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Pure PC (pure + pc)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Mechanical properties and flammability of polycarbonate alloys containing nanosize additives

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009
Zhiyi Zhang
Abstract Different organic,inorganic composite particles [montmorillonite/poly(butyl acrylate) (PBA)/poly(methyl methacrylate) (PMMA), SiO2/PBA/PMMA, and CaCO3/PBA/PMMA] were synthesized by emulsion polymerization. Furthermore, polycarbonate (PC) alloys were prepared via the doping of these composite particles into PC with a twin-screw extruder. The structure, mechanical properties, and flammability of the PC alloys were studied in detail. Although the tensile modulus of PC decreased a little, the flexibility and impact resistance were improved by the addition of these composite particles. This result was attributed to the fact that the composite particles were well dispersed in the PC matrix, with a cocontinuous phase formed between the particles and PC. In addition, the combustion behavior of the PC alloys, compared with that of the pure PC, resulted from a ceramic-like char that formed on the surface of the PC alloys during burning. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Crack Toughness Behaviour of Multiwalled Carbon Nanotube (MWNT)/Polycarbonate Nanocomposites

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2005
Bhabani K. Satapathy
Abstract Summary: The morphology and fracture behaviour of polycarbonate (PC)/multiwalled carbon nanotube (MWNT) composites have been studied by AFM and post-yield fracture mechanics. The essential work of fracture (EWF) method has been used to distinguish between two terms representing the resistance to crack initiation and crack propagation. A maximum in the non-essential work of fracture was observed at 2 wt.-% MWNT, demonstrating enhanced resistance to crack propagation compared to pure PC. At 4 wt.-% MWNT, a tough-to-brittle transition has been observed. The time-resolved in-situ strain field analysis revealed that the onset of crack initiation was shifted to a shorter time for nanocomposites with 4 wt.-% MWNT compared to that with 2 wt.-%, and thus explained the existence of a tough-to-brittle transition in these nanocomposites. [source]

Melt flow properties, mechanical properties, thermal properties and morphology of polycarbonate/highly branched polystyrene blends

POLYMER INTERNATIONAL, Issue 5 2006
Aiying Li
Abstract A highly branched polystyrene (HBPS) was synthesized via the copolymerization of 4-(chloromethyl) styrene with styrene using the self-condensing atom transfer radical polymerization method. The addition of HBPS as a melt modifier for polycarbonate (PC) was attempted. Melt flow properties, mechanical properties, thermal properties and morphology of the blends were studied. The results showed that a significant drop in the blend viscosity occurs immediately on addition of HBPS. Impact strength, tensile strength and glass transition temperature (Tg) of all the blends have not been significantly reduced compared with those of pure PC. The TGA analyses showed that an initial weight loss temperature of all the blends is above 458 °C and slightly low compared with that of pure PC, but all the blends still have excellent thermal stability. Morphological studies using SEM showed that a two-phase morphology is characteristic of all the blends, with more or less spherical droplets of the minor HBPS phase dispersed in the continuous PC phase. Copyright © 2006 Society of Chemical Industry [source]

Polycarbonate/SiC nanocomposites,influence of nanoparticle dispersion on molecular mobility and gas transport,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 2-3 2005
Martin Böhning
Abstract Plasma synthesized silicon carbide (SiC) nanoparticles were dispersed in dichloromethane/poly(bisphenol-A-carbonate) (PC) solutions by high power ultrasonification. Samples were then prepared by film casting under well adapted preparation conditions. The influence of the SiC nanoparticles on the molecular mobility of the PC is studied by dielectric relaxation spectroscopy. No effect on the cooperative segmental mobility (glass transition) was detected. But the relaxation region corresponding to localized fluctuations is strongly broadened and the activation energy is reduced with increasing nanoparticle concentration. The most significant change was observed in the relaxation region between , - and , -process. The gas transport properties of these nanocomposite films are characterized in terms of permeability, diffusivity and solubility. Results can be interpreted based on an altered local free volume distribution and a change of molecular mobility of the polymer matrix near the nanoparticle surface which is in agreement with the dielectric results. Concentration dependent CO2 permeation experiments reveal a significant reduction of plasticization effects in the nanocomposites compared to the pure PC. Copyright © 2005 John Wiley & Sons, Ltd. [source]