The Cure of Cross-Linked Urethane Polymers

Darr, W. C.; Gemeinhardt, Péter; Saunders, J. H.

doi:10.1177/0021955x6600200508

Cited by 6 publications

(3 citation statements)

References 1 publication

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“…Although relatively high levels of isocyanate have been measured in some fresh foams by dibutylamine titration [91, low level residual isocyanate in a piece of foam is difficult to obtain by direct titration techniques [3]. The polymeric nature of the material prevents quantitative reaction with the target group buried within the matrix.…”

Section: Absolute Isocyanate Concentrationmentioning

confidence: 99%

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Attenuated Total Reflectance Infrared Spectroscopic Analysis of High Index Foams

Gheluwe

Cole

Hébrard³

et al. 1987

Journal of Cellular Plastics

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Section: Absolute Isocyanate Concentrationmentioning

confidence: 99%

“…The fast reactions involved in the blowing process and the rapid gel times ensuing prevent total consumption of the bound NCO groups. These are locked in the gelled matrix, but if sufficiently high temperatures are maintained long enough, greater mobility of the chains ensures a more complete reaction [3].…”

Section: Introductionmentioning

confidence: 99%

Attenuated Total Reflectance Infrared Spectroscopic Analysis of High Index Foams

Gheluwe

Cole

Hébrard³

et al. 1987

Journal of Cellular Plastics

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“…Several conflicting findings have been reported: Valles and Macosko (1975) found the reaction rate to increase, Villesova et al (1972) found no change, while French et al (1970) reported that the reaction stopped completely. This last finding has been disputed by several investigators, even for highly crosslinked systems (Darr et al, 1966;Lipshitz and Macosko, 1977). Some of the uncertainty probably arises from the strong diffusional hindrance beyond the gel point which can greatly mask the intrinsic kinetics if the reacting mixture is not perfectly mixed.…”

Section: Reaction Kineticsmentioning

confidence: 99%

Modelling of rapidly‐mixed fast‐crosslinking exothermic polymerizations. Part I: Adiabatic temperature rise

Chella

Ottino

1983

AIChE Journal

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A lamellar mixing approach has been applied to the modelling of an imperfectly R. CHELLA and J. M. OTTINO mixed, fast, crosslinking, exothermic polymerization. The model involves the solution of coupled nonlinear partial differential equations representing mass and energy transfer in locally structured lamellar domains with diffusion and reaction occurring between initially segregated lamellae.Several seemingly unusual features of experimental results can be explained qualitatively in terms of this simplified model. The phenomena investigated include: effect of variations in mixing, catalyst concentration (intrinsic reaction rate), and initial temperature for equal mixing conditions SCOPE Reactive polymer processing, the simultaneous formation and processing of polymers into their final shape, offers several important advantages of reduced capital, operational and energy costs. In particular, considerable commercial interest has centered on Reaction Injection Molding (RIM), a relatively new process in which two or more highly reactive monomer streams are rapidly contacted, generally by impingement, and conveyed to a mold cavity where polymerization proceeds. Requirements of fast, complete reaction with no side products and good mechanical properties have limited major commercial development to polyurethane systems. Requirements of fast mixing without moving parts have limited mixing to impingement mixing.While several attempts have been made at modelling conversions and product distributions in RIM processes (cf. Domine

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