چكيده به لاتين
In this research, the effect of polyolefin elastomer on the structure and Impact strength of the branched and linear polypropylene foam which is produced via the extrusion process was investigated. Also, the compatibility of POE particles in the polypropylene matrix was studied. The POE type plays the most important role in the particle size and dispersed phase shape of the PP matrix, which also affects the cellular structure of the foam, so that POE is more compatible with PP shows smaller cells, higher cell density, and also Cellular structure is more uniform. By increasing the POE concentration up to 30% for the PP branch, the cell sizes have always been slowing down, especially for the POE with propylene base. This resize was more than 30 micrometers. An increase in the concentration of POE up to 20% reduced the cell wall thickness, but in larger amounts of POE concentration cell wall thickness increased. The type of blowing agent has also significantly affected the structural properties of foams so that by changing from sodium bicarbonate to azo di carbonate in a same concentration and type of POE in the same process conditions, the average diameter of the cell is reduced to 6 times and This has led to an increase of 200-300 times the cell density. Since POE concentrations, foam density and morphology play a direct role in foam impact strength, these factors were studied in different foam samples. It was observed that the impact strength has a direct correlation with increasing the concentration of POE. Increasing the concentration of POE up to 30% can increase the foam Impact strength by more than 400%. Also, increasing the cell wall thickness to combine high percentage of POE has the effect of increasing the Impact strength of the branched PP foam. At the end, we tried to establish a relationship between the impact strength and the parameters of the cell structure. Unlike branched PP-foamed, linear PP with addition of POE, except in the 20% concentration of POE with propylene base, has had a negative effect on the structure of foam.
