STUDY ON THE SYNTHESIS OF POLY(METHYL METHACRYLATE)-POLY(METHACRYLIC ACID) COMPOSITE LATEX AND THEIR HUMIDITY SENSITIVE PROPERTIES

The composite latex particles of poly(methyl methacrylate)-poly(methac rylic acid) [poly(MMA-MAA)] were synthesized through either soapless s eeded emulsion polymerization or a soapless emulsion copolymerization technique. The reaction kinetics, morphology, and size of latex partic les, composition, glass transition temperature (T-g), and molecular we ight of polymer products were studied under different experimental con ditions. Moreover, this work also focused on the humidity sensitive pr operties of the polymer films fabricated by melting under the temperat ure of 200 degrees C and followed by chemical modification with aqueou s solution of NaOH. It is confirmed that there exists both an optimum ratio of hydrophilic to hydrophobic monomers and the initial structure of the latex particle to provide the humidity-sensitive polyelectroly te film with excellent water resistivity and good sensitivity to humid ity. Besides, little hysteresis and quick response were observed. (C) 1999 John Wiley & Sons, Inc.