Sharif Digital Repository

Homo-polymer of Polypropylene is a commodity thermoplastic with good physical and mechanical properties along with fair recyclability and cost. However, its application is limited in some cases, especially in automotive industry, due to a lack of toughness. One of the approaches for PP toughening is the copolymerization of PP with some ethylene co-monomers. However, existence of elastomers in this kind of polymers causes a decrease in tensile properties. Besides, glass fibers improve tensile properties of homo-and co-PP and decrease toughness of co-polymers but result in an increase for homo-polymers. A rise in expenditure of energy due to increasing the processing temperature and... 

Polymer blending has an important role in preparation of materials with suitable properties without synthesizing new polymers. One of these blends is polypropylene (PP)/ polyethylene (PE). PE is added for improving the impact strength and toughness of PP. For improvementof the properties, a compatibilizer is used due to incompatibility of the PP/PE blend. Improving the impact properties is usually related to the reduction in stiffness. Considering the importance of stiffness in many industrial applications, mineral fillers are employed for increasing the stiffness. In this research, the goal has been to manufacture polypropylene-based ternary composite(Polypropylene/ Polyethylene/Nanometric... 

Engineering polymers are being increasingly used in a wide number of applications related to tribological properties. Many chemical and physical methods have been utilized to modify polymer surfaces by depositing thin inorganic films. Most of these techniques are based upon the use of high energy sources that ultimately can damage polymer surfaces either chemically or physically. Incorporation of fillers as reinforcing materials significantly changes various properties of thermoplastics. Friction stir processing (FSP) is a tool to modify the surface properties of materials. It has been developed for upper surface modification of metals in recent studies, exclusively by making surface...