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Title: Surface grafting of Kevlar fibers for improved interfacial properties of fiber-reinforced composites

Matrix-specific chemical modification of the Kevlar fiber surfaces was carried out with the aim of enhancing adhesion, through covalent bonding, to selected thermoset matrix resins such as vinyl ester, unsaturated polyester and epoxy. A two-step grafting method, involving initial metalation followed by subsequent substitution, was used to graft vinyl and epoxy terminated groups onto Kevlar fiber surfaces. The physical changes in fiber surface were characterized by scanning-electron microscopy and surface area measurement and the chemical changes due to grafting were measured by contact angle measurement and neutron activation analysis; high concentrations of double bonds and epoxy groups were measured. The change in interfacial sear strength due to the surface grafting was measured by means of a single fiber pull out test. The results show a nearly twofold increase in the interfacial shear strength due to vinyl terminated grafts in the case of Kevlar/vinyl ester and Kevlar/polyester composites. Kevlar fibers containing the epoxy functionality on the surface had enhanced adhesion to epoxy matrix resin.
Authors:
Publication Date:
OSTI Identifier:
5470981
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Publisher:
Ithaca, NY (US); Cornell Univ.
Research Org:
Cornell Univ., Ithaca, NY (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ARAMIDS; SURFACE TREATMENTS; COMPOSITE MATERIALS; FABRICATION; FIBERS; ADHESION; CHEMICAL PREPARATION; MATRIX MATERIALS; PROCESSING; REINFORCED MATERIALS; SURFACES; MATERIALS; PETROCHEMICALS; PETROLEUM PRODUCTS; PLASTICS; SYNTHESIS; SYNTHETIC MATERIALS 360601* -- Other Materials-- Preparation & Manufacture