Preparation And Application Of Polypropylene Composites For Trenchless Pipe

Compared with the traditional excavation construction, moderntrenchless technology is a technical revolution. It can be constructed withoutdestroying the road, vegetation, and affecting the environment, trafficconditions. It effectively solves the difficult problem of laying pipes underthe railways, rivers and existing buildings. It has great application value onthe development and upgrading transformation of power, communicationand building drainage industries. There is a remarkable significance ineconomics and society.Polypropylene (PP) is widely used in industry and civilian areasbecause of its good mechanical and processing properties as well as low costof production. Modified polypropylene (MPP) cable pipe is widely used inelectricity, telecommunications, drainage and other fields.In this paper,2500mesh calcium carbonate and2500mesh kaolin wereused as the fillers for reinforcing agents. Titanate（NDZ-105） was used ascoupling agent for the modifications of the calcium carbonate and kaolinsurfaces. PP/calcium carbonate and PP/kaolin composites were preparedthrough the double-screw extrusion mechanism, followed by being injectedinto the spline. The mechanical properties, rheological properties, and thechange law of crystallization properties of the composites materials weresystematically studied via universal testing machine, scanning electronmicroscope (SEM), differential scanning calorimeter (DSC) and other methods.The surface properties of calcium carbonate kaolin were amelioratedfor better cohering to PP matrix and the dosage of modification agent andthe technology were confirmed. With the increase of the content of calciumcarbonate and kaolin, tensile strength and tensile modulus of the compositesincreased to drop, reaching the peak values at30%, the notched impactstrength and elongation decreased gradually, flexural strength increasedslightly. The melt flow rate (MFR) test results show that the MFR of thecomposites descended with the increase of additives, especially obviousfilling with kaolin. Vicat softening temperature (VST) rising indicated thatthe thermal stability was improved. But the processability of the compositeswas not influenced by adding calcium carbonate or kaolin.The valuable composition and the production technology have beenused in industry, and the trenchless pipeline products also been applied incivil construction.