Morphology and mechanical properties of injection‐molded specimens of two‐phase polymer blends

Abstract

SynopsisAn experimental study was carried out to investigate the moldability of polymer blends which form two phases in the molten state and the effect of mixing on the morphology and mechanical porperties of molded specimens. Blends of polystyrene with polypropylene and blends of polystyrene with high-density polyethylene were used for this study. A plunger-type injection molding machine (Van Dorn) was employed for molding specimens. To improve the mixing performance of the plunger machine, a Static Mixer (Kenics Corp., Super Nozzle) was installed between the heating cylinder and the sprue. A number of different molding conditions (injection pressure. temperature, injection time, cooling time) were varied, and molded specimens were collected under each molding condition. 'The specimens were used for studying the degree of dispersion in the blends and for determining the mechanical properties. A differential thermal analysis (DTA) experiment was also carried out to determine the degree of dispersion of the blends in molded specimens. It was found that a linear correlation exists between the blend composition and thermal spectra area of the blends tested.

Melt rheological properties of polypropylene-maleated polypropylene blends. I. Steady flow by capillary

“…Blends of polypropylene (PP) for improving properties suited to some specific application were extensively studied with a large number of polymers, including polyethylene, [1][2][3][4][5] polycarbonate, 6 polyamide, [7][8][9][10] polystyrene, 11,12 acrylonitrile-butadienestyrene (ABS), 13 ethylene-vinyl acetate (EVA), 14 elastomers. [15][16][17][18] However, the blends of PP and PP grafted with maleic anhydride (PP-g-MA) seem to have been scantily studied.…”

Miscibility of isotactic polypropylene with atactic polystyrene

“…Recently it has been found [1][2][3][4][5][6][7][8][9][10][11][12] that both components in the blends (with one crystallizable component) may influence each other giving rise to very interesting effects such as: depression of the melting temperature of the crystallizable component, decrease or increase of its crystallinity degree and of the crystallization rate, change in morphological structure and mechanical properties.…”

“…Recently the morphology and physical properties of isotactic polypropylene -atactic polystyrene blends were investigated [6,12,23,24]. It was found that a melting peak area is linearly proportional to the blend composition indicating [12] a high degree of dispersion in the blends prepared by injection molding using a screw static mixer.…”

“…It was found that a melting peak area is linearly proportional to the blend composition indicating [12] a high degree of dispersion in the blends prepared by injection molding using a screw static mixer. In blends of atactic polystyrene with isotactic polypropylene a fibril-like morphology was observed [6].…”

Preferential migration of blend components leading to different intercalated morphology

“…The effect of processing conditions on the state of dispersion of the rubber phase plays an important role in the morphology of the blend formed, and hence on its resulting properties [7][8][9][10]. Three distinct types of morphologies that are evident from its fractured surface are separated, core and shell, and mixed type.…”