Crosslinking free-radical kinetics and the pultrusion processing of composites
The purpose of this work is to (1) develop and test models for curing kinetics of unsaturated polyester resins, and (2) to utilize the kinetic model in an analysis of temperature, cure, pressure, and pulling force during pultrusion. In Part A, methods of curing rate are studied. Differential scanning calorimetry (DSC) is often used for measuring cure rate, but systematic errors arise when studying free radical kinetics because of oxygen-inhibition and heat transfer constraints. Adiabatic reactor methods are also used to supplement DSC data for kinetic characterization at higher temperatures. In Part B, a new model for crosslinking free radical polymerization is derived for polymerization up to high conversions. The kinetics were tested with a model chemical system and a commercial vinyl ester resin. In Part C, the reaction kinetics are applied to a heat transfer model for pultrusion. The analysis is verified with both previously published and new process temperature data. This is the first pultrusion model that has been successfully verified for unsaturated polyester resins. Resin pressure due to backflow at the die entrance is analyzed to optimize taper geometry. The pulling force analysis predicts changes in surface traction as fibers pass through the die. Used in the pulling force analysis is a new fiber-contact deformation model which predicts fiber elastic forces during compaction. Lastly, in Part D, processing of liquid silicone rubber molding is analyzed. A new mechanistic kinetic model is tested with DSC kinetic data and then applied to a curing model for injection molded plaques. Throughout this work, the fundamentals of reaction kinetics and heat transfer are analyzed and reduced to relatively simple models which can be used by the manufacturing industry.
- Research Organization:
- Minnesota Univ., Minneapolis, MN (USA)
- OSTI ID:
- 7023588
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360601* -- Other Materials-- Preparation & Manufacture
CALORIMETRY
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPACTING
COMPOSITE MATERIALS
CROSS-LINKING
CURING
DEFORMATION
ELASTOMERS
ENERGY TRANSFER
EQUATIONS
ESTERS
EXTRUSION
FABRICATION
FIBERGLASS
FORCING FUNCTIONS
HEAT TRANSFER
KINETIC EQUATIONS
KINETICS
MATERIALS
MATERIALS WORKING
MATHEMATICAL MODELS
MOLDING MATERIALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYESTERS
POLYMERIZATION
POLYMERS
PRESSURE DEPENDENCE
RADICALS
REACTION KINETICS
REINFORCED MATERIALS
RESINS
RUBBERS
TEMPERATURE DEPENDENCE