The Study Of Coal Filled Polymer Composites

The coal is a material of complex aromatic cross-linked macromolecule. There is severe environmental pollution in the process of traditional coal utilization for their thermochemic conversion. The advance of rigid particle filled polymer composites creates new opportunities for developing coal filled polymer composites. It is a new way of direct utilization of coal aromatic macromolecule structure without the thermochemic conversion of coal.A coal filled polyolefin master batch has been developed. The manufacturing process of this master batch consists of ultra-fine jet milling, partial devolatilization and surface modification of the coal, blending and extruding of the modified coal/polymer with enforced venting. The coal filled polyolefin master batch has been applied to produce the anticorrosive pipe and the wire or cable coating material.In this dissertation, they were studied of ultra-fine jet milling and cyclone classifying of coal, F-C alkylation's surface modification, surface wetting of coal powder, mechanical properties and direct current conductance of coal filled polypropylene composites. The in-situ polymerization on coal surface was also been discussed.(1) The ultra-fine jet milling and cyclone classifying of coalThe ultra-fine jet milling and double cyclone classifying and their influences on composition and property of coal were investigated. The results show that the volume weighted mean sizes of coal particle can reach about 5.0μm and 2.5μm after jet milling and cyclone classifying, and the number weighted mean size is about 0.2μm. The composition of each class coal samples has a great difference, this indicates that the macerals and mineral of coal are sufficiently separated and recomposed.(2) The F-C alkylation's surface modificationThe F-C alkylation is an effective way to modify the surface polarity and reduce the surface tension of coal while not destroying the macromolecular structure. The surface alkylation of coal under condition of alkane as solvent or no solvent was studied by FTIR spectrometry and elemental analysis. The results show that the number of possibly grafted alkyl is about 0.5-2.3 per 100 carbon atoms.The F-C acylation reaction with Maliec anhydride as acylated agent was used to measure the activity of F-C reaction in aromatic structure of coal surface. The results showthat the number of activity sites of F-C reaction in aromatic structure on coal surface is about 0.06-0.56 per 100 carbon atoms.(3) The surface wetting of the ultra-fine coal and modified coalThe surface wetting of coal was surveyed by capillary rise technique. To avoid the effect of particle diameter, the capillary mean radius of ultra-fine coal powder was deduced for the first time, a modified Washburn equation was derived: When the depositing density of the ultra-fine particle is the same, the value of A is bigger, the contact angle is smaller, and the surface wetting is better.The results show that the surface tension of coal powder was decreased after ultra-fine pulverizing; The F-C alkylation's surface modification decreases the surface tension markedly, and increases the compatibility of coal with benzene and hexane; The pretreatment of coupling agent have no obvious effect on the coal surface tension.(4) The mechanical properties of coal filled polymer compositesThe mechanical properties of coal/PP composites were investigated, and the effects of coal rank, particle size, surface modification of coupling and alkylation were discussed. The results show that the anthracite and bituminous coal all can be used as filler of plastic after pretreatment of part devolatilization and surface modification; The modulus of composites increase with the content of coal filler; The coupling agent is of no effect for reinforcing the coal/PP composites, except that there are new oxygenous function group forming on the surface in the process of pulverizing; The F-C alkylation reinforce coal(under 10um)/PP composites obviously.When the content of coal filler is 20wt%, the tensile strength o...