Preparation And Properties Of Odd Numbered Carbon Transparent Polyamide

Transparent polyamide was widely used in various fields with good solvent resistance, heat resistance and excellent mechanical properties. With the consumption of transparent polyamide increasing year by year, the research of transparent polyamide became a hot spot of transparent polymer materials. In current, the domestic transparent polyamide was still depend on imports and the cost was high.The monomer feed mole ratio was very important to the degree of polymerization as the preparation of polyamide belonging to condensation polymerization. Even long carbon chain dicarboxylic acid (dodecanoic acid and tetradecanoic acid) was used as dibasic acid monomer. The salt forming method and polymerization mechanism were studied. In this paper, the primary selection of diamines was the aliphatic 4,4-diaminodicyclohexylmethane (PACM). It was found that transparent polyamide were more concentrated on the use of an even number of carbon dicarboxylic acid, the odd carbon dicarboxylic acid (undecane diacid and tridecane dicarboxylic acid) preparation of transparent polyamide was rarely been reported. In this paper, two odd carbon dicarboxylic acids were used to prepare transparent polyamide. Due to the expense of transparent polyamide,3,3-dimethyl-4,4-diaminodicyclohexylmethane (MACM) and odd carbon dicarboxylic acid were studied as their price lower than the above mentioned two dicarboxylic acid and diamine.One step melt polymerization method was adopted for the polymerization of transparent polyamide at home and abroad. But in one-step polymerization, the catalyst was needed to ensure that the ratio of reaction. In this paper, two-steps were used to prepare transparent polyamide to control the molar ratio of monomers in the reaction. In the first step, according to different solubility of the monomer and the amide salt, the high purity of the amide salt was prepared by selecting the suitable solvent. The second step, by using of the amide salt, a series of transparent polyamide was obtained at high temperature and high pressure conditions.In this paper, the process of forming salt was studied. The optimum conditions were obtained:the most suitable solvent was dimethyl sulfoxide (DMSO), the optimum temperature was 70?80?. optimum reaction length was 1.5?2h.The transparent polyamide polymerization was studied in research according to some properties of the amide salt. Ultimately the optimum polymerization conditions were obtained: pre-polymerization reaction temperature was 190?220?, reaction pressure was 2.0?2.7 MPa, the pre-polymerization time was 2-3 h. The pressure was decreased to constant pressure in 1h after pre-polymerization; the temperature of viscosity increasing reaction was 230-260 ?, the time of viscosity increasing was 2 h, vacuum time was 0.5?1.0 h.