Furan resins were prepared by the polymerization of furfuryl alcohol with either acid or thermal catalysis. The effect of catalysts, solvents, polymerization time, and atmosphere were studied for their effects upon the chemical structure of the polymer produced. It has been found that, regardless of the technique employed, the resins contained appreciable amounts of ketonic species. Examination of the infrared spectrum of these resins indicated that the relative amount of ketonic material to furan ring–containing species was the same, regardless of the resin viscosity. It is proposed that the ketonic species arise during the polymerization by ring–opening of the furan unit, forming γ‐diketone functional systems as part of the polymer unit. The resins were separated into crude fractions by vacuum distillation, base extraction, and fractional precipitation. From heat‐catalyzed resins a lactonic component identified as 5‐hydroxy‐3‐pentenoic γ‐lactone was isolated. The curing of furan resins in nitrogen was shown to proceed through further condensation of furan methylol groups with furan rings having an available α‐hydrogen. β‐Hydrogen crosslinking reactions were not supported by infrared examination of the curing process.

The oxidative curing and oxidative degradation of cured furfuryl alcohol polycondensates was examined, with infrared spectroscopy, by following the functional group changes occurring in the solid phase of the resin. It has been found that the oxidative degradation of nitrogen‐cured resins initially proceeds through the oxidation of methylene linkages to bifuryl ketonic species activated by adjacent furan rings. The second stage of oxidation is the scission of the bifuryl ketonic chain positions to produce substituted furoic acids. The process is postulated to proceed in a manner analogous to that observed in phenolic resin systems. The curing of furfuryl alcohol resin in air is shown to be a multistep process in which the initial oxidation of methylol groups to carboxylic acids is competitive with further polymerization through methylol condensation at adjacent furan ring alpha hydrogen positions. In addition, the oxidation of already formed methylene linkages to the bifuryl ketones is a competitive process removing methylene linkages after they are produced during further condensation (curing reactions). These routes of degradation are in good agreement with observed oxidations of furfuryl alcohol resins under more drastic conditions and offer a reasonable mechanism for resin degradation consistent with observations in analogous polymer systems.

This paper reviews different types of zinc-rich coatings and lists the advantages and disadvantages of organic and inorganic zinc-rich coatings. The general types and curing mechanisms of some recently developed self-cured inorganic zinc-rich coatings are also discussed. The major characteristic, which distinguishes a zinc-rich coating from ordinary zinc dust paint and other protective coatings, is illustrated.A review of various test procedures for determining the degree of galvanic protection and their shortcomings is made. At the present time, there is no single, simple method available that can be used to establish the cathodic properties of zinc-rich coatings. Although there is a relationship between the amount of zinc dust present in the dry film and the galvanic protection, the type of binder also plays an important role.This study shOWS that humidity chamber (Vshaped window) exposure and immersion in sodiumchloride solution are inexpensive methods for determining the galvanic property of a zinc-rich coating. The bare steel area of the panel can develop rust when a coating without galvanic protection is used in an immersion period of 2 hours. However, a coating with good galvanic action provides protection for a longer period of time.References and illustrations at end of paper.