Accession Number : AD0692212

Title :   THE EXAMINATION OF THE STRUCTURE OF ANTIFOULING COATINGS BY SCANNING ELECTRON MICROSCOPY,

Corporate Author : DEFENCE STANDARDS LABS MARIBYRNONG (AUSTRALIA)

Personal Author(s) : Bishop,J. H. ; Silva,S. R.

Report Date : 20 NOV 1968

Pagination or Media Count : 19

Abstract : The recently developed scanning electron microscope yielded information of much more value in the study of antifouling paint films than was obtained from the conventional transmission instrument. The significance of the information obtained is discussed and it is shown that current theories of the mechanism by which toxicant is released from the film require revision. Film porosity and surface texture, which are dependent upon the pigment loading, and also the wide variation in particle size and shape are shown to be important controlling factors. The critical pigment volume concentration is the parameter which determines whether or not a film is porous, rather than a pigment loading calculating on the assumption that the pigment particles can be regarded as uniform spheres as previously surmised. The thickness of the layer of matrix material over the surface of the cuprous oxide particles and the degree to which the layer is ruptured, probably by osmotic pressure forces, also have a bearing on the rate of leaching. Defects in antifouling paint films are easily detected. A green patina observed on some surface areas of antifouling paint films removed from ships after service at sea is attributed to the presence of large numbers of diatoms and not necessarily to the presence of precipitated copper salts. (Author)

Descriptors :   (*ANTIFOULING COATINGS, *ELECTRON MICROSCOPY), SURFACE PROPERTIES, VINYL PLASTICS, PAINTS, COPPER COMPOUNDS, OXIDES, AUSTRALIA

Subject Categories : Coatings, Colorants and Finishes

Distribution Statement : APPROVED FOR PUBLIC RELEASE