| Illite/Smectite mixing layer mineral clay is a transition mineral transforming fromSmectite to illite (I/S mixing layer clay or I/S clay), which has a complex structure andvarious ingredient proportions. In nature, I/S clay has a wide distribution in soil, rockweathering crust, modern marine lake sediments, new generation to Paleozoic sedimentaryrock, hydrothermal vein rocks, volcanic sediment and other geologic bodies. This claymineral has been found in the southeasten China.The existing work on I/S clay mainly involves the corresponding geological and mineralstudies. There is little work on the preparation and application of I/S clay as an inorganicnonmetallic material. I/S clay can be used as a natural mineral material in various industriessuch as rubber, plastics, paper, ceramic, paint and medicine industries. However, it is difficultto produce and use ultrafine or even nano-sized powder of I/S clay due to their agglomeration.,Advanced process techniques like superfine grinding and surface modification must be usedto obtain the well-dispersive powder for subsequent effective applications.This thesis was to prepare modified I/S clay nano-powders as a reinforcing filler ofstyrene butadiene rubber by ultrafine grinding, subsequent dispersing and swelling withchemicals before drying and surface modification with coupling agents after drying..In Chapter1, recent development on the preparation technology and application ofnanopowders was reviewed. The structure and properties of I/S clay mineral was repersentedin detail. The objectives and contents of this thesis were given.In Chapter2, I/S clay nano-slurry was prepared by breaking, stirring, sieving andultrafine grinding in a high energy density stirred bead mill. In addition, the effects of slurrysolid content, dispersant dosage and grinding time on the product fineness were alsoinvestigated. The results show that the product fineness of I/S clay nano-slurry obtained underthe optimum process conditions is70-72%less than100nm.In Chapter3, an effective pre-treatment technique with surface modification andswelling before drying was used to achieve the dispersed I/S clay nanopowder. The effects ofpH value and dispersant dosage on the dispersion, and the effects of slurry solid content andfoaming agent dosage on the swelling behavior were investigated. The results show that theparticles in the slurry can be dispersed at pH value of10when a dispersant named WF-211isused, and the swelled slurry with smaller and uniform bubbles can be obtained after swellingtreatment, which can improve the subsequent drying efficiency and dried powderdispersibility. In Chapter4, I/S clay nano-slurry after dispersing and swelling was dried by threedifferent drying methods (i.e., evaporative drying, azeotropic distillation drying and spraydrying). The particle morphology and powder fineness were analyzed. The results show thatthe dispersed I/S clay nano-slurry is readily dried by a combined technique of evaporativedrying with pre-treatment of dispersing and swelling.In Chapter5, I/S clay nanopowder was modified with coupling agents for theenhancement of coupling effect between the nanopowder and styrene butadiene rubber. Thecoupling effect was analyzed by dispersion rate determination, activation index analysis,Fourier transform infrared spectroscopy (FTIR) and contact angle measurement, respectively.The results show that the dispersion rate and activation index of I/S clay nanopowder inparoline after the modification are96%and99.35%, respectively. The contact angle is>135°,exhibiting a superior hydrophobicity of the modified powder as a filler of styrene butadienerubber.In Chapter6, the properties of I/S clay nanopowder (i.e., dynamic flow properties, bulkproperties and shear properties) were analyzed to evaluate the flowability and dispersibility.The results show that the dispersibility, flowability and filling ability of I/S clay nanopowderprepared by “dispersing and swelling pre-treatment+evaporative drying†are improved.In Chapter7, a composite of styrene butadiene rubber (SBR) with I/S clay nanopowderwas prepared when I/S nanopowder was modified with silicone oil. The mechanical properties(i.e. tensile strength, tensile rate, tearing strength, etc.) of the composite were examined. It isindicated that the tensile strength and tensile rate of the SBR-I/S clay nanopowder compositeare10.63MPa and792.50%, respectively.Finally, the conclusions obtained in this work and further studies on I/S claynanopowders were presented. |
