Polypropylene–waste ground rubber tire powder microcellular composites: Effect of processing variables on morphology and physico‐mechanical properties

Abstract

Microcellular composites made from polypropylene and waste ground rubber tire powder using azodicarbonamide as chemical blowing agent have been investigated. A small quantity of SEBS-g-MA has been added as compatibilizer. The effect of variation in processing variables such as pressure, heating time, and operating variables such as blowing agent and crosslinker concentrations have been investigated to establish a relationship between the structure and morphology of the microcellular composite and ultimate performance characteristics such as tensile strength, tear strength, and elongation at break. The results indicate that both processing and operating variables have tremendous effect on the morphological features such as average, minimum, and maximum cell size as observed from scanning electron microscopy. FIG. 5. Effect of pressure on cell structure of PP/WGRT foam: (a) 80 kg cm 22 , (b) 120 kg cm 22 , (c) 160 kg cm 22 , and (d) 200 kg cm 22 . FIG. 6. Effect of crosslinking agent loading on cell structure of PP/WGRT foam: (a) 0.4 pphp (b) 0.8 pphp (c) 1.2 pphp, and (d) 1.6 pphp.

Morphology and physical properties of composite foams based on low‐density polyethylene and ground tire rubber

“…In the mechanochemically milled blends, the cells are more uniform and well‐defined, and the cell wall is thinner. It is known that raw GTR powder has three‐dimensional crosslinked structures and is difficult to deform during the foaming process, a property which sterically hinders the formation of uniform cell walls. Nevertheless, the GTR phase that is finely dispersed in the LDPE matrix after mechanochemical milling appears to act as a heterogeneous nucleation site for cells.…”

Reinforcement of irradiated waste polyamide/reclaimed rubber powder composites with glass fiber

“…Accordingly, blending with waste rubber is important both from the point of view of disposal of waste and the reduction in the product cost. More attention has been focused on compounding finely ground tire rubber (GRT) with thermoplastics which can be subsequently re-melted and formed into a wide range of molded and extruded products [4][5][6][7][8][9][10][11][12][13].The mechanical properties of such compounds depend upon the modulus and concentration of GRT, polymer matrix type, and adhesion between the GRT and polymer matrix as well as the dispersion and interaction between them [14].…”

Preparation and characterization of polypropylene/waste ground rubber tire powder microcellular composites by supercritical carbon dioxide

“…The addition of compatiblizer (SEBS-g-MA) leads to the chemical interactions between the phenolic hydroxyl groups in WGRT and maleic anhydride groups in SEBS-g-MA in which an interphase between the dispersed phase (WGRT) and the polymer matrix (PP) was formed. 21 Therefore, the addition of WGRT to PP without SEBS-g-MA leads to a poor surface adhesion between PP and WGRT. The poor surface adhesion provides a channel through which CO 2 can quickly escape from the composites.…”