Guosheng Gai

Preparation and Major Properties of Montmorillonite/Epoxy Nanocomposites

Montmorillonite/epoxy nanocomposites are prepared by intercalation of monomers, which are subsequently polymerized. The results of the structure cha acterization of the composites by XRD and TEM showed that the composites had realized nanometer-dis p sion. Additionally, the testing of mechanical and thermal properties of the nanocomposites s howed that heat distortion temperature of the composite was increased by 10.5%, and plane-stra i fracture toughness by 22.4%, when the ratio of ZZ-MMT(an interlayer spacing of 4.05nm) to epoxide resin was 3w t%.

Preparation of Composite Micro-Bead with Nano-SiO2 Structure Shell by Carbonization

Following the mechanism of heterogeneous nucleation, orthosilicate nuclei deposited on surface of fly ash micro-bead, forming a shell with micro and nanoscale structure, just like nanoscale structure on lotus leaf. Optimized coating-reaction condition is discussed. These composite micro-beads can be used for cheaper super-hydrophobic coating.

Fabrication and Characteristics of Al2O3/Cu Composite Particles by MA & PCS

This paper describes a dry composite process, in which fine α-Al2O3 ceramic guest particles with a mean size of 150 nm were mechanically compounded with metal Cu host particles with a mean size of 25 μm by embedding and curling the guest particles on the surface and inside of host particles using mechanical alloying (MA) and micron/nano particles composite system (PCS). The optimum rotor speed and processing time were determined according to the treatment effect under different conditions. Particles size and other features were investigated. Particles size decreased quickly, and bulk density and tap density of the composite particles increased noticeably under appropriate process conditions. Al2O3/Cu composite material was fabricated via using hot-press sintering technique in argon shield. Microstructure of the composite material was studied by SEM, and the results have shown that a-Al2O3 particles distribute evenly in Al2O3/Cu composite material, which also proved that Al2O3/Cu composite particles could be fabricated perfectly by MA & PCS.

Surface Nano-Particle Coating of Fly Ash

The purpose of the work is to investigate the problems associated with utilization of purified fly ash (PFA) as filler in polymer. The goal is to expand the application field of fly ash. The wet-collected fly ash used in this study was sampled from Huaneng Dezhou Power Plant. Preparation of PFA and composite fly ash (CFA) with nano-structured surface was described in detail. Experimental results show that CFA with rough surface and high whiteness-value had successfully been prepared in Ca(OH)2-H2O-CO2 system. The specific surface area of CFA was thrice or above higher than that of PFA with 2.86 m2·g-1. The whiteness-value of CFA was increased to the range from 63.67 to 73.13 which is more double than that of PFA with 33.54. Filling tests show that the mechanical properties of CFA/PE(polyethylene) composites are superior to these of PFA/PE composites at the same filling ratio of 30/100. This means that change of CFA surface morphology increases contacting opportunities between CFA and polymer matrix and improve the matching state between them when CFA is blended with PE. The results show that CFA as filler appears to have good application, and yet, little serious research has been conducted in the field.

Preparation of Conductive Composite Particles by Impact Coating Process

PCS (particle composite system) is a kind of dry coating equipment. The PCS process involves encapsulating UHMWPE (ultra-high molecular polyethylene) particles with a layer of SCB (super conductive carbon black) or ACB (acetylene black), and subsequently compacting these CB-encapsulated UHMWPE powders by compression molding to manufacture conductive polymer composites respectively. Morphologies of these composite particles were investigated by SEM. By SEM, we can see the conductive networks of CB in polymer composites. Coating-molding process with PCS can be used to form network structure in ceramics and metal as well.

Fractal Dimension of Al(OH)3 Particle and Fractal Simulation of Boundary Micro-Topography

Based on the fractal theories, using image processing software (IPS) to handle the scan electron microscope photos of particles, this paper gives a simple and applied method to pick up the boundary line’s fractal dimension (FD) of particles’ projective numerical images. Take example for Al(OH)3 material particles, adopting respectively relative Box-counting (BC) method and relative C-S method, we have calculated the boundary FD values of the research objects and compared FD with other quantitative token parameters, which shows FD is a sort of more refined quantitative token parameter. Finally, utilizing the method of Generator, we get some fractal figures which have nearly same FD values with Al(OH)3 material particles, utilizing that we can simulate and analyze the complexity of the boundary and surface micro-topography of Al(OH)3 material particles.

Surface Coating of Anhydrite Powders with CaCO3 Nano-Particles Prepared in Ca(OH)2-H2O-CO2 System

Anhydrite powders with nanostructure surface were prepared in Ca(OH)2-H2O-CO2 system. The effects of preparation parameters such as Ca(OH)2 concentration, revolution speed of mixer, temperature on surface finish and reaction speed were investigated. SEM was used to observe the changes of the morphology of anhydrite powders before and after surface coating. The results show that the appropriate condition is: the concentration of Ca(OH)2 should be 2~3%, the temperature between 20~25°C is better, the revolution speed should be big enough and so on. In order to gain nanostructure surface, appropriate technological parameter should be chosen carefully. The SEM photographs show that Anhydrite powders had fine surface morphology after surface finish that the smooth cleavage planes were coated with nanometer particles and the sharp edge angles were blunt by the coating of CaCO3 nanometer particles.

Nanostructured Surface Coating Layer of Calcium Carbonate Composite Particles

The calcium carbonate composite particles with nanostructured surface were prepared by heterogeneous nucleation. The calcium carbonate composite particles consisted of a core of groundcalcium carbonate particle and a shell of nanometer calcium carbonate particles. The thickness of theshell of composite calcium carbonate was observed by TEM. The bond intensity between the core and the shell was measured by means of ultrasonic comminution and stirred ball milling. It was found that the composite calcium carbonate had a compact structure. The linkage between the core and shell was so strong that it must be chemical bond instead of physical adsorption.