Hyperbranched polymer with alternating ureido and urethano units was prepared by direct polymerizarion of isophorone diisocyanate(IPDI, A 2) with diethanolamine(DEOA, CB 2) in the absence of catalyst. In the reaction,...Hyperbranched polymer with alternating ureido and urethano units was prepared by direct polymerizarion of isophorone diisocyanate(IPDI, A 2) with diethanolamine(DEOA, CB 2) in the absence of catalyst. In the reaction, one isocyanato group of IPDI reacts fast with amino group of DEOA, generating an intermediate with one isocyanato group and two hydroxyl groups. Now the intermediate formed is a new kind of AB 2 type monomer. Further self-condensation of this AB 2 species leads to hyperbranched poly(urea-urethane). The reaction mechanism was characterized with in situ FTIR. Temperature and concentration have great influence on the polymerization process. When the feed ratio of IPDI to DEOA is equal to \{1∶\}1, no gelation is observed if the reaction temperature within initial several hours is lower than 20 ℃. Cross-linking would occur if the reaction temperature during initial period is high. The degree of branching(DB) of the resulting hyperbranched poly(urea-urethane) is 46.5%-48.5%.展开更多
In the presence of catalyst BF 3 ·OEt 2 , using ethylene glycol as initiator and CH 2 Cl 2 as solvent hydroxylterminated poly(cyclohexene oxide)(PCHO) was synthesized by cationic ring opening polymerization of mo...In the presence of catalyst BF 3 ·OEt 2 , using ethylene glycol as initiator and CH 2 Cl 2 as solvent hydroxylterminated poly(cyclohexene oxide)(PCHO) was synthesized by cationic ring opening polymerization of monomer cyclohexene oxide(CHO). The effect of catalyst amount, polymerization temperature and polymerization time on polymerization results were discussed. The best technical condition was:polymerization temperature 0 ℃, n (BF 3 ·OEt 2 )/ n (CHO)=0 02, n (EG)/ n (CHO)=0 01, polymerization time 5 h. The average molecular weight of PCHO obtained was about 1 200, and the conversion of polymer could be up to 92%. The structure of the product was identified by IR and 1 H NMR.展开更多
文摘Hyperbranched polymer with alternating ureido and urethano units was prepared by direct polymerizarion of isophorone diisocyanate(IPDI, A 2) with diethanolamine(DEOA, CB 2) in the absence of catalyst. In the reaction, one isocyanato group of IPDI reacts fast with amino group of DEOA, generating an intermediate with one isocyanato group and two hydroxyl groups. Now the intermediate formed is a new kind of AB 2 type monomer. Further self-condensation of this AB 2 species leads to hyperbranched poly(urea-urethane). The reaction mechanism was characterized with in situ FTIR. Temperature and concentration have great influence on the polymerization process. When the feed ratio of IPDI to DEOA is equal to \{1∶\}1, no gelation is observed if the reaction temperature within initial several hours is lower than 20 ℃. Cross-linking would occur if the reaction temperature during initial period is high. The degree of branching(DB) of the resulting hyperbranched poly(urea-urethane) is 46.5%-48.5%.
文摘In the presence of catalyst BF 3 ·OEt 2 , using ethylene glycol as initiator and CH 2 Cl 2 as solvent hydroxylterminated poly(cyclohexene oxide)(PCHO) was synthesized by cationic ring opening polymerization of monomer cyclohexene oxide(CHO). The effect of catalyst amount, polymerization temperature and polymerization time on polymerization results were discussed. The best technical condition was:polymerization temperature 0 ℃, n (BF 3 ·OEt 2 )/ n (CHO)=0 02, n (EG)/ n (CHO)=0 01, polymerization time 5 h. The average molecular weight of PCHO obtained was about 1 200, and the conversion of polymer could be up to 92%. The structure of the product was identified by IR and 1 H NMR.
