Effect of oxygen content in solid-phase viscosity increasing environment on crystal points of ultra-high viscosity nylon 6 films
Using nylon 6(PA 6)chip with a relative viscosity of 3.3 as raw materials,ultra-high viscosity PA 6 chips were prepared by solid-phase viscosity increasing under different oxygen content environments.The corresponding ultra-high viscosity PA 6 films were obtained using a small-scale laboratory film blowing machine.The effect of environmental oxygen content on the melting crystallization behavior and ultraviolet performance of ultra-high viscosity PA 6 chips and the number and morphology of crystal points of the corresponding ultra-high viscosity PA 6 films were studied.The results showed that the initial crystallization temperature,crystallization peak temperature and crystallization enthalpy of ultra-high viscosity PA 6 chips increased first and then decreased with the increase of environmental oxygen content;the number of crystal points in the ultra-high viscosity PA 6 film increased with the increase of environmental oxygen content,and the number of crystal points in the ultra-high viscosity PA 6 film exceeded 3/cm2 when the environmental oxygen content was higher than 10 mg/kg,which could not meet the usage requirements;the crystal points of the ultra-high viscosity PA 6 film zonally distributed at room temperature,and the PA 6 around the crystal points completely melted,but the morphology of the crystal points remained unchanged when the temperature rose to 300℃;and the main reason for the formation of crystal points was the cross-linking reaction of PA 6 chips to form gel material under the action of hot oxygen.
nylon 6solid-phase viscosity increasingfilmoxygen contentcrosslinkingcrystal point
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