The Preparation Of Aliphatic Polyurea Elastomers And Nanocomposites

Polyurea elastomeric material is one of elastomers reacted from isocyanate component and amino compound component. The elastomeric material is a green eco-friendly materials, which has excellent physical and chemical properties, such as mechanical properties, wear resistance, corrosion, etc., without catalyst. During construction, the material is free from ambient temperature and humidity. To further improve the overall performance of polyurea material and expand applications, this paper mainly studied the synthesis of aliphatic elastomeric polyurea and the preparation of nanocomposites.In this study, we have used1,6-hexamethylene diisocyanate(HDI) trimer, isophorone diisocyanate(IPDI) and amino terminated polyether as the main raw materials, dimethylthiotoluenediamine(E300), hexamethylene diamine,4,4-diamino cyclohexylmethane(H12MDA) as chain extender, respectively to synthesize a series of polyurea elastomeric by two-step method. This result shows that the aliphatic polyurea of HDI and IPDI system accord with our expected structure. We have determined the reaction temperature is0℃, the reaction time is30min and used the solvent evaporation deposition. And we knows that the polyurea of IPDI’s mechanical properties is better than the polyurea of HDI. We found the polyureas using different chain extenders’heat resistance order is hexamethylene diamine>E300> H12MDA.In this paper, we have modified IPDI polyurea systems and prepared a series of polyurea nanocomposites by using nano-TiO2and amino nanotubes. The experimental results show that the two polyurea nanocomposites has accorded with our expected structure, better mechanical properties and heat resistance. When the content of nanoparticles is0.7wt%, the polyurea nanocomposites has maximum tensile strength.In order to investigate whether the gel time can be extended, we used piperazine,1,4-cycloheptane dinitrogen(homopiperazine) as the secondary amine chain extender to synthesis polyurea. The study shows that the three polyureas accord with our expected structure. In the case of the same weight loss, the polyurea using1,4-cycloheptane dinitrogen(homopiperazine) has better heat resistance. We found the secondary amine chain extenders have the same gel time with the primary amine chain extenders by testing gel time.