• Macromolecular Research
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• 제10권5호
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• pp.259-265
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• 2002

The cure kinetics of blends of epoxy (DGEBA, diglycidyl ether of bisphenol A)/anhydride resin with polyamide copolymer, poly(dimmer acid-co-alkyl polyamine), were studied using differential scanning calorimetry (DSC) under isothermal condition. On increasing the amount of polyamide copolymer in the blends, the reaction rate was increased and the final cure conversion was decreased. Lower values of final cure conversions in the epoxy/(polyamide copolymer) blends indicate that polyamide hinders the cure reaction between the epoxy and the curing agent. The value of the reaction order, m, for the initial autocatalytic reaction was not affected by blending polyamide copolymer with epoxy resin, and the value was approximately 1.3, whereas the reaction order, n, for the general n-th order of reaction was increased by increasing the amount of polyamide copolymer in the blends, and the value increased from 1.6 to 4.0. A diffusion-controlled reaction was observed as the cure conversion increased and the rate equation was successfully analyzed by incorporating the diffusion control term for the epoxy/anhydride/(polyamide copolymer) blends. Complete miscibility was observed in the uncured blends of epoxy/(polyamide copolymer) up to 120 $^{\circ}C$, but phase separations occurred in the early stages of the curing process at higher temperatures than 120 "C. During the curing process, the cure reaction involving the functional group in polyamide copolymer was detected on a DSC thermogram.gram.

• The Journal of Advanced Prosthodontics
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• 제8권6호
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• pp.504-510
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• 2016

PURPOSE. Polyamide polymers do not provide sufficient bond strength to auto-polymerized resins for repairing fractured denture or replacing dislodged denture teeth. Limited treatment methods have been developed to improve the bond strength between auto-polymerized reline resins and polyamide denture base materials. The objective of the present study was to evaluate the effect of surface modification by acetic acid on surface characteristics and bond strength of reline resin to polyamide denture base. MATERIALS AND METHODS. 84 polyamide specimens were divided into three surface treatment groups (n=28): control (N), silica-coated (S), and acid-treated (A). Two different auto-polymerized reline resins GC and Triplex resins were bonded to the samples (subgroups T and G, respectively, n=14). The specimens were subjected to shear bond strength test after they were stored in distilled water for 1 week and thermo-cycled for 5000 cycles. Data were analyzed with independent t-test, two-way analysis of variance (ANOVA), and Tukey's post hoc multiple comparison test (${\alpha}=.05$). RESULTS. The bond strength values of A and S were significantly higher than those of N (P<.001 for both). However, statistically significant difference was not observed between group A and group S. According to the independent Student's t-test, the shear bond strength values of AT were significantly higher than those of AG (P<.001). CONCLUSION. The surface treatment of polyamide denture base materials with acetic acid may be an efficient and cost-effective method for increasing the shear bond strength to auto-polymerized reline resin.

• The Journal of Advanced Prosthodontics
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• 제7권4호
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• pp.278-287
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• 2015

PURPOSE. The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. RESULTS. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. CONCLUSION. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.

• 유변학
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• 제10권2호
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• pp.57-64
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• 1998

A pultrusion resin impregnation (PRI) die, which has been developed recently in our laboratory, was used to pre-pare various composite system. The continuous fiber reinforced composites of glass fiber/polypropylene(GFPP) and glass fiber/polyamide 6 (GFPA) were first manufactured by means of the PRI die and then cut into chopped pellets of predet-ermined length. These pellets and either virgin or modified thermoplastic resin were melt-mixed by a twin screw extruder to prepare GF/PA/PP and GF/PA/PPMA system. The mechanical properties of these blends were investigated and discussed in terms of their morphological observations. These preliminary results revealed that this new impregnation die could be suc-cessfully applied to produce prepregs suitavle for the final shaping process.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.287-295
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• 2013

PURPOSE. This study investigated the effect of laser parameters and air-abrasion on the peel strength of silicon-based soft denture liner to different denture resins. MATERIALS AND METHODS. Specimens (N=180) were prepared out of three different denture base resins (Rodex, cross-linked denture base acrylic resin; Paladent, heat-cured acrylic resin; Deflex, Polyamide resin) ($75mm{\times}25mm{\times}3mm$). A silicon-based soft denture liner (Molloplast B) was applied to the denture resins after the following conditioning methods: a) Air-abrasion ($50{\mu}m$), b) Er,Cr:YSGG laser (Waterlase MD Turbo, Biolase Technology) at 2 W-20 Hz, c) Er,Cr:YSGG laser at 2 W-30 Hz, d) Er,Cr:YSGG laser at 3 W-20 Hz, e) Er,Cr:YSGG laser at 3 W-30 Hz. Non-conditioned group acted as the control group. Peel test was performed in a universal testing machine. Failure modes were evaluated visually. Data were analyzed using two-way ANOVA and Tukey's test (${\alpha}$=.05). RESULTS. Denture liner tested showed increased peel strength after laser treatment with different parameters ($3.9{\pm}0.4-5.58{\pm}0.6$ MPa) compared to the control ($3.64{\pm}0.5-4.58{\pm}0.5$ MPa) and air-abraded groups ($3.1{\pm}0.6-4.46{\pm}0.3$ MPa), but the results were not statistically significant except for Paladent, with the pretreatment of Er,Cr:YSGG laser at 3 W-20 Hz. Polyamide resin after air-abrasion showed significantly lower peel strength than those of other groups ($3.1{\pm}0.6$ MPa). CONCLUSION. Heat-cured acrylic resin, PMMA, may benefit from Er,Cr:YSGG laser treatment at 3 W-20 Hz irradiation. Air-abrasion of polyamide resins should be avoided not to impair their peel bond strengths to silicon-based soft denture liners.

• 공업화학
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• 제7권1호
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• pp.194-202
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• 1996

기존의 ethylene-vinyl acetate 핫멜트 접착제는 시간에 따른 크리프 특성과 내열성 등의 한계로 사용에 제한이 있으므로 물성의 향상을 위해 폴리아미드계 수지를 이용한 새로운 핫멜트 접착제 개발에 관하여 연구하였다. 폴리아미드 단일중합체의 경우 융점과 용융점도가 매우 높기 때문에 대신 나일론6, 나일론66, 나일론12로 이루어진 삼원공중합체 혹은 블렌딩 수지를 사용하므로써 분자쇄의 규칙성 파괴로 인해 용융점도와 용융점을 강하시킬 수 있었다. 이로써 선택된 수지가 핫멜트 접착제의 베이스 수지로 적절함을 알 수 있었다. 또한 베이스 수지에 테르펜 수지, butyl benzyl phthalate, 파라핀왁스 등을 첨가하여 접착제를 구성함에 따라 유변학적 거동도 쉽게 조절될 수 있었다. 용융점도와 접착제 자체의 인장물성 결과에 따르면 사용된 CM831과 843형 폴리아미드 수지를 약 75/25~50/50의 무게비로 블렌딩함이 최적의 접착력을 나타내리라 평가되었다. 또한 steel간의 접착력 평가 결과 steel 표면의 거칠음 정도가 접착력에 직접 영향을 미치는 결과를 얻었다.

• 공업화학
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• 제16권6호
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• pp.827-833
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• 2005

본 연구에서는 폴리아미드계 수지를 이용하여 최적의 핫멜트 접착제 배합설계를 접착제 합성, 물성평가 및 철에 대한 접착력 평가를 통해 구축하고자 하였다. 최적 배합설계를 위해 앞선 연구결과에 따라 CM831과 843P의 기본 수지에 점착부여수지로 테르펜수지의 무게비를 각각 75/25/10으로 고정한 후 왁스, 충전제 등이 사용되었으며 이들의 종류와 첨가량이 접착제의 흐름 특성과 접착력에 미치는 영향을 조사하였다. 결과에 따르면 왁스의 경우 폴리에틸렌 왁스의 첨가량이 증가함에 따라 용융점도는 다소 감소하였지만 철과의 최적 접착력은 5 wt%에서 나타났다. 이는 접착제 자체의 기계적 물성과 밀접한 관계가 있음을 알 수 있었다. 충전제의 경우는 탈크가 10 wt% 첨가되었을 때 다소 높은 용융점도에 비해 우수한 접착성능을 나타내었다.

• 한국응용과학기술학회지
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• 제19권2호
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• pp.117-122
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• 2002

A silicone softner (SS-5), a permanent press (PP) finish, was prepared by blending silicone oil KF-96 (as a lubricating component) and beef tallow hardened oil (as a softening component) which was synthesized from fatty polyamide salts. The prepared SS-5 and the PP finishing resin were applied to PP finishing cotton cloth and P/C gingham sample by one-bath method. The properties such as crease recovery, tear strength, and bending resistance were tested. The samples treated with SS-5 and PP finishing resin showed improved properties when comparing with the untreated ones, with the ones treated only with PP finishing resin, with ones treated with commercial PP finishing softners and PP finishing resin. The grades of fabric samples treated with 3% SS-5 were fifth grade in the bending resistance test.

• 한국식품과학회지
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• 제31권1호
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• pp.30-35
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• 1999

기존의 PC나 TLC에 의한 타르색소의 정성은 많은 시간이 소요되고 회수율이 낮아 혼합색소의 경우 주 색소만이 검출되는 단점이 있고, 많은 표준용액이 동시에 전개되어질 수 없다는 단점이 있어 분 실험에서는 Polyamide와 Photodiode array 검출기가 장착된 HPLC를 이용하여 타르색소의 추출, 정제 및 정량을 여러 각도로 검토하여 정량분석의 최적 조건을 확립하였다. 검출 파장은 각 타르색소마다 고유의 최대흡수부가 있으나 동시분석을 위해서는 254 nm의 파장에서 가장 광범위한 타르색소의 검출이 가능하였으며 적색 계통은 $520{\sim}540\;nm$, 청색이나 녹색계통은 620 nm에서 최소검출한계가 낮음을 알 수 있었다. 따라서 타르색소의 분석에는 photodiode array detector가 장착된 HPLC를 이용함으로써 220 nm에서 800 nm까지의 넓은 영역의 파장에 걸쳐 일시에 분석하므로서 시간 절약과 함께 타르색소 피크마다 3차원 스펙트럼을 제공함으로서 실험의 정확도를 높일 수 있었다. 한편 Polyamide column을 사용하였을 때의 회수율을 측정한 결과 청색 1호가 가장 낮은 94.4%를 보였으며, 전체적으로 100% 부근의 아주 높은 만족할만한 회수율을 얻었다. 타르색소를 사용한 국내산 빙과류, 캔디류, 청량음료류를 시료로 하여 타르색소의 정량을 시도한 결과 허용의 타르색소는 검출되지 않았으며, 주로 적색 계통의 적색 2호와 40호가, 황색계통의 황색 4호, 5호가 많이 사용되고 있음을 알 수 있었고 타르색소의 사용량도 200 ppm을 초과하는 것은 발견되지 않았다. 한편 녹색은 황색 4호에 청색 1호를, 보라색은 적색과 청색을 혼합한 혼합색소를 사용되어지고 있는 것을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.235-238
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• 2003

Thermo-plastic has generally bad electrical characteristics at high temperature comparing to thermoset-plastics when the plastic apply to electrical power apparatus as an electrical insulator. To solve the problem, we study engineering plastics such as Polyamide and Polyphthalamide as a base resin. And filler of the engineering plastics is glass fiber. Electrical characteristics studied are permittivity, loss factor and breakdown strength according to temperature and frequency of measuring signal. Electrical characteristics of Polyphthalamide has good temperature and frequency dependency comparing to those of Polyamide.