Enhanced thermal stability of biomedical thermoplastic polyurethane with the addition of cellulose nanocrystals
Enhanced thermal stability of biomedical thermoplastic polyurethane with the addition of cellulose nanocrystals
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DOI：
10.1002/app.41970
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发表时间：
2015-06
影响因子：
3
通讯作者：
Jen-Chieh Liu;Darren J. Martin;R. Moon;J. Youngblood
中科院分区：
文献类型：
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作者：
Jen-Chieh Liu;Darren J. Martin;R. Moon;J. Youngblood
采用溶剂浇铸法将冻干纤维素纳米晶（CNC）分散在热塑性聚氨酯[Pellethane 2363- 55 D（P55 D）]中，制备了CNC增强的纳米复合材料。该研究表明，向P55 D中加入少量（1-5重量%）的CNC提高了热降解温度，同时保持了与纯P55 D相似的刚度、强度和伸长率。CNC添加到P55 D没有改变玻璃化转变温度，但是当1重量%的CNC分散在基质中时，起始分解温度从286 ° C移动到327 ° C。较高的起始分解温度归因于CNC表面上的羟基与P55 D硬嵌段中的氨基甲酸酯基团之间形成氢键。纳米复合材料的极限拉伸强度和失效应变（ε（f））的影响最小，通过添加高达5重量%的CNC，而弹性模量增加了约70%。观察到添加最多5重量%的CNC时α（f）不变，表明在塑性变形期间，硬嵌段和链的流动/滑动不受CNC的存在阻碍。本研究的结果是，CNC添加导致各种生物医学器械的P55 D的加工温度更宽，同时保持相似的刚度、强度和伸长率。(c)2015 Wiley Periodicals，Inc. J.应用聚合物Sci. 2015，132，41970。
Freeze-dried cellulose nanocrystals (CNCs) were dispersed in the thermoplastic polyurethane [Pellethane 2363-55D (P55D)] by a solvent casting method to fabricate CNC-reinforced nanocomposites. This study demonstrated that the addition of small amounts (1-5 wt %) of CNCs to P55D increased the thermal degradation temperature while maintaining a similar stiffness, strength, and elongation of the neat P55D. CNC additions to P55D did not alter the glass-transition temperature, but the onset decomposition temperature was shifted from 286 to 327 degrees C when 1 wt % CNCs was dispersed in the matrix. The higher onset decomposition temperature was attributed to the formation of hydrogen bonds between the hydroxyl groups on the CNC surface and urethane groups in the hard block of P55D. The ultimate tensile strength and strain to failure (epsilon(f)) of the nanocomposites were minimally affected by additions up to 5 wt % CNCs, whereas the elastic modulus was increased by about 70%. The observation that epsilon(f) was unchanged with the addition of up to 5 wt % CNCs suggested that the flow/sliding of the hard blocks and chains were not hindered by the presence of the CNCs during plastic deformation. The ramifications of this study was that CNC additions resulted in wider processing temperatures of P55D for various biomedical devices while maintaining a similar stiffness, strength, and elongation. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41970.