【摘要】 利用二苯基甲烷二异氰酸酯(MDI)、聚醚多元醇及小分子扩链剂、交联扩链剂合成了一系列适用于快速硅胶模具浇注成形的二组分聚氨酯(PU)树脂.通过粘度测试考察了PU树脂的浇注性能,使用示差扫描量热分析(DSC)和热重分析(TGA)分析了树脂的热性能,并对其相关的力学性能进行了分析测试.结果表明,PU树脂两组分及其混合液的粘度较小,釜内寿命适中,浇注性能优良;通过调节硬段含量及混和扩链交联剂中三羟甲基丙烷(TMP)含量,使得PU树脂具有较高的力学性能和热性能,浇注成形件可在高负荷、高温下的使用.更多还原

【Abstract】 A series of two-ingredient vacuum casting polyurethane resin(PU) for silicone rubber mold casting were synthesized from diphenylmethane diisocyanate(MDI),polyol,chain extender and crosslinking agent. The effects of hard segment content and hard segment structure on mechanical and thermal properties of PU were systematically investigated by mechanical property test and analyzed using differential scanning calorimetry(DSC) and thermogravimetry(TGA). It is found that PU not only has high tensile strength,flexural strength,flexural modulus,hardness and glass transition temperature(Tg),but remains moderate elongation at break,impact strength and thermal stability. The viscosities and pot lives of two parts of PU resin were tested as well. The results show that the viscosities are very low and pot lives are appropriate for silicone rubber mold casting.更多还原