Study On The Effect Of End-Group Of Polyazomethine On Mechanical Properties Of Polyazomethine/Monomer Casting Nylon Composites

In this paper, two kinds of Polyazomethine/nylon-6 (PAM/PA-6) composites with different chemical structures were prepared by means of in-situ polymerization. PAM1 and PAM2 were prepared from the reaction of Terephthalaldehyde with l,6-Hexanediamine(PAMl), and Terephthalaldehyde with 4,4'-Diamiediphenyl(PAM2). During the preparation, PAM chain ends played a retard role in the polymerization of s-caprolactam obviously. The effect of kind of PAM chain ends on the sub-micro morphologies and mechanical properties of PAM/PA-6 composites were characterized systematically.The preparation conditions of composite were optimized, including the initiator concentration (NaOH) and the molar ratio of aldehyde to amine. The polymerization kinetics of PAM, the feeding pattern of the initiator NaOH and a method used to characterize the spherulite morphology of monomer casting nylon were investigated.The mechanics of inhibition of PAM to the polymerization of nylon was certificated by means of a series of experiments. The results showed that the aldehyde end-group of PAM reacted with initiator NaOH of the polymerization of e-caprolactam through Cannizarro reaction by means of FT-IR technology.For the PAM1/nylon-6 composite, tensile strength reduced with the decreasing molar ratios of aldehyde to amine slightly. When the NaOH content was fixed 0.09g/100g e-caprolactam, and the aldehyde/amine was decreased from 1.0 to 0.95, the tensile strength of composite was changed from 63.6MPa to 59.7Mpa (<8%), while impact strength was increased from 5.07KJ/m2 to 23.14 KJ/m2 (increasing by 3.56 times). Through the characterization of the molecular weights of PAM, SEM and DSC of composite, the results clarified the change of mechanical properties of composites.The tensile strength and impact strength of PAM2/PA-6 composite showed that were related to the content of initiator NaOH for the polymerization of e-caprolactam. The intrinsic viscosity of PAM, SEM and the crystallinity of nylon phase carried out the results, which explained the change of mechanical properties of composites.Three methods of avoiding the effect of aldehyde end-group on the polymerization of e-caprolactam were compared. It was useful for the industrial application through the salting e-caprolactam monomer with the initiator NaOH firstly.