• Composites Research
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• 제33권4호
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• pp.213-219
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• 2020

최근 플라스틱 폐기물로 인한 환경 문제가 이슈화되면서 친환경 소재에 대한 관심이 점점 증가하고 있으며, 이에 따라 천연섬유를 활용한 복합재의 연구가 지속적으로 이루어지고 있지만 친환경 복합재의 강도나 계면 접착력에 대한 연구가 많이 부족한 실정이다. 복합재료의 강도나 계면 접착력을 향상시키는 방법들 중 한 가지 방법은 나노 입자를 첨가하여 기계적 물성을 향상시키는 방법이 있다. 본 연구에서는 기존에 사용되는 고가의 나노소재를 대체할 수 있는 친환경적이면서 경제적인 천연섬유를 해초로부터 추출하여 첨가제를 제조하고, 복합재료의 제조 및 기계적 특성평가를 수행하였다. 시험결과 제조한 첨가제가 복합재료의 인장, 굽힘, 충격 등의 물성 향상에 효과가 있을 뿐만 아니라 친환경성과 경제성도 가지고 있어 후속연구를 통해 다양한 분야에 적용할 수 있을 것이라 기대된다.

• Composites Research
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• 제27권5호
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• pp.196-200
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• 2014

A novel, simple and totally recyclable method has been developed for the synthesis of nontoxic, biocompatible and biodegradable bio-composite films from soy protein and silk protein. Bio films are defined as flexible films prepared from biological materials such as protein. These materials have potential application in medical and food as a packaging material. Their use depends on various parameters such as mechanical (strength and modulus), thermal, among others. In this study, prepare and characterization of bio films made from Soy Protein Isolate (SPI) (matrix) and Silk Fiber (SF) (reinforcement) through solution casting method by the addition of plasticizer and crosslinking agent. The obtained SPI and SPI/SF composites were subsequently subjected to evaluate their mechanical and thermal properties by using Universal Testing Machine and Thermal Gravimetric Analyzer respectively. The tensile testing showed significant improvements in strength with increasing amount of SF content and the % elongation at break of the composites of the SPI/SF was lower than that of the matrix. Though the interfacial bonding was moderate, the improvement in tensile strength and modulus was attributed to the higher tensile properties of the silk fiber.

• Journal of the Korean Wood Science and Technology
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• 제44권6호
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• pp.852-863
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• 2016

Wood-plastic composite (WPC) is a promising and sustainable material, and refers to a combination of wood and plastic along with some binding (adhesive) materials. In comparison to pure wood material, WPCs are in general have advantages of being cost effective, high durability, moisture resistance, and microbial resistance. The properties of WPCs come directly from the concentration of different components in composite; such as wood flour concentration directly affect mechanical and physical properties of WPCs. In this study, wood powder concentration in WPC was determined by Fourier transform near-infrared (FT-NIR) and Fourier transform infrared (FT-IR) spectroscopy. The reflectance spectra from WPC in both powdered and tableted form with five different concentrations of wood powder were collected and preprocessed to remove noise caused by several factors. To correlate the collected spectra with wood powder concentration, multivariate calibration method of partial least squares (PLS) was applied. During validation with an independent set of samples, good correlations with reference values were demonstrated for both FT-NIR and FT-IR data sets. In addition, high coefficient of determination (${R^2}_p$) and lower standard error of prediction (SEP) was yielded for tableted WPC than powdered WPC. The combination of FT-NIR and FT-IR spectral region was also studied. The results presented here showed that the use of both zones improved the determination accuracy for powdered WPC; however, no improvement in prediction result was achieved for tableted WPCs. The results obtained suggest that these spectroscopic techniques are a useful tool for fast and nondestructive determination of wood concentration in WPCs and have potential to replace conventional methods.

• Advances in nano research
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• 제2권2호
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• pp.111-119
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• 2014

The chemical synthesis of anisotropic defective polyaniline/Ag composite (PANI/Ag) is explored using silver nitrate ($AgNO_3$) as the precursor material. This study provides a simple method for the formation of PANI/Ag nanocomposites at two different aniline concentrations $5{\mu}l$ (PANC5) and $10{\mu}l$ (PANC10). The composite PANC5 exhibits UV-Visible absorption peaks at 436 nm and 670 nm whereas, PANC10 exhibits absorption peaks at 446 nm and 697 nm. This shift is caused by the strong interaction between polyaniline and silver. The characterized FTIR peaks observed at around $3410cm^{-1}$ (PANC5) and $3420cm^{-1}$ (PANC10) was due to the N-H stretching vibrations. The appearance of a broad band instead of a sharp peak can be attributed due to the presence of a high concentration of N-H groups in the nanocomposite. The TEM images show that the sample contains defective spherical, truncated triangular and rod shaped particles. The results showed that the PANI/Ag nanocomposites are composed of nano-sized particles of 43-53 nm that contain Ag domains of 33-37 nm with polymer thickness 5.7-11.2 nm at two different aniline concentrations.

• 한국가구학회지
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• 제25권3호
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• pp.223-232
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• 2014

To make metalized wood composites of 10 different korean wood species, it was tested by Low temperature melting Bi-Sn alloy injection method at high temperature and high pressure condition. Metalized wood composite of each wood species had light ash color, but still maintained its own natural wood grain and wood figures. It was evaluated on coating properties. Furthermore, it also was check on effect of coating as like a changes of main color, wood grain and wood figures. The results of test were following as; a coating properties as like a cold resistance, heat resistance, acid resistance, alkali resistance, durability of abrasion, and cross-cut test was proper on the conditions of the KS standard. And, In aspect of color changes, the metalized wood composites of 10 different korean wood species had a light ash color, but still maintained its own natural wood grain and wood figures. Also, the more weight per gain of alloy is, the more grey background of metalized wood composite is.

• Advanced Composite Materials
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• 제16권4호
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• pp.315-334
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• 2007

In the present study, chopped henequen natural fibers without and with surface modification by electron beam (E-beam) treatment were incorporated into a polypropylene matrix. Prior to composite fabrication, a bundle of raw henequen fibers were treated at various E-beam intensities from 10 kGy to 500 kGy. The effect of E-beam intensity on the interfacial, mechanical and thermal properties of randomly oriented henequen/polypropylene composites with the fiber contents of 40 vol% was investigated focusing on the interfacial shear strength, flexural and tensile properties, dynamic mechanical properties, thermal stability, and fracture behavior. Each characteristic of the material strongly depended on the E-beam intensity irradiated, showing an increasing or decreasing effect. The present study demonstrates that henequen fiber surfaces can be modified successfully with an appropriate dosage of electron beam and use of a low E-beam intensity of 10 kGy results in the improvement of the interfacial properties, flexural properties, tensile properties, dynamic mechanical properties and thermal stability of henequen/polypropylene composites.

• Advanced Composite Materials
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• 제16권4호
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• pp.299-314
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• 2007

In the present study, natural fibers (jute, kenaf and henequen) reinforced thermoplastic (poly(lactic acid) and polypropylene) and thermosetting (unsaturated polyester) matrix composites were well fabricated by a compression molding technique using all chopped natural fibers of about 10 mm long, respectively. Prior to green composite fabrication, natural fiber bundles were surface-treated with tap water by static soaking and dynamic ultrasonication methods, respectively. The interfacial shear strength, flexural properties, and dynamic mechanical properties of each green composite system were investigated by means of single fiber microbonding test, 3-point flexural test, and dynamic mechanical analysis, respectively. The result indicated that the properties of the polymeric resins were significantly improved by incorporating the natural fibers into the resin matrix and also the properties of untreated green composites were further improved by the water treatment done to the natural fibers used. Also, the property improvement of natural fiber-reinforced green composites strongly depended on the treatment method. The interfacial and mechanical results agreed with each other.

• Steel and Composite Structures
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• 제33권2호
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• pp.299-306
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• 2019

The natural fibre composites are termed as bio-composites. They have shown a promising replacement to the current carbon/glass fibre reinforced composites as environmental friendly materials in specific applications. Natural fibre reinforced composites are potential materials for various engineering applications in automobile, railways, building and Aerospace industry. The natural fibre selected to fabricate the composite material is plant-based fibre e.g., sisal fibre. Sisal fibre is a suitable reinforcement for use in composites on account of its low density, high specific strength, and high hardness. Epoxy is a thermosetting polymer which is used as a resin in natural fibre reinforced composites. Hand lay-up technique was used to fabricate the composites by reinforcing sisal fibres into the epoxy matrix. Composites were prepared with the unidirectional alignment of sisal fibres. Test specimens with different fibre orientations were prepared. The fabricated composites were tested for mechanical properties. Impact test, tensile test, flexural test, hardness test, compression test, and thermal test of composites had been conducted to assess its suitability in industrial applications. Scanning electron microscopy (SEM) test revealed the microstructural information of the fractured surface of composites.

• Journal of the Korean Wood Science and Technology
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• 제33권6호통권134호
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• pp.55-62
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• 2005

본 연구는 섬유판 가공 부산물 분말을 충전제로 첨가한 바이오복합재를 제조하여 그 적용가능성을 평가하기 위하여 수행하였다. 섬유판 가공부산물인 고밀도섬유판(high density fiber board, HDF) 부산물 분말을 polyolefin계 고분자인 low-density polyethylene (LDPE)과 polypropylene (PP)에 첨가하여 바이오복합재를 제조하였다. 제조된 바이오복합재를 이용하여 기계적 성질과 가공성을 측정하였다. 이후 각각 목분(wood flour, WF)과 왕겨분말(rice-husk flour, RHF)을 LDPE와 PP에 충전제로 첨가한 바이오복합재와도 그 기계적 성질과 가공성을 비교하였다. HDF 분말-LDPE 바이오복합재와 HDF 분말-PP 바이오복합재의 인장강도 및 충격강도는 각각 목분이나 왕겨분말을 LDPE나 PP에 충전제로 첨가한 바이오복합재와 비슷한 기계적 강도값을 나타내었다. 바이오복합재의 가공성은 토크를 측정하였는데, HDF 분말-LDPE 바이오복합재와 HDF 분말-PP 바이오복합재는 동일한 기질고분자에 목분이나 왕겨분말을 첨가한 바이오복합재보다 낮은 값을 보였다. 또한, HDF 분말-LDPE 바이오복합재 및 HDF 분말-PP 바이오복합재는 HDF 분말의 입자분포와 상관없이 일정한 가공성을 보였다. 따라서 섬유판 가공 부산물이 첨가된 바이오복합재를 현재 바이오복합재 산업에서 이용되고 있는 바이오복합재를 대처하여 적용할 수 있다고 볼 수 있다.

• International Journal of Industrial Entomology and Biomaterials
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• 제26권2호
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• pp.81-88
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• 2013

Wet-spun silk fibers have attracted the attention of many researchers because of 1) the unique properties of silk as a biomaterial, including good biocompatibility and cyto-compatability and 2) the various methods available to control the structure and properties of the fiber. Cellulose nanofibrils (CNFs) have typically been used as a reinforcing material for natural and synthetic polymers. In this study, CNF-embedded silk fibroin (SF) nanocomposite fibers were prepared for the first time. The effects of CNF content on the rheology of the dope solution and the characteristics of wet-spun CNF/SF composite fibers were also examined. A 5% SF formic acid solution that contained no CNFs showed nearly Newtonian fluid behavior, with slight shear thinning. However, after the addition of 1% CNFs, the viscosity of the dope solution increased significantly, and apparent shear thinning was observed. The maximum draw ratio of the CNF/SF composite fibers decreased as the CNF content increased. Interestingly, the crystallinity index for the silk in the CNF/SF fibers was sequentially reduced as the CNF content was increased. This phenomenon may be due to the fact that the CNFs prevent ${\beta}$-sheet crystallization of the SF by elimination of formic acid from the dope solution during the coagulation process. The CNF/SF composite fibers displayed a relatively smooth surface with stripes, at low magnification (${\times}500$). However, a rugged nanoscale surface was observed at high magnification (${\times}10,000$), and the surface roughness increased with the CNF content.