Synthesis of highly monodisperse polystyrene microspheres via dispersion polymerization using an amphoteric initiator

Document Type

Article

Publication Date

6-15-2006

Abstract

The highly monodisperse polystyrene (PS) microspheres were produced by dispersion polymerization using an amphoteric initiator, 2, 2′-azobis [N-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057). The polymerization characteristics were investigated and compared with conventional initiators, 2,2-azobis(isobutyronitrile) (AIBN) and benzoyl peroxide (BPO). The monodisperse PS microspheres having the coefficient of variation ( Cv) of diameter all less than 4% are obtained at very low stabilizer, poly(vinyl pyrrolidone) (PVP) concentrations of 1 and 2 wt%. It is found that the size dependence of the VA-057 system, Dn ∝ [VA-057]0.267, is less sensitive than a conventional initiator system. When the same amount, 2 wt%, of AIBN, BPO, and VA-057 is used under the identical PVP concentration of 2 wt%, the Dn / Cv's are 1.95/11.57, 1.47/22.44, and 2.08 μm/2.50%, respectively. The uniformity of particles was characterized employing an optical analyzer, Turbiscan. For the VA-057 system, the back scattering intensity is linearly reduced with time having a constant sedimentation rate of 48.98 μm/min throughout the settling process. The uniformity of PS particles in the VA-057 system stems from (1) the higher rate of polymerization in early stage of polymerization, followed by significantly faster reduction of the rate, and (2) good dispersion stability of primary particles. Therefore, it is found that the use of an amphoteric initiator, VA-057, is promising for producing monodisperse particles in dispersion polymerization. © 2006 Elsevier Inc. All rights reserved.

Identifier

33747778399 (Scopus)

Publication Title

Journal of Colloid and Interface Science

External Full Text Location

https://doi.org/10.1016/j.jcis.2006.01.001

ISSN

00219797

First Page

663

Last Page

671

Issue

2

Volume

298

Grant

D00028

Fund Ref

Ministry of Education and Human Resources Development

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