The Study On Preparation And Performance Of Transparent Copolyamide MACM12/610

The transparent polyamide, as a new type of transparent material with outstanding transparency, impact resistance, abrasion resistance, heat resistance, flame retardancy and low moisture absorption, has been widely used in packaging, lens manufacturing, sports equipment and other fields. In order to further expand the scope of its application, the transparent polyamide with better comprehensive properties attracts researchers’s attention. By using 3,3’-dimethyl-4,4’-diaminodicyclohexylmethane (MACM), dodecanedioic acid, sebacic acid adipic amine salt (PA610 salt) as the monomers, transparent copolyamide MACM 12/610 was prepared by melt polycondensation.The optimum preparation conditions were determined by the viscosity method. The effects of PAMACM12 content on heat resistance, thermal transition, crystallization behavior and optical properties of the copolymer were studied.First of all, the monomers compound amide salt were prepared by MACM and dodecanedioic acid. In the process of the synthetic reaction, different solvents and different reaction temperatures were set to determin the optimum condition. It was found that the best solvent was ethanol and the optimum dosage was two times as much as total monomer mass, by comparing the production rate, purity and color of amide salt and reaction rate.The optimum temperature was from 45℃ to 50℃. The chemical structure were confirmed by means of infrared spectrometer and nuclear magnetic resonance characterization. The melting point of PAMACM12 salt was 167.6℃ tasting by microscopic melting point meter.Secondly, by using PAMACM12 salt and PA610 salt as the monomers transparent copolyamide MACM 12/610 were prepared through melt polycondensation. The optimum technological conditions of preparing transparent copolyamide MACM 12/610 with 40% mass fraction of PAMACM12 salt. In performed stage, experimental temperature was set at 200℃, experimental pressure was from 2 MPa to 2.5 MP. In the final polycondensation phase, experimental temperature was set at 250℃, reaction time from3 hour to 3.5 hour, vacuum time at 0.5 hour. The molecular structure was confirmed by infrared spectrometer and nuclear magnetic resonance characterization. The water absorption test results turned out that water absorption is 0.31%. The solvent resistance test results indicated that it can be dissolved in formic acid, acetic acid and concentrated sulfuric acidwell but cound’t be dissolved in hydrocarbon solvent, alcohol, acetone, chloroform.Therefore, it had a good solvent resistance.Finally, transparent copolyamide MACM12/610 with the mass fraction of PAMACM12 salt from 40% to 70% was prepared, The heat resistance, thermal transition, crystallization properties and light transmittance were tested by hermogravimetric analyzer, differential scanning calorimeter, X-ray diffractometer and ultraviolet spectrophotometer. The results showed that with the increase of mass fraction of PAMACM12 salt, the heat resistance of the copolymer increased linearly and then decreased and then increased. When the mass fraction of PAMACM12 increased to 40%, the heat resistance of transparent copolyamide MACM12/610 achieved best. With the increase of mass fraction of PAMACM12 salt in the copolymer, the melting point of the copolymers decreased, the crystal ability decreased, and the glass transition temperature showed a nonlinear change. When the mass fraction of PAMACM12 salt was higher than 40%, there were not melting and crystallization process. With the increase of salt mass fraction of PAMACM12, the diffraction angle of copolymer decreased and the crystallinity decreased, when the salt mass fraction of PAMACM12 reached 50% or more, the copolymer was amorphous. With the increase of PAMACM12 salt mass fraction, the transparency of the copolymer increased, and the transmittance increased continuously.