Department of Applied Organic Materials Engineering, Chungnam National University, Daejeon, 34134, Republic of Korea.
ANPOLY, Pohang-si, Gyeongsanbuk-do, 37666, Republic of Korea.
Carbohydr Polym. 2021 Apr 15;258:117728. doi: 10.1016/j.carbpol.2021.117728. Epub 2021 Jan 30.
To attain eco-friendly polyurethane composites with enhanced thermal and mechanical properties, in this study, a series of cationic waterborne polyurethane (cWPU) nanocomposite films reinforced with 1-50 wt% chitin nanofiber (ChNF) loadings was fabricated by a facile aqueous dispersion casting. The microstructure, thermal and mechanical properties of the nanocomposite films were investigated by considering the loading content and the interfacial interaction of ChNF in the cWPU matrix. For the purpose, a hard/soft segmented cWPU with an average particle size of ∼151 nm in aqueous dispersion was synthesized by using poly(tetramethylene glycol), isophorone diisocyanate, N-methyldiethanolamine, and 1,4-butanediol. The FT-IR spectra confirmed the existence of specific hydrogen-bonding interactions between hydroxyl/acetyl amine/ammonium groups of ChNFs and urethane/protonated amine groups of cWPU hard segments. Accordingly, the thermal decomposition temperatures of cWPU/ChNF nanocomposite films increased with increasing the ChNF content. In addition, the storage moduli of cWPU/ChNF nanocomposite films increased significantly with the increment of ChNF content up to ∼7 wt%, which stems from the restricted chain mobility of cWPU backbones composed of semicrystalline soft segments and hard segments interacting with ChNFs via multiple hydrogen-bonding interactions.
为了获得具有增强的热性能和机械性能的环保型聚氨酯复合材料，本研究通过简单的水性分散浇铸法制备了一系列阳离子水性聚氨酯（cWPU）纳米复合材料薄膜，其中负载了 1-50wt%的壳聚糖纳米纤维（ChNF）。考虑到 ChNF 在 cWPU 基体中的负载含量和界面相互作用，研究了纳米复合材料薄膜的微观结构、热性能和机械性能。为此，通过使用聚四氢呋喃二醇、异佛尔酮二异氰酸酯、N-甲基二乙醇胺和 1,4-丁二醇，合成了一种在水性分散体中平均粒径约为 151nm 的硬/软段分段 cWPU。FT-IR 谱证实了 ChNFs 的羟基/乙酰基/氨基团与 cWPU 硬段的氨酯/质子化胺基团之间存在特定的氢键相互作用。因此，cWPU/ChNF 纳米复合材料薄膜的热分解温度随着 ChNF 含量的增加而升高。此外，cWPU/ChNF 纳米复合材料薄膜的储能模量随着 ChNF 含量的增加显著增加，最高可达约 7wt%，这归因于由半结晶软段和硬段组成的 cWPU 骨架的链流动性受到限制，硬段与 ChNF 之间通过多种氢键相互作用相互作用。
