通过缺氧条件下煅烧富含有机质的内蒙硅藻土制备了一种含炭的硅藻土,并将这种炭化硅藻土代替部分炭黑用于天然橡胶的补强.采用红外光谱、X射线衍射、热分析、扫描电子显微镜、能谱和万能材料试验机对炭化硅藻土进行结构表征和力学性能测试.结果表明,于600℃进行2 h的缺氧煅烧处理后,硅藻土中的有机质已经转化为无定形碳紧密吸附于硅藻土壳表面和内部的微孔中,而无定形碳的存在提高了硅藻土和天然橡胶的相容性,有利于天然橡胶力学性能的补强.当炭化硅藻土代替25%(质量分数)的炭黑补强天然橡胶时,橡胶复合材料的拉伸强度和撕裂强度均得到了显著的提升.
A carbonized diatomite was prepared by calcining Inner Mongolia diatomite rich in organic matter under reducing atmosphere.The carbonized diatomite was partly substituted for carbon black to reinforce natural rubber(NR).Fourier-transform infrared spectra(FTIR),X-ray diffraction(XRD),thermoanalysis(TG-DTA),scanning electron microscope(SEM),energy-dispersive spectrometer(EDS) and mechanical properties test were employed to characterize the resultant carbonized diatomite and NR vulcanizates.The results showed that the organic matter in diatomite could be translated into amorphous carbon adsorbed on the surface of diatomite and in the micropore of diatomite after 600 ℃ calcination under reducing atmosphere.Because the carbon in carbonized diatomite could improve the compatibility between diatomite and NR,the introduction of carbonized diatomite into NR matrix could enhance the mechanical properties.When 25%(mass fraction) carbon black was replaced by carbonized diatomite,the tensile strength and tear strength of NR vulcanizates were significantly improved.