Papadopoulos Lazaros, Kluge Marcel, Bikiaris Dimitrios N, Robert Tobias
Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University ofThessaloniki, GR-541 24 Thessaloniki, Greece.
Fraunhofer Institute for Wood Research - Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108Braunschweig, Germany.
Polymers (Basel). 2020 Apr 22;12(4):980. doi: 10.3390/polym12040980.
In the field of polymer chemistry, tremendous efforts have been made over the lastdecade to replace petrochemical monomers with building blocks from renewable resources. In thisrespect, itaconic acid has been used as an alternative to acrylic acid or maleic acid in unsaturatedpolyesters for thermal or UV-curing applications. However, examples of poly(ester amide)s fromitaconic acid are scarce. Under standard polycondensation reactions, the presence of free aminesleads to aza-Michael addition reactions at the α,β-unsaturated double bond of the itaconic acid andisomerization reactions to mesaconic acid. Both reactions make the resulting materials useless asUV-curing polymer resins. To avoid these undesired side reactions, we herein report the use ofpreformed, well-defined diols containing internal amide bonds. The resulting unsaturatedpoly(ester amide) resins were analyzed before and after UV-induced crosslinking. Viscositymeasurements revealed a strong thixotropic behavior induced by the amide groups, which isusually not detected in structurally similar polyester resins.
在高分子化学领域，过去十年人们付出了巨大努力，用可再生资源的结构单元替代石化单体。在这方面，衣康酸已被用作不饱和聚酯中丙烯酸或马来酸的替代品，用于热固化或紫外线固化应用。然而，由衣康酸制成的聚（酯酰胺）的例子却很少。在标准缩聚反应中，游离胺的存在会导致在衣康酸的α,β-不饱和双键处发生氮杂-Michael加成反应以及异构化为中康酸的反应。这两种反应都会使所得材料无法用作紫外线固化聚合物树脂。为避免这些不良副反应，我们在此报告使用含有内酰胺键的预制、结构明确的二醇。对所得的不饱和聚（酯酰胺）树脂在紫外线诱导交联前后进行了分析。粘度测量显示，酰胺基团引发了强烈的触变行为，而在结构相似的聚酯树脂中通常检测不到这种行为。
