RESISTANCE OF MATERIALS TO MARINE BIOLOOICAL ATTACK 1109 



Table XI — Hydrogen Sulfide Production by Marine Bacteria 



IN Anaerobic Sea Water Test with Polyethylene, 



Polyester Casting Resin or Poly(Vinyl Chloride) 



Resin as Only Sources of Carbon 



Test Material 



Polyethylene — 0.7 melt index (High Dens.) 

 Nat. + antioxidant 



Polyethylene — 0.7 melt index (High Dens.) 

 Blk. + antioxidant 



Silica-filled styrene polyester 



Poly (Vinyl Chloride) resin 



Controls (inoculated sea water) 



HjS Production After Weeks of Incubation 



ppm 



0.35 



0.26 

 0.83 

 0.48 

 0.45 



ppm 



0.58 



0.48 

 0.83 

 0.58 

 0.86 



12 



ppm 



0.90 



0.38 

 1.02 

 0.58 

 0.91 



16 



ppm 



1.12 



0.74 

 1.02 

 0.58 

 0.91 



as the test material (Tables IX and XI), significantly greater than in 

 j the control bottles. In fact, in most cases it is actually less than that for 

 I the controls. 



Four polyvinyl chloride plastics appear to have served as a source of 

 carbon for the anaerobic organisms. In order of decreasing susceptibility 

 they are the compounds plasticized with (1) polyester E/DOP, (2) poly- 

 ester A, (3) nitrile rubber/polyester C, and (4) no plasticizer (rigid). 

 Just as in the case of the aerobic procedure, the plastic plasticized with 

 polyester E/DOP is used much more rapidly than any of the other 

 polyvinyl chloride compounds. There is no e\'idence of attack on poly- 

 \'inyl chloride resin, again indicating that the attack is on the plasticizers, 

 not the polyvinyl chloride itself. In this regard, it should be pointed out 

 again that although the polyvinyl chloride compound listed as "no plas- 

 ticizer (rigid)" in the tables and text does not contain an external plas- 



Table XII — Hydrogen Sulfide Production by Marine Bacteria 



IN Anaerobic Sea Water Test with Elastomers as the 



Only Sources of Organic Carbon 



Elastomer 



GR-S jacket (54-14) 



GR-A jacket (54-18) 



Biitvl jacket (54-19) 



Natural rubber jacket (54-23) . . 



Neoprene jacket (54-164) 



Controls (inoculated sea water) 



HzS Production after Weeks of Incubation 



ppm 



0.66 

 0.96 

 1.52 

 1.62 

 1.06 

 0.37 



8 



ppm 



0.77 

 0.95 

 6.64 

 2.48 

 1.20 

 0.43 



12 



ppm 



0.56 

 0.72 

 8.03 

 3.58 

 0.99 

 0.43 



16 



ppm 



0.75 

 0.87 

 9.65 

 3.74 

 0.96 

 0.42 



