Poly(styrene-alt-maleic anhydride)(SMA) was prepared by solution polymerization of styrene(St) and (MAH).SMA was saponified with KOH to get SMAA

and the resulting SMAA then served as polymeric surfactant for the suspension polymerization of St.The influence of ionization degree of SMAA

rotation speed and weight ratio of St to water on the size and morphology of the obtained PS particles has been studied in detail by optical microscopy and SEM.When ionization degree of the SMAA was 50%

the SMAA was partially saponified product containing both carboxylic acid and carboxylate groups.By using this SMAA as polymeric surfactant

spindle PS particles were prepared at high ratios of St to water(3.0∶3.5~3.0∶4.5) and medium rotation speeds.At optimum reaction conditions

the average size of the particles was 6.8 mm in length

1.4 mm in width

0.5 mm in thickness and the ratio of length to width was 5.0.With increasing rotation speed

the size of the particles decreased gradually and the ratio of length to width became higher.Based on these experiment results

the formation mechanism of the PS nonspherical particles by suspension polymerization in the presence of SMAA was preliminarily proposed.