Exploring The Novel Synthetic Method Of High-Performance Polymer Containing Triazine Moieties At Standard Atomsphere

Most papers were focused on polymers with heterocyclic structure in the backbone for their balance of thermal stability,chemical inertness,and physical strength recently.As a class of heterocyclic resin,poly-1,3,5-triazine starting from aromatic nitriles always possess outstanding thermal properties for their extremely rigid aromatic or heteroaromatic structures.However,it was not easy to obtain poly-1, 3,5-triazine by the trimerizaiton of aromatic nitrile without using high pressures,high temperatures and strong acids acting as catalysts.The applications of poly-1,3, 5-triazines were limited for the strict reaction conditions and expensive costs in their preparation.Thus,it is essential and of great importance to polymerize aromatic nitriles in mild conditions for the wide applications of poly-1,3,5-triazine.In this paper,a series of s-triazine dereatives were synthesized through four kinds of commercial aromatic nitriles under normal pressure catalysied by anhydrous zinc chloride.And their structures were confirmed by FTIR and NMR measures.A kind of poly-1,3,5-triazine was prepared by the trimerization of 1,4-dicyanobenzene at the same conditions.The FTIR spectrums of the resultant polymers were found to be consistent with the proposed structures.Differential scanning calorimetry(DSC)and thermal gravimetic analyses(TGA)were applied to study the thermal properties and the effect of polymerization time on the thermal stabilities of resultant polymers.The procedure for preparing s-triazines starting from aromatic nitriles was developed and optimizied and the effect of monomer activity,catalyst and catalytic activity,reaction time and reaction temperature on yields were also investigated.in our work.It was found that selecting aromatic nitrile with para-substitution or meta-substitution brought by strong electron-drawing groups,metal halid or complex of several catalystes,increasing the concentration of catalystes,higher polymerization temperature or raising temperature step by step and longer reaction period were useful to obtain s-triazines in high yields to some content. A convenient method for the synthesis of 4.4'-dicyano-diphenyl was also studied. The structure of 4.4'-dicyano-diohenyl was confirmed by IR and NMR.The 4,4'-dicyano-diphenyl was subjected to polymeriaziton and another kind of poly-1,3, 5-triazine with biphenyl moiety was obtained.And its structure was confirmed by FTIR and NMR measures.The experimental study indicated that the yield increased exponentially with the coupling time being up to 4h and the yield was found to be the greatest while the crude product was washed with 800 ml distilled water and 70ml n-heptane,subsequently by 30ml n-heptane three times.