Plastics

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  • Topic: Polymer, Young's modulus, Charpy impact test
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Materials Sciences and Applications, 2011, 2, 404-410
doi:10.4236/msa.2011.25052 Published Online May 2011 (http://www.SciRP.org/journal/msa)

Some Mechanical and Thermal Properties of PC/ABS Blends
Rachida Krache, Ismahane Debbah
LMPMP, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas, Sétif, Algérie. Email: rachida2000fr@yahoo.fr Received March 9th, 2011; revised March 16th, 2011; accepted March 30th, 2011.

ABSTRACT
A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young’s modulus changed gradually and monotonically with the polycarbonate content. This effect was tentatively explained as the antiplasticization of the PC which is ascribed to the chain mobility, which permits the PC chains to pack more tightly, to the secondary cross-linking between the PC chains, or to the secondary attachment of bulky side-chains to the PC, thus producing steric hindrance to the rotation of the PC main chains. The experimental values found for the impact strength were intermediate between those of the neat polymers, depending upon the dispersed rubber particles of butadiene in the matrix of SAN (Styrene-Acrylonitrile), and the dispersed PC particles which generally make the ABS more brittle. A maximum value of about 88 KJ/m2 for the impact strength was observed for the blend with 90% PC. This may be attributed to the strong polymer-polymer interactions for this particular composition. The variations in the heat deflection temperature HDT and the Vicat softening point with the blend composition were very similar, and allowed us to assume that the phase inversion between the matrices of the two polymers takes place at 50% PC. The morphology of the blends revealed by SEM observation, show a co-continuous structure. Keywords: PC, ABS, Blends, Impact Strength, Tensile and Flexural Properties, HDT, Vicat Point, Hardness, FTIR, Morphology

1. Introduction
The mixing or blending of polymers can be an efficient way of developing materials with novel or selectively enhanced properties. It is possible to modify some characteristics of polymer blends by varying the composition. Incompatible blends present phase separation as dispersed nodules in the matrix phase, the consequent low adhesion leading to undesirable properties. By controlling the fraction of each component, a resulting polymer with the desired properties can be obtained. Usually, the final objective is to reach a balance between maximum temperature resistance, toughness, etc, and ease of fabrication. The behavior of polymer blends can be discussed according to the variation of their properties with the blend composition. The blending of two or more polymers always affects the properties of the resulting material. Three different effects on those properties can be distinguished: synergistic, antagonistic and additive effect. Copyright © 2011 SciRes.

Polycarbonate PC is characterized for its high modulus, high toughness, high impact strength and difficult processability, due to its high melt viscosity. AcrylonitrileButadiene-Styrene (ABS) is a rubber toughened thermoplastic, characterized by its notch insensitivity and low cost. On the other hand, the ABS limitations are: poor flame and chemical resistance, and low thermal stability [1]. The commercialization of PC began in 1958; the production of the PC/ABS blends started on 1977. The addition of ABS to PC minimizes its drawbacks without affecting its superior mechanical properties, and also generates other useful characteristics, such as glossiness and low temperature toughness [2]. A number of patents concerning these blends have been issued in the past, but the scientific knowledge about their behavior is still limited owing to the complexity of the system. The blends consist, in fact, of four polymeric species and three phases, their morphology depending on a variety...
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