Polymer blend

About: Polymer blend is a research topic. Over the lifetime, 18474 publications have been published within this topic receiving 437183 citations. The topic is also known as: polymer mixture & Polymerblend 或者 Polyblend.

Study on morphology of ternary polymer blends. I. Effects of melt viscosity and interfacial interaction

Abstract: The morphology of some ternary blends was investigated. In all of the blends polypropylene, as the major phase, was blended with two different minor phases, ethylene–propylene–diene terpolymer (EPDM) or ethylene–propylene–rubber (EPR) as the first minor phase and high-density polyethylene (HDPE) or polystyrene (PS) as the second minor phase. All the blends were investigated in a constant composition of 70/15/15 wt %. Theoretical models predict that the dispersed phase of a multiphase polymer blend will either form an encapsulation-type phase morphology or phases will remain separately dispersed, depending on which morphology has the lower free energy or positive spreading coefficient. Interfacial interaction between phases was found to play a significant role in determining the type of morphology of these blend systems. A core–shell-type morphology for HDPE encapsulated by rubber was obtained for PP/rubber/PE ternary blends, whereas PP/rubber/PS blends showed a separately dispersed type of morphology. These results were found to be in good agreement with the theoretical predictions. Steady-state torque for each component was used to study the effect of melt viscosity ratio on the morphology of the blends. It was found that the torque ratios affect only the size of the dispersed phases and have no appreciable influence on the type of morphology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1129–1137, 2001

heat sealable films and articles made therefrom.

Abstract: Heat sealed articles and heat sealable films comprising a polymer blend of a first polymer having a narrow molecular weight and composition distribution and a second polymer having a broad molecular weight distribution and composition distribution. The articles and films have significantly improved physical characteristics and remarkably low heat seal initiation temperatures, high seal strength, high hot tack and therefore provide improved processibility and higher line speeds on commercial heat sealing equipment.

Conformational Entropy Contributions to the Glass Temperature of Blends of Miscible Polymers.

Abstract: Because of negligible contributions of combinatorial entropy, miscibility of polymers is attributed predominantly to favorable (exothermic) enthalpic effects of mixing, i.e., to strong interactions between the blend components, which have to overcome the cohesive forces acting within the components. Miscibility of amorphous polymers usually is associated with the presence of a single glass temperature of the blend. Although stronger hetero-contact interactions are thermodynamically required for polymer miscibility, the majority of miscible binary polymer blends exhibit negative deviations of the glass temperature from values predicted by the free volume or flexible bond additivity rules, suggesting a looser packing within those blends. A reasonable explanation assumes that binary hetero-contact formation within the blend may be accompanied by local interchain orientation contributing consequently to conformational entropy changes. The smaller the induced interchain orientation by hetero-contact formation, the larger the mobility in the neighborhood of the contacts and the probability of related conformational entropy changes, causing an equivalent increase of the "free volume" within the blend, i.e., a corresponding decrease of the blend Tg, which finally can be situated below the values predicted by the additivity rules. Vice versa, the corresponding argument will hold for blends with higher interchain orientation induced by intensive exothermic hetero-contact forces.