Because of their unique magnetic features and good biocompatibility, magnetic poly(lactic-co-glycolic) acid (PLGA) microspheres have great application potential in magnetic targeted drug-delivery systems. In this research, magnetic PLGA microspheres with controllable particle sizes were successfully prepared from a composite emulsion with a T-shaped microchannel reactor. A water-in-oil-in-water composite emulsion was generated by the injection of a dichloromethane/gelatin water-in-oil initial emulsion into the microchannel together with a coating aqueous phase, that is, the aqueous solution of glucose and poly(vinyl alcohol). The mean particle size of the microspheres could be controlled by the manipulation of the osmotic pressure difference between the internal and external aqueous phases via changes in the glucose concentration. Curcumin, a drug with an inhibitory effect on tumor cells, was used to exemplify the release properties of the magnetic PLGA microspheres. We found that the mean particle size of the microspheres ranged from 16 to 207 μm with glucose concentrations from 0 to 20 wt %. The resulting microspheres showed a rapid magnetic response, good superparamagnetism, and a considerable magnetocaloric effect, with a maximum magnetic entropy of 0.061 J·kg−1·K−1 at 325 K. An encapsulation efficiency of up to 77.9% was achieved at a loading ratio of 3.2% curcumin. A release ratio of 72.4% curcumin from the magnetic PLGA microspheres was achieved within 120 h in a phosphate-buffered solution. The magnetic PLGA microspheres showed potential to be used as drug carriers for magnetic targeted tumor therapy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43317.
Due to their widespread applications, the production and consumption of plastics have increased sharply and also brought about a lot of waste. However, only one-fourth of plastic solid waste is effectively recycled, and the rest is almost entirely disposed in landfills. In this article, high performance synthetic paper used for printing was successfully prepared from ultrahigh molecular weight polyethylene waste adopting thermally induced phase separation method. Silicon dioxide was added as filler and mineral oil was used as diluent. Whiteness, chemical resistance, tensile strength, thermal stability, surface morphology, and inkjet print of synthetic paper was investigated, respectively. It is indicated that the resulting synthetic paper possesses excellent printing effect. Its whiteness equally distributes around 80% and the highest tensile strength is up to 5.5 MPa. They also reveal good resistance to chemical corrosion and have good shape maintenance. As a result, the preparation of high performance synthetic paper for industrial applicability is expected to perform by recycling plastics waste. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44159.
The production of traditional cellulose paper not only consumes lots of timber, but also brings about some environmental issues. Therefore, it is being increasingly replaced by synthetic paper. In this study, ultrahigh molecular weight polyethylene (UHMWPE)/SiO2 synthetic paper with high application performance was prepared by the thermally induced phase separation method using mineral oil as diluent. The corresponding properties of synthetic paper, including surface morphology, overall porosity, tensile strength, thermal stability, acid and alkali resistance, whiteness, and inkjet print effect were investigated respectively. The results show that the overall porosity of UHMWPE/SiO2 synthetic paper is above 45%, and the tensile strength exceeds 4.3 MPa. UHMWPE/SiO2 synthetic paper also presents light weight, as well as good resistance to heat, acid and alkali. Meanwhile, the average whiteness of the samples is up to 91.8%. The sample K-50, which contains 31.5 wt % SiO2, takes on the best print performance caused by its dense surface and higher SiO2 content. It is indicated that UHMWPE/SiO2 synthetic paper has good market prospects in the color printing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41529.
Poly(lactic-co-glycolic acid) (PLGA) microspheres prepared using a traditional solvent evaporation or double emulsification method are usually polydisperse with an uncontrollable particle size distribution, which brings about poor application performance. In our research, monodisperse magnetic PLGA microspheres were prepared using a microchannel device based on a water-in-oil-in-water composite emulsion. The composite emulsion was formed by injecting a dichloromethane–gelatin water-in-oil emulsion into a microchannel together with an external water phase, i.e. poly(vinyl alcohol) (PVA) aqueous solution. Mean particle size control of the microspheres was executed using the osmotic pressure difference between internal and external aqueous phases caused by regulating NaCl concentration in PVA aqueous phase. It is found that monodisperse magnetic PLGA microspheres with high magnetic responsiveness can be successfully prepared combining the microchannel device with composite emulsion method. Mean particle size of the microspheres with coefficient of variation value below 4.72% is controllable from 123 to 203 µm depending on the osmotic pressure. The resulting samples have pyknotic and smooth surfaces, as well as spherical appearance. These monodisperse magnetic PLGA microspheres with good superparamagnetism and magnetic mobility have potential use as drug carriers for uniform release and magnetic targeting hyperthermia in biological fields. © 2015 Society of Chemical Industry
Microencapsulated disperse dye can be used to dye hydrophobic fabric in the absence of auxiliaries and without reduction clearing. However, little available information for dyeing practice is provided with respect to the effect of microencapsulation on the dyeing behaviors of disperse dyes. In this research, disperse dyes were microencapsulated under different conditions. The dyeing behaviors and dyeing kinetic parameters of microencapsulated disperse dye on PET fiber, e.g., dyeing curves, build up properties, equilibrium adsorption capacity C∞, dyeing rate constant K, half dyeing time t1/2, and diffusion coefficient D were investigated without auxiliary solubilization and compared with those of commercial disperse dyes with auxiliary solubilization. The results show that the dyeing behaviors of disperse dye are influenced greatly by microencapsulation. The diffusion of disperse dyes from microcapsule onto fibers can be adjusted by the reactivity of shell materials and mass ratios of core to shell. The disparity of diffusibility between two disperse dyes can be reduced by microencapsulation. In addition, the microencapsulation improves the utilization of disperse dyes due to no auxiliary solubilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011