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
The radical copolymerization of acrylamide(AM) with octadecyl acrylate(OA) has been carried out in DMF at 80 ℃ using benzoyl peroxide as initiator. The copolymers were characterized by DMTA and Kjeidahl nitrogen dete...The radical copolymerization of acrylamide(AM) with octadecyl acrylate(OA) has been carried out in DMF at 80 ℃ using benzoyl peroxide as initiator. The copolymers were characterized by DMTA and Kjeidahl nitrogen determination. The effects of copolymer composition, amount of initia tor , reaction temperature on the thickening efficiency of copolymer towards emulsion based on styre nebutyl acrylate acrylic acid polymer have been investigated. The results showed that the molecular weight of poly(AM co OA) obtained was big enough for hydrophobic associative thickening agent.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The radical copolymerization of acrylamide(AM) with octadecyl acrylate(OA) has been carried out in DMF at 80 ℃ using benzoyl peroxide as initiator. The copolymers were characterized by DMTA and Kjeidahl nitrogen determination. The effects of copolymer composition, amount of initia tor , reaction temperature on the thickening efficiency of copolymer towards emulsion based on styre nebutyl acrylate acrylic acid polymer have been investigated. The results showed that the molecular weight of poly(AM co OA) obtained was big enough for hydrophobic associative thickening agent.
