sodium silicate permeation of 5.5 X 10+ gram per year per cm* of coating surface. Without agitation the dissolution rate is expected to be considerably smaller. According to this calculation, any 2-hr test a t 50°C corresponds to exposure a t room temperature for approumately 15 days. Similarly, 2 hr at 60°C corresponded to approximately 105 days a t room temperatures. Above 60°C the coating is in the rubbery state, and the data cannot be correlated directly nith room temperature data. The accumulation rate of 1.7 ppm per year can be contrasted nith the computed attainment of approximately 48,600 ppm of sodium ions per year for an uncoated sodium silicate glass rod a t 25”C, assuming continuous agitation. In all thew calcnlations, it is assumed that the surface area of the rod samples remains constant, although the diameter of uncoated rod< nil1 actually become slightly fmaller as dissolution progresses, and therefore, so \t 111 the surface area. Evaluation of the slope of the -4rrhenius plot pwmits a calculation of the activation energy E,, since E , = - (slope) X 2.3 R . For the glaqiy state the activation energy n a s calculated to be approximately 35 kcal/mol, but for the rubbery state the activation energy n as calculated to be significantly lower, namely. ahout 4 kcal/mol. Because of deterioration of coatings 111 alkaline media, the latter type of calculations
could only be performed with data from the experimental series that used distilled water or acidic test solutions. Aside from the visualized application on surfaces of container structures, the reported coating system can conceivably find uses in contact with glass compositions other than soda glass. I n experimental tests various glass specimens were successfully adhered to by the PVHP undercoating, and a hard, water-resistant water barrier was then provided by the topcoat formulation described. literature Cited
Billmeyer, Jr., F. W., “Textbook of Polymer Science,” p 502, Interscience, New York, N.Y., 1962. M;ser, F., “Selecting Glass Adhesives by Strength Tests,” in Adhesion and rldhesives-Fundamentals and Practice,” Wiley, New York, N.Y., 1954. Riddle, E. H., “1Ionomeric Acrylic Esters,” pp 67-132, Reinhold, New York, K.Y., 1954. Seymour, R. B., Steiner, R. H., “Plastics for Corrosion-Resistant Applications,” p 52, Reinhold, Xew York, N.Y., 1955. RECEIVED for review February 7 , 1972 A 4 ~December ~ ~ 15, ~1972 ~ Presented at the Division of Organic Coatings and Plastic Chemistry, 162nd Jleetini, .4CS, Washington, D.C., September 1971. Work siipported by Grant EC-00033 from the Environmental Protection Agency.
Macroreticular Polymeric Adsorbents David C. Kennedy Research Division, Rohm and Haas Co., 5000 Richmond Street, Philadelphia, Pa. 19157
A series of new macroreticular resinous adsorbents has been developed. These materials are hard, insoluble beads of porous polymer characterized b y a spectrum of surface polarities and b y a variety of surface areas, porosities, and pore-size distributions, Owing to these differences in surface properties, the polymeric adsorbents display a wide range of sorption behavior and can be employed in both aqueous and nonaqueous systems. A sizable amount of adsorption data suggests that these materials will have practical applications in diverse fields. A major field i s in waste treatment where the polymeric adsorbents show promise for decolorizing kraft pulp mill effluents and for removing phenols and chlorinated pesticides from industrial wastes. Other interesting applications exist in chemical processing, particularly for product stream purification, and in the pharmaceutical field for adsorbing vitamins and enzymes.
R e c e n t studies have led to the cievelopment of a new series of synthetic polymeric adsorbents (identified as .Imberlite XAI) macroreticular adsorbents. hmberlite is a registered trademark of the Rohm and Haas Co., Philadelphia, Pa.). r . 1hese materials have a varietl- of surface polarities aiid caii be prepared wit,h varying surface areas aiid average poresize distributions. They have demonstrated applicabilit’y iii waste treatment areas-particularly for the treatment of kraft pulp niill effluents. The synthesis of polymeric adsorbents was derived from a study of the preparation of porous macroreticular ioii-excliaiige re,siiis (Kuiiiii et al.. 1962). The first step in the preparation of ioii-exchange resiiis is the formation of a styreiietliviiiylbenzene copolymer polymei,ized in an aqueous suzl c >ellsion. The average particle size of these spherical beads is 56 Ind. Eng. Chem. Prod. Res. Deve!op., Vol. 1 2 , No. 1, 1973
approximately 0.5 mm. This size is chosen as a compromise because ion-exchange processes are diffusion controlled, and it is desirable from a kinetic point of view to have as small a particle (giving as short a diffusion path) as possible. However, the hydraulic expansion and pressure drop would be excessively high if particles significantly smaller than 0.5 mm were used in large columii installations. Macroreticular resins are highly porous structures in which each 0.5-nim bead consists of many small microspheres whose dianiet,er is as small as 10-4 inm (Kim and I
