Preparation Of Nylon6/66/EVA Terpolymer By In Situ Polymerization And Its Toughening Effects

In this thesis, firstly, Nylon 6/66 copolymer was synthesized successfully by employing different ratios of caprolactam and AH-salt(hexamethylene adipamide salt). The best comprehensive properties of copolymer composition was confirmed by relevant measurements, such as the infrared spectroscopy(IR), differential scanning calorimetry(DSC) and scanning electron microscope(SEM), and based on the mechanical and thermal performance tests to determine the monomer component of PA6/66 copolymer under optimal comprehens ive performance. It was found that the overall performance of copolymer was the best with 50wt% content of AH-salt. Compared with the performance of nylon 6 under the same condition, the elongation at break was increased by 14 times(the stretching rate was 500mm·min-1), reaching 580.4%, and the impact strength was increased by 35%, reaching 66.00J·m-1, while the tensile strength and melt index(MI) were close to PA6.Secondly, ethylene-vinyl acetate(EVA) elastomer was added to prepare nylon6/66/EVA terpolymer(VA: 32%) by in situ polymerization based on nylon6/66 copolymer containing 50wt% content of AH-salt, confirm the content of EVA under the best comprehensive properties by molecular structure, mechanical and thermal performance measurements. The results showed that with 6wt% content of EVA, the average impact strength was increased by 133%, reaching 114.00 J·m-1, and the average elongation at break was increased by 19 times, reaching 774.25%. Meanwhile, the melt index was increased by 81%, reaching 86.56 g·10min-1, which showed excellent mechanical properties..Finally, a series of PA6/66/EVA terpolymer with different VA content was synthesized based on the best toughness ratio(caprolactam: AH-salt: EVA was 50:50:6) by in situ polymerization. Explore the influence of EVA with different VA content on the comprehensive performance of the alloy through mechanical and thermal performance test. The results showed that VA content affected the compatibility between EVA elastomer and PA6/66 substrate, the mechanical and thermal performance both decreased in some extent with the decrease of the VA content of EVA, it meaned that the higher the VA content of EVA, the better its compatibility with nylon matrix and the more excellent the comprehensive performance.