Talc reinforcement

Yua Sheng et al. [153] and Leong et al. [155] measured the tensile, flexural, and impact properties of ultra-fine-talc-filled polypropylene composites. Experimental results indicated that the addition of talc inflnenced the crystallization, morphology, and mechanical properties of talc-polypropylene composites. When the talc content was increased from 0% to 25%, the crystallinity of the polypropylene phase reached a maximnm at 15% talc and the tensile and flexural strengths of talc-polypropylene composites also attained a maximum, while the impact strength declined to its lowest level. Scanning electron microscopy photographs of impact 

Relative modulus versus talc clay-reinforced agent content for nanocomposites based on a thermoplastic polyolefin or a triphenylene oxide matrix polypropylene plus ethylene-based elastomer showed that relative to a particular filler content, an appreciably higher modulus content was obtained for the montmorillonite reinforcing agent than for talc [156]. Doubling the modulus of the phenylene oxide requires about four times more talc than montmorillonite, with the talc-reinforced polymer having an improved surface finish. In the case of the talc-reinforced polymer, exfoliation is appreciably better than with clay reinforcement. The talc-reinforced polymer has automotive applications. 

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The application of this technique to talc-reinforced polypropylene has shown that the microstructure of platelets and the resulting physical properties of the moulded composites are markedly affected [171)]. With two live feeds located at either end of the mould cavity, the talc platelets exhibited strong talc platelet alignment throughout the thickness of the moulding in the direction of the ap-... 

O. Noel and R. Clark. Recent advances in talc-reinforced wood-plastic composites. In Intertech s 4th Conference of Natural Fiber Wood Composites, Intertech, Portland, ME, Orlando, FL, 2005. 

Firebrake ZB 415 with Dechlorane Plus gives flame-retardant properties superior to those of antimony oxide alone. Grade ZB 500 makes it possible to suppress fumes from fluoropolymers, and gives good flame-retardant properties to poly(ether ketone)s and polyfether sulphone)s. Other key applications are talc-reinforced PP replacing PVC. ABS, and PA 66 in electrical/electronic applications, and EVC cable compounds. 

Seldon et al. [96] measnred weld line impart strength and tensile strengths on mjertion-molded specimens of fiberglass-reinforced polyamide 6 and talc-reinforced polypropylene. The effect of hold pressure, impart velocity, melt temperature, and mold tanperature on weld line strength was studied. 

With talc reinforcements, both crystallization kinetics and crystal microstructure of the polymer (PLA) are significantly altered, for example, the overall crystallinity is reached more quickly due to increase in crystallization kinetics. The degree of crystallinity obtained from DSC measurements increased from 3.6% in neat PLA to 15.4% in PLA-talc composites with a filler content of 7.0 wt% [68]. This in turn can lead to reduced cycle time in injection molding and stiffer materials than neat PLA, when molded under the same conditions. At similar loading level of talc (7.0 wt%), the tensile modulus increased by 15%, while flexural modulus increased by 22% [68]. 

Chemical coupling agent for glass, aica, and talc reinforced polypropylene giving enhanced physical and thermal properties Coapatabilizer for blends such as polyprc ylene/polyaaide and polypropylene/EVOH to improve processability and mechanical prc>perties. 

Chemical coupling agent for glass, mica, and talc reinforced polypropylene giving enhanced physical Uid thermal properties. 

Talc reinforced thermoplastics yield higher heat distortion temperatures and lower thermal expansion. These characteristics indicate an extended service temperature range and improved dimensional stability. In processing, talc builds torque which promotes fusion in rigid vinyls. Talc also provides good hot strength for downstream operations. 

Polymer nanocomposites consist of a polymer matrix with embedded filler particles with at least one dimension at the nanometre level, (i.e. 1-100 nm), much smaller than for the conventional polymer composites described above. The inclusion of nanoparticles can effect significant improvements in mechanical properties such as modulus, yield stress and fracture toughness for filler levels as low as a few per cent by weight. This is much lower than in conventional polymer composites, as illustrated in Figure 9.7, where the effect of talc reinforcement and clay nanoparticle reinforcement in a polypropylene matrix are compared. Talc filler is regarded as a conventional reinforcement, with particle diameters in the range 1-10 qm and thickness around 20 times less, whereas the clay particles are of length around 100 nm and thickness as low as 1 nm. Clay occurs in the form of platelets and has been... 

Figure 9.7 Comparison of talc reinforcement with nanoclay (montmorillonite) reinforcement, in terms of the ratio of composite modulus to matrix modulus. The matrix material is a blend of polypropylene and thermoplastic elastomer (TPO). (Reproduced from Lee H-s. et al. (2005) TPO based nanocomposites. Part 1. Morphology and mechanical properties Polymer, 46, 11673-11689. Copyright (2005) Elsevier Ltd.)...

The water repellence effect is very important for the products used in insulating compounds for electrical equipment as well as in talc reinforced PP for leisure furniture. 

PP has no inherent flame-retardant properties. High shrinkage means that dimensional stability is poor. This shortcoming can be countered only by using talc-reinforced, mineral-filled, or glass-ball-filled PP for reduced and more isotropic shrinkage. Talc reinforcement reduces heat distortion resistance [8,40, 48]. 

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