乳液聚合法制备PSA纳米微球与PS纳米微球的性能测定

以苯乙烯(St)和甲基丙烯酸(MAA)为原料,采用乳液聚合法共聚制备羧基化聚苯乙烯(PSA)纳米微球。通过改变乳化剂(SDS)的用量、St/MAA的质量配比控制微球性质和大小。利用透射电镜(TEM)、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、差示扫描量热仪(DSC)、热重分析仪(TGA)和Zeta电位仪对PSA纳米微球进行表征。FTIR结果证实MAA成功引入到微球中,TEM和SEM表明当乳化剂用量为单体总质量的10%时,得到大小均匀,直径为45 nm的PSA微球。PSA的玻璃化转变温度和热分解温度随MAA的含量增加而提高。纯PS表面带负电荷,Zeta电位为-17 mV。共聚后的PSA纳米颗粒,其St与MAA物质的量比为10/1. 0,10/1. 5和10/2. 5时,Zeta电位分别为-31. 9、-39. 6和-44 mV。上述结果表明,采用共聚是调节PS微球热性质及表面性质的有效途径。

Performance of PSA and PS Nanoparticles by Emulsion Polymerization

Carboxylated polystyrene( PSA) nanoparticles were prepared by emulsion copolymerization of styrene( St) and methacrylic acid( MAA). The properties and size of the PSA nanoparticles were tailored by controlling the feed ratio of St to MAA and emulgator. Transmission electron microscope( TEM),scanning electron microscope( SEM),fourier infrared spectroscopy( FTIR),differential scanning calorimeter( DSC), thermogravimetric analyzer( TGA) and Zeta potential were used to characterize PSA nanospheres. The results showwhen the amount of emulsifier is 10%of the total mass of the monomers,the obtained particle size is 45 nm. FTIR results showthat the MAA has been successfully introduced into the PS microspheres. The glass transition temperature and thermal decomposition temperature of PSA could increase with the increase of MAA concentration. The PS nanopartiles is negatively charged with the Zeta potential-17 mV. The Zeta potential of PSA particles is-31. 9 mV,-39. 6 mV and-44 mV,respectively,corresponding to the molar mass ratio of St to MAA is 10/1. 0,10/1. 5 and 10/2. 5. The above results indicate that the co-polymerization is an effective way to adjust the surface properties of PS microspheres.