Antidesma ; plastic rods such as delrin, nylon, phenolic laminate, polycarbonate. 

 Teflon, cellulose acetate, polyethylene, extruded acrylic, cast acrylic, and polysty- 

 rene; vinyl tubes; manlla ropes; phenolic laminated sheet; and high-Impact styrene 

 sheet. 



6. Electrical cable insulation composed of silicone rubber was deteriorated by the 

 nibbling and biting action of some marine animals. White polyvinyl chloride insula- 

 tion changed to black when exposed to hydrogen sulfide produced by su I fate-reducing 

 bacteria in the mud. 



7. The following materials in various forms and for various uses were not affected by 

 marine organisms: unplasticized polyvinyl chloride pipe; butyl rubber, neoprene, 

 natural rubber, plasticized polyvinyl chloride, nylon, fluorinated ethylene propylene, 

 GR-S rubber, and Teflon electrical cable Insulation; various plastic laminated sheets; 

 glass microscope slides; rubber vacuum tubing; nylon nuts and bolts; nylon and poly- 

 propylene ropes; ethyl cellulose cable clamps; and a plastic, pressure-sensitive 

 electrical insulation tape. 



Figure 43. Sections of white polyvinyl chloride insulation exposed 

 to bottom mud had changed to black. 



44 



