ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Adiabatic reactive rheometry involves the simultaneous measurement of viscosity and temperature changes during adiabatic polymerization. Using the adiabatic reactor method to relate temperature to fractional conversion results in a useful rheokinetic tool ideally suited for fastreacting reaction injection molding (RIM) systems for which the mold-filling step is nearly adiabatic. In this work, a small laboratory RIM machine is used to mix the reactants and deliver them to a constant stress rheometer retrofitted with a wide-gap Couette geometry and two thermocouples. Measurements on two polyurethane systems are reported. A simple cross-linking system is used to verify the adiabatic rheokinetic method through comparison to a known gel conversion. Subsequent measurements on a phase-separating RIM system show that increases in catalyst level, hard segment content, and initial reactant temperature result in a decreased gel time and an increased gel conversion. The viscosity rise profiles aid our understanding of the onset and development of phase separation. They are also essential for mold-filling models and establishing moldability criteria for these RIM systems.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760271606
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