Preparation of micron-sized, monodisperse nonspherical polymeric particles with a variety of shapes via seeded dispersio
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ORIGINAL CONTRIBUTION
Preparation of micron-sized, monodisperse nonspherical polymeric particles with a variety of shapes via seeded dispersion polymerization initiated by ammonium persulfate Younes Saadat & Soleyman Hosseinzadeh & Samira Abdolbaghi & Faramarz Afshar-Taromi Received: 24 May 2012 / Revised: 8 October 2012 / Accepted: 15 October 2012 / Published online: 7 November 2012 # Springer-Verlag Berlin Heidelberg 2012
Abstract In this work, the preparation of nonspherical particles via seeded dispersion polymerization of styrene in the presence of various methacrylic seed particles initiated by ammonium persulfate (APS) as a water soluble initiator in the methanol/ water media using poly(vinyl pyrrolidone) as a dispersant was discussed. It was observed that in the presence of poly(methyl methacrylate), poly(ethyl methacrylate), poly(n-butyl methacrylate) (Pn-BMA), and poly(2-ethylhexyl methacrylate) seed particles, particles with velvet-like surface, unique uneven surface, bead-like shape, and void-containing anomalous shape can be produced, respectively. Moreover, the effect of various polymerization conditions such as dispersant and initiator concentration, methanol/water weight ratio, and styrene/Pn-BMA seed particle weight ratio on the shapes of the obtained Pn-BMA/PS composite particles was studied. The experimental results showed that seeded dispersion polymerization initiated by APS is expected as a novel method for the production of polymeric particles with a variety of nonspherical shapes. Keywords Composite particles . Morphology . Nonspherical particles . Seeded dispersion polymerization . Ammonium peroxide sulfate
Introduction The production of polymeric nonspherical particles and particles with special morphologies in 1–5 μm has received Y. Saadat (*) : S. Abdolbaghi : F. Afshar-Taromi Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran 15914, Iran e-mail: [email protected] S. Hosseinzadeh Department of Chemistry, Payame Noor University, PO Box 19395-3697, Tehran, Iran
a great deal of attention in recent years because of their numerous applications in new technical fields like microelectronics, biomedical devices, chromatography, and so forth. In general, polymeric particles produced by emulsion, suspension, and dispersion polymerizations are spherical which is because of minimization of the interfacial free energy between the particles and medium. However, several techniques [1–16] have been developed for the production of polymeric nonspherical particles among which seeded emulsion and dispersion polymerizations have many advantages compared with others. The preparation of various nonspherical particles with these methods has been reported as follows: “raspberry-like” [9, 10], “confetti-like” [11], “golf ball-like” [12], “disk-like and polyhedral” [13, 14], “red blood corpuscle-like” [15, 16], and so forth. Many researchers have suggested that seeded dispersion polymerization (SDP) is a powerful technique for the preparation of nonspheri
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