Journal of Applied Polymer Science · 2002 · 25 citations · 6 references
Natural SciencesChemical EngineeringMaterials SciencePolymer ChemistryPolymer EngineeringPolymer MaterialsPolymer CharacterizationPolymer NetworksPolymer ProcessingPolymer RheologyPolymerization ChemistryPolymerization KineticsActivation EnergyCuringCuring KineticsCuring RateFree-radical Polymerization KineticsPolyurethane MaterialsPolyurethane NetworksRate Constant Determination
Abstract Hydroxy‐terminated polybutadiene (HTPB) prepolymer prepared by free‐radical mechanism at Chemical Engineering Complex, Vikram Sarabhai Space Center, Thiruvananthapuram was reacted with toluene diisocyanate (TDI), a curative at varying stoichiometric ratios ( r = [NCO]/ [OH]) equal to 0.7, 0.8, 0.9, 1.0, and 1.1 at a constant temperature of 70°C. The increased rate of viscosity of polyurethane networks formed was used to calculate the rate constant. Similarly, the rate of change of viscosity of curing networks at different r values (0.7–1.1) and temperature intervals (30–70°C) was used to calculate activation energy. The results of the curing networks showed that the rate constant at r > 0.9 is constant and the rate of decrease of activation energy is lower at r ≤ 1; thereafter, it becomes quite significant. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 842–846, 2002
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AIChE Journal · 1956 · 196 citations
Isabelle Deschères, Quang Tho Pham · Die Makromolekulare Chemie · 1986 · 28 citations