Preparation and reshaping of composite microparticles for color toner based on the encapsulated nanoparticles

Abstract

In this paper, the styrene–acrylic resin‐encapsulated organic pigment composite nanoparticles were synthesized by mini‐emulsion polymerization first, and then the aggregated microparticles used for color toner were prepared via the emulsion aggregation method. Transmission electron microscopy, dynamic light scattering, and zeta potential analysis manifest that when the emulsifier dosage was 5 wt% of the monomer, the composite nanoparticles owned clearly core‐shell structure, uniform size, and appropriate zeta potential, which was conducive to the subsequent aggregation. The evolution of aggregated particle size and morphology under different stirring rates, coagulant concentrations, and temperatures was investigated by mastersizer and scanning electron microscopy. The result shows that when the stirring rate was 1,000 rpm, coagulant concentration was 0.2 mol/L, and the curing temperature was 65°C, aggregated particles with suitable size, narrow size distribution, and regular shape could be obtained. The reshaping of aggregated particles can further improve their morphology. When the reshaping temperature was 75°C, the product particles owned perfect spherical shape, and there were almost no cracks and pores on the surface of the particles. This synthesis strategy is believed to provide a guide for the fabrication of composite microparticles with controllable particle size and morphology.

Kinetics of Drug Release via Nicardipine Hydrochloride‐loaded Carboxymethyl Cellulose/Poly(D,L‐lactic‐co‐glycolic acid) Nanocarriers Using a Contemporary Emulsion Process

“…[18] Polymeric nanocarriers with a zeta potential less than � 30 mV tend to aggregate faster. [35] The NCH-CMC/PLGA nanocarriers had a zeta potential of~20.4 mV, suggesting probable aggregation, with consistent zeta potential results after further PLGA addition (Figure 3). A possible explanation for the nanoparticle's stability could be the steric stabilization effect of the emulsifier adsorbed on the nanocarriers surface instead of electrostatic stabilization.…”

“…This phenomenon occurs because nanocarriers are less affected by the gravitational field than microparticles (∼5 μm), which will precipitate on the first day [18] . Polymeric nanocarriers with a zeta potential less than ±30 mV tend to aggregate faster [35] . The NCH‐CMC/PLGA nanocarriers had a zeta potential of ∼20.4 mV, suggesting probable aggregation, with consistent zeta potential results after further PLGA addition (Figure 3).…”

“…CMC is a cellulose derivative and stabilizer emulsion that can protect nanocarriers against rapid aggregation. [35] The nanocarriers are a colloid that exhibits stochastic particle motion, which leads to aggregation of nanocarriers to reduce surface energy. This colloid phenomenon can result in inefficient delivery of the drug.…”