Glass additives flour

As discussed in Chapter 10, a wide variety of additives is used in the polymer industry. Stabilizers, waxes, and processing aids reduce degradation of the polymer during processing and use. Dyes and pigments provide the many hues that we observe in synthetic fabrics and molded articles, such as household containers and toys. Functional additives, such as glass fibers, carbon black, and metakaolins can improve dimensional stability, modulus, conductivity, or electrical resistivity of the polymer. Fillers can reduce the cost of the final part by replacing expensive resins with inexpensive materials such as wood flour and calcium carbonate. The additives chosen will depend on the properties desired. 

For many applications, the homopolymer of styrene is too brittle. To overcome that, many different approaches were originally tried. These included use of high molecular weight polymers, use of plasticizers, fillers (glass fiber, wood flour, etc.), deliberate orientation of the polymeric chains, copolymerization and addition of rubbery substances. Effect of plasticizers is too severe for practical use, and use of high molecular weight polymers exhibits only marginal improvement. Use of fillers. 

Water-blown low density rigid polyurethane foams have been prepared with poly(ether polyol)s, polymeric isocyanates, DSF, water, a catalyst mixture, and a surfactant the immiscible character of the blend composites. Soy flour and the initial water content were varied from 0 to 40 per cent and from 4.5 to 5.5 per cent of the poly(ether polyol) content, respectively. The addition of soy flour in the rigid polyurethane foam system contributed to a higher glass transition temperature, and increasing the initial water content also resulted in an increase in the glass transition temperature [85]. 

The authors found that the depression of glass transition temperature (Tg) due to the addition of plasticiser is substantially reduced by the loading of wood flour. In addition, various wood-plastic composites were compounded into different colours, and several pairs of the compounds with different rheological properties were extruded in single and twin-screw extruders to see whether any wood-patterns are developed. When the differences in the shear viscosity and the Tg of the two compounds were too large, the incomplete plasticisation of the higher viscosity component was observed due to the lower viscosity component. It was found also that distinct wood-patterns were only developed both inside and on the snrface of the extruded prodncts for the pairs of the composites with optimal differences in both viscosity and plasticiser content. 

Additives used in final products Fillers aluminum hydroxide, antimony trioxide, calcium carbonate, carbon black, chopped glass fiber, crashed marble, flyash, glass fiber, hollow glass spheres, kaolin, marble, mont-morillonite, nano-TiO, polymeric bubbles, quartz, saw dust, silica, talc, wood flour ... 

A higher value of the modulus of elasticity indicates a rigid material (the E value is about 200 000 MPa for steel), a lower value indicates a more brittle material (such as glass, where = 50 000-90 000 MPa), and a very low value represents a ductile material (such as rubber with = 10-100 MPa). The values of certain foods are, as an fllustration, Hsted in Table 7.9. These values depend on many factors. For example, the modulus of elasticity in bread changes during storage and depends on the type of flour and addition of emulsifiers and a range of other variables. 

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