• Elastomers and Composites
• /
• 제50권3호
• /
• pp.205-209
• /
• 2015

Magnesium oxide (MgO) reinforced polyamide-66 (PA66) composites were prepared through melt-compounding method in order to determine the possibility of using MgO particle as conductive filler in the polymer-based composite. The effects of MgO filler content on the thermal conductivity and mechanical properties for the PA66/MgO composites were investigated. The results showed that the addition of MgO filler to the PA66 matrix led to a large increase in thermal conductivity of the PA66/MgO composites. Tensile strengths of the PA66/MgO composites were slightly decreased as MgO filler loading increased. However, flexural strength and flexural modulus were improved with increasing filler loading. Notched Izod impact strengths were dramatically lowered by the addition of MgO filler.

• Tribology and Lubricants
• /
• 제35권1호
• /
• pp.1-8
• /
• 2019

Demand for plastic gears are increasing in many industries due to their low production cost, light weight, applicability without lubricant, corrosion resistance and high resilience. Despite these benefits, utilizing plastic gears is limited due to their poor material properties. In this work, DLC coating was applied to improve the tribological properties of polyamide66 gear. 0 V, 40 V, and 70 V of negative bias voltages were selected as a deposition parameter in DC magnetron sputtering system. Pin-on-disk experiment was performed in order to investigate the wear characteristics of the gears. The results of the pin-on-disk experiment showed that DLC coated polyamide66 with 40 V of negative bias voltage had the lowest friction coefficient value (0.134) and DLC coated PA66 with 0 V of negative bias voltage showed the best wear resistance ($9.83{\times}10^{-10}mm^3/N{\cdot}mm$) among all the specimens. Based on these results, durability tests were conducted for DLC coated polyamide66 gears with 0 V of negative bias voltage. The tests showed that the temperature of the uncoated polyamide66 gear increased to about $37^{\circ}C$ while the DLC coated gear saturated at about $25^{\circ}C$. Also, the power transmission efficiency of the DLC coated gear increased by about 6% compared to those without coating. Weight loss of the polyamide66 gears were reduced by about 73%.

• Elastomers and Composites
• /
• 제55권1호
• /
• pp.1-5
• /
• 2020

This study examined the effects of the addition of maleic anhydride-grafted polypropylene (PP-g-MA) and polyolefin elastomer (POE) on polyamide 66 (PA66) and polypropylene (PP) blends. The blends of PA66/PP with PP-g-MA and POE were prepared using a twin screw extruder. Mechanical testing results revealed that the tensile, flexural, and izod impact strengths of the blends were maximized at a PP-g-MA content of 2 phr. The increased mechanical strength of the blends with PP-g-MA was attributed to the compatibilizing effect of the PA66 and PP blends. In addition, as the POE content increased, the impact strength of the blends increased. However, at a high POE content, the tensile and flexural strengths decreased, seemingly because of the lower mechanical properties of POE.

• 한국안광학회지
• /
• 제18권4호
• /
• pp.365-371
• /
• 2013

목적: 본 연구에서는 사출형 안경테 소재로 사용되고 있는 폴리아미드-12 수지인 TR-90을 대체하기 위하여 폴리아미드-66에 유리섬유(glass fiber)를 함량별로 블렌드하여 각 조성물의 물리적, 열적 특성을 평가하여 안경테로써의 적용 가능성을 검토하였다. 방법: 유리섬유의 함량 변화에 따른 폴리아미드-66 조성물의 특성변화를 고찰하기 위해 이축압출기를 이용하여 함량별 조성물을 제조하였다. 제조된 조성물의 기계적강도, 열적 특성, 코팅성 및 절삭가공성을 평가하였다. 이를 통하여 기존 TR 안경테 제품과의 성능 비교 및 안경테로써 적용 가능성을 평가하였다. 결과: 폴리아미드-66/유리섬유 조성물의 특성 평가 결과, 유리섬유의 함량이 증가할수록 성형수축율이 감소하며, 기계적 강도가 증가하는 것으로 나타났다. 유리섬유의 함량이 0 wt%인 경우 인장강도는 $498kg/cm^2$에서 30 wt%가 함유된 경우 $849kg/cm^2$까지 증가하였다. 코팅성 평가 결과 유리섬유 5 wt%에서는 코팅강도가 4 B였고, 그 이상에서는 5 B로 매우 우수한 코팅 특성을 나타내었다. 결론: 30 wt%의 유리섬유가 블렌드된 경우 기계적 강도가 크게 향상되나 이와 더불어 경도가 상승되며, 점도가 증가하여 사출온도가 높아지며, 제품에 플로우 마크가 생기는 것으로 나타났다. 유리섬유가 블렌드된 폴리아미드-66의 도료 코팅성은 모두 우수하였다. 전반적으로 물성 및 가공성 등을 평가해볼 때, 유리섬유의 함량이 약 10 wt% 내외의 경우 안경테로써의 적용이 가능하다고 판단된다.

• Elastomers and Composites
• /
• 제52권1호
• /
• pp.1-8
• /
• 2017

Hydrolysis resistance and mechanical property changes of polyketone (POK)/glass fiber (GF) composites were investigated for GF concentrations varying between 30 and 50%. The hydrolysis resistance of GF filled POK and polyamide66 (PA66, hydrolysis resistant grade) composites were compared. As shown by the experimental results, increasing the immersion time of the composites in a monoethylene glycol (MEG)/water solution at $120^{\circ}C$ had no impact or resulted in slightly decreased mechanical properties such as the tensile strength, tensile modulus, and strain at break in case of POK composites, whereas the mechanical properties of PA66 composites showed a significant drop. Increasing GF concentrations increased the tensile strength, tensile modulus, flexural strength, and flexural modulus of POK composites; however, impact strength did not show significant changes. Hydrolysis mechanisms of POK and PA66 are discussed.

• 방사선산업학회지
• /
• 제5권1호
• /
• pp.69-73
• /
• 2011

Polyamide 66 (PA66) nanofibers with Triallyl cyanurate (TAC) were obtained by electrospinning of formic acid and chloroform solution. Electron beam irradiation of PA66 nanofiber with and without TAC was carried out over a range of absorbed doses (20~100 kGy) in nitrogen. The characterization of the irradiated PA66 nanofibers and PA66 nanofibers with TAC was done by scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and universal testing machine (UTM). The results of the SEM image analysis confirmed that the morphology of PA66 nanofibers was not altered by electron beam. The amount of TAC in PA66 nanofiber with TAC was identified by $^1H-NMR$ analysis. The degradation temperature of PA66 nanofibers with TAC at an absorbed dose of 20~100 kGy was higher than the irradiated PA66 nanofiber without TAC. On the other hand, the decreasing rate of modulus of irradiated PA66 nanofibers with TAC was less than PA66 nanofibers.

• 폴리머
• /
• 제30권5호
• /
• pp.391-396
• /
• 2006

플라스마 표면처리는 접착력, 친수성, 소수성 등과 같은 고분자의 표면 특성을 개질시키기 위하여 사용되고 있다. 플라스마를 이용하여 표면을 처리하게 되면 고분자의 전체적인 물성은 유지한 채 표면의 특성만을 변화시키는 장점을 가지고 있다. 본 연구에서는 다양한 가스를 사용한 플라스마를 이용하여 상업용 Polyarlide66 (PA66) /polyphenylene(PPE) 고분자의 표면의 접착력 향상을 위해 표면 유기물 제거와 친수성으로 개질을 시도하였다. 플라스마 처리 공정 변수인 공정 파워, 처리 시간, 가스 종 들을 변화시키면서 표면을 개질하였으며 PASS/ PPE 고분자의 친수성 개질을 확인하기 위하여 접촉각 및 표면 자유에너지 변화를 측정하였다. 또한 유기물 제거를 FTIR 분석을 통하여 확인하였다. 플라스마를 이용한 표면처리 결과, 공정 파워 100 W, 처리 시간 2분, 아르곤/산소 공정가스에서 가장 낮은 접촉각(73도에서 14도)과 가장 높은 표면 자유에너지 ($44.20 mJ/m^2$에서 $50.03 mJ/m^2$)를 나타내었다.

• Elastomers and Composites
• /
• 제56권2호
• /
• pp.65-71
• /
• 2021

In recent times, the demand for electronic devices has increased because of advancements in the electronics industry. Consequently, research on shielding against electromagnetic interference (EMI) from electronic devices has also progressed significantly. In particular, research on imparting electrical conductivity to plastic has seen substantial progress. In this study, the effect of hybrid fillers comprising carbon fiber (CF) and carbon nanotubes (CNTs) on the electrical properties of polyamide 66 (PA66) composites was investigated. PA66 composites were prepared using a BUSS Co-Kneader single-screw extruder. EMI shielding effectiveness (SE) increased with the increasing addition of unsized CF (UCF), sized CF (SCF), and CNTs. For the PA66/SCF/CNT hybrid filler composites, EMI SE significantly increased with the increase in SCF content. Finally, the hybrid filler comprising SCF and CNTs may have a synergistic effect on the EMI SE and surface resistivity of PA66/SCF/CNT composites.

• Elastomers and Composites
• /
• 제38권3호
• /
• pp.262-272
• /
• 2003

말레인산 무수물을 그라프트시킨 폴리프로필렌(PP-g-MA)을 폴리아마이드 66(PA 66)/PP-g-MA 이원 블렌드 및 PA 66/polypropylene(PP)/PP-g-MA 삼원블렌드에 한 성분 및 상용화제로 각각 사용하였다. 본 연구는 이원 및 삼원블렌드 사이의 여러가지 물성의 차이를 조사하는 것이다. 평가된 물성으로는 인장강도, 굴곡탄성율. 열변형온도, 충격강도, 용융흐름지수 그리고 전단속도 증가에 따른 점도변화가 포함된다. 이원 블렌드의 충격강도는 모든 조성에서 삼원 블렌드 보다 우수하였는데 이는 PA 66 말단의 아민 그룹과 PP-g-MA의 산 무수물이 반응하여 이미드(imide) 그룹이 형성되어 PP-g-PA 66 공중합체의 합성이 분자량을 증가시키고 이 반응이 삼원 블렌드에서 보다 이원 블렌드에 더 많이 일어나는 것에 기인하는 것이다. 삼원 블렌드계의 경우 대부분의 물성이 이원 블렌드 보다 우수하였는데 이는 PP의 물성이 PP-g-MA의 물성보다 우수하기 때문이다. 충격에 매우 강한 70/30(PA 66/pp-g-MA) 및 80/20 조성의 이원 블렌드는 가공성이 나빠 상업적 응용에는 불리하다. 따라서, 상업적 응용에는 낮은 용융점도를 보이는 삼원 블렌드를 사용하는 것이 추천된다.

• Bulletin of the Korean Chemical Society
• /
• 제28권12호
• /
• pp.2354-2358
• /
• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.