Polymer composites liquid composite molding

Reactive Melt Polymerization. The liquid composite molding (LCM) method is established for the fahricarion of thermosets. In contrast, reac-rive thermoplastic LCM processes are developed to only a few engineering polymers. The technique was applied to low-melting PA 6T/6I oligo-... 

P. Simacek, Neacsu, V. and S. G. Advani. A phenomenological model for fiber tow saturation of dual scale fabrics in liquid composite molding. Polymer Composites, 31(11), 1881-1889, 2010. 

Hsiao, K.-T, Gillespie Jr., J. W., Advani, S. G. and Fink, B. K. (2001), Role of vacuum pressure and port locations on flow front control for liquid composites molding processes , Polymer Composites, 22(5), 660-667. 

Ruiz, E. and Trochu, E., 2005. Comprehensive thermal optimisation of liquid composite molding to reduce cycle time and processing stresses . Polymer Composites, 26, 209-230. 

Manufacturing techniques for polymer matrix composites (PMCs) 14.4.4 Cure kinetics Liquid composite molding (LCM)... 

Luthy T, Ermanni P. How monitoring in liquid composite molding based on linear direct current sensing technique. Polymer Composites, 2003 24(2) 249-262. DOI http //dx.doi.org/10.1002/pc. 10026. 

Bensadoun F, Kchit N, Billotte C, Bickerton S, Trochu F, Ruiz E (2011) A study of nanoclay reinforcement of biocomposites made by liquid composite molding . International Journal of Polymer Science, Article ID 964193. 

Wu, C. Wang, T.G. Lee, L.J. Trans-plane fluid permeability measurement and its application in liquid composite molding. Polym. Compos. 1994,15, 289-298. 

U.S. Pat No. 6,578,368 [51] discloses a method for cooling extruded and molded cellulosic-polymer composites, among other plastics and plastic compositions the said method uses cryogenic fluid with a temperature below about 250° F, such as liquid oxygen, liquid nitrogen, liquid neon, liquid hydrogen, and liquid helium. 

Injection molded polymer composite products containing liquids are characterized by minimal residual stresses. Cracking under internal stresses is not evidently characteristic for this type of materials at all. Shrinkage of the articles of inhibited composites depends on the liquid phase content and does not surpass 2-3% for PE- and PA-based materials. 

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. 

At first glance, rotational molding is a relatively simple process. It utilizes high molding temperatures, thin-walled metal or composite molds, biaxial rotation in two perpendicular axes, finely divided powder or liquid polymers, and cooling using air and/or water to produce hollow, seamless parts with relatively low levels of molded-in stress. 

Isayev AI, Modic M (1987) Self-reinfOTced melt processible polymer composites extrusion, compression, and injection molding. Polym Compos 8 158 James SG, Donald AM, MacDonald WA (1987) Blends of a liquid crystalline copolyester with polyethersulphone. Mol Cryst Liq Cryst 153 491 Jerman RE, Baird DG (1981) Rheological properties of copolyester liquid crystalline melts. I. Capillary rheometry. J Rheol 25 275... 

FIGURE 10.7 Fabrication of polymer/carbon architectures for bioelectrodes, (a) (1) Sucrose template is mixed with (2) carbon nanofibers and placed in a (3) Teflon mold along with a Ni mesh current collector attached to a Ti wire, (b) The mixture is coated with liquid PHBV polymer, (c) After the polymer solidifies, the composite is submerged in water to dissolve the sucrose template leaving behind a conductive porous architecture [21]. 

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