• Title/Summary/Keyword: Cystallinity

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Manufacture of Continuous Glass Fiber Reinforced Polylactic Acid (PLA) Composite and Its Properties (연속 유리섬유 강화 폴리유산 복합재료의 제조 및 물성)

  • Roh, Jeong U;Lee, Woo Il
    • Composites Research
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    • v.26 no.4
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    • pp.230-234
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    • 2013
  • The continuous glass fiber reinforced poly-lactic acid (PLA) composite was manufactured by direct melt impregnation. The mechanical and thermal properties of continuous glass fiber reinforced PLA composite were observed. Measured properties were compared with the reference values of neat PLA and the injection molded glass fiber/ PLA composite. The continuous glass fiber reinforced PLA composite having a fiber volume fraction of 27.7% shows enhanced tensile strength of 331.1 MPa, flexural strength of 528.6 MPa, and flexural modulus of 24.0 GPa. The enhanced heat deflection temperature (HDT) and the increased cystallinity were also observed. The degree of impregnation as a function of pulling speed was also assessed. The degree of impregnation at the pulling speed of 5 m/min was over 90% in this research.

Effect of Heat-Moisture Treatments on Physico-Chemical Properties of Chestnut Starch (수분-열처리에 의한 밤전분의 물리화학적 성질의 변화)

  • Park, Hong-Hyun;Lee, Kyu-Han;Kim, Sung-Kon
    • Korean Journal of Food Science and Technology
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    • v.18 no.6
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    • pp.437-442
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    • 1986
  • Physicochemical properties of chestnut starch, which was adjusted at 14, 18, 21 and 24% moisture and heated for 16 hr at $100^{\circ}C$, were investigated. The cystallinity, swelling power and solubility of the starch were decreased upon heat-moisture treatments. The swelling power of the heat-moisture treated starch showed an inverse relation with moisture levels, while the solubility showed opposite trend. The swelling power and the solubility of both raw and heat-moisture treated starches held a liner relationship. The. water binding capacity of the starch was drastically increased upon heat-moisture treatments. Amylograms revealed that the heat-moisture treated starches had higher initial pasting temperature and lower viscosity than untreated starch. No peak viscosity was observed for the heat treated starches above 21% moisture. The minimum moisture contents for gelatinization of raw and heat-moisture (18%) treated starches were 45 and 40%, respectively. The gelatinization temperature of raw and heat-moisture (18%) treated starches was $65^{\circ}C$.

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Synthesis and Property of Titanium Dioxide Nanosol with a High Crystalline Characteristics (고결정성을 갖는 이산화티탄 나노 졸의 합성 및 특성)

  • Sim, Jae-Kyung;Park, Jong-Kwon;Cho, Jung-Eun;Jeong, Noh-Hee
    • Applied Chemistry for Engineering
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    • v.30 no.6
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    • pp.694-697
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    • 2019
  • In recent years, titanium dioxide powders were produced as nanoparticles or nanowires or nanotubes in one-dimensional structure, and mesoporous spheres in 3-D to improve their crystallinities, which were further used as photo-electrode materials and for preventing photo-aging. In this study, a nano sol composed of titanium dioxide exhibiting a high crystallinity was synthesized using n-alcohol as a solvent. The crystallinity of the nano sol was confirmed by FE-SEM, and XRD, while the UV blocking rate confirmed by UV-Vis spectrometry results. Changes in the crystallinity were investigated by varying the types of solvents such as butanol, propanol and ethanol. The synthesized particle sizes were from 200 to 250 nm, and the optical transmittance showed a high blocking rate in the UVB and UVA range. It is expected that a high transmittance at 550 nm wavelength can increase the photoelectric conversion efficiency of solar cells and the UV blocking efficiency.