采用3种有机改性剂分别对无机粘土进行改性,然后通过熔融共混制得了天然橡胶(NR)/有机粘土纳米复合材料。通过热重分析(TGA)和X-射线衍射(XRD)表征了粘土的有机改性程度。用扫描电镜(SEM)和流变手段表征了纳米复合材料的形态和流变特性。结果表明,含有2条长烷基链和含有2个羟乙基官能团的改性剂对粘土具有更好的改性效果,但由于羟乙基官能团具有强极性,与非极性的NR相容性差,导致有机粘土在基体中大量团聚。各纳米复合材料的储能模量在低频区表现出不同程度的"二次平台"或者"上翘",在时间扫描过程中随着时间变化表现出不同的结构演变。
Three kinds of organic modifiers were chosen to modify the inorganic clay and then natural rubber/organoclay nanocomposites were prepared by melt blending.The modification degree was evaluated by thermal gravimetric analysis(TGA)(and X-ray diffraction(XRD).Morphology and rheological behavior of nanocomposites were characterized by scanning electron microscope(SEM)and rheological technology.The results revealed that modifiers with two long alkyl chains or two hydroxyethyl functional groups were more efficient for the modification of the inorganic clay.However,due to the strong polarity of hydroxyethyl functional groups which was incompatible with nonpolar natural rubber,large agglomerations were formed by the corresponding organoclays in polymer matrix.The nanocomposites exhibited"second plateau"or"upturns"with varying degrees in the storage modulus at low frequencies.The structural changes during dynamic time sweeps were quiet different for the nanocomposites.