Ms. Silverstein et J. Sadovsky, SURFACE MODIFICATION OF DRAWN GEL-CAST ULTRA-HIGH-MOLECULAR-WEIGHT POLYETHYLENE FILMS, Journal of adhesion science and technology, 9(9), 1995, pp. 1193-1208
Gel-spun ultra-high molecular weight polyethylene (UHMWPE) fibers have
superior properties but their use in composite material applications
is limited by their poor adhesion to polymer matrices. Previous studie
s have shown that etching improves the adhesion of epoxy to the fibers
, but leads to a reduction in mechanical properties. The purpose of th
is research was to use uniaxially drawn gel-cast UHMWPE films as a mod
el system since both films and fibers have a highly oriented fibrillar
structural hierarchy. Etching has detrimental effects on the mechanic
al properties and crystallinity of these very thin films. The small am
ount of carbonyl and carboxyl groups added to the surface through etch
ing raises the film's surface tension and enhances wetting by epoxy. E
ven though the unmodified film cannot be bonded with epoxy, the interl
aminar shear strength between epoxy and the etched films approaches th
e cohesive strength of the epoxy. A combination of interfacial and UHM
WPE cohesive failures is observed. The increase in adhesion is attribu
ted to the slight increase in surface oxygen.