The Research On New Macromolecule Vehicle Crashworthy-Guardrail Material

It is the researchers'target to seek for preparing a new kind of macromolecule vehicle crashworthy-guardrail material, especially with properties of a high impact strength,an enough bend Young's modulus, a low price, no pollution and no servicing, etc. After the development course and progress, existent shortcoming and crashworthy mechanism were introduced in and outside domestic's macromolecule crashworthy-guardrail, the preparation of the new macromolecule crashworthy-guardrail has been studied and analyzed detailedly in this paper.The vehicle crashworthy-guardrail material system has been determined by comparing, the results of the preliminary experiments of the PVC composite,PVC/ABS composite and ABS composite which have been manufactured by the extruder and injection molding machine successively; To check the accuracy in simulating the injection molding by Moldflow software, the rationality of structure design of the mould that will be used in injection molding have been analyzed by Moldflow,and the material data has been self-defined;NanoCaCO3/PTW/P83/ABS composite was prepared by the orthogonal experiment design and extrusion—injection molding, and the best batch formula was obtained by range and variance analysis according to the main index- notch impact strength and bend Young's modulus; Finally, the crashworthy mechanism has been analyzed by SEM in notch impact cross-section of the final prepared crashworthy-guardrail material.The results show that the PVC composite and PVC/ABS composite can be easily extruded, but not be easily injected in the preliminary experiment,and the composite can be easily charried and a bad property would be showed if the molding parameter cannot be controlled well.However, the NanoCaCO3/PTW/P83/ABS composite has a good liquidity and a excellent processability, it is suitable for a automobile crashworthy-guardrail material usage; the design of gate position of mould is relatively rational, but the cavity thickness is irrational, just so, the optimize technics results of composite injection molding that gained by Moldflow simulation just as a guidance during the experiment. The best preparation program of NanoCaCO3/ PTW/P83/ABS composite is that the mass percent of PTW is about 10%,P83 , about 10%, NanoCaCO3 , about 2.5% and NDZ-201 is suilable for the surface treatment of PTW.After being re-prepared, the notch impact strength, bend Young's modulus, flexural strength and tensile strength of the composite are increased by 39.8%,176%,79.3% and 20.1% separately increaser than the pure ABS resin, and its main properties can be satisfied with the industry standard. The crashworthy mechanism of the crashworthy-guardrail composite shows that the cavities are generated and lots of small cavities created in its surface; Serious tearing, deep cavities and biggish fluctuation are main features in the notch impact cross-section, which reasons are that cavities are generated on the surface and inside the rubber particle, then the stretch and shear phenomena are raised among the cavities of polymer chains when composite was impacted, so that the plastic deformation of matrix is raised, which make the composite has better crashworthiness.