A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectromet...A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectrometry （MS）. Ring- opening metathesis polymerization （ROMP） of these monomers using the Grubbs third generation catalyst （G3） generated high molecular weight polymers with much improved solubility compared with the NDCA＇s homopolymer. It was found that the solubility of these polymers increased with increased substituent＇s steric hindrance. The living polymerization of NDCA derivative containing the bulkiest substituent （M4） catalyzed by G3 in tetrahydrofuran was confirmed by the kinetic studies with low polydispersity indices （PDI） （〈 1.30）. By using sequential ROMP, well-defined diblock copolymers containing anhydride groups were synthesized.展开更多
Cyclic olefin polymers（COPs） with high glass transition temperature, high transparency（higher than 80%） in the visible light range, excellent thermal stability and outstanding mechanical properties have been synth...Cyclic olefin polymers（COPs） with high glass transition temperature, high transparency（higher than 80%） in the visible light range, excellent thermal stability and outstanding mechanical properties have been synthesized by effective ring opening metathesis polymerization（ROMP） of exo-1,4,4 a,9,9 a,10-hexahydro-9,10（1′,2′）-benzeno-l,4-methanoanthracene（HBM） and dicyclopentadiene（DCPD） or norbornene（NBE） using WCl6/i-Bu3Al/ethanol/1-hexene catalyst system, followed by hydrogenation of double bonds. 1-Hexene acted as a molecular weight controller in the polymerization reaction, tuning the number-average molecular weight（Mn） of P-HBM from 5.8 × 10^4 to 41.1 × 10^4. The monomer composition and thermal properties of the copolymers were characterized by nuclear magnetic resonance（NMR）, differential scanning calorimetry（DSC） and thermogravimetric analysis（TGA）. The saturated polymers exhibited high decomposition temperatures（Td） around 340 ℃ and glass transition temperatures（Tg） in the range from 117.5 ℃ to 219.7 ℃. What is more, tensile tests indicated that the mechanical properties of the COPs could be effectively tuned in a wide range by introducing varying amount of small cyclic olefin such as DCPD or NBE.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21234006 and 21574098)
文摘A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectrometry （MS）. Ring- opening metathesis polymerization （ROMP） of these monomers using the Grubbs third generation catalyst （G3） generated high molecular weight polymers with much improved solubility compared with the NDCA＇s homopolymer. It was found that the solubility of these polymers increased with increased substituent＇s steric hindrance. The living polymerization of NDCA derivative containing the bulkiest substituent （M4） catalyzed by G3 in tetrahydrofuran was confirmed by the kinetic studies with low polydispersity indices （PDI） （〈 1.30）. By using sequential ROMP, well-defined diblock copolymers containing anhydride groups were synthesized.
基金financial support by the National Natural Science Foundation of China(Nos.21234006 and U1510124)
文摘Cyclic olefin polymers（COPs） with high glass transition temperature, high transparency（higher than 80%） in the visible light range, excellent thermal stability and outstanding mechanical properties have been synthesized by effective ring opening metathesis polymerization（ROMP） of exo-1,4,4 a,9,9 a,10-hexahydro-9,10（1′,2′）-benzeno-l,4-methanoanthracene（HBM） and dicyclopentadiene（DCPD） or norbornene（NBE） using WCl6/i-Bu3Al/ethanol/1-hexene catalyst system, followed by hydrogenation of double bonds. 1-Hexene acted as a molecular weight controller in the polymerization reaction, tuning the number-average molecular weight（Mn） of P-HBM from 5.8 × 10^4 to 41.1 × 10^4. The monomer composition and thermal properties of the copolymers were characterized by nuclear magnetic resonance（NMR）, differential scanning calorimetry（DSC） and thermogravimetric analysis（TGA）. The saturated polymers exhibited high decomposition temperatures（Td） around 340 ℃ and glass transition temperatures（Tg） in the range from 117.5 ℃ to 219.7 ℃. What is more, tensile tests indicated that the mechanical properties of the COPs could be effectively tuned in a wide range by introducing varying amount of small cyclic olefin such as DCPD or NBE.
