In-plane shear tests were performed to investigate the shear property change of FRP by plasma modification. Graphite/epoxy prepreg was used as a test material and plasma source was a microwave (2.4㎓) type. Plasma was induced by oxygen gas and its flow rate was kept 4~5sccm with low vacuum state of 10?³ Torr. Prepreg was stacked unidirectionally ([0?]?) after plasma modification. Wettability was determined by measuring a contact angle. The results showed that the contact angle was decreased from 86° to 45° after plasma modification. Shear strength was also improved by~10%. SEM examination was made on the fracture surface and functional group produced by the plasma modification was investigated by XPS.
