Teaching Old Polymers New Tricks: Improved Synthesis and Anomalous Crystallinity for a Lost Semi‐Fluorinated Polyaryl Ether via Interfacial Polymerization of Hexafluoroacetone Hydrate and Diphenyl Ether
Teaching Old Polymers New Tricks: Improved Synthesis and Anomalous Crystallinity for a Lost Semi‐Fluorinated Polyaryl Ether via Interfacial Polymerization of Hexafluoroacetone Hydrate and Diphenyl Ether
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教授旧聚合物新技巧：通过六氟丙酮水合物和二苯醚的界面聚合改进损失的半氟化聚芳基醚的合成和异常结晶度
DOI：
10.1002/marc.202200737
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发表时间：
2022
影响因子：
4.6
通讯作者：
Smith, Jr., Dennis W.
中科院分区：
文献类型：
--
作者：
Muñoz, Gustavo;Chamberlain, Kari M.;Athukorale, Sumudu;Ma, Guorong;Gu, Xiaodan;Pittman, Jr., Charles U.;Smith, Jr., Dennis W.
报道了一种实用的六氟丙酮水合物与二苯醚直接亲电聚合制备半氟聚芳醚（PAE）的方法。在界面条件下，使用相转移催化剂（Aliquat 336）在三氟甲磺酸酐中进行亲电芳族取代（EAS）聚合，通过原位生成三氟甲磺酸和质子化的六氟丙酮（HFA），得到具有高区域选择性（4，4 '-DPE）和高分子量（约60 kDa）的1，1，1，3，3，3-六氟异亚丙基（6 F）PAE。虽然杜邦公司在1966年的美国专利中首次报道了使用苛刻条件的合成方法，但直到现在还没有公开改进的合成方法或现代表征。尽管存在已知赋予无序形态的6 F基团，但这种简单的半氟化PAE表现出异常结晶度，多晶型熔点（Tm）范围为230-309 °C，在常见有机溶剂中的高溶解度，163 °C的玻璃化转变（Tg）和高于500 °C的热氧化稳定性。由溶液制备的坚韧光学透明膜在整个可见光区的透射率高于90%。合成，机械方面，和表征，包括表面和介电性能进行了讨论。
A practical and direct electrophilic polymerization of hexafluoroacetone hydrate with diphenyl ether toward the preparation of semi‐fluorinated polyaryl ethers (PAE) is reported. Electrophilic aromatic substitution (EAS) polymerization under interfacial conditions with phase transfer catalyst (Aliquat 336) proceeds in trifluoromethanesulfonic anhydride by generation of trifluoromethanesulfonic acid and the protonated hexafluoroacetone (HFA) in situ affording 1,1,1,3,3,3‐hexafluoroisopropylidene (6F) PAE with high regioselectivity (4,4’‐DPE) and high molecular weight (≈60 kDa). Although first reported in a 1966 US Patent by DuPont using harsh conditions, improved synthetic methods or modern characterization has not been disclosed until now. Despite the presence of the 6F group, known to impart disordered morphology, this simple semi‐fluorinated PAE exhibits anomalous crystallinity with polymorphic melting points (Tm) ranging from 230–309 °C, high solubility in common organic solvents, a glass transition (Tg) of 163 °C, and thermo‐oxidative stability above 500 °C. Tough optically clear films prepared from solution give transmittance higher than 90% throughout the visible region. Synthesis, mechanistic aspects, and characterization including surface and dielectric properties are discussed.