The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlor...The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.展开更多
通过亲核取代反应引入硫醇官能团,利用缩合反应形成苯甲酸联苯酯基元,合成了以苯甲酸联苯酯为液晶基元分子端部含有硫醇基团的棒状分子--4′-(6-巯基己烷氧基)-4-烷氧基-苯甲酸联苯酯(4a^4c),其结构经1 H NMR、IR、HR-MS(ESI)和元素分...通过亲核取代反应引入硫醇官能团,利用缩合反应形成苯甲酸联苯酯基元,合成了以苯甲酸联苯酯为液晶基元分子端部含有硫醇基团的棒状分子--4′-(6-巯基己烷氧基)-4-烷氧基-苯甲酸联苯酯(4a^4c),其结构经1 H NMR、IR、HR-MS(ESI)和元素分析表征。偏光显微观察和差示扫描量热分析结果表明:4在60~170℃表现出热致性近晶A相与向列相。随着端部烷氧链的增长,4的近晶A相温度区间由14℃拓宽到38℃,而清亮点由170℃逐渐降低至129℃。展开更多
文摘The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.
文摘通过亲核取代反应引入硫醇官能团,利用缩合反应形成苯甲酸联苯酯基元,合成了以苯甲酸联苯酯为液晶基元分子端部含有硫醇基团的棒状分子--4′-(6-巯基己烷氧基)-4-烷氧基-苯甲酸联苯酯(4a^4c),其结构经1 H NMR、IR、HR-MS(ESI)和元素分析表征。偏光显微观察和差示扫描量热分析结果表明:4在60~170℃表现出热致性近晶A相与向列相。随着端部烷氧链的增长,4的近晶A相温度区间由14℃拓宽到38℃,而清亮点由170℃逐渐降低至129℃。
