29 Result(s)
within
Haksoo Han
Chemistry
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Article
Synthesis and characterization of novel PPC-silica hybrid with improved thermal, mechanical, and water sorption properties
Organic-inorganic hybrids (H1-H5) based on environmentally friendly and biodegradable polymer, poly (propylene carbonate) (PPC) and tetraethoxysilane (TEOS) were synthesized using the sol-gel technique. The sy...
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Article
Thermal properties and water sorption behaviors of epoxy and bismaleimide composites
In this work, we prepared epoxy/BMI composites by usingN,N′-bismaleimide-4,4′-diphenylmethane (BMI), epoxy resin (diglycidyl ether of bisphenol-A (DGEBA)), and 4,4’-diamino diphenyl methane (DDM). The thermal pro...
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Article
Photocatalytic Properties of Silica-supported TiO2
TiO2 supported on SiO2 surface is effective on the recovery of photocatalyst, morphological control, and coating on the substrate. Furthermore, it shows much higher photocatalytic activity than pure TiO2. The sil...
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Article
Optical Properties of Polyimide Thin Films. Effect of Chemical Structure and Morphology
The optical properties of polyimide (PI) thin films with various backbone structures were investigated with prism coupler. PI films were prepared from two types of dianhydrides: pyromellitic dianhydride (PMDA)...
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Article
Effects of Diamines (1,4-Phenylene Diamine and 4,4′-Oxydianiline) on Water Sorption Behavior of Polyimide Thin Film
Several polyimide thin films based on two widely commercialized diamines, 1,4-phenylene diamine (PDA) and 4,4′-oxydianiline (ODA), were prepared from respective poly(amic acid) precursors. Water sorption behav...
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Article
Effects of Thickness on the Residual Stress Behavior of High Temperature Polyimide Films
The effects of thickness on the residual stress behavior of the hinged structure poly(4,4-oxydiphenylene pyromellitimide) (PMDA-ODA) and rigid planar structure poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA...
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Article
Effect of Poly(amic diethyl ester) Precursor on Residual Stress Behavior of Aromatic Polyimides
The influence of poly(amic diethyl ester) (PAE) and poly(amic acid) (PAA) precursors on the residual stress behavior of polyimide thin films was investigated. Rodlike poly(p-phenylene pymellitimide) (PMDA-PDA), p...
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Article
Effect of Isomeric Oxydiphenylene Diamine on the Water Sorption Behavior of High Temperature Polyimide Thin Films
The effects of isomeric oxydiphenylene diamines (ODA), 3,4′ODA and 4,4′ODA, on the water sorption behavior in pyromellitic dianhydride (PMDA)-ODA, biphenyltetracarboxylic dianhydride (BPDA)-ODA, 3,3′,4,4′-benz...
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Article
The Effect of Amic Ester Precursor on the Water Sorption Behavior and the Stress Relaxation of High Temperature Polyimide Thin Films
Poly(4,4′-oxydiphenylene pyromellitimide) (PMDA-ODA) and poly(1,4-phenylene pyromellitimide) (PMDA-PDA) polyimides were prepared from poly(amic acid) (PAA) and poly(amic ester) (PAE) precursors, respectively. ...
