Thermoplastic nanocomposites filled with wheat straw cellulose whiskers .1. Processing and mechanical behavior
Thermoplastic nanocomposites filled with wheat straw cellulose whiskers .1. Processing and mechanical behavior
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DOI：
10.1002/pc.10650
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发表时间：
1996-08-01
影响因子：
5.2
通讯作者：
Dufresne, A
中科院分区：
文献类型：
--
作者：
Helbert, W;Cavaille, JY;Dufresne, A
从小麦秸秆中获得尺寸类似于5 nm X 150-300 nm的纤维素微晶。为了评价这些填料在热塑性基体中的增强效果，通过冷冻干燥和模塑微晶和聚（苯乙烯-共-丙烯酸丁酯）胶乳的水性悬浮液的混合物来加工纤维素重量分数为0至30重量%的复合材料。结果发现，这些微晶，或晶须，带来了很大的增强效果，在温度高于基体的玻璃化转变温度（Tg），提高复合材料的热稳定性。松弛模量随着填料含量的增加而不断增加，对于含有30wt%晶须的膜，其松弛模量比基体的松弛模量高一千倍以上。这种效果进行了讨论与理论计算的基础上的平均场方法（Halpin-Kardos模型）。它的结论是，观察到的巨大的增强似乎是由于不仅稻草纤维素晶须的几何形状和刚度，但也微晶的相互作用，它们的拓扑结构的安排，和可能形成的热塑性基体内的晶须簇，纤维素填料可能是通过氢键连接。
Cellulose microcrystals with dimensions of similar to 5 nm x 150-300 nm were obtained from wheat straw. To evaluate the reinforcing effect of these fillers within a thermoplastic matrix, composites with a weight fraction of cellulose ranging from 0 to 30 wt% were processed by freeze-drying and molding a mixture of aqueous suspensions of microcrystals and poly(styrene-co-butyl acrylate) latex. It was found that these microcrystals, or whiskers, bring a great reinforcing effect at temperatures higher than the glass transition temperature (T-g) of the matrix and improve the thermal stability of the composite. The relaxed modulus increased continuously with the filler content, and for a film containing 30 wt% of whiskers, it was more than a thousand times higher than that of the matrix. This effect is discussed with regard to theoretical calculations based on a mean field approach (Halpin-Kardos model). It is concluded that the great reinforcement observed seems to be due not only to the geometry and stiffness of the straw cellulose whiskers but also to the interactions of the microcrystals, their topological arrangement, and the probable formation of whisker clusters within the thermoplastic matrix, the cellulose fillers probably being linked through hydrogen bonds.