New Negative Poisson's Ratio Of New Formulations Of Materials Synthesis And Flame-retardant Anti-static Pvc Design

Through molecular design, a series of liquid crystalline copolyesters, which possibly possessed the auxetic behavior, were prepared by solution condensation reaction between 2, 5-bis(p-alkoxy benzoyloxy) hydrobenzoquinone, 4, 4'- (decanoxy) dibenzoyl chloride and 4, 4'-dihydroxy-oc, co-diphenoxydecane. The chemical structures of all the intermediates and monomers were confirmed by melting point, 'H-NMR, IR and Elemental Analysis and their liquid crystalline behavior was examined by using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The resulting polymers were characterized by 'H-NMR, IR, DSC, POM, gel permention chromatography (GPC). The relations between structures and properties were studied systemtically. The influences of the lateral rod content on the polymers' solubility and the stability of liquid crystalline states and chemical structures were discussed in detail. The impacts of the volume of end groups on the properties of synthesized polymers were also investigated.All the polymers had lower melting points, which indicated that the polymers could easily turn into a liquid crystalline state. The liquid crystalline field of the polymers could be well kept at room temperature and the initial decomposition temperature of all the polymers was higher than the clearing point. These afforded a easier fabrication in obtaining auxetic materials. Besides, multiple decomposition peaks appeared in the TG and DTG curves, which resulted from the existance of different segments in the polymers.The results of DSC and POM indicated that the polymers were nematic liquid crystalline polymers, the relative molecular weights of which roughly ranged from 4000 to 6000. The introduction of lateral rods firstly induced the decrease of crystallization ability, which resulted in the descent of melting points. Further increasing the lateral rods centent resulted in the increase of polymers' melting points. But it was interesting that the solvability was enhanced all the time. With the increase of the end-group's volume, the melting points and clearing points followed the same trend while the stability of liquid crystalline states became worse.The calculation about the Negative Poisson Ratio of nematic liquid crystalline polymers was systemtically performed based on the A. C. Griffin's molecular model. Based on the understanding of Netative Poisson Ratio mechanism and the characteristics of liquid crystalline polymers, the ability for the smectic liquidcrystalline polymers possibly to bear the auxetic behavior was firstly proposed. At the same time the ideal molecular model was upbuilt and the calculation about the Negative Poisson Ratio of smectic liquid crystalline polymers was theoretically carried out.In addition, two recipes of the PVC solid-core flame retardant conveyor belt for coal mine were excellently analyzed aiming to reduce the cost and to improve the product's compositive performance. The effects of all kinds of factors and additives on the viscosity of the PVC paste and blends were sysmetically examined. Viscosities, flame-retardant properties, surface resistances, mechanical performances of all the improved recipes were investigated. The cost of the improved recipes was largely fallen down and the compositive properties were better than those of the initial recipes. The results made clear that the economic benefit of 1.2 million RMB can be obtained annually.