Study On Process And Properties Of SiO₂ Aerogel/PP Melt-blown Nonwovens

With the rapid development of industry and the improvement of people's living standard,the air pollution became more and more serious,the high-efficiency and low-resistance composite filter material is required in the new century.The fiber diameter of PP melt-blown nonwovens is very thin,SiO₂ aerogel has excellent properties as high specific surface area,high porosity,etc.In this paper,SiO₂ aerogel/PP melt-blown nonwovens were prepared to provide theoretical basis for the development of high-efficiency and low-resistance composite filter material by researching its structure and properties.The mass ratio of 0/100,1/100,2/100,3/100 of SiO₂ aerogel/PP blend materials were prepared by melt-blending.And the apparent morphology,thermal properties,crystallization properties,melt flow and rheology of SiO₂ aerogel/PP blends with different SiO₂ aerogel content were studied respectively with SEM,TG,DSC,MFI and rotary rheometer.The experimental results show that with the increase of the content of SiO₂ aerogel,the agglomerate phenomenon is serious;The crystallization of pure PP is imperfect,the Crystallization ability of SiO₂ aerogel/PP blends is improved and tend to complete crystallization with the increase of the content of SiO₂ aerogel.In addition,the thermal stability of SiO₂ aerogel/PP blends is increased prominently.When the content of SiO₂ aerogel increases,the melt index and viscosity of composites is increase and the melt mass-flow rate is decrease,the reasonable temperature of melt-blown nonwoven is 215²25 ?.PP melt-blown nonwovens were prepared under different process parameters,such as belt rate,extrusion velocity,die-collector distance and hot air pressure,etc.The surface morphology,mechanical properties,air permeability and filter property were studied respectively with SEM,universal material testing machine,air permeability instrument and filter material test bench.The experimental results show that the integrated performance of PP melt-blown nonwovens is very excellent when the parameters are 7.5 Hz,20 Hz,30 cm,0.06 MPa.It is intended to be the optimum parameters.The mass ratio of 0/100,1/100,2/100,3/100 of SiO₂ aerogel/PP melt-blown nonwovens were prepared by melt-blown nonwoven technology.And the surface morphology,crystallization properties,crystal structure,mechanical properties,air permeability and filter property of SiO₂ aerogel/PP melt-blown nonwovens with different SiO₂ aerogel content were studied respectively with SEM,DSC,XRD,universal material testing machine,air permeability instrument and filter material test bench.The experimental results showed that the fiber diameter of SiO₂ aerogel/PP melt-blown nonwovens was thicker and the fiber-network was looser compared with pure PP melt-blown nonwovens;The crystallinity of SiO₂ aerogel/PP melt-blown nonwovens increased with the increase of the SiO₂ aerogel content,the crystal form was not changed;The filter property of SiO₂ aerogel/PP melt-blown nonwovens was improved by 1.5 times of pure PP melt-blown nonwovens,the air permeability of the melt-blown nonwovens also increased;but the tensile strength and tensile strain was decreased with the increase of SiO₂ aerogel content.