No abstract

No abstract

No abstract

Nanocomposites of hydrophobic organo-clay/polypropylene (organo-clay/PP) were efficiently developed through a solution-blending technique. For this, we utilized various smectite clays as host agents; namely, Na-montmorillonite (Mt, ~1000 nm), Na-fluorine mica (Mica, ~1500 nm), and Na-hectorite (Ht, ~60 nm) with varied sizes, layer charges, and aspect ratios. Such clays were functionalized with cetyltrimethylammonium (CTA) bromide via an intercalation technique to obtain hydrophobic organic clays. The as-made clay particles were further mixed with a PP/xylene solution; the latter was removed to obtain the final product of the CTA-clay/PP nanocomposite. An X-ray diffraction (XRD) analysis confirmed that there were no characteristic (001) diffraction peaks for CTA-Mica in the PP nanocomposites containing CTA-Mica, assuring the fact that the Mica layers could be completely exfoliated and thereby homogenously composited within the PP. On the other hand, the CTA-Mt and CTA-Ht incorporated composites had broader (001) peaks, which might have been due to the partial exfoliation of CTA-Mt and CTA-Ht in the composites. Among the three CTA-clay/PP nanocomposites, the CTA-Mica nanohybrid showed an enhanced thermal stability by ~42 °C compared to the intact host polymer matrix. We also noted that when the CTA-Mica content was ~9 mass % in the nanocomposites, the Young’s modulus was drastically maximized to 69%. Our preliminary results therefore validated that out of the three tested clay-PP nanocomposites, the CTA-Mica nanofiller served as the best one to improve both the thermal and mechanical properties of the PP nanocomposites.

The present study aimed to evaluate the concentration of odor substances and fine dust in areas where livestock farms are densely located, and to perform a correlation analysis of these concentrations to characterize the composition of fine dust. The mass concentration of fine dust in the areas tested was 33.6~46.68 μ/m3 for particulate matter with a diameter ≤ 10 μm (PM₁₀) and 16.85~32.82 μ/m3 for particulate matter with a diameter ≤ 2.5 μm (PM_2.5). These concentrations were higher than those in most of the neighboring areas. Ammonia concentration was measured in the range of 2.82~11.42 μ/m3. The concentrations of the volatile organic compounds (VOCs), methyl ethyl ketone and toluene, were 0.24~11.82 μ/m3, and 3.08~30.61 μ/m3, respectively. Composition analysis showed that fine dust was composed of 8.2~10.2% carbon, 0.3~1.7% sulfur, and 0.1~0.9% nitrogen. Anions were detected at a higher concentration than cations, and SO₄2- was measured at the highest concentration. Of the four most prevalent metals detected (i.e., Al, B, Cu, and Zn), Al showed the highest concentration in both PM₁₀ and PM_2.5, and accounted for the majority of the total metal component (84.7% and 82.2%, respectively). A correlation analysis of find dust with ammonia and VOC (methyl ethyl ketone and toluene) concentrations showed that ammonia generated from livestock facilities affected the formation of fine dust in nearby areas. VOCs emitted from nearby industrial facilities were also considered to contribute to the constituents of fine dust.