The Dow Chemical Company

Earl E Burt, Iii

Richard D Peffley

Oomman P Thomas

Richard G Melcher

A liquid prepolymer composition is disclosed which contains free isocyanate groups which is the reaction product of a stoichiometric excess of a polyisocyanate and an active hydrogen-containing compound which contains an internal rigid polyaromatic grouping. Polyurethane and/or polyurea polymers made from these prepolymer compositions are also disclosed.

Polyisocyanate prepolymers prepared from rigid polyaromatic precursor

A chromatographic method for the determination of individual phenols in water by adding a halogenating agent to the water, e.g., using the bromate-bromide reaction to generate tribromide ions which react with the phenols to form bromo-derivatives of the phenols, then to permeate the bromo-derivatives across a membrane, e.g., a silicone rubber membrane, into a liquid extractant, e.g., a dilute aqueous solution of sodium hydroxide and acetonitrile, and then determining the permeated bromo-derivatives in the liquid extractant by chromatography, e.g., by injecting the liquid extractant containing the permeated bromo-derivatives into a reverse phase liquid chromatographic system. The use of a membrane is essential in the present invention because it allows the use of a high enough concentration of halogenating agent to completely halogenate most any sample and provides for the removal of the halo-derivatives from the halogenation reaction site before any substantial degradation of the halo-derivatives occurs from a relatively high concentration of halogenating agent. Total phenols as a group can be determined by modifying the method to use backflow liquid chromatography to eliminate potential interferences and to elute the halo-derivatives in a single chromatographic peak.

Method for the determination of phenols in water

Polyisocyanates containing dissolved or colloidally dispersed polymers containing rigid moieties are disclosed. Included among the dissolved or colloidally dispersed polymers are polymers ethylenically unsaturated polyaromatic compounds, ethylenically unsaturated benzoic acid derivatives, ethylenically unsaturated steroid derivatives, and rigid aromatic polyurethane and/or polyurea polymers. The dissolved or colloidally dispersed polymers provide substantial reinforcement and physical property improvement to polyurethane or polyurea polymers made from the polyisocyanate solution or dispersion.

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Clute, TX, United States of America

Earl E Burt, Iii