Center for Biobased Chemistry, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea.
Center for Biobased Chemistry, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Yuseong-gu, Daejeon, 34114, Republic of Korea; Department of Green Chemistry and Environmental Biotechnology, University of Science & Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea.
Carbohydr Polym. 2017 Mar 1;159:125-135. doi: 10.1016/j.carbpol.2016.12.019. Epub 2016 Dec 8.
A series of elastomeric nanocomposites with superior tensile strength and extensibility, simultaneously exhibiting softening, was prepared using in situ polymerization by homogeneously dispersing TEMPO-oxidized cellulose individualized nanofibers (TOCNs) in a polyurethane urea (PUU) matrix. The structure of these PUU composites covalently cross-linked with the TOCNs was characterized. It was interesting to find that the amount and size of the hard domains in the composites gradually decreased by introducing crosslinkable TOCNs. With only 2wt% of TOCNs incorporated, a 10.4-fold increase in tensile strength, 5.5-fold increase in strain-to-failure, and a decrease of 35% in the coefficient of thermal expansion were achieved, compared with those of neat PUU. However, the elastic modulus of the nanocomposites gradually decreased with up to 1wt% of TOCNs. Conversely, with 2wt% of TOCNs, the stiffness of the elastomers again increased, due to filler-filler interaction over the CNFs percolation in the nanocomposites.
采用原位聚合法，通过在聚氨酯脲（PUU）基体中均匀分散 TEMPO 氧化纤维素纳米纤维（TOCNs），制备了一系列具有优异拉伸强度和伸长率、同时表现出软化的弹性体纳米复合材料。对这些与 TOCNs 共价交联的 PUU 复合材料的结构进行了表征。有趣的是，发现通过引入可交联的 TOCNs，复合材料中硬段的数量和尺寸逐渐减小。与纯 PUU 相比，仅加入 2wt%的 TOCNs，拉伸强度提高了 10.4 倍，断裂伸长率提高了 5.5 倍，热膨胀系数降低了 35%。然而，纳米复合材料的弹性模量随着 TOCNs 的用量增加到 1wt%而逐渐降低。相反，当 TOCNs 用量为 2wt%时，由于纳米复合材料中 CNFs 的渗滤导致填料-填料相互作用，弹性体的刚度再次增加。
