The Dow Chemical Company

Russell J Raymond

Syamalarao Evani

Dennis McKeever

Low molecular weight polymers of an unsaturated dicarboxylic anhydride monomer (e.g., maleic anhydride) and a copolymerizable monomer (e.g., styrene) are prepared by an improved process which comprises polymerizing the monomers in the presence of the hydroxide or a nucleophilic salt of a monovalent cation (e.g., a nucleophilic salt or the hydroxide of the ammonium cation, a quaternary ammonium compound, a protonated primary, secondary or tertiary amine, a sulfonium compound, a phosphonium compound or an alkali metal cation). By the practice of this process, low molecular weight polymers are conveniently and economically obtained without the use of high catalyst concentrations, high temperatures, conventional chain transfer agents, high boiling chain transfer solvents or combinations thereof.

Process for the preparation of low molecular weight anhydride

Low molecular weight polymers of an unsaturated dicarboxylic anhydride monomer (e.g., maleic anhydride) and a copolymerizable monomer (e.g., styrene) are prepared by an improved process which comprises polymerizing the monomers in the presence of the hydroxide or a nucleophilic salt of a monovalent cation (e.g., a nucleophilic salt or the hydroxide of an ammonium compound or of an alkali metal). By the practice of this process, low molecular weight polymers are conveniently and economically obtained without the use of high catalyst concentrations, high temperatures, conventional chain transfer agents, high boiling chain transfer solvents or combinations thereof.

Dispersions of finely divided particulate solids in an organic liquid in which the solids are insoluble are stabilized by the addition of a polymeric dispersant having a degree of polymerization of about 10 to 100. An example of the polymeric dispersant is an interpolymer of styrene, maleic anhydride and a vinyl benzyl ether of ethoxylated nonyl phenol.

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Midland, MI, United States of America

Russell J Raymond