Morphology-property relationships in polycarbonate-based blends. II. Tensile and impact strength

Inorganic Particles Contribute to the Compatibility of Polycarbonate/Polystyrene Polymer Blends

Polycarbonate (PC), an engineering plastic, has excellent mechanical strength and toughness. Moreover, this transparent polymer material can be used in fields where materials require mechanical properties and transparency. Nevertheless, PC is known to have a high melt viscosity. Moreover, blending with polystyrene (PS), an inherently brittle material, has been used to adjust its melt viscosity. As a result, the PS makes PC/PS polymer blends more brittle than PC alone. As described herein, after attempting to achieve compatibility with inorganic particles, the results show that the dispersion of small amounts of inorganic clay and silica particles in PC/PS polymer blends maintained transparency while improving the impact strength to a level comparable to that of polycarbonate. Apparently, the inorganic particles promote the fine dispersion of PS. Moreover, the spherical morphology of the inorganic particles is more effective at compatibilizing the polymer blend because the inorganic particles can apply isotropic interaction forces.

Improvement in Processability for Injection Molding of Bisphenol-A Polycarbonate by Addition of Low-Density Polyethylene

The rheological properties and processability at injection molding were studied for bisphenol-A polycarbonate (PC) that was modified by low-density polyethylene (LDPE) having a low shear viscosity. The LDPE addition significantly decreased the steady-state shear viscosity, especially in the high shear rate region. The decrease did not originate from slippage on the die wall but due to interfacial slippage between the PC and dispersed LDPE droplets that deformed to the flow direction to a great extent. As a result of the viscosity decrease, injection pressure largely decreased from 150 to 110 MPa with the addition only 5 wt.% of LDPE. The enhanced flowability also reduced the warpage of the molded product significantly, demonstrating that the processability at injection molding was improved by the addition of LDPE.

Experimental and theoretical investigations of the high performance blends of PEEK/PEI

Polyether ether ketone (PEEK) and polyether imide (PEI) blends were made by melt blending using a twin-screw extruder. The blends were characterized by mechanical testing, thermal, rheological and morphological studies. Predictive models were used to explain the tensile modulus and strength properties. The impact strength increases when percentage of the PEI increases in composite. This has been analyzed on the basis of the interphase adhesion. Tensile and flexural strength also increased with increase in the PEI content. Incorporation of PEI increases the glass transition temperature (Tg) and facilitates its processing. Scanning electron microscopy (SEM) was employed to study the phase structure. These experimental findings are in agreement with predictive models based on the rule of mixture and the Nicolais-Narkis model. Multi quadric radial basis function (MQRBF) was applied to study the static and dynamic response of the PEEK/PEI blend plate at uniformly distributed load. The present results were compared with numerical and analytical results.

Excellent impact strength of ethylene-methyl acrylate copolymer toughened polycarbonate

The notched izod impact strength of PC/EMA blends showed a positive blending effect and increased 381% with incorporation of a very little amount of EMA (5%) with a marginal decrease in tensile strength of PC.