Liquid molding

Liquid-molding resins, based on poly(dicyclopentadiene), 20 432 Liquid monomer phase, in PVC polymerization, 25 667 Liquid NaK alloy, 20 603. See also NaK entries... 

Consider the possible heterogeneous nucleation of a solid phase from a liquid in a conically shaped pit in the wall of a mold as illustrated in Fig. 19.22. Let the energies of the liquid/mold, solid/mold, and liquid/solid interfaces be 1LM> 7 , and yLS, respectively, and assume that ySM = yLM. 

Cured liquid-molding resins based on polydicyclopentadiene are uses in the manufacture of automotive parts for trucks, snowmobiles, wheel loaders, recreational vehicles, and also in other areas that require toughness and good all-weather impact resistance. 

Molded Objects Immersed in Liquids. Molded, non-foamed articles, such as drinking cups from rubber-modified polystyrene, are immersed... 

The vacuum assisted liquid molding process has been used for the manufacture of large composite parts. In this process, a preform is placed in an open mold and a plastic vacuum bag placed on top of the mold. A vacuum is created in the mold using a vacuum pump. A resin source is connected to the mold. As vacuum is drawn through the mold, resin infuses into the preform. Application includes the fabrication of large products with complex geometry such as panels of allcomposite buses, railroad cars, and vehicle components. 

Properties Colorless liquid mold odor. D 0.908 (20/4C), bp 160-161C (0.26 mm Hg), flash p 420F (215C). Insoluble in water miscible with most common organic solvents. Combustible. 

Such a derivation was originally developed and used by Kirchoff [1858] and Rankine [1849] ( ) to express the temperature dependence of vapor pressure. It was also successfully used by Brostow (O to express the temperature dependence of the isothermal compressibility of a wide variety of organic liquids, some metallic liquids and water. By a similar analogy, we have used it to express the viscosity of liquid mold fluxes. 

Rudd, C., Long, A., Kendall, K. Mangin, C. (1997) Liquid Molding Technologies, Cambridge Woodhead Publishing. 

In the laboratory, styrene can be prepared by the decarboxylation of cinnamic acid, as shown in Reaction 1, using dry distillation. However, styrene is produced commercially from ethylene and benzene, two basic ingiedienis of the petrochemical industry. With electrophilic addition of ethylene to benzene, a mixture of ethyl benzene and diethylbenzene is obtained as own in Reaction 2. The dehydrogenation of these benzene derivatives produces slyrene and divinylbenzene, respectively (Reaction 3). A detailed synthesis of styrene is described by Berthelot et al (6). As mentioned earlier, styrene is an important monomer in many industrial polymers. Additionally, divinylbenzene which is produced as a by-product is an effective crosslinker for ion-exchange resins, polystyrene-based supported reagents and catalysts, and low profile additive in a number of liquid molding resin systems. 

E. Can, S. H. Ksefoglu and R. P. Wool, Rigid, thermosetting liquid molding resins from renewable resources. 1. Synthesis and polymerization of soy oil monoglyceride maleates ,/AppZ Polym Sci, 2001,81, 69-77. 

Golden Wax, Liquid mold release wax. Specialty Products Co. 

Rotational A predetermined amount of powdered or liquid molding thermoplastic or thermoset material is poured... 

Simacek, P. and Advani, S. G., Desirable features in mold filling simulations for liquid molding processes . Polymer Composites, 25, 355-367, 2004. 

Advani, S. G. and Sozer, E. M., Resin impregnation in liquid molding processes . In A. Kelly (ed.). Comprehensive composite materials. Amsterdam Elsevier Science, 2000, Chapter 24. 

This study focuses on a new liquid molding process called VAP. The process adds a membrane to the SCRIMP process allowing uniform venting on the complete preform surface. It evaluates the flow behavior, membrane material and final material properties resulting from the process. Overall, the membrane approach provides a more robust process with the correct selection of the membrane material. 

SQRTM has been developed and is now in the process of commercialization by Radius Engineering Inc. (Salt Lake City, Utah). SQRTM is a closed molding method that combines prepreg processing and liquid molding to produce net-shape, highly unitized composite parts. 

This schematic structure allows for the perception of some processes from a different point of view. For example, rotational molding is a special liquid molding process with the resin drawn by centrifugal forces and roll forming is a continuous thermoforming process. 

Bourban P E (2000) Liquid molding of thermoplastic composites, in Comprehensive Composite Materials (Eds. Talreja R and M nson J A E) Elsevier, Amsterdam, Netherlands, pp. 965-977. 

A model was developed to estimate properties of polymer composites which have voids of various sizes (large and small). Such voids are typically found between fiber tows (macrovoids) and inside the fiber tows (microvoids) in composites produced by liquid molding. The presence of these voids does prevent the matrix from adhering to the fiber which reduces the composite s mechanical performance. Larger voids do not seem to afiect performance as much as smaller voids do. In practice, the volume of voids in normal production is within 5% of the total volume of the composite. At 5% void volume, the mechanical strength of composite can be reduced by as much as 30%. This is considered a substantial imperfection but it is found in practice. The model developed predicts values of mechanical properties which correlate with void volume. In another application, magnetic resonance imaging helped to determine voids in solid rocket propellants and liners similar to those used in space shuttle. The voids were found to be in close proximity to the filler particles. 

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