Core-shell polymer latex particles containing carboxyl-groups inside were prepared via multistage seeded emulsion polymerization

and could evolved into hollow polymer particles after alkali post-treatment because of osmotic swelling.The effects of monomer feeding mode and polymerization recipes on the morphology of resultant particles were investigated.Orthogonal experiment design and range as well as variance analysis were utilized to figure out the influence degree on the morphology of alkali-treated particles from various alkali post-treatment conditions.Results showed that

controlling the feeding time of monomers and introducing polarity transition interlayer were beneficial to synthesizing particles with distinct core-shell structure.The alkali dosage had the most significant impact on the morphology of alkali-treated particles

followed by alkali post-treatment temperature

and the least effective for alkali post-treatment time.Moreover

polymer microspheres with stable and excellent hollow structure could be achieved with NaOH/MAA mole ratio range from 1 to 1.15

alkali post-treatment temperature range from 80 to 90 ℃

and time range from 1 to 5 h.