Microcellular injection molding

Figure 9.6. A representative image of microcellular PLA-MWCNT nanocomposite produced via microcellular injection-molding.

Figure 9.7. TEM Images of (a) Solid PLA-MWCNT Nanocomposite at 500 nm (Inset-a magnified view of agglomerated MWCNTs at 100 nm) (b) Microcellular PLA-MWCNT Nanocomposite at 500 nm (arrow indicates micro cell formed during microcellular injection-molding) (c) Solid PLA-MWCNT Nanocomposite at 100 nm and (d) Microcellular PLA-MWCNT Nanocomposite at 100 nm. Reprinted with permission from S. Pilla et al.. International Polymer Processing, XXII, p. 418,2007, 2007, Polymer Processing Society.

Turng, L.-S. et al. (2003) Applications of nano-composites and woodfiber plastics for microcellular injection molding. Proceedings of the Seventh International Conference on Woodfiber-Plastic Composites, Forest Products Society, Madison, WI, pp. 217-226. 

Neat PLA, PLA/cellulose fiber composites (10-30 wt%), and PLA/carbon nanotube nanocomposites were successfully foamed in a microcellular injection molding process using nitrogen gas [3, 76]. All foamed samples exhibited a sandwich-type structure, with solid walls encapsulating a foamed... 

TABLE 17.9 Cell Morphology of Microcellular Injection Molded Neat PLA and PLA/Cellulosic Fiber Composites [3]... 

S. Hwang, S. Liu, P. P. Hsu, J. Yeh, K. Chang and Y. Lai, Effect of organoclay on the mechanical/thermal properties of microcellular injection molded PBT-clay nanocomposites, Int. Commun. Heat Mass Transfer, 37 1036-1043,2010. 

Mi, H.-Y, Sahck, M.R., Jing, X., Jacques, B.R., Crone, W.C., Peng, X.-E, Tumg, L.-S., 2013. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding. Materials Science and Engineering C 33 (8), 4767-4776. 

Melt temperature and fill rates have been demonstrated to be very important process variables for microcellular injection molding. Recent work has studied the use of fast response thermocouples along with traditional pressure transducers to determine their effectiveness in providing practical process monitoring tools for the microcellular molding process [7]. Behind the ejector pin, pressure transducers and fast... 

Berry M, Kishbaugh L. Process monitoring and control for microcellular injection molding. SPE ANTEC 2010. 

Yuan, M. J., Q. Song, and L. S. Turng. 2007. Spatial orientation of nanoclay and crystallite in microcellular injection molded polyamide-6 nanocomposites. Polym Eng Sci 47 765-79. 

Chen, S. C., Liao, W. H., and Chen, R. D. 2012. Structure and mechanical properties of polystyrene foams made through microcellular injection molding via control mechanisms of gas counter pressure and mold temperature. International Communications in Heat andMass Transfer 39 1125-1131. 

The crystallization behavior of PA6 and its nanocomposites undergoing a microcellular injection molding process was studied using TEM, XRD, SEM, and PLM the addition of polarized light microscopy was important to study crystal formation [492]. A synthesis approach to make PP nanocomposites by in situ polymerization was studied by OM, TEM, and... 

Zhenhao, X., Fanglln, Z., Hua, Z., Tao, L, Ling, Z., Lih-Sheng, T. (2013). Microcellular injection molding of in situ modified poly(ethylene terephthalate) with supercritical nitrogen, Polym. Eng. ScL, 54,2739-2745. 

In response, microcellular injection molding was developed[3] and commercialized by Trexel Co. Ltd. as the Mucell process. The key insight of this process is the application of a supercritical fluid. The supercritical fluid is injected during the injection stage cycle, creating millions of micron-sized voids in otherwise solid thermoplastic polymer parts. 

In this study, we have investigated the efifeets of process parameters on the variation of the rim thickness (Fig. 3) by conventional and microcellular injection molding. The specification of the rim thickness is 0.02mm. If the rim thickness tolerance is out of specification, there is a running noise from the roller, and the textile roller should be replaced after a certain time. 

Fig. 7 shows the rim thickness variation of the glass fiber filled PBT by microcellular injection molding. The thickness variation is around 0.04 mm, which is on the margin of the specification, and the thinnest occurs at point 5. The thickness trend is similar to that of solid molding, but the thickness variation is smaller for microcellular molding. 

For the rim thickness, microcellular injection molding has smaller thickness variation than conventional molding. 

Keyword Microcellular, Injection Molding, Three-Plate-Mold, PBT, Glass Fiber, Miner Fiber. 

This study investigated the effect of the Polyethylene-octene-elastomer (POE) content on the meehanical and thermal properties of PP/POE and HDPE/POE composites by microcellular injection molding. Batches of PP and HDPE with POE content of, 0 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, and 50 wt% for each material were prepared. Nitrogen was used as the blowing agent. DSC was used to study the thermal properties of the samples and SEM was employed to study the microstructure of the fracture surface. The results showed that as POE content increases, tensile strength and flexural modulus decreases. However, as POE content rises, impact strength is increased. 

In this study, we investigate the effeets of POE content on the mechanical and thermal properties of PP and HDPE, using the microcellular injection molding process as the blending process. 

S. S. Hwang, S. C. Chen, and M. H. Chung, Study on the Mechanical Properties of Microcellular Injection Molded Parts , SPE-ANTEC Tech. Papers, p 776-780, (2005).)... 

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