Preparation And Properties Of Modified Melt-Blown Polypropylene Fabric

The specific technical characteristics of melt-blown, give Polypropylene (PP) melt-blown fibre special crystal structure, affecting its practical application. This dissertation presents a method of heat treatment and nanoparticles blending to the problems.The polypropylene melt-blown nonwoven fabric was heat treated at 90℃,110℃, 130℃and processed with corona discharge. Crystal structures of the treated melt-blown fabric have been studied by using wide-angle X-ray diffraction. The mechanical properties, breathable, surface electrostatic potential and the filtration efficiency of the treated fabric were also tested. The results show that along with the increase of temperature, crystal form of the PP melt-blown nonwoven was gradually transformed from quasi hexagonal crystal to a-crystal, crystallinity increased from 34.31% to 43.42% and grain size increased from 6.55nm to 9.85nm. Heat treatment temperature has a greater effect on the melt-blown fabric strength and elongation, permeability, surface electrostatic potential and the filtration efficiency. Change of the crystal structure is the main reason to the modification of mechanical properties and electret performance.The surface of nano-SiO2 was modified by silane coupling agent KH560, then blend with PP with the twin-screw extruder to get PP/SiO2 masterbatch. Test results of TG, contact angle, IR, degree of oil-affinity show that the grafting of the modifier reacted with nano-SiO2, effectively changing the surface properties of nano-SiO2. Compared with before modification, the particle size and distribution of modified particles in the section of the composite masterbatch are greatly improved. Nano-SiO2 combined well with PP, nano-SiO2 acted as nucleating agents during the crystallization of PP.The applicability of the SiO2/PP masterbatch was tested; six kinds of electret PP melt-blown nownovens were prepared, respectively containing nano-SiO2 0wt%,0.1 wt%, 0.2wt%,0.5wt%,0.8wt% and lwt%. The test results show that with adding nano-SiO2, the fibre average diameter increased, and fabric structures sparse. A small amount of nano-SiO2 can toughen and reinforce PP fiber effectively; with the increase of the content of nano-SiO2, breaking strength and breaking elongation of the cloth first increases, then decreases. Crystallinity and crystalline forms of PP melt-blown fiber were changed after join nano-SiO2, SiO2/PP melt-blown fibre crystal form and interface complicated, thermally stimulated discharge (TSD) result show that SiO2/PP melt-blown fabric have a better space charge storage; The efficiency of filtering tests show that, in the same filter resistance conditions, SiO2/PP composite fabric has a higher filter efficiency and stability.