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Variables that Determine the Fiber‐Matrix Bond Strength in Ethylene‐Type Ionomer Composites
Author(s) -
Sadiku Emmanuel R.,
Sanderson Ronald D.
Publication year - 2001
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(200108)286:8<472::aid-mame472>3.0.co;2-6
Subject(s) - materials science , composite material , ultimate tensile strength , shear strength (soil) , polymer , ionomer , bond strength , adhesive , layer (electronics) , copolymer , environmental science , soil science , soil water
The effects of some variables, namely, ion concentration, matrix tensile strength, matrix yield strength and the matrix tensile modulus on the fiber‐matrix bonding strength were determined for six ionomers (coded PEA‐1 to PEA‐6) bonded to surface‐modified poly( p ‐phenylene terephthalamide) (PPTA) fibers. The results obtained show that the mean bonding shear strength of the ionomers correlates well with both their ultimate tensile strengths and their tensile yield stresses. However, correlation of the bonding shear strengths with the matrix yield stresses reveals that the bonding shear strength was about 1.1 times that of the matrix tensile stress. Failure criteria for all the materials predict maximum shear stress to be either 0.5 or 0.577 of the tensile yield stress, hence a value greater than unity cannot be interpreted nor theoretically justified. It was found that the bonding shear strength of the ethylene‐type ionomer PEA‐6 compared to carboxymethyl surface‐modified PPTA is about 20% lower than the bonding shear strength of this resin against sized PPTA fibers. The reduction of entanglements and/or ionic crosslinking across the bound polymer/bulk polymer interface leads to a weak interface with a subsequent decrease in the measured shear strength.