微生物矿化改性蒙脱土补强天然橡胶的效果

Effect of Microbial Mineralization Modified Montmorillonite Reinforced Natural Rubber

亲水性蒙脱土在亲油性橡胶基体中因易团聚而达不到良好补强效果,采用传统化学或物理方法对其表面做亲油性改性则存在环境污染、能耗大或耗时长等诸多问题。本工作利用微生物硫酸盐还原菌的腐蚀及矿化作用对蒙脱土插层改性,制备具有插层/剥离结构的微生物蒙脱土并将其应用于橡胶补强。与原始蒙脱土相比,微生物蒙脱土的红外图谱中出现微生物胺化腐蚀的特征峰,Zeta电位降低也表明微生物对蒙脱土发生腐蚀作用,而X衍射图谱中(001)衍射峰下降至6.15°且在1~3°出现新衍射峰,是因为微生物矿化产生CaCO_(3)晶体从而增大蒙脱土层间距。微生物蒙脱土作为补强材料加入非极性的天然橡胶,由于层间距变大的微生物蒙脱土更容易让橡胶分子链穿插其间,且附着于蒙脱土表面的生物被膜有利于改善橡胶-蒙脱土界面相容性,所制备的硫化胶拉伸强度高达20.4 MPa,改性微生物蒙脱土补强效果与单用炭黑N774补强效果接近。将该微生物蒙脱土应用于极性的氯丁橡胶可获得相似补强效果,这显示出微生物矿化蒙脱土应用于橡胶补强材料的广阔前景。

The hydrophilic montmorillonite in the lipophilic rubber matrix tends to aggregate and cannot achieve an ideal reinforcement effect.Using Traditional physical or chemical methods to modify the surface of montmorillonite can cause many problems such as environmental pollution,huge energy or time consuming.In this work,a novel microbial montmorillonite was prepared through both the microbial corrosion and mineralization.The microbial montmorillonite with exfoliated/intercalated lamellar structures was initially achieved by utilizing biomineralization of sulfate-reducing bacteria and then applied to the reinforcement of rubber compounds.Compared with the pristine montmorillonite,the microbial montmorillonite had characteristic peaks of amination corrosion of microorganism in FTIR spectra and the decrease of the zeta potential,showing the effect of microbial corrosion;the(001)diffraction peaks in X-ray spectra dropped to 6.15°while new diffraction peaks appeared at 1—3°,indicating that the microbial mineralization generated CaCO_(3)crystals which expanded the distance between montmorillonite layers.When the microbial mont-morillonite was added into the natural rubber,the tensile strength of the compound achieved 20.4 MPa,which was almost the same as the rei-nforcement effect of carbon black N774,attributing to the enlarged interlayer space allowing the easy penetration of rubber chains and the surface-attached biofilms acting as the compatibilizer.Similar results were also obtained from microbial corrosion reinforcing the polar neoprene rubber,showing the good application prospects of microbial mineralized montmorillonite as reinforcing fillers in rubber industry.