Characterization of PEEK and short-fiber PEEK thermoplastic composites
Various topics in the areas of processing, structure, and properties in PEEK and its short-fiber composites are treated. Crystallization at constant temperatures and under nonisothermal conditions was analyzed using time-temperature-transformation curves. Correlation between isothermal and continuous cooling curves allows the rate of cooling needed to manufacture a product with a specific microstructure to be determined. The crystallization range (time or temperature) can be predicted for various heat treatments. In large-dimensioned polymer parts, crystallization does not develop uniformly. A finite-difference approach predicts the temperature distributions within the part for a variety of conditions, so that processing conditions that cause the inhomogeneities can be avoided. Crystallization temperature is important with respect to spherulitic morphology. The lathlike crystallites of adjacent spherulites formed at medium temperatures interweave, whereas a noncrystalline layer separates spherulites formed at higher temperatures. Carbon fibers are more effective nucleating agents than glass fibers, though not all fibers show transcrystallinity. Generally, the fibers did not seem to accelerate the crystallization process. But, they improve the mechanical properties, strength and modulus, at the expense of toughness.
- Research Organization:
- Delaware Univ., Newark (USA)
- OSTI ID:
- 6366591
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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COMPOSITE MATERIALS
MECHANICAL PROPERTIES
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CRYSTALLIZATION
FIBERS
FINITE DIFFERENCE METHOD
NUCLEATION
PROCESSING
ITERATIVE METHODS
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NUMERICAL SOLUTION
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PLASTICS
POLYMERS
SYNTHETIC MATERIALS
360603* - Materials- Properties
360601 - Other Materials- Preparation & Manufacture