• Composites Research
• /
• v.26 no.4
• /
• pp.230-234
• /
• 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.

• Composites Research
• /
• v.31 no.6
• /
• pp.371-378
• /
• 2018

In this study, the thermoelastic properties of poly lactic acid (PLA) based nanocomposites are predicted by molecular dynamics (MD) simulation and a micromechanics model. The stereocomplex mixed with L-lactic acid (PLLA) and D-lactic acid (PDLA) is modeled as matrix phase and a single walled carbon nanotube is embedded as reinforcement. The glass transition temperature, elastic moduli and thermal expansion coefficients of pure matrix and nanocomposites unit cells are predicted though ensemble simulations according to the hydrolysis. In micromechanics model, the double inclusion (D-I) model with a perfect interface condition is adopted to predict the properties of nanocomposites at the same composition. It is found that the stereocomplex nanocomposites show prominent improvement in thermal stability and interfacial adsorption regardless of the hydrolysis. Moreover, it is confirmed from the comparison of MD simulation results with those from the D-I model that the interface between CNT and the stereocomplex matrix is slightly weak in nature.

• The monthly packaging world
• /
• s.36
• /
• pp.110-115
• /
• 1996

• Composites Research
• /
• v.27 no.3
• /
• pp.96-102
• /
• 2014

In this study, we fabricated jute fiber reinforced polylactic acid (PLA) composite in the form of sandwich panel structure which includes core foam of chopped jute fiber reinforced PLA and outer skin layer of continuous glass fiber reinforced PLA. Flexural properties of the composite were assessed for different jute fiber weight fractions. Density of the core foam ranged from 0.31 to 0.67 $g/cm^3$ and void content fraction 0.51 to 0.71. The maximum flexural strength was 92.7 MPa at 12.5 wt.% of jute fiber content, and the maximum flexural modulus was 7.58 GPa at 30.0 wt.%. Cost analysis was also conducted. The cost to enhance the flexural strength of the applied structure was estimated to be $0.010USD/m^3/MPa$ for 12.5 wt.% fiber content.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.2
• /
• pp.399-408
• /
• 2022

As part of research on the development of functional materials for antlers, lactic acid fermentation of antler extract was performed. It was intended to develop a functional material with enhanced total polyphenol and flavonoid content and enhanced antioxidant activity. During the fermentation of lactic acid bacteria, the number of proliferation, total polyphenol and total flavonoid content, DPPH radical scavenging and antioxidant activity were quantified and evaluated. As a result of adding these four types of lactic acid bacteria to the antler water extract substrate, the number of lactic acid bacteria measured was 2.04~5.00×10⁷. Meanwhile, a protease (Baciullus amyloliquefaciens culture: Maxazyme NNP DS) was added to the antler extract to decompose the peptide bonds of the contained proteins. Then, these four types of lactic acid bacteria were added and the number of lactic acid bacteria increased to 2.84×10⁷~2.21×10⁸ as the result of culture. The total polyphenol contents were 4.82~6.26g/mL in the lactic acid bacteria fermentation extracts, and after the reaction of protease enzyme and lactic fermentation, increased to 14.27~20.58 g/mL. The total flavonoid contents were 1.52~2.21 g/ml in the lactic acid bacteria fermentation extracts, and after the protease reaction and fermentation, increased to 5.59~8.11 mg/mL. DPPH radical scavenging activities of lactic acid bacteria fermentation extracts was 17.03~22.75%, but after the protease reaction and fermentation, remarkably increased to 32.82~42.90%.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1671-1676
• /
• 2015

A unique crystallization behavior of poly(L-lactide)(PLLA)/poly(D-lactide)(PDLA) stereocomplex(SC) was observed when a PLLA/PDLA blend was subjected to the specific melting conditions. Therefore, we tried to blend PLLA and PDLA at overall composition to form PLA stereocomplexes. Moreover, impact modifier and reinforcement materials such as talc and glass fiber added to enhance the mechanical and thermal properties such as impact strength and heat distortion temperature(HDT). As a result, we got one representative result, one composite recipe with HDT $115^{\circ}C$. For more economic technology, we tried to blend PLLA and Polypropylene at overall composition and we got another representative result which could be applied to current PP/talc composites and ABS materials. The core technology of this might be the well dispersion of glass fibers into the matrix resin such as PP, PLLA and impact strength modifier.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.545-547
• /
• 2007

본 연구에서는 생체 적합성이 뛰어난 HA가 고분자와의 낮은 친화성을 개선하기 위하여 HA를 화학적으로 개질하여 고분자와의 친화성을 높이는 연구를 수행하였다. 결과에서 나타나 바와 같이 효과적으로 개환중합을 이용하여 HA를 효과적으로 개질하였고 고분자와의 복합재료에 대한 특성을 고찰 하였다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.558-560
• /
• 2007

l-PLA와 d-PLA사이의 complex형성은 화학 양론적으로 동일 몰비에서 강력한 상호 작용력에 기인한다. 이러한 특성을 이용하여 PLA블렌드 계에서 stereochemistry를 이용하여 블렌드 한 성분에 defect를 부여함으로서 complex정도를 조절함으로서 다성분 고분자계의 표면 조성의 조절(표면 물성의 조절)과 생분해성의 조절이 가능함을 보였다.

• Polymer Science and Technology
• /
• v.21 no.1
• /
• pp.41-44
• /
• 2010

• Journal of Adhesion and Interface
• /
• v.15 no.1
• /
• pp.14-21
• /
• 2014

In the present work, PLA/PBS blends with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) at different contents were processed by using a twin-screw extruder and an injection molding machine, and then their mechanical, thermal and morphological properties were investigated. The mechanical properties such as flexural strength, flexural modulus, tensile strength and tensile modulus and thermal properties such as melting behavior, dynamic mechanical thermal properties and thermal stability significantly depended on the contents of PLA and PBS. However, the heat deflection temperature of the blends was not significantly influenced by the contents of PLA and PBS. Also, the fracture surfaces of PLA/PBS blends were changed from a brittle pattern to a ductile pattern with increasing the PBS contents.