Isocyanate trimerization kinetics and heat transfer in structural reaction injection molding.: An article from: Polymer Engineering and Science
Book Details
Author(s)G.G. Viola, W.R. Schmeal
PublisherSociety of Plastics Engineers, Inc.
ISBN / ASINB00092W4WG
ISBN-13978B00092W4W9
AvailabilityAvailable for download now
Sales Rank11,703,431
MarketplaceUnited States 🇺🇸
Description
This digital document is an article from Polymer Engineering and Science, published by Society of Plastics Engineers, Inc. on August 15, 1994. The length of the article is 8902 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.
From the author: Guidelines are developed for molding large composite parts via structural reaction injection molding using glass preforms and polyisocyanurate resins. These are based on numerical simulations of the simultaneous heat transfer and reaction kinetics of a commercial system during and after mold filling. Premised requirements are that resin does not gel before the mold is filled, yet, reactions are sufficiently vigorous to approach completion. An existing mechanistic kinetic model is used and material parameters found from a chemical kinetics study employing an insulated cup. It is found desirable to use a high mold temperature and a low preform temperature in molding. Nondimensionalization of the governing equations reveals the existence of a Nusselt number ([N.sub.u]), which describes the relative importance of heat transfer between resin and glass relative to thermal diffusion to the mold wall. With a Nusselt number of about 50 or higher it is possible to use the cooling capacity of the preform to extend gel time. The magnitude of [N.sub.u] is influenced by part thickness, glass fraction, strand diameter, and flow velocity. Thus, the effect of the preform on extending resin gel time is within control of the molder.
Citation Details
Title: Isocyanate trimerization kinetics and heat transfer in structural reaction injection molding.
Author: G.G. Viola
Publication:Polymer Engineering and Science (Refereed)
Date: August 15, 1994
Publisher: Society of Plastics Engineers, Inc.
Volume: v34 Issue: n15 Page: p1173(14)
Distributed by Thomson Gale
From the author: Guidelines are developed for molding large composite parts via structural reaction injection molding using glass preforms and polyisocyanurate resins. These are based on numerical simulations of the simultaneous heat transfer and reaction kinetics of a commercial system during and after mold filling. Premised requirements are that resin does not gel before the mold is filled, yet, reactions are sufficiently vigorous to approach completion. An existing mechanistic kinetic model is used and material parameters found from a chemical kinetics study employing an insulated cup. It is found desirable to use a high mold temperature and a low preform temperature in molding. Nondimensionalization of the governing equations reveals the existence of a Nusselt number ([N.sub.u]), which describes the relative importance of heat transfer between resin and glass relative to thermal diffusion to the mold wall. With a Nusselt number of about 50 or higher it is possible to use the cooling capacity of the preform to extend gel time. The magnitude of [N.sub.u] is influenced by part thickness, glass fraction, strand diameter, and flow velocity. Thus, the effect of the preform on extending resin gel time is within control of the molder.
Citation Details
Title: Isocyanate trimerization kinetics and heat transfer in structural reaction injection molding.
Author: G.G. Viola
Publication:Polymer Engineering and Science (Refereed)
Date: August 15, 1994
Publisher: Society of Plastics Engineers, Inc.
Volume: v34 Issue: n15 Page: p1173(14)
Distributed by Thomson Gale
