Preparation of nonspherical particles via dual-seeded dispersion polymerization in the presence of saturated hydrocarbon droplets

Abstract

In this study, the effect of various polymerization conditions on the shape of the particles produced by dualseeded dispersion polymerization of a second monomer with polystyrene (PS) and poly(methyl methacrylate) (PMMA) seed particles in the presence of saturated hydrocarbon droplets in a polar media was discussed. It was observed that with changing the affinity between the hydrocarbon and PS seed particles, second monomer type, polarity, and alcohol type of the medium nonspherical particles with a variety of shapes can be produced. Furthermore, we suggested that the presence of PMMA seed particles in the medium affects the distribution of the second polymer domains on the surface of the PS seed particles in addition to the absorbed amount of the hydrocarbon by PS particles and second polymer domains and the distribution of the hydrocarbon between them. Moreover, the experimental results showed that almond shell-like PS particles can be prepared under certain conditions.

Dual-seeded dispersion polymerization: formation mechanism of novel and unique ring-like and almond-shell-like polystyrene particles

“…Such observations are very important due to different functionalities each one of the mentioned shapes have. In our previous work, we reported the production of novel and unique almond-shelllike PS particles via DSDP technique, but formation mechanism of them remained unclear even though the obtained results helped us to introduce a hypothetical one [24]. Therefore, in order to illustrate this point clearly as well as achieving exceptional results that was referred to above, we tried monitoring the DSDP system.…”

“…2. One of the challenges in the DSDP system is to characterize each one of the seed particles apart from each other during microscopic tests; however, in this type of DSDP, it is not so hard to do so since it was found in previous studies that PMMA seed particles coagulate during polymerization [23,24]. Nevertheless, monitoring the reaction was expected to be an excellent way to determine the time when this phenomenon happens.…”

“…The experimental results revealed that the presence of PMMA seed particles in the medium can contribute in changing the distribution of poly(ethylhexyl methacrylate) (PEHMA) and solvent on the surface of PS seed particles, resulting in asymmetric growth of PEHMA/solvent domains, and therefore, formation of asymmetric structures. Moreover, it was shown that DSDP in the presence of solvent droplets is an effective, strong technique for the production of nonspherical particles with a variety of shapes since by implementing a little change in reaction conditions, different shapes can be obtained [23,24]. Nevertheless, the formation mechanism of the particles during such interesting polymerization system was unclear; hence, in this study, time course analysis of this reaction system was carried out in order to obtain a clear image about this mechanism.…”

Micromolding-polymerization as a novel method for production of nonspherical polymer particles: formation mechanism of polystyrene particles

“…In the past years, several efforts have been done to prepare such particles using different techniques [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. We also reported the production of particles with a variety of shapes [19][20][21][22][23][24]. However, in all of such reports, nonspherical particles have been produced by changing the shape of a precursor; therefore, this question would be raised: Bis it feasible to prepare nonspherical particles of one component directly by polymerization without changing the shape of a precursor?Î n our previous work, we answered this question by introducing a new synthesis method which we called it micromolding-polymerization.…”

Fabrication of unique cage-like polystyrene particles having lots of dents on the surface via unstable seeded dispersion polymerization

“…Several studies have been reported regarding the production of polymer particles with a variety of shapes such as "egg-like" [1], "confetti-like" [2], "raspberry-like" [3][4][5][6], "snowman-like" [2,7], "rugby-ball-like" [8], golf-ball-like [9], disk-like [10][11][12][13], red blood corpuscle-like [14], and so forth. We have also reported the fabrication of particles with novel almond shell-like shape via dual-seeded dispersion polymerization (SDP) [15,16] as well as half-shell polystyrene (PS) particles with controllable surface area using micromolding-polymerization [17].…”