Preparation Of Activated Nano-sized Kaolin Clay As Rubber Filler

Kaolin clay, which is a compound of Si-O tetrahedral sheets and Al–(O)OH octahedralsheets and belongs to two-sheet type layered lattice silicate, is an envormental-friendly naturalmaterial. This material is extensively used in various industries like ceramic, ploymer (rubberand plastic), paper, pigment/coating, chemicals and pharmaceutical. The effective preparationof nano-sized kaolin clay (NKC) is a promising aspect of recent development and applicationof kaolin clay material. The objective of this thesis was to prepare an activated nano-sizedkaolin clay (ANKC) by a combined processing technique with various methods such as ureaintercalation-ultrafine grinding, sulfuric acid treatment, dispersion, drying and surfacemodification, and to investigate the ANKC used as a filler of butadiene styrene rubber (SBR).In the chapter2, the micro-sized kaolin particles that were pre-intercalated with ureawere ground in a high-energy density stirred beads mill to prepare NKC effectively.Pre-intercalation effect on grinding energy and product fineness were evaluated. Also, theeffects of parameters (i.e. stirrer speed, solid content, addition of dispersant and feed rate) onthe specific surface area and characteristic particle size of ground product were investigatedvia the experiment with the orthogonal experimental design in order to optimize theparameters. The NKC product with the particles of70%<100nm was obtained via thepre-intercalation with urea and subsequent ultrafine grinding. The lamella thickness and thespecific surface area of the NKC are10～30nm and65.05m2/g, respectively. This hybridmethod could reduce the energy consumption in the preparation of the NKC, compared to thesingle method (i.e. chemical intercalation or mechanical grinding).The Chapter2also investigated that the NKC was etched by sulfuric acid in order toobtain the ANKC with the greater activation. The specific surface area of the ANKC is127.42m2/g. X-ray diffraction indicated that the layered structure of kaolinite could not bedestroyed, and the urea on the kaolinite was desorbed by the sulfuric acid with a lowconcentration.In the Chapter3, the adsorption of surfactants and inorganic electrolytes on kaolin claysamples were analyzed, respectively. The effect of adsorbents on the dispersion andmodification of kaolin samples were investigated using various characterization methods (i.e.absorbance and dispersion coefficient).In the Chapter4, two drying methods (i.e. spray drying and azeotropic distillationdrying) were applied to prepare the well dispersive NKC and ANKC powders. The particlemorphologies were characterized by Scanning Electron Microscope (SEM). Also, the dispersion property of powders pretreated with various dispersants was characterized withimage analysis and particle size measurement.In the Chapter5, the clay particles(i.e. ANKC-CTAB) were coated by hydrogensilicone oil or coupling agent. The influence of silicone oil content on the activation index anddispersion coefficient was evaluated. Various characterization methods (i.e. Fourier transforminfrared spectra, Thermogravimetry and differential scanning calorimetry, dynamic or staticcontact angle) were applied to investigate the modification and adsorption of CTAB andsilicon oil.The Chapter6shows the experimental results of the modified ANKC or NKC used as afiller of the SBR. The mechanical properties (i.e. tensile strength and tearing strength) of thecomposites were examined. The tensile strength and tensile rate of SBR/D-ANKC were14.0MPa and898%, respectively. The tensile strength and tensile rate of SBR/D-ANKC modifiedwith silicone oil were15.4MPa and689%, respectively. The tensile strength and tensile rateof SBR/D-NKC modified with SI69were14.3MPa and811%, respectively.In addition, this thesis suggested the corresponding future work.