Papers by Author: Yu Hua Yi

Abstract: The present study described the effect of the different synthetic methods, hard segment types, chain extension coefficient and the starting NCO/OH molar ratio on the compression set and the other properties of castable polyurethanes based on polytetrahydrofuran glycol (PTMG).The result showed that the system of PTMG/TDI/MOCA prepared by a quasi-prepolymer method and with the starting molar ratio of TDI to PTMG of 6:1 exhibits lower compression set.

Abstract: A series of castable polyurethane elastomers, based on polytetramethylene glycol as soft segments and toluene diisocyanate, 4, 4’-diphenylmethane diisocyanate, P-phenylene diisocyanate as diisocyanates respectively, were synthesized. The dynamic mechanical analysis method was utilized to determine tan delta property (tanδ). Also the influence of diisocyanates on the dynamic mechanical properties of castable polyurethane elastomers was analyzed. It can be concluded that the P-phenylene diisocyanate system elastomers have the most excellent dynamic mechanical properties.

Abstract: Aqueous polyurethane (APU) dispersions with improved hydrophilicity were presented and characterized. In order to make APU products more competitive, anionic diols and dimethylopropanic acid (DMPA) were introduced into the macromoleculars of APU. The particle sizes of the APU dispersions have been reduced from 0.7~3μm to 0.05~0.6μm, and the storage stability has been prolonged from 6 months to 12 months. It is efficient to prepare the self-emulsifiable APU dispersions by applying anionic polyester diols and using triethanolamine (TEOA) as a neutralization agent.

Abstract: Based on PTMEG and TDI as raw materials,a polyurethane prepolymer with low free TDI monomer was synthesized by molecular distillation method,then a castable polyurethane solid tire was preparaed with MOCA as chain extender,and the dynamic performance of this elastomer and the durable properties of this solid tire was investigated.The results showed that the polyurethane elastomer based on the low free prepolymer has excellent dynamic performance, a low heat build-up and the solid tire has excellent endurance quality.

Abstract: Castable polyurethane elastomer based on polytetramethylene glycol (PTMEG) and 2,4-toluene diisocyanate (TDI) was prepared with low free TDI monomer content prepolymer (LF-prepolymer), the structure and properties of the prepolymers and corresponding elastomers were characterized. The result showed that, LF-prepolymer exhibit low viscosity, low molecular weight and narrow molecular weight distribution. The polyurethane prepolymer based on LF-prepolymer show higher bashore rebound, lower compression set and better dynamic properties.