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The polymerizable azo initiator 2,2 0 -azobis[N-(2-propenyl)-2-methylpropionamide] (APMPA) has both vinyl groups and azo groups. To develop a new graft polymerization method, the radical polymerization kinetics of APMPA and graft polymerization with the produced macromolecular azo initiator were studied. Because the azo group of APMPA was stable below 80 C, the vinyl group of APMPA could be polymerized with 2,2 0 -azobis(2,4-dimethylvaleronitrile) as an initiator at 60 and 70 C. However, the homopolymerization of APMPA could not proceed because of APMPA self-circulation reactions. Using comonomers such as styrene (ST), methyl methacrylate (MMA), and vinyl acetate, we synthesized copolymers of APMPA. The 1 H-NMR spectra of the resulting copolymers showed the incorporation of APMPA. With the copolymer composed of ST and APMPA used as an initiator, the gel permeation chromatogram showed that the high-molecular-mass fraction of the grafted polymer increased with time. By this method, grafted copolymers having branched chains composed of ST, MMA, or an amphiphilic macromonomer were obtained.

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Some discussions about the mechanism of the unexpected severe impingement corrosion of condenser tubes were made in relation to hydrotalcite. It was elucidated experimentally that hydrotalcite is the initial corrosion product of Aluminum Brass in the natural sea water. Even if iron rich protective films are formed on hydrotalcite, they will be broken quite easily by the collision of foreign bodies with smaller energy in the sea water. This will increase the possibility of corrosion. The most important countermeasure is to supress the initial corrosion of condenser tubes by the effective ferrous ion dosing and to prevent hydrotalcite formation. It was pointed out that more attension should be paid to hydrotalcite from the standpoint of corrosion engineering of condenser tubes.