Study Of NBR/PA TPV With Excellent Solvent Resistance

The dynamical vulcanization technique,recipe,heat processing condition and relationship between structure and properties of NBR/PA blend was investigated. NBR/PA TPV with good resistance to solvent which composed of gasoline and toluene was prepared.NBR and PA were chosen as the fundamental materials for the study. Both of them were polar. There was good compatibility between them. The results of IR showed that there were chemical reaction between NBR and PA at high temperature and strong shear action. That further proved that it was possible to prepare good blends with even micro morphology.Two techniques were used to prepare the NBR/PA blends. One was static vulcanization and the other was dynamical vulcanization. In the former way, NBR was continuous phase and Nylon was dispersed phase. However,the situation was opposite in the later one. Because Nylon had high strength and excellent oil-resistance,a blend with outstanding properties could be prepared by the later way.The effects of blending technology on the mechanical, rheology properties and microstructure of TPV were studied by transmission microcopy, infrared spectroscopy and capillary rheometer. The results showed that the best technique for the TPV with the chemical reaction between rubber and plastic was "pre-blending rubber and plastic method". The optimal condition for dynamical curing was 170℃*0.7t90.The effects of different vulcanizing systems were investigated. The results showed that SP 1045 not only cured NBR but also cured Nylon,sulfur could led to conglomeration of rubber particles,the hardness and the oil resistance of TPV cured by HVA-2 were worse than DCP. So DCP was the best cure agent. The optimal content was 3 phr. The addition of filler could not improve the solvent- resistance obviously. What's more,the flow property became worse. So the addition of filler was not a good method for the preparation of good oil resistant materials.Effect of heat processing condition on the properties of NBR/ PA TPV was studied. With the temperature decreasing,the oil resistance was improved. The best condition of heat processing condition was 170℃*12min. The crystal structures of TPV were investigated by WXRD and DSC. The results show that the crystal structure was more perfect in nylon phase at lower annealing temperature. This was the key factor for the improvement of the solvent resistance.Effects of nucleating agents on crystallization, mechanical properties and solvent-resistance of dynamically vulcanized NBR/ PA blends were studied. The results showed that Nylon 66/6 copolymer could increase crystallization rate, increase crystalline degree and reduce crystal-size of Nylon. Therefore not only the solvent resistance but also the modulus at 100% of TPV with Nylon 66/6 copolymer was improved.