| This paper analyzes and verifies the factors affecting HTPB-PUA performance. MOCA and E-300 were used to cure the HTPB prepolymer. Mechanical properties were tested in the means of strain-stress and DMA. The influence of HTPB molecular weight, chain extender, crosslinking agent, crosslinking density and the filler were determined. The results showed that:as the HTPB molecular weight increased, the tensile elongation increased and the strength reduced. The mechanical properties of the samples were best when the ratio of prepolymer/E-300 was 50/2.5, E-300 was used as chain extender and the HTPB molecular weight was 2900. The TDI type polyurethane had greater hardness and bigger strength and IPDI type polyurethane was more flexible and had larger tensile elongation.20% of carbon black filler can effectively improve the strength and tensile elongation of the samples. Using SiO2 deteriorated the mechanical properties.On the basis of these studies, the different proportion of polyether and E-300 was applied as curing agents for TDI and IPDI type IV-HTPB prepolymer. Properties of the two-soft segments PUA were tested in the means of low temperature stress-strain, DMA, swelling test and compression test. The results showed that:the curing speed was controlled by changing the ratio of ATPTMO. The elongation increased greatly while the strength decreased little. TDI type samples had good low temperature mechanical properties than IPDI type samples. Crosslinking density increased with the increase of soft segment content. The rebound performance of the samples deteriorated with increasing ATPTMO content.The soft segment ratio of the two-soft segments polyurethane is up to 90%. The two segments are chemically incompatible, so that it has the advantages of the both: good low temperature performance, excellent water resistance, simple and convenient for engineering applications. It is a promising product in the industrial sealant area. |
