| Nylon 6 industrial yarn is widely used in tire cord, conveyor belt, filter material, sewing thread, airbags and other fields for its good performance such as high strength, fatigue resistance, impact resistance. However, Nylon 6 industrial yarn inevitably is limited in the use and storage due to the aging problem. The mechanical properties of nylon 6 industrial yarn were decreased greatly after it became aged, which limited its application. It has great value on researching and application field to improve the anti-aging properties of nylon 6 industrial yarn by adding anti-aging agent.As a reactive modifier agent, N, N-bis (β-naphthyl)-p-phenylenediamine (DNP) has good resistance to oxidation and UV absorption. DNP as anti-aging agent was added in nylon 6 polymerization stages. And then the PA6/DNP industrial yarn was prepared by spinning and stretching method. The structure and properties of the PA6/DNP industrial yarn were discussed in this paper, which was summarized as following:(1) PA6/DNP granules were obtained by in-situ polymerization. The effects of DNP proportions on the melt viscosity, rheological properties, and crystalline properties were studied. The results show that the adding of DNP has little effect on its melt viscosity, but it will increase the complex viscosityη*, storage modulus G', loss modulus G" at some degree, and transform its crystal type.(2) Through the polymerization and spinning study,0.5 wt.% DNP was found to be the appropriate adding proportion. The effect of addition of DNP on the structure and performance of industrial yarn was discussed. From the results of XRD, it was found that the crystal size crystallinity and increased, crystal space changed little after adding of DNP. The static mechanical properties increased, while the mechanical stability reduced. The boiling water shrinkage and dry shrinkage ratio decreased. The thermodynamic performance improved, while dynamic mechanical properties became worse.(3) The PA6/DNP, PA6/DNP/Seed granules with different DNP/Seed proportions were obtained by polymerization, where Seed as UV resistance agent was mixed with DNP. The UV resistance property was discussed through ultraviolet absorption spectrum. The results show that DNP can improve the UV aging properties of nylon 6, and has a synergistic effect with Seed.(4) Thermal oxidative aging properties of nylon 6 industrial yarn were studied by the artificial accelerated aging method. Experimental results show that the breaking strength of PA6/DNP under high temperature was significantly increased, which indicates the brittle fracture was reduced and the PA6/DNP industrial yarn has good thermal oxidative aging ability. Infrared spectrum of nylon 6 industrial yarn shows that the chromospheres containing carbonyl groups will be generated after aging. The life model of the aging of two kinds of industrial yarns was established by adopting Arrhenius equation. The aging life time of PA6 and PA6/DNP at 25□C were predicted to be 3.3 years and 6.8 years respectively.(5) The environmental aging capacity of nylon 6 industrial yarn was studied by simulating different natural environment in the laboratory. From the results of the mechanical properties and SEM analysis, it was found that nylon 6 industrial yarn has good resistance to moisture and neutral environment, while has intolerance to strong alkali and will be corroded easily by strong acid. |
PDF Full Text Request