Role of dispersion stabilizer with hydroxy groups in preparation of monodisperse polylactide microspheres

Abstract

Monodisperse poly(D,L-lactide) (PDLLA) microspheres were prepared by dispersion polymerization of D,L-lactide in xylene/heptane (1/2, v/v) with poly[(dodecyl methacrylate)-co-(2-hydroxyethyl methacrylate)] (P(DMA-co-HEMA)) as a dispersion stabilizer. P(DMA-co-HEMA) contains hydroxy groups, which act as an initiation group for pseudoanionic dispersion polymerization. The best coefficient of variation (CV) values concerning particle diameter distribution and the particle diameter of obtained PDLLA microspheres were 3.7% and 5.3 lm, respectively. The particle diameter decreased with increasing concentration of P(DMA-co-HEMA) and HEMA maintained low CV (\10%) values. As a result, monodisperse PDLLA microspheres ranging from 1.3 to 5.3 lm were obtained. In addition, it was found that monodisperse PDLLA microspheres were obtained by sufficient capture of growing polymers and monomers in the particle growth stage. Therefore, the HEMA concentration in P(DMA-co-HEMA) strongly affecting the capturing capability is the most important factor.

Polylactides—an overview

“…Polymerization was carried out at 95°C. In later studies, 2,2‐dibutyl‐2‐stanna‐1,3‐dioxepane and Sn(Oct) 2 /polyalcohols were also used as initiators, and poly{(octadecyl methacrylate)‐co‐(dimethylaminoethyl methacrylate)} and poly (dodecyl methacrylate)‐g‐poly(D,L‐lactide) were used as colloid stabilizers . Diameters of synthesized microspheres were in the range from 2.5 to about 7 µm .…”

Poly (acrylonitrile – co -1-vinylimidazole): A new melt processable carbon fiber precursor

“…A number of block and graft copolymers were popularly used as stablilizers [102][103][104][105][106][107][108][109][110]. But random copolymers become more attractive in industry because they are synthesized more easily and affordably [111][112][113][114]. There are also several homopolymers [115], such as poly (vinyl pyrrolidone) [116], hydroxyl propyl cellulose and poly (acrylic acid) have been successfully applied as stabilizers in dispersion polymerization [100,[117][118].…”

Polythiophene microspheres synthesized by transition metal mediated oxidative dispersion polymerization

“…Additionally, the relatively broad particle size distribution on the increased monomer concentration indicates that the efficiency of stabilizer needs improvement. Regarding the previous studies on conventional dispersion polymerization, [23][24][25][26][27][28][29][30] elaborately designed amphiphilic block copolymer stabilizers or reactive macromonomers may show higher stabilizing efficiency and allow better control on PT microspheres morphology. They may also be used for the preparation of conducting polymer composite microspheres and the surface functionalization of conducting polymer particles.…”