Abstract: Novel polyanhydroaspartic acids (containing not more than 3% of NH groups of the imide moieties thereof relative to the total amount of CH moieties of the succinimide moieties thereof) and the at least 90%.+-.5% biodegradable hydrolysates thereof (containing not more than 3% of primary amide groups relative to the secondary amide groups of the aspartic moieties thereof) are well suited as detergent (co)builders, the former being prepared by thermally polymerizing aspartic acid in the presence of an effective amount of at least one boron compound having at least one B-OH group, or precursor thereof, and the latter by hydrolyzing the polyanhydroaspartic acid thus obtained.

Abstract: Organometallic boron/nitrogen polymers, precursors of boron nitride, are prepared by reacting at least one trihalogenoborane with at least one silazane compound containing at least one .tbd.Si--NH--Si.tbd. group, by gradually introducing the silazane compound into the trihalogenoborane, while maintaining the reaction medium at a temperature ranging from -100.degree. to 0.degree. C. and wherein the ratio of the gram equivalents of the .tbd.Si--NH--Si.tbd. groups of the silazane to the number of moles of trihalogenoborane is greater than 1; the resulting organometallic polymers are facilely pyrolyzed into boron nitride ceramic materials.