Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their st...Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their structures were characterized by 1H NMR,GPC and DSC analysis.The multi peaks within δ 4.04～4.18 (RCH 2OCOR′) in the 1H NMR spectra were analyzed and the peaks at δ 4.15, δ 4 06～4 07 and δ 4.04 can be assigned to terminal ( T ),linear ( L ) and dendritic units ( D ),respectively.Based on 1H NMR spectra,the degree of branching ( DB) for these polymers were calculated by using both the Fréchet method and the Frey method.With the molar ratio between pizine and TMPTA increased to 1/1,the terminate units decreased,both of the dendritic and linear units increased,while M n and M w/ M n became large and the T g value became high,accordingly.Moreover,cured films were obtained through UV radiation of the polymers.The gel contents for the films decreased with increasing the molar ratio between pizine and TMPTA,which may account for the changes of their mechanical properties.展开更多
Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6H4 N（Me）]2C5H3N}FeCl2（1） and {2,6-[1-(2,6-Me2-4-Br-C6H4N（Me）]2C5H3N} FeCl2（2） activated with methy...Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6H4 N（Me）]2C5H3N}FeCl2（1） and {2,6-[1-(2,6-Me2-4-Br-C6H4N（Me）]2C5H3N} FeCl2（2） activated with methylaluminoxane （MAO） .The products of polymerization were characterized by DSC,GPC and （）13C-NMR.The results revealed that the copolymer produced by in situ copolymerization of ethylene was a mixture of branched polyethylene and α-olefin.The content of α-olefin in the mixture was increased with increasing the molar ratio of catalysts 1/2.The MWD paramelers of polyethylene and copolymer were 28\^6 and 7\^9, respectively.（）13C-NMR spectra showed that there were ethyl groups,butyl groups and long chain alkyl groups in the copolymer.The average degree of branching of such branched polyethylene was less than 5C/1000C.展开更多
A series of hyperbranched polyurethane-benzyltetrazoles （H-PBTZs） with different linkage structures were synthesized via the polycondensation of hexamethylenediisocyanate as an A2 type monomer with （4-（1H-tetrazol...A series of hyperbranched polyurethane-benzyltetrazoles （H-PBTZs） with different linkage structures were synthesized via the polycondensation of hexamethylenediisocyanate as an A2 type monomer with （4-（1H-tetrazol-5- yl）benzyl）-diethanolamine （TBDEA） as a BB＇2 type monomer in the absence of catalyst at different temperatures. The FTIR, and 13C and 1H-NMR spectroscopy were used to characterize the molecular structures of TBDEA and H-PBTZs as well as the counterpart linear polyurethane-benzyltetrazole （L-PBTZ）. The molecular composition was determined by the reaction selectivity that the isocyanate group reacted with the hydroxyl group in diethanolamine segment or the active hydrogen atom on tetrazole ring. Raising reaction temperature was propitious to the reaction of isocyanate group with the active hydrogen atom on tetrazole ring. The degrees of branching （DB） for H-PBTZs obtained from the 1H-NMR spectra increased with raising reaction temperature. The wider molecular weight distribution of 1.7-2.9 for H-PBTZs was obtained via GPC analysis. TGA results showed that H-PBTZs had high thermal stability compared with L-PBTZ.展开更多
文摘Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their structures were characterized by 1H NMR,GPC and DSC analysis.The multi peaks within δ 4.04～4.18 (RCH 2OCOR′) in the 1H NMR spectra were analyzed and the peaks at δ 4.15, δ 4 06～4 07 and δ 4.04 can be assigned to terminal ( T ),linear ( L ) and dendritic units ( D ),respectively.Based on 1H NMR spectra,the degree of branching ( DB) for these polymers were calculated by using both the Fréchet method and the Frey method.With the molar ratio between pizine and TMPTA increased to 1/1,the terminate units decreased,both of the dendritic and linear units increased,while M n and M w/ M n became large and the T g value became high,accordingly.Moreover,cured films were obtained through UV radiation of the polymers.The gel contents for the films decreased with increasing the molar ratio between pizine and TMPTA,which may account for the changes of their mechanical properties.
文摘Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6H4 N（Me）]2C5H3N}FeCl2（1） and {2,6-[1-(2,6-Me2-4-Br-C6H4N（Me）]2C5H3N} FeCl2（2） activated with methylaluminoxane （MAO） .The products of polymerization were characterized by DSC,GPC and （）13C-NMR.The results revealed that the copolymer produced by in situ copolymerization of ethylene was a mixture of branched polyethylene and α-olefin.The content of α-olefin in the mixture was increased with increasing the molar ratio of catalysts 1/2.The MWD paramelers of polyethylene and copolymer were 28\^6 and 7\^9, respectively.（）13C-NMR spectra showed that there were ethyl groups,butyl groups and long chain alkyl groups in the copolymer.The average degree of branching of such branched polyethylene was less than 5C/1000C.
基金financially supported by the National Natural Science Foundation of China(Nos.50633010 and 50973100)
文摘A series of hyperbranched polyurethane-benzyltetrazoles （H-PBTZs） with different linkage structures were synthesized via the polycondensation of hexamethylenediisocyanate as an A2 type monomer with （4-（1H-tetrazol-5- yl）benzyl）-diethanolamine （TBDEA） as a BB＇2 type monomer in the absence of catalyst at different temperatures. The FTIR, and 13C and 1H-NMR spectroscopy were used to characterize the molecular structures of TBDEA and H-PBTZs as well as the counterpart linear polyurethane-benzyltetrazole （L-PBTZ）. The molecular composition was determined by the reaction selectivity that the isocyanate group reacted with the hydroxyl group in diethanolamine segment or the active hydrogen atom on tetrazole ring. Raising reaction temperature was propitious to the reaction of isocyanate group with the active hydrogen atom on tetrazole ring. The degrees of branching （DB） for H-PBTZs obtained from the 1H-NMR spectra increased with raising reaction temperature. The wider molecular weight distribution of 1.7-2.9 for H-PBTZs was obtained via GPC analysis. TGA results showed that H-PBTZs had high thermal stability compared with L-PBTZ.
