Fabrication of amino-containing hollow polymer latex and its composite with inorganic nanoparticles

Using N,N′-dimethylaminoethyl methacrylate (DMAEMA) as functional co-monomer and styrene (St) as main monomer, the amino-containing hollow latexes were fabricated via one-step emulsion copolymerization and following stepwise acid-alkali post-treatment. Influences of DMAEMA content and post-treatment condition on the morphology and volume expansion of the P(St-co-DMAEMA) latex particles were investigated based on the TEM characterization, and the hollow-forming mechanism was proposed. Results showed that the introduction of 2-butonane promoted the mobility of the polymer chains and the hollow structure generated under moderate post-treatment conditions. Many factors should be balanced to obtain fine hollow particles, an appropriate content of DMAEMA was 15 mol% to all the monomers, and the optimized post-treatment conditions were at 70 °C for 1 h both for acid treatment (initial pH 4.0) and for alkali treatment (initial pH 9.0). Under the optimized conditions, the mean diameter and volume expansion of the resulted hollow particles were 264 nm and 934%, respectively. Finally, the hollow P(St-co-DMAEMA)/laponite composite latex particles were fabricated simply by electrostatic adsorption process, and the resulted composite hollow particles loaded 4.1 wt% of laponite platelets and showed better thermal stability. This simple and facile method can be applied to fabricate the functional hollow latex particles with amino groups including polymeric and polymeric-inorganic composite materials.