Interfacial studies in fiber-reinforced thermoplastic-matrix composites

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6947116

Brady, R L

The major theme of this dissertation is structure/property relationships in fiber-reinforced thermoplastic-matrix composites. Effort has been focused on the interface: interfacial crystallization and fiber/matrix adhesion. Included are investigations on interfacial nucleation and morphology, measurement of fiber/matrix adhesion, effects of interfacial adsorption and crystallization on fiber/matrix adhesion, and composites reinforced with thermotropic liquid crystal copolyester fibers. Crystallization of a copolyester and polybutylene terephthalate with glass, carbon, or aramid fibers has been studied with regard to interfacial morphology. Techniques employed included hot-stage optical microscopy and differential scanning calorimetry. Nucleation by the fibers was found to be a general phenomenon. Morphology could be varied by changing the cooling rate. In order to better monitor fiber /matrix adhesion, a buckled plate test has been developed. The test measures transverse toughness as the parameter characterizing interfacial adhesion in unidirectional, continuous-fiber composites. The test is simple to perform yet has advantages over other interfacial evaluation techniques. The buckled plate test was found to be a sensitive measure of fiber/matrix adhesion. The buckled plate test has been used along with the transverse tensile test to examine how interfacial adsorption and crystallization affect fiber/matrix adhesion in polycarbonate/carbon fiber composites. Adsorption was found to be of primary importance in developing adhesion, while crystallization is a secondary effect. The toughness data have been fit successfully for annealing time and temperature dependence. The dependence of adsorption and transverse toughness on matrix molecular weight was found to be large, with higher molecular weights adsorbing more effectively.

• Research Organization: Massachusetts Univ., Amherst, MA (USA)
• OSTI ID: 6947116
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ADHESION
BENCH-SCALE EXPERIMENTS
ELECTRON MICROSCOPY
ESTERS
FAILURES
FIBERS
FRACTURES
FUNCTIONS
INTERFACES
MATERIALS
MATRIX MATERIALS
MECHANICAL PROPERTIES
MICROSCOPY
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYESTERS
POLYMERS
SCANNING ELECTRON MICROSCOPY
STRUCTURE FUNCTIONS
SYNTHETIC MATERIALS
THERMOPLASTICS