Polymerization of N-Octadecylmaleimide was studied using rare earth coordination catalysts in toluene.The dependence of polymerization on molar ratio of catalyst components,different rare earth elements,catalyst conce...Polymerization of N-Octadecylmaleimide was studied using rare earth coordination catalysts in toluene.The dependence of polymerization on molar ratio of catalyst components,different rare earth elements,catalyst concentration,monomer concentration,polymerization time and polymerization temperature was investigated in detail.The results showed that the rare earth catalysts were favorable catalysts for the polymerization of N-Octadecylmaleimide.A suitable condition for the polymerization was [La(P507)3]= 1×10-2?mol·L-1;（[Al（i-Bu）3]）=8.0×(10-2?mol·L-1);[NODMI]=5.0×(10-1?mol·L-1);60℃;6?h.Characterization of the polymer obtained showed that polymerization of N-Octadecylmaleimide proceeded via opening the double bond in the monomer molecules.The heat-resistant property of the polymer was investigated primarily.The polymer showed excellent thermal stability.The thermal decomposition of the polymer proceeded via a one-step reaction and no substantial weight loss was observed below 350℃.The initial decomposition temperature(Tini) was 360℃,the maximum decomposition temperature(Tmax) was 441℃,and the residual weight at 500℃ was about（3.4?wt%）.展开更多
The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetam...The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetamide (DMAc). The poly (amic acid) films were obtained by solution-cast method from DMAc solutions and thermally converted into transparent, flexible and tough polyimide films. The wide-angle X-ray diffraction diagrams revealed that all the polyimides possessed amorphous character, and the regulation of those polyimides were decreased with the increase of the molar ratio of SIDA to PMDA. Differential scanning calorimeter measurements showed that the introduction of SIDA to polyimide backbone would make glass transition temperature shift to lower temperature. Thermogravimetric analyses indicated that the silicon-containing polyimides lowered decomposition temperature as compared with PMDA/4, 4′-ODA polyimides. However, UV-visible transmission and reflection spectra showed that the optical transparency of silicon-containing polyimide thin films was superior to that of PMDA/4, 4'-ODA polyimide thin films.展开更多
N-(5-phenylseleno)pentyl succinimide 1, C15H19NO2Se (Mr = 324.27), was prepared by treating Br(CH2)5SePh with potassium succinimide. Its crystal structure has been determined by X-ray single-crystal diffraction. The c...N-(5-phenylseleno)pentyl succinimide 1, C15H19NO2Se (Mr = 324.27), was prepared by treating Br(CH2)5SePh with potassium succinimide. Its crystal structure has been determined by X-ray single-crystal diffraction. The crystal of 1 belongs to monoclinic system, space group P21/c with the crystal cell parameters: a = 18.018(6), b = 5.980(2), c = 14.682(5) ? = 109.977(6)? V = 1486.7(9) 3, Z = 4, Dc = 1.449 g/cm3, (MoK? = 2.523 mm-1, F(000) = 664,the final R = 0.0302 and wR = 0.0666 for 2623 independent observed reflections with I > 2(I). Structure analyses revealed that there exist strong nonclassical hydrogen bonds (CH…O).展开更多
文摘Polymerization of N-Octadecylmaleimide was studied using rare earth coordination catalysts in toluene.The dependence of polymerization on molar ratio of catalyst components,different rare earth elements,catalyst concentration,monomer concentration,polymerization time and polymerization temperature was investigated in detail.The results showed that the rare earth catalysts were favorable catalysts for the polymerization of N-Octadecylmaleimide.A suitable condition for the polymerization was [La(P507)3]= 1×10-2?mol·L-1;（[Al（i-Bu）3]）=8.0×(10-2?mol·L-1);[NODMI]=5.0×(10-1?mol·L-1);60℃;6?h.Characterization of the polymer obtained showed that polymerization of N-Octadecylmaleimide proceeded via opening the double bond in the monomer molecules.The heat-resistant property of the polymer was investigated primarily.The polymer showed excellent thermal stability.The thermal decomposition of the polymer proceeded via a one-step reaction and no substantial weight loss was observed below 350℃.The initial decomposition temperature(Tini) was 360℃,the maximum decomposition temperature(Tmax) was 441℃,and the residual weight at 500℃ was about（3.4?wt%）.
文摘The silicon-containing poly (amic acid)s were synthesized from bis (3, 4-dicarboxyphenyl) dimethylsilane dianhydride (SIDA), pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (4,4'-ODA) in N, N-dimethylacetamide (DMAc). The poly (amic acid) films were obtained by solution-cast method from DMAc solutions and thermally converted into transparent, flexible and tough polyimide films. The wide-angle X-ray diffraction diagrams revealed that all the polyimides possessed amorphous character, and the regulation of those polyimides were decreased with the increase of the molar ratio of SIDA to PMDA. Differential scanning calorimeter measurements showed that the introduction of SIDA to polyimide backbone would make glass transition temperature shift to lower temperature. Thermogravimetric analyses indicated that the silicon-containing polyimides lowered decomposition temperature as compared with PMDA/4, 4′-ODA polyimides. However, UV-visible transmission and reflection spectra showed that the optical transparency of silicon-containing polyimide thin films was superior to that of PMDA/4, 4'-ODA polyimide thin films.
基金This work was supported by the NNSFC (No. 29832030)
文摘N-(5-phenylseleno)pentyl succinimide 1, C15H19NO2Se (Mr = 324.27), was prepared by treating Br(CH2)5SePh with potassium succinimide. Its crystal structure has been determined by X-ray single-crystal diffraction. The crystal of 1 belongs to monoclinic system, space group P21/c with the crystal cell parameters: a = 18.018(6), b = 5.980(2), c = 14.682(5) ? = 109.977(6)? V = 1486.7(9) 3, Z = 4, Dc = 1.449 g/cm3, (MoK? = 2.523 mm-1, F(000) = 664,the final R = 0.0302 and wR = 0.0666 for 2623 independent observed reflections with I > 2(I). Structure analyses revealed that there exist strong nonclassical hydrogen bonds (CH…O).
