Effects of shell composition,dosage and alkali type on the morphology of polymer hollow microspheres

Polymer hollow microspheres were prepared by performing alkali treatment on the multilayer core/shell polymer latex particles containing carboxyl groups.Effects of the shell composition and dosage as well as alkali type on the morphology of the microspheres were investigated.Results showed that in comparison with acrylonitrile (AN) and methacrylic acid (MAA),using butyl acrylate (BA) as the shell co-monomer decreased the glass transition temperature (Tg) of shell effectively and was beneficial to the formation of uniform and big hollow structure.Along with the increase of the shell dosage,the alkali-treated microspheres sequentially presented porous and hollow morphology,and the size ofmicrospheres increased,while the hollow diameter increased first and then decreased,and the maximum hollow ratio reached 39.5％.Furthermore,the multilayer core/shell microspheres had better tolerance to NH3·H2O than to NaOH.When the molar ratio of alkali to methacrylic acid (MRalkali/acid) for NaOH ranged from 1.15 to 1.30 or MRalkali/acid for NH3·H2O ranged from 1.30 to 2.00,the regular polymer hollow microspheres could be obtained.