The Study Of Synthesis And Characterization Of The Hydroxyl-terminated Cyclohexene Oxide-Tetrahydrofuran Copolyether

As a main raw material for polyether polyol, polyurethane material products have been extensively utilized. The properties of polyurethane are determined mainly by the structure of polyether polyol. Cyclohexene Oxide (CHO), as a novel monomer for polyether polyol, has a structure of six rigid annulus and has attracted increasing attention because of its better mechanical properties endowed to polyurethane compared than linear paraffin. But there are still some disadvantages in its synthesis technology. The difficulty of regulation and controlling structures and molecular weight of the synthesized polyether limits the extensive application of the polyether polyol.This study investigates the synthetic method of cyclohexene oxide-tetrahydrofuran (THF) copolyether (CHO-THF), using methylene dichloride as solvent through cationic ring-opening polymerization mechanism. Improvement in synthetic method is made in our studies:the mixture ethyl ether boron fluoride and water is used as catalyst; CHO and THF is mixed, then added simultaneously with catalyst dropwisely to solvent. The method can control the structure better as well as improve the reaction rate.The product is characterized by IR and1H NMR. The characterization results indicated that the hydroxyl terminated copolyether is synthesized. The product is transparent and viscous liquid; the yield of the product is92%. The study investigates the effect of catalyst ratio, catalyst amount, the ratio of CHO to THF, and the amount of EG on the polymerization. The method of synthesis copolyether with different molecular weight is found. The molecular weight of the product could be controlled within1500-4000g/mol. The study also investigates modifying conditions to synthesizing copolyether with target molecular weight. The maximum relative error between the target value and experimental value is5.1%.The study investigates using copolyether with different molecular weight and normal polyether (PTMG,PPG) to synthesize polyurethane products and the mechanical properties of these polyurethane products has also been tested. The comparation results suggest that the mechanical properties of polyurethane products are affected by the molecular weight of copolyether. The elongation at break increased with the increasing molecular weight and the tensile strength is decreased with the molecular weight. When the molecular weight of copolyether increased from1423.9g/mol to3397.5g/mol, the tensile strength decreased from40.6MPa to33.5MPa, while elongation at break306%to468%.Moreover, compared with PTMG and PPG, CHO-THF could improve the tensile strength of polyurethane products effectively; at the same time, the effect of polyurethane products on the elongation at break is not obvious. The mechanical properties of polyurethane products produce by CHO-THF are better than that produced by normal polyether, so the polyurethane products produce by CHO-THF is very promising.