Research On Nanoparticle Dispersion Promoted By Water-assisted Extrusion

The preparation and control of high performance polymer nanocomposites and microcellular material have get much more attention of industry and academia. In this work, water-assisted extrusion and batch foaming equipments were developed to launch related research. First, based on the effect of water to polymer, water-assisted extrusion equipment was set up. Second, PP/HNTs and PVDF/GO composites were prepared by water-assisted extrusion to explore the mechanism of water. Finally, then the foam of PP/HNTs, PVDF/GO nanocomposites and PP/POE blends had been launched.PP/HNTs 85/15 composites have been prepared by water-assisted extrusion. The results showed that HNTs dispersed much more uniform with the increase of the water injection rate. When the water injection rate was 2 L/h, HNTs dispersed uniformly. This explained that water have the plasticizing, vaporizing and exploding effects to promote the HNTs to obtain uniform dispersion clearly. The trend to disperse uniform of HNTs can result in the increase of storage modulus, complex viscosity, mechanical and thermal stablilty properties.Water-assisted extrusion combined the GO solutions that prepared by Hummers method and sonication, and PVDF compounding to prepare PVDF/GO nanocomposites. The results showed that PVDF intercalated into the GO sheets to obtain uniform disperse and hydrogen bonding, also stripped of the debris of GO surface to generate the in situ thermal reduction of GO. The storage modulus, complex viscosity, mechanical properties and thermal stability of PVDF/GO nanocomposites are increased to a certain extent.Batch foaming of PVDF/GO composites and PP-based multi-phase system were prepared by using the autoclave to explore the relation between foaming beheaver, foaming condition and material properties. By using the difference of crystallization and viscoelastic properties of PVDF and PVDF/GO nanocomposites, the diameter and density of the cells can be controlled. For PP/HNTs composites by using the system characteristics of PP/HNTs nanocomposie and controlling the foaming conditions, ellipsoidal cell and high aspect ratio cell structure were obtained. For PP/POE blends, using the phase morphology and elasticity differences and Sc-CO2 solubility, ellipsoidal, elongated shape and openings cell structure were achieved, and the cell shape, size and density of the dispersed phase morphology of the blends were closely related. In summary, by utilizing the material properties and control foaming conditions, the shape of the cell, the distribution and size can be effectively controlled to gain diversifying cell structure to meet different needs.