The Synthesis Of Nonisocyanate Polyurethanes

Polyurethanes obtained from isocyanates and polyether polyols are widely used in various fields because of its excellent properties, but with the improvement of people's health, safety awareness, weaknesses of traditional polyurethane in performance and security are gradually exposed. New generation polyurethane named nonisocyanate polyurethane (NIPU) obtained from multifunctional cyclic carbonates and multifunctional primary polyamines is expected to replace traditional polyurethane as an green materials. First of all, epoxy-terminated polyether (ETP) with flexible backbone was synthesized using polyether as the raw material, then the cyclocarbonate- terminated polyether (CCTP) was synthesized through the reaction of ETP and carbon dioxide. Finally NIPU was obtained from CCTP and difunctional primary amine. The synthesis route and conclusion are as follows:1. Epoxy-terminated polyether with flexible backbone was synthesized through alkoxylation and grafting reaction using polyether as the raw material. The structure of products were confirmed by 1HNMR spectra. Different reaction conditions were discussed and the studies showed that: sodium methoxide is the best alkoxylation reagent. The molecular weight of polyether has a significant impact on conversion. ETP with high conversion can be obtained when the alkoxylation reaction temperature is 110℃, grafting reaction temperature is 40℃, the mole ratio of sodium methoxide to hydroxyl is 1.3, the mole ratio of ECH to hydroxyl is 2.5.2. A novel cyclocarbonate- terminated polyether was synthesized in the presence of catalysts at high temperature and under high pressure using ETP as the raw material. The structure of cyclocarbonate was confirmed by 1HNMR and FTIR spectra. The effects of catalysts, reaction temperature, pressure and reaction time on the fractional conversion were discussed. The results showed that the yield can be reached over 90% and the products have a good appearance when the reaction temperature is 120℃, the carbon dioxide pressure is 2.5MPa, reaction time is 4h and CTAB is used as the catalysts. The molecular weight of raw materials have great impact on the conversion rate. The higher molecular weight, the lower conversion rate.3. NIPU was synthesized by tri-functionality cyclocarboanate and difunctional primary amine. FTIR spectra have been used to analyze target product. The studies showed that: ethylenediamine based NIPU have the most excellent properties and the highest level of crosslinking network. The products have the most favorable overall performance when the mole ratio of carbonate-to-amine is 1:1. Swelling in toluene also showed that ethylenediamine based NIPU have highest crosslinking density.