INTRODUCTION 



In the present consideration of materials for construction of deep 

 ocean fixed structures, the emphasis is on the use of materials such as 

 metals and concrete. However, when one considers that the proposed 

 structures will probably be required to remain at great depths for long 

 periods, then such problems as corrosion of metals and water permeabil- 

 ity of concrete must be considered. The objective of this study was to 

 investigate the possibility of formation of resins in porous materials 

 such as concrete to prevent the passage of water through these 

 materials . 



Work has and is being done to form resins (plastics) in porous 

 materials to improve their dimensional stability and moisture 

 resistance. The processes which give desirable results consist of 

 either (1) impregnation of the porous material with methyl methacrylate 

 followed by radiation polymerization, or (2) impregnation of the mate- 

 rial with methyl methacrylate, catalyst, and promoter followed by heat- 

 ing to polymerize the monomer. 



However, each of these processes has disadvantages. Radiation 

 cure involves all of the problems inherent in maintaining and operating 

 a high energy radiation source, and catalyst plus heat cure involves 

 the use of organic peroxides with the hazard of a sudden explosion. 



Therefore, two other methods, chemical crosslinking by reaction 

 between two or more compounds and complex foirmation between two or more 

 compounds were investigated to determine their suitability for the 

 formation of insoluble resins in-situ. 



Three constraints were placed on the selection of starting mate- 

 rials for these reactions: 



1. The materials be soluble in aqueous solutions rather than 

 requiring organic solvents which create problems in recovery and in 

 pollution. 



2. The materials used should have low toxicity so that they could 

 be easily handled during treatment of a structure or structural compo- 

 nents and so that any waste or residual materials would not have a 

 deleterious effect on the environment, 



3. The materials should be commercially available at low to 

 moderate cost. 



The initial phase of the work was a literature survey on the 

 crosslinking of water-soluble polymers. 



MBL/WHOI 



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