An ambient self-curable latex based on colloidal dispersions in water of two functionalized polymers and the thermally reversible crosslinked films generated

Abstract

An ambient self-curable latex (ASCL) was prepared by mixing colloidal dispersions in water of a chloromethylstyrene (CMS)-functionalized polymer and a tertiary-amine-functionalized polymer. The two dispersions were obtained via the conventional emulsion copolymerization of CMS and 2-(dimethylamino)ethylacrylate (DMAEA), respectively, with styrene (St), butyl acrylate (BA), or both. No visible coagulation was observed either in the blends after 6 months of storage or after the latexes were introduced into aqueous media with pHs in the range of 3–11. Continuous, transparent, crosslinked elastic films with smooth surfaces were obtained via casting and drying the ASCL at room temperature, when one or both of the two functional polymer particles contained BA monomeric units. Thermocompression cycles; swelling experiments; solubility tests; and 1H NMR, IR, DSC, and transmission electron microscopy tests were carried out to investigate the crosslinking and morphology of the films. The following observations were made: (1) the crosslinks in the films were generated via the Menschutkin reaction (quaternization) between the CH2-Cl groups of the CMS containing particles and the amine groups of the DMAEA containing particles; (2) the crosslinked films were thermally remoldable due to reversible decrosslinking (dequaternization) on heating and recrosslinking (requaternization) on cooling; and (3) phase separation in the films was observed when one of the functional polymers (for instance, the nonpolar CMS-St copolymer) was incompatible with the other one (for instance, the polar BA-DMAEA copolymer). The present ASCL might be useful in producing water-borne coatings and adhesives, elastic films, and functional membranes. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 389–397, 2001