PDF Publication Title:
Text from PDF Page: 017
Ogila et al. – eXPRESS Polymer Letters Vol.11, No.10 (2017) 778–798 catalyst concentration and the polymerization induc- tion time for reactive LPSs. As expected higher con- centrations of activator/catalyst reduced induction times and increased the reaction rates. 6. Conclusions Amongst the theoretical models evaluated, the fixed domain techniques yield the most reliable results [10, 20–26]. Enthalpy based models; specifically the semi empirical approaches suitably represent the melting and crystallization events during the RM cycle [23–26]. An issue of concern however is their reliance on experimental data which can be severely limiting when such is unavailable. Nonetheless, these models enable the accurate prediction of the RM process and optimization of its parameters. Similarly advances in process control, especially advances in the sphere of automatic control for the RM process, may significantly improve the reproducibility of components over numerous runs [31–33]. Surface finish in RM is evaluated primarily in terms of the prevalence of porosity [38, 57, 60], severity of degradation [36] and warpage levels [37, 79, 80]. This previous work provides valuable insight into the bubble dissolution, degradation and warpage mech- anisms; and perhaps more importantly the variables that affect them. Pressurized molding conditions present the greatest potential for eradicating surface defects in RM. Pressure increases bubble dissolution rates [54, 59, 60]; which lowers PIAT resulting in re- duced polymer degradation. Pressure also keeps the polymer in contact with the mold surface. This not only reduces warpage, but improves heat transfer through the mold wall as well, which shortens cycle times [30]. In addition this improved contact can also result in high quality exteriors if highly polished mold surfaces are used. LPSs, in a similar manner, present a potential solu- tion to some of the problems encountered in RM. Because they require only short heating durations with little cooling, the application of LPSs can result in reduced cycle times while simultaneously provid- ing a wider range of applicable polymers for the process. Also, LPSs with their low initial viscosity (η < 10–2 Pa·s) and good surface reproducibility, as well as the low over pressures sufficient for good fiber impregnation, are extremely attractive structural molding materials [121]. The potential for LPSs may however be hindered by the shortage of predictive thermal and mold filling models for these materials in the RM process. Acknowledgements This research was funded by the National Key Research and Development Plan (grant numbers 2016YFB0302002 and 2016YFB0302003) and the China Scholarship Council (grant number 2013404006). Special thanks to Wenling Rising Sun Rotational Moulding Technology Co., Ltd. for graciously pro- viding their technical assistance during course of this work. References [1] Crawford R. J., Throne J. L.: Rotational moulding of plastics. Research Studies Press, Somerset (1996). [2] Khan W. A., Methven J.: Control of the uniformity of direct electrical heating for rotational moulding. in ‘Proceedings of the 36th International MATADOR Con- ference. London, UK’ Vol 1, 87–90 (2010). [3] McCourt M. P., Kearns M. P., Hanna P. R.: The adap- tion of microwave heating to the rotational moulding process. in ‘SPE-ANTEC Annual Technical Confer- ence. Orlando, USA’ Vol 2, 1274–1278 (2010). [4] Von Kries K.: System, method and apparatus for solar heated manufacturing. U.S. Patent 8662877, USA (2014). [5] Memering L. J., Schott S.: Rotational molding process. U.S. Patent 3514508 A, USA (1970). [6] McCourt M. P., Kearns M. P.: The development of in- ternal water cooling techniques for the rotational mould- ing process. in ‘SPE-ANTEC Annual Technical Con- ference. Chicago, USA’ Vol 4, 1961–1965 (2009). [7] Marrero M. D., Hernández P., Suárez L., Pestana D., Benítez A., Martín J., Rivero S., Calero E.: Rotational molding applied to the manufacturing of blades of small wind turbine. in ‘ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. Copen- hagen, Denmark’ Vol 3, 1–5 (2014). [8] Sarrabi S., Colin X., Tcharkhtchi A.: Kinetic modeling of polypropylene thermal oxidation during its process- ing by rotational molding. Journal of Applied Polymer Science, 118, 980–996 (2010). https://doi.org/10.1002/app.32459 [9] Crawford R. J.: Recent advances in the manufacture of plastic products by rotomoulding. Journal of Materials Processing Technology, 56, 263–271 (1996). https://doi.org/10.1016/0924-0136(95)01840-9 [10] Lim K. K., Ianakiev A.: Modeling of rotational molding process: Multi-layer slip-flow model, phase-change, and warpage. Polymer Engineering and Science, 46, 960– 969 (2006). https://doi.org/10.1002/pen.20481 [11] Gogos G., Olson L. G., Liu X., Pasham V. R.: New models for rotational molding of plastics. Polymer En- gineering and Science, 38, 1387–1398 (1998). https://doi.org/10.1002/pen.10309 793PDF Image | Rotational molding: A review
PDF Search Title:
Rotational molding: A reviewOriginal File Name Searched:
Rotational_molding_A_review_of_the_models_and_mate.pdfDIY PDF Search: Google It | Yahoo | Bing
Development of a solar powered Electric Ship The Electricship website originally started off as a project to develop a comprehensive renewable, affordable, modular electric ship... More Info
Modular Boat Hull Composite The case for a unsinkable, modular composite hybrid boat hull... More Info
MS Burgenstock Hybrid Electric Catamaran Lake Lucerne Unique shuttle servicing Lucerne to the Burgenstock Resort... More Info
Ground Power Unit GPU Powered by Lithium Ion Batteries The goal of the Ground Power Unit is to provide a readily accessible, modular, ready-to-power solution for remote power... More Info
CONTACT TEL: 608-238-6001 Email: greg@electricship.com (Standard Web Page)