Study On The Preparation, Morpholoy And Properties Of PA6/sepiolite Composeties

Due to the unique pore structure and large specific surface area, therefore the sepiolite has good adsorption properties, mechanical properties and structural stability et al. After activated, sepiolite is added to PA6, it affected the aggregation of PA6 resin, and made the performance of PA6/sepiolite composite changed. Experimental research is the use of sepiolite strong adsorption and special mechanical properties and structural stability, in order to decrease the water absorption of PA6 and improving the mechanical properties of blends, also investigated the crystallization behavior of blends and thermal stability etc.At the beginning, sepiolite was activated by using hydrochloric acid, the changes in its structure and morphology were studied. Then the PA6/sepiolite blends were prepared by using a twin-screw extrusion machine and a injection moulding machine, the dispersion in the composite of the sepiolite were studied through scanning electron microscope(SEM).The relationship between mechanical properties of PA6/sepiolite composites and sepiolite contents is study by means of mechanical properties testing.The diffusion of water in composites with different sepiolite contents and water absorbing rate, the moisture spread coefficient were studied at different temperature and in different moisture absorption medium, the influence on the mechanical properties of composites which caused by moisture absorption was also studied.The crystallization behaviors of PA6/sepiolite under different conditions was studied through differential scanning calorimetry (DSC), wide angle X-ray diffraction(WAXD), polarizing microscope(PLM). The impact on PA6/sepiolite composite crystallization properties was aslo investigated.The melting temperature(Tm), vicat softening temperature of PA6/sepiolite composite was tested. The thermal degradation was also investigated through thermogravimetric analysis (TGA). After hydrochloric acid, sepiolite fibers get better release. Sepiolite dispersed uniformity in the composite. With sepiolite added, in comparison to pure PA6, the tensile strenght and bending strenght of composites reach to 81.5 MPa, 112.0 MPa separately,has an improvement of 13.5% and 26.1%, the Young's modulus and elastic modulus reach to 775.7 MPa and 1952.4 MPa, has an improvement of 15.7% and 39.6%.The saturated water absorption rate of material reduced, with sepiolite added, it shift from 11% of pure PA6 to 8.3% of composite, the water absorption performance was improved. Environmental temperature increase can enhance the initial water absorption capacity and water absorption speed of the composites, the saturated water absorption rate was also reduced. Different mediums can also influence the water absorption performance. With the entry of water molecule, the mechanical properties of composites decreased, according to the study, sepiolite made the mechanical properties of composites a high keeping rate.According to the WAXD and DSC results, it is concluded that sepiolite made the degree of crystallinity decreased, it also improved the crystallization temperature. Sepiolite played the role of heterogeneous nucleation. It changed the relative content of two kinds of crystal typeαandγ. PLM observations showed that: sepiolite made the PA6 crystal morphogenesis changed.The melting temperature and enthalpy of PA6/sepiolite blends have slightly reducing with sepiolite added, and the vicat softening temperature shows rise first , then reduce.