Three kinds of aromatic diamines (DETDA,tBu-TDA,CPA) as chain extenders and novel polypropylene glycols (designated PPGs) were used for polyurethaneurea reaction injection molding (designated RIM) elastomer. The morphology and physical properties of each polyurethaneurea RIM elastomer were studied by using TEM, SEM, dynamic mechanical thermal analysis. The polyurethaneurea RIM elastomer by using CPA as a chain extender showed superior heat sag data as compared with DETDA and tBu-TDA .
As novel PPGs contain an extremely smaller amount of by-products (monools), the actual functionalities of novel PPGs are higher than that of conventional ones. Polyurethaneurea RIM elastomers by using novel PPGs showed good physical properties and productivity. Especially, heat resistance property from 150 °C to 230 °C was improved by the increase of crosslinking density of polyurethaneurea RIM elastomers. It was also revealed that the increase in molecular weight of novel PPGs and a rise of the post cure temperature accelerate the phase separation of polyurethaneurea RIM elastomers. The transformation of morphology was observed.