| The polyurethane composites reinforced by continuous glass fib er have higher workability and toughness than traditional thermosetti ng resin matrix composites such as epoxy resin and phenol resin. T he high active of -NCO result in polyurethane resin usually has sh orter pot life, so that it is essential to develop one kind of polyuret hane resin with long pot life.First, we prepared polyurethane casting body and composites to research the relationship of some element such as the mole ratio o f [-NCO]:[-OH],the content of polyester polyol and chain extension coefficient. The mole ratio of isocyanate group can improve the h ardness of cured resin. The tensile and bending property could be i mproved by increase the content of the polyester polyol. The cured resin has the better performance of tensile and bending when the chain extension coefficient at the rang from 0.8 to 0.85, the coeffic ient has little effect on the cured resin's hardness.Second, preparing the blocked pre-polymer of polyurethane and two-component polyurethane in the method of blocking method a nd semi pre-polymer process respectively. The viscosity of the bloc ked pre-polymer is increasing with the content of blocked agent. Th e mix viscosity of the blocked pre-polymer and another constituent is above 2000mp's under 25?. The viscosity of two-component pol yurethane is about 1000±200mp's under 30?. The pot life of two-component polyurethane resin is about lhour and its viscosity incre asing slowly. The cured resin's glass transition temperature was abo ut 160?, and its thermal decomposition process could be divided i nto three stage, the cured resin has better tensile performance.Finally, the two-component polyurethane resin was used to pre pared the composites reinforced by continuous glass fiber. The com posites will have the biggest data of bending strength when the con tent of fiber was 72 percent, under 120? for 4hour. The morpholo gy of the composites indicated the resin has good cohesiveness wit h glass fiber. |
PDF Full Text Request