@Article{sdhm.2007.003.081,
AUTHOR = {J.  Mohan, D.  Carolan, N.  Murphy, A.  Ivankovic, D.  Dowling},
TITLE = {Influence of an Atmospheric Pressure Plasma Surface Treatment on the Interfacial Fracture Toughness on Bonded Composite Joints},
JOURNAL = {Structural Durability \& Health Monitoring},
VOLUME = {3},
YEAR = {2007},
NUMBER = {2},
PAGES = {81--86},
URL = {http://www.techscience.com/sdhm/v3n2/34986},
ISSN = {1930-2991},
ABSTRACT = {The aim of this work is to investigate the influence of a variety of plasma treatments on the surface properties of an epoxy-based composite material and to establish a relationship between these properties and the subsequent mechanical behaviour of adhesively bonded joints. To this end, specimens were subjected to three different types of plasma treatment: two short treatments (2min) of He and He plus O<sub>2</sub>, and one long treatment (15min) of He plus O<sub>2</sub>. The variation in surface energy of the composite specimens was examined in each case over a period of up to 3 days using contact angle measurements. Initial results show that the surface energy was increased from an untreated value of approximately 40 mJ/m<sup>2</sup> to a value of 65 mJ/m<sup>2</sup> immediately after treatment. The surface energy then fell by approximately 10 mJ/m<sup>2</sup> over the course of three days for each treatment. The composite substrates were then bonded together using an epoxy film adhesive and the Mode I fracture toughness of the joint was determined from a series of symmetric and asymmetric double cantilever beam (DCB) tests. It was found that for both test geometries the adhesive failed cohesively. As a result, the values calculated for the mean propagation strain energy release rate, G<sub>IC</sub>, were those of the cohesive fracture toughness of the adhesive as opposed to the interfacial fracture toughness between the composite surface and adhesive.},
DOI = {10.3970/sdhm.2007.003.081}
}