Morphology-Controlled Fabrication And Investigation Of The Mechanism On The Formation Of Anisotropic PS-Based Particles

The emergence and development of polymer microspheres has enormous influence on human economy and life. More and more attention has been paid to the morphology control of polymer particles. All kinds of morphological particles have been fabricated. Amongst, golf ball-like and bowl-like polymer particles have received considerable attention over the last decade. However, due to the asymmetric feature in the particles, the preparation of golf ball-like and bowl-like polymer particles remains challenging for a long time. For polymer particles, their surface free energy tend to be lowest to maintain the thermodynamic stability, so finally they easily lead to the final microspheres into spherical particles. Anisotropic polymer particles have a unique advantage in a low density and high specific surface area. The preparation and morphology control of golf ball-like and bowl-like polymer particles have great significance not only in enriching the theory in interface and colloid surface science, but also in expanding their practice application fields. This paper aims at the preparation of golf ball-like and bowl-like polymer particles with controllable morphologies and the mechanism on the formation based on the interface physical chemistry theory. The main contents are as follows:1P(St-co-MMA-co-MAA)(St/MMA=7/3(w/w),MAA=5%w) and P(St-co-MMA-co-MAA)(St/MMA=5/5(w/w),MAA=5%w) were prepared by emulsifier free emulsion polymerization, respectively. The emulsion polymerization conversion was calculated by measuring solid content. The morphology of the templates was seen by transmission electron microscope (TEM). The experimental results showed that the PS (7/3) and PS (5/5) of the conversion rate were88.56%and90.45%respectively. TEM showed that microspheres particle size were350nm and400nm respectively with good monodispersity.2Golf ball-like polymer microspheres were prepared by solvent/non-solvent induced phase separation method with template PS(7/3). The effects of the variety of dispersion medium (ethanol/water, n-butyl alcohol/water, cyclohexanol/water) and dosage, the dosage of the good solvent, dispersion methods (ultrasonic, magnetic stirring) on golf ball-like microspheres morphology were studied and the corrosion process of the particles was investigated. The corrosion composition was analysed. The experimental results showed that when choosing n-butyl alcohol/water as dispersion medium, volume ratio being5mL/15mL, and2ml n-heptane, in temperature60℃, the reaction time remaining30minutes, a perfect golf ball-like polymer particles can be prepared. The morphology between bowl-like particles and golf ball-like particles can be changed by different dispersion method (ultrasonic shaking and magnetic stirring). The copolymer containing MAA and St was more likely to be corroded than that containing St and MMA.3Bowl-like polymer particles were fabricated by template PS(5/5). The effects of the variety of dispersion medium (ethanol/water, n-butyl alcohol/water, cyclohexanol/water) and dosage, the dosage of the good solvent, dispersion methods (ultrasonic, magnetic stirring) to golf ball-like microspheres morphology were studied. The corrosion process of the particles was investigated and a analysis of the corrosion composition was made. The formation mechanism of the bowl-like microspheres was preliminarily discussed. The experimental results showed that when the dispersion medium choosing cyclohexanol/water, and volume ratio being5mL/15mL, and2ml n-heptane, in temperature60℃, the reaction time remaining30minutes, a perfect bowl-like polymer particles can be prepared. The morphology between bowl-like particles and golf ball-like particles can be changed by different dispersion method (ultrasonic shaking and magnetic stirring). The study of the corrosion process of the particles showed that at the beginning of the reaction the dimpled surface comes from the swelling and aggregation of oil droplets in the surface of polymer spheres. Finally bowl-like particles were obtained by washed with ethanol and centrifugation.4The reduction of nitrite ion in ITO wastewater is discussed, and the results showed that hydrogen peroxide and Cu can restore nitric acid. When H2O2is used as reductant, the product is water and there is no pollution to the environment. In this experiment we describe a feasible method for determination of nitrate ion concentration with UV detection. This method provides a convenient tool for determination of the concentration of nitrate ion.