Film properties of monodispersed model composite latexes with particle size of 190 nm, which consist of n-butyl acrylate as a soft phase monomer and methyl methacrylate as a hard phase monomer with different morphology was examined. Five different types of model latexes were used in this study such as random copolymer particle, soft-core/hard-shell particle, hard-core/soft-shell particle, gradient type particle, and mixed type particle. Tensile strength and tensile elongation at break of final films were evaluated. Those properties can be interpreted in terms of PBA/PMMA phase ratio and their morphology. The interfacial adhesion strength was also evaluated using 180˚ peel strength measurement and cross hatch cutting test.

The use of natural paint for the application to walls and furnishings is now increasing to improve indoor air quality, thereby the natural paint could be a significant source of biogenic volatile organic compounds (BVOCs) in indoor environments. Recent studies have shown that gas-phase reactions between terpenes and ozone can generate sub-micron size particles and toxic volatile organic compounds such as aldehydes and ketones. In this research, we have studied the formation of particles and secondary organic compounds during the reaction of ozone with terpenes emitted from commercial natural paint. The paint applied onto stainless steel was dried and oxidized in a teflon chamber. Two monoterpenes (α- and β-pinenes) were identified by FTIR and GC/MS. Several tests were performed to evaluate the effects of ozone concentration on particle formation. Increased ozone levels significantly affect the increase of particle number concentration (monitored with SMPS), which results in the increase of particle counts ranging from 8,000 to 70,000 particles/㎤. Gas-phase products such as formaldehyde, acetaldehyde, acetone + acrolein, and propionaldehyde were identified during the terpene/ozone reactions by HPLC. These compounds are potential hazardous chemical compounds having harmful health effects to animals and plants. The results obtained from this study provide an insight on the adverse effect of eco-friendly natural product on indoor air quality (IAQ).

In this study, various model composite latexes were synthesized using n-butyl acrylate and methyl methacrylate as comonomers by seeded multi-staged emulsion polymerization. Monodispersed model composite latex particles with size of 190 nm and polydispersity index of 1.05, which have various morphology including random copolymer particle, soft-core/hard-shell particle, hard-core/soft shell particle, and gradient-type copolymer particle, homopolymers particles were prepared. The designed morphology of model composite particles were confirmed.

Al-l4wt.%Ni-l4wt.% Mm(Mm=misch metal) alloy powders rapidly solidified by the gas atomization method were subjected to mechanical milling(MM). The morphology, microstructure and hardness of the powders were investigated as a function of milling time using scanning electron microscopy(SEM), transmission electron microscopy(TEM) and Vickers microhardness tester. Microstructural evolution in gas-atomized Al-l4wt.%Ni-l4wt.% Mm(Mm=misch metal) alloy powders was studied during mechanical milling. It was noted that the as-solidified particle size of decreases during the first 48 hours and then increases up to 72 hours of milling due to cold bonding and subsequently there was continuous refinement to on milling to 200 hours. Two microstructurally different zones, Zone A, which is fine microstructure area and Zone B, which has the structure of the as-solidified powder, were observed. The average thickness of the Zone A layer increased from about 10 to in the powder milled for 24 hours. Increasing the milling time to 72 hours resulted in the formation of a thicker and more uniform Zone A layer, whose thickness increased to about . The TEM micrograph of ball milled powder for 200 hours shows formation of nano-particles, less than 20 nm in size, embedded in an Al matrix.