Characterization of Styrene–Vinyl Alcohol Copolymers by CP-MAS NMR Spectroscopy
Characterization of Styrene–Vinyl Alcohol Copolymers by CP-MAS NMR Spectroscopy
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DOI：
10.1021/acs.macromol.2c01009
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发表时间：
2022-08
期刊：
影响因子：
5.5
通讯作者：
Yuyang Ji;Jonathan Catazaro;Qifeng Jiang;Sophia J. Melvin;Jennifer Jiang;R. Klausen
中科院分区：
文献类型：
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作者：
Yuyang Ji;Jonathan Catazaro;Qifeng Jiang;Sophia J. Melvin;Jennifer Jiang;R. Klausen
本文首次用交叉偏振魔角旋转（CP-MAS）光谱对乙烯醇和苯乙烯的统计共聚物（聚（VA-stat-St））进行了固态表征。由于竞聚率的不匹配，聚（VA-stat-St）不能从传统的原料苯乙烯（St）和乙酸乙烯酯（VAc）获得。BN 2-乙烯基萘（BN 2 VN）是应对这一挑战的合成解决方案，因为它与活化单体（例如，苯乙烯、甲基丙烯酸甲酯），并且BN萘侧链可以氧化转化为羟基（−OH）侧链。虽然容易实现高水平的BN 2 VN掺入（例如，> 75mol%BN2VN），先前的工作已经确定当VA的摩尔分数超过0.50时，聚（VA-stat-St）在有机溶剂中溶解性差，推测是由于羟基的亲水性以及可能的链间氢键。为了避免这种溶解度挑战，我们描述了定量固态13 C CP-MAS光谱，证明聚（BN 2 VN-stat-St）向聚（VA-stat-St）的高转化率（85-99%）。11 B CP-MAS证实了有机硼烷官能团的去除。
The first solid-state characterization of statistical copolymers of vinyl alcohol and styrene (poly(VA-stat-St)) by cross-polarization magic angle spinning (CP-MAS) spectroscopy is described. Poly(VA-stat-St) is not available from the traditional feedstocks styrene (St) and vinyl acetate (VAc) due to a mismatch in reactivity ratios. BN 2-vinylnaphthalene (BN2VN) is a synthetic solution to this challenge as it copolymerizes with activated monomers (e.g., styrene, methyl methacrylate), and the BN naphthalene side chain can be oxidatively converted to hydroxyl (−OH) side chains. While high levels of BN2VN incorporation are readily achieved (e.g., >75 mol % BN2VN), prior work has identified that poly(VA-stat-St) is poorly soluble in organic solvents when the molar fraction of VA exceeds 0.50, presumably due to the hydrophilic character of the hydroxyl group as well as possible interchain hydrogen bonding. Circumventing this solubility challenge, we describe quantitative solid-state13C CP-MAS spectra demonstrating high conversion (85–99%) of poly(BN2VN-stat-St) to poly(VA-stat-St).11B CP-MAS confirmed the removal of organoborane functional groups.