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Lee Y.-K.,Seoul National University | Kim H.-J.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Seoul National University
Building and Environment | Year: 2012

The environmental chamber method is used to determine the area specific emission factor of VOCs emitted from building products, which is calculated from the small emission test chamber concentration by considering the passing air flow rate and surface area at 23-28 °C. Although indoor air temperatures are generally between 17 and 28 °C, floor heating can create exceptional conditions in flooring materials.To determine the effect of temperature, the emission of VOCs and carbonyl compounds from engineered flooring and laminate flooring were measured using a thermal extractor (TE), which was applied at 25, 35 and 45 °C for 30 min.At 35 °C, the level of TVOC emission was more than double that at 25 °C. At 35 °C and 45 °C, the level of formaldehyde emission was more than two and five times of that at 25 °C, respectively. Therefore, this TE method of VOCs and formaldehyde emission analysis will be a good alternative to the traditional chamber method for determining the VOC emission levels from flooring products. In conclusion, some wooden flooring may contribute to the contamination of indoor air with the use of floor heating. © 2011 Elsevier Ltd. Source


Kim H.-S.,Samsung | Kim H.-S.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Seoul National University
Fibers and Polymers | Year: 2013

This research evaluates the miscibility and performance of polypropylene (PP)/polybutylene succinate (PBS) and PP/polylactic acid (PLA) blend and natural-flour-filled, PP/PLA and PP/PBS blend bio-composites. The melting temperature (Tm) and glass transition temperature (Tg) of pure PP, PBS and PLA showed a single peak but differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) presented two peaks for the Tm and Tg of the PP/PBS and PP/PLA blends. These results indicated that the PP/PBS and PP/PLA blend systems existed as immiscible blends. These results were also confirmed by the scanning electron microscopy (SEM) micrographs of the tensile fracture surface of the PP/PBS and PP/ PLA blends. At a PP/PBS and PP/PLA blend ratio of 70/30, the tensile and flexural strengths of bamboo flour (BF)- and wood flour (WF)-filled, PP/PBS and PP/PLA blend bio-composites were similar to those of BF- and WF-filled, PP and PBS bio-composites. In addition, these strengths of maleic anhydride-grafted PP (MAPP)- and acrylic acid-grafted PP (AAPP)-treated, BF- and WF-filled, PP/PBS and PP/PLA blend bio-composites were higher than those of non-treated bio-composites. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht. Source


Lee Y.-H.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Seoul National University
Progress in Organic Coatings | Year: 2016

Four types of cycloaliphatic structure of polyester were synthesized, using 1,4-cyclohexanedicarboxylic acid (1,4-CHDA). Those resins were formulated to make polyester/melamine coatings to control the formability, and to have good stone-chip resistance. The characteristics, viscoelastic behavior and flexibility of those resins were measured by DMA and tensile test. Cycloaliphatic structure of polyester coatings were coated on the cold roll steel sheets to verify formability, using a deep drawing test and stone-chip resistance was measured by the chipping resistance test at the -20 °C. Results showed that storage modulus decreased, and glass transition temperatures shifted to lower temperatures with increasing contents of cycloaliphatic structure. So, cycloaliphatic structure of 1,4-CHDA provides lower stiffness and higher softness to the polyester coating and has better elasticity than aromatic structure of IPA. To analyze the formability, we calculated FU (the forming coefficient based on strain energy) and Fϵ (the forming coefficient based on strain). When FU and Fϵ are both larger than 1, the polyester coatings have good formability. Also, BCHDA-20 had 0.44% of removed area by the chipping resistance test and it means that cyclic structure of 1,4-CHDA has better elasticity than aromatic structure, and can give better impact resistance From those tests, BCHDA-20 which had 20 mol of 1,4-CHDA had good formability and also showed good stone-chip resistance. So, cycloaliphatic structure provides lower stiffness and higher softness to the polyester coating for automotive pre-coated metals. © 2016 Elsevier B.V. All rights reserved. Source


Kim H.-S.,Samsung | Lee B.-H.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Laboratory of Adhesion and Bio Composites | Kim H.-J.,Seoul National University | Yang H.-S.,University of Minnesota
Journal of Polymers and the Environment | Year: 2011

The mechanical-thermal properties and volatile organic compound (VOC) emissions of natural-flour-filled, biodegradable polymer bio-composites were investigated according to variation in porous inorganic filler types. At a porous inorganic filler content of 3%, the tensile and flexural strengths of the hybrid bio-composites were not significant changed. However, the coefficient of thermal expansion and thermal expansion of the bio-composites were slightly decreased. Furthermore, the incorporation of the porous inorganic materials into bio-composites slightly increased the E' values of the hybrid bio-composites over the entire temperature range, although the tan δ max temperature (T g) of the hybrid bio-composites was not significantly changed. At a porous inorganic filler content of 3%, the various odor and VOC emissions of the hybrid bio-composites were significantly decreased because the various oxidation and thermal degradation gases of the natural flour and matrix were absorbed in the pore structures of the porous inorganic fillers and thereby prevented the migration into the final products. © 2011 Springer Science+Business Media, LLC. Source

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