Extraordinary Reinforcement Effect of Three-Dimensionally Nanoporous Cellulose Gels in Poly(ε-caprolactone) Bionanocomposites
Extraordinary Reinforcement Effect of Three-Dimensionally Nanoporous Cellulose Gels in Poly(ε-caprolactone) Bionanocomposites
复制标题
三维纳米多孔纤维素凝胶在聚（ε-己内酯）生物纳米复合材料中的非凡增强效果
DOI：
10.1021/am500337p
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发表时间：
2014-05-28
影响因子：
9.5
通讯作者：
Cai, Jie
中科院分区：
文献类型：
--
作者：
Li, Kai;Song, Jianhui;Cai, Jie
采用碱金属氢氧化物-尿素水溶液溶解和凝聚纤维素制备三维纳米多孔纤维素凝胶（NCG），并在NCG中原位开环聚合ε-己内酯（PCL）单体制备NCG/PCL纳米复合材料。NCG/PCL纳米复合材料的NCG含量可以通过压缩脱水改变起始水凝胶的水含量来控制在7和38%v/v之间。FT-IR和固态C-13 NMR表明PCL在纤维素上的接枝最可能发生在C6-OH基团上，对于含有7%v/v NCG的纳米复合材料，PCL的接枝率为25wt%。1H-1 NMR、XRD和DSC结果表明，NCG的存在显著地限制了复合材料中PCL的数均分子量和晶体的形成。AFM图像证实，相互连接的纳米纤维状纤维素网络结构的NCG是精细分布和保存良好的PCL矩阵聚合后。DMA结果表明，上述的玻璃化转变和熔融温度的PCL矩阵的纳米复合材料的拉伸储能模量显着增加。逾渗模型被用来评估的纳米复合材料的机械性能，其中相互连接的纳米原纤网络之间的应力传递，促进通过强分子间氢键和缠结的纤维素纳米纤维。
Three-dimensionally nanoporous cellulose gels (NCG) were prepared by dissolution and coagulation of cellulose from aqueous alkali hydroxide-urea solution, and used to fabricate NCG/poly(epsilon-caprolactone) (PCL) nanocomposites by in situ ring-opening polymerization of epsilon-CL monomer in the NCG. The NCG content of the NCG/PCL nanocomposite could be controlled between 7 and 38% v/v by changing water content of starting hydrogel by compression dewatering. FT-IR and solid-state C-13 NMR showed that the grafting of PCL onto cellulose are most likely occurred at the C6-OH groups and the grafting percentage of PCL is 25 wt % for the nanocomposite with 7% v/v NCG. H-1 NMR, XRD, and DSC results indicate that the number-average molecular weight and crystal formation of PCL in the nanocomposites are remarkably restricted by the presence of NCG. AFM images confirm that the interconnected nanofibrillar cellulose network structure of NCG are finely distributed and preserved well in the PCL matrix after polymerization. DMA results show remarkable increase in tensile storage modulus of the nanocomposites above glass transition and melting temperatures of the PCL matrix. The percolation model was used to evaluate the mechanical properties of the nanocomposites, in which stress transfer among the interconnected nanofibrillar network is facilitated through strong intermolecular hydrogen bonding and entanglement of cellulose nanofibers.