Studies On The Properties Of PA/AT Nanocomposite

Attapulgite(AT) are especially attractive candidate for the reinforcement modifer of polymer owing to their characteristics such as a high aspect ratio. In the dissertation, naturally attapulgite nanofibers were modified by KH550, the modified particles were used nylon 6(PA6) and the resulted AT/PA6 nanocomposites possessed promising mechanical performance. The preparation, sructure and properties of AT/PA6 nanocomposites were investigated fully. The main contents are as follows:PA6/AT composite were introduced by melt blending using a twin screw extruder. Results show that the mechanical properties of PA6/AT nanocomposite which is pretreatmented by KH550 composites is superior to untreated AT/PA6 composites. SEM observation showed that AT nano-rods were well dispersed in the PA6 matrix in a nanometer scale. AT can promote the generation of stable ?-crystal phase. And else, it can be used as an effective nucleating agent and has effects on the growth of crystallites in the crystallization process of PA6 matrix.Studied on rheological behavior of PA6/AT composites under two kinds of test temperature(235? and 250?). The complex viscosity(?*) of PA6/AT samples was increased at low frequency and then decreased with the increase of the sweep frequency, moreover, the increase of AT content leads to the shear thinning and this trend becomes more obvious. The storage modulus(G') and Loss modulus(G") of each sample enhances with the increase of AT content and frequency. By comparing the two kinds of temperature rheological curve is found that the rheological behavior of PA6/AT composites at 250? of AT content dependence is sensitive than 235?.By examining the humidity and heat oxygen experiment influence on PA6/AT performance. It was found that, the addition of AT could reduce the water absorption of PA6, Slow down the nylon 6 in the damp and hot oxygen aging speed, while the mechanical properties of PA6/AT composite could maintain excellent performance. When the samples were placed in air environment for 396 hours, the equilibrium moisture content of PA6/AT(5%) composite decreased by 39.9% compared with pure nylon. When the pure nylon samples were placed in air environment for 108 hours, the tensile strength and flexura strength of composite decrease respectively 33.9% and 46.4%, while the intensity of composite reduction of small, PA6/AT(5wt%) composite tensile strength and flexura strength decreased only 18.1%, 25.0%. As well, when the samples were placed in water for 132 hours, the equilibrium moisture content of PA6/AT(5wt%) composite decreased by about 31.7%; When the samples reached the equilibrium of water absorption, the strength of pure nylon reduced obviously about 50%, the composite fell by about 20%. When the samples were placed in Electric Blast Drying Oven at 120? for 288 hours, the tensile strength of pure nylon reduced 37.2%, PA6/AT(5wt%) composite tensile strength decreased only 0.3%. The bending strength of pure PA6 decreased most obvious. Moreover, Heat oxygen treatment makes ? crystal type of PA6 reduced or even disappeared, and PA6/AT systems by ? and ? crystal two kinds of crystallization is mixed into a single ? crystal shape.From the moisture absorption test and hot oxygen experiments of PA6/AT composites found in the addition of attapulgite could reduce the water absorption of PA6. And the mechanical properties of PA6/AT composite could maintain excellent performance. By using wollastonite to verify this is the peculiarity of AT.