Preparation And Characterization Of Copolyamide 11/6

The novel materials with high performance is the developing direction in the currentmaterials fields. In our country, polymer materials with high performance have being listed asone of emphasis developing materials by the development of national science and technology.And the modification of general engineering plastic has being listed as major project of "973".As one of the general engineering plastic, nylon 11 is a kind of polymer matrix with highperformance. Due to its excellent comprehensive properties, nylon 11 resin was used widelyin those fields such as automobile, military apparatus, coal gas and oil pipe, and electricappliance. However, the shortcomings including high cost and low impact strength of purenylon 11 limit its further application. Therefore, to widen the application fields of nylon 11resin, the performance of nylon 11 matrix is generally improved by using the method ofphysical or chemical modification. Up to the present, the method of physical modification for nylon 11 is dominant, there isfew reports on the study on the copolymer in which nylon 11 matrix is key component. It iscontributed to that the processing technology of 11-amino-undecanoic acid is monopolized byATO company, and also the ternary copolyamide in which the nylon 11 matrix is keycomponent has been developed and manufactured commercially just by the above company.Therefore, the copolyamide 11/6 is prepared by using 11-amino-undecanoic acid andcaprolactam as raw materials in this paper. Our major and creative research works are listedmainly as following: (1) Preparation and characterization of copolyamide 11/6 In the presence of water, the caprolactam is hydrolyzed under 170-190°C and the activeanions are formed by the ring-opening of caprolactam. Then through bulk meltingpolymerization, the copolyamide 11/6 in which nylon 11 is key component is prepared. Thereaction conditions are optimized by studying the intrinsic viscosity of different copolyamide11/6 copolymer. The optimum reaction time and temperature are also determined. Thefractional conversion of unit is above 97% in all of our experiments. The copolyamide 11/6 copolymer is characterized by using FTIR and DSC. The resultsof FTIR revealed that the copolyamides prepared in our experiments are random copolymers.It also showed that the structures of copolyamides are influenced by the verification of thecontent of caprolactam. The fact that there is a unique melting absorb peak in the DSC curveconfirms that the materials prepared in our experiments is a uniform copolymer and thehomopolymer of nylon 11 or nylon 6 is not formed during the preparation. The results of DSCanalysis also reflect that the melting temperature of copolyamide 11/6 rises with the content ofcaprolactam increasing. Although so, the melting temperature of copolyamide is far lowerthan that of homopolamide 11 or homopolyamide 6, which confirms further that thecopolyamide 11/6 prepared in this paper is a random copolymer. (2) Study systemically the mechanical properties of copolyamide 11/6 copolymer In this part, the influence of the content of caprolactam on the mechanical property suchas tensile strength, elongation at break and impact strength is investigated. It was found thatthe tensile strength of copolyamide upwards with the content of caprolactam increasing. Theelongation at break of copolyamide 11/6 is the maximum when the content of caprolactam isup to 20wt%, then it downwards sharply until the content of caprolactam is 55wt%, and whilerises slightly when the content increases further. The results of the research works on themechanical properties also revealed that the Izod impact strength at room temperature and lowtemperature deviates slightly from the pure nylon 11 when the content of caprolactam is lowerthan 30wt%, and decreases sharply when the content of caprolactam increases further. (3) Study systemically the rheological behavior of copolyamide 11/6 copolymer The research...