增加，模量呈预期的增加趋势。据推测，意外的溶胀结果是由联苯侧基之间的分子内相互作用导致非共价交联引起的。
