以异佛尔酮二异氰酸酯和三羟甲基丙烷为单体,采用溶液聚合法,在无催化剂的条件下合成了端羟基的超支化聚氨酯多元醇(HBPU),并采用二正丁胺滴定法对反应进行了动力学研究。实验结果表明,HBPU的反应分为预聚反应和聚合反应两步进行。预聚...以异佛尔酮二异氰酸酯和三羟甲基丙烷为单体,采用溶液聚合法,在无催化剂的条件下合成了端羟基的超支化聚氨酯多元醇(HBPU),并采用二正丁胺滴定法对反应进行了动力学研究。实验结果表明,HBPU的反应分为预聚反应和聚合反应两步进行。预聚反应最佳反应条件为n(NCO)∶n(OH)=2∶1,反应温度80℃,反应时间60 min;聚合反应的最佳条件为n(NCO)∶n(OH)=1∶3,反应温度80℃,反应时间120 min。HBPU的预聚反应动力学遵循二级反应,反应活化能为71.4 k J/mol,聚合反应动力学遵循三级反应,反应活化能为51.1 k J/mol;聚合反应的活化能比预聚反应的活化能小,说明预聚反应受温度的影响更大,无催化剂的情况下,氨基甲酸酯的自催化效应在HBPU聚合反应中起着重要的作用。展开更多
Flexible Polyurethane （PU） foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI：TDI （80：20）, in the presence of water （bl...Flexible Polyurethane （PU） foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI：TDI （80：20）, in the presence of water （blowing agent） with molding process. This experiment was to analyze the physical properties of soy polyol and elaborate the principle of catalyst within the synthesis. The use of liquid and solid catalyst on the polyol synthesis results in significant cellular morphology and properties of polyurethane foam. It is found that the PU which was synthesized using bentonite catalyst has an irregular form of cell morphology, and it has higher density than using sulphuric acid catalyst.展开更多
Tung oil-based polyols were synthesized by the esterification and transesterification between Tung oilbased anhydride and butanediol. The hydroxyl values of the polyols prepared were tested and discussed. Polyurethane...Tung oil-based polyols were synthesized by the esterification and transesterification between Tung oilbased anhydride and butanediol. The hydroxyl values of the polyols prepared were tested and discussed. Polyurethane was prepared by using Tung oil-based polyols and/or poly(propylene glycol) as polyols and by using isophorone diisocyanate as isocyanate. The effect of the ratio of Tung oil-based polyols to poly(propylene glycol) on the properties of polyurethane prepared was investigated by the water resistance, alcohol resistance and hardness tests. The results show that Tung oil-based polyols are effective to improve the hardness, water resistance and alcohol resistance of polyurethane.展开更多
Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07：0.027 and diethylene glycol （DEG） was also taken in varying hydroxyl numbers to achieve...Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07：0.027 and diethylene glycol （DEG） was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane （PU） coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.展开更多
文摘以异佛尔酮二异氰酸酯和三羟甲基丙烷为单体,采用溶液聚合法,在无催化剂的条件下合成了端羟基的超支化聚氨酯多元醇(HBPU),并采用二正丁胺滴定法对反应进行了动力学研究。实验结果表明,HBPU的反应分为预聚反应和聚合反应两步进行。预聚反应最佳反应条件为n(NCO)∶n(OH)=2∶1,反应温度80℃,反应时间60 min;聚合反应的最佳条件为n(NCO)∶n(OH)=1∶3,反应温度80℃,反应时间120 min。HBPU的预聚反应动力学遵循二级反应,反应活化能为71.4 k J/mol,聚合反应动力学遵循三级反应,反应活化能为51.1 k J/mol;聚合反应的活化能比预聚反应的活化能小,说明预聚反应受温度的影响更大,无催化剂的情况下,氨基甲酸酯的自催化效应在HBPU聚合反应中起着重要的作用。
文摘Flexible Polyurethane （PU） foam is the material most widely used among urethanes. The foams were synthesized via the reaction of soy polyol, mixtures of isocyanates MDI：TDI （80：20）, in the presence of water （blowing agent） with molding process. This experiment was to analyze the physical properties of soy polyol and elaborate the principle of catalyst within the synthesis. The use of liquid and solid catalyst on the polyol synthesis results in significant cellular morphology and properties of polyurethane foam. It is found that the PU which was synthesized using bentonite catalyst has an irregular form of cell morphology, and it has higher density than using sulphuric acid catalyst.
文摘Tung oil-based polyols were synthesized by the esterification and transesterification between Tung oilbased anhydride and butanediol. The hydroxyl values of the polyols prepared were tested and discussed. Polyurethane was prepared by using Tung oil-based polyols and/or poly(propylene glycol) as polyols and by using isophorone diisocyanate as isocyanate. The effect of the ratio of Tung oil-based polyols to poly(propylene glycol) on the properties of polyurethane prepared was investigated by the water resistance, alcohol resistance and hardness tests. The results show that Tung oil-based polyols are effective to improve the hardness, water resistance and alcohol resistance of polyurethane.
文摘Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07：0.027 and diethylene glycol （DEG） was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane （PU） coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.
