Blending glass concentration

Blending a reinforced pellet concentrate with unreinforced pellets to obtain the desired glass concentration... 

Other things being equal, normally, at the same glass concentration the direct molding of powder blended with glass is less expensive than molding glass-reinforced pellet concentrate with unreinforced pellets. This is because the pellet concen-... 

The mechanical properties of the blend of silane/size and bulk epoxy matrix (at concentrations representing likely compositions found at the fiber-matrix interface region) also suggest that the interaction of size with epoxy produces an interphase which is completely different to the bulk matrix material (Al-Moussawi et al., 1993). The interphase material tends to have a lower glass transition temperature, Tg, higher modulus and tensile strength and lower fracture toughness than the bulk matrix. Fig. 5.4 (Drown et al., 1991) presents a plot of Tg versus the amount of... 

The solutions are always clear.They are then poured together in varying ratios. A few ml of the initially clear solutions are concentrated by evaporating the solvent in small glass dishes with flat bottoms in a drying oven until a film of the polymer blend forms (solvent not to be removed by distillation ). 

Mijovic et al. analyzed the annealed blends from melts using dynamic mechanical thermal analysis and achieved similar results after an adjustment for shifting factors, AT s, as shown in Figure 7.3. The results were extended to include blends having a PVDF concentration greater than 80 wt %. It can be observed that the glass transition temperatures of the annealed blends reduce rapidly when the PVDF concentrations are above 80 wt %. 

The growth of these materials is reflected in the number of polymers which are being glass reinforced. These include polypropylene, polystyrene, styrene acrylonitrile, nylon, polyethylene, acrylonitrile-butadiene-styrene, modified polyphenylene oxide, polycarbonate, acetal, polysulfone, polyurethane, poly (vinyl chloride), and polyester. In addition, the reinforced thermoplastics available now include long-fiber compounds, short-fiber compounds, super concentrates for economy, a combination of long and short fibers, and blends of polymer and fibrous glass. 

Lodge TP, McLeish TCB (2000) Self-concentrations and effective glass transition temperatures in polymer blends. Macromolecules 33(14) 5278—5284... 

Epoxy resins may be blended with certain vinyl polymers to improve the impact strength and peel strength of the adhesive. Polyvinyl acetals, such as polyvinyl butyral and polyvinyl formal, and polyvinyl esters are compatible with DGEBA epoxy resins when added at concentrations of 10 to 20% by weight. The addition improves the resulting impact resistance and peel strength of the cured adhesive. However, temperature and chemical resistance are sacrificed by the addition of the low-glass-transition-temperature vinyl resins. 

Several hybrid epoxy emulsions have been commercially prepared. An epoxy emulsion blended with waterborne aliphatic urethanes exhibited peel strength on aluminum of 10 lb/in—1.5 times greater than with the polyurethane itself. The optimum concentration of urethane in the final emulsion was about 50 percent by weight.13 Epoxy-phenolic dispersions have also been developed to provide waterborne adhesive systems with high glass transition temperature and chemical resistance. 

The compatibility of blends of PVC and the terpolymer was investigated by dynamic mechanical, dielectric, and calorimetric studies. Not only did each technique show a single glass transition for each mixture, but also the temperature of the transition, as defined by the initial rise in E" at 110 Hz, e" at 100 Hz, and Cp at 20°/min, agreed to within 5°C. Tg was found to increase with increasing concentration of PVC. 

---