Laponite/聚氨酯纳米复合材料制备与性能研究

通过溶剂交换法将无机Laponite从水相转移到N,N-二甲基乙酰胺(DMAC)中,在超声波作用下,Laponite与热塑性聚氨酯(TPU)溶液进行共混复合,Laponite插层到PU分子链间而制备Laponite/聚氨酯纳米复合材料.利用TEM,AFM,TGA,DSC,DMA和静态拉伸对其结构、组成、形貌和性能进行表征,研究结果表明,Laponite优先插层到聚氨酯的硬段中,片层和硬段通过氢键相互作用和尺寸匹配性,进而形成一种插层网络结构.由于这种网络结构的存在,使Laponite/聚氨酯复合材料的强度、硬度及韧性得到同步提高.

PREPARATION AND PROPERTIES OF LAPONITE/POLYURETHANE NANOCOMPOSITES

Laponite/polyurethane nanocomposites were successfully prepared by following two steps:(1) solvent-exchange approach to efficiently exfoliate Laponite into N,N-dimethyl acetamide(DMAC) solvent;(2) under ultrasound insert Laponite into polyurethane macromolecules.The structure and properties of the resulting nanocomposites were characterized by transmission electron microscopy(TEM),atomic force microscopy(AFM),thermogravimeric analysis(TGA),differential scanning calorimetry(DSC),thermodynamic mechanical analysis(DMA) and tensile testing.The results of TEM and AFM indicated that the most of Laponite was fully exfoliated into individual layers and uniformly dispersed in the polyurethane matrix.The Laponite platelets preferentially reinforce the hard segments or micro-domains of polyurethane because of the similar characteristic dimensions of Laponite and hard micro-domains and the hydrogen bond interaction,which was also further confirmed by DMA and DSC.The tensile testing results showed that the incorporation of Laponite into PU gave rise to significant improvements in mechanical properties,including tensile modulus,tensile strength and ultimate elongation.The hierarchical order induced by the addition of discotic Laponite platelets creates a percolated network that significantly improves the stiffness and toughness of the nanocomposites without reducing their extensibility.