염지 온도와 기간이 삶은 돼지고기 등심의 이화학적 특성과 기호성에 미치는 영향

현재석,강희곤,김미숙,정인철,문윤희 한국축산식품학회 2003 한국축산식품학회지 Vol.23 No.1

식염농도 7%의 염지액을 이용하여 돼지고기 등심을 염지할 때에 염지온도와 기간이 염지육의 이화학적 특성과 기호성에 미치는 영향을 검토하였다. 열지온도 1$0^{\circ}C$에서 15일째에 염지육의 pH와 보수력이 현저히 저하되었다. 염지온도 1$0^{\circ}C$에서 염지액과 염지육 표면부위의 일반세균수는 12째에 현저히 많아졌으나 중심부위는 거의 검출되지 않았다. 임시 온도가 높을수록 염지기간에 관계없이 식염 침투가 빠르고 염지육 식염함량이 많아졌으며, 표면부위에 대한 중심분위의 식염함량 비율은 염지기간이 길수록 크게 나타났다. 염지육의 식염함량은 가열에 의하여 적어졌다. 염지 가열육의 짠맛과 풍미는 염지 초기에는 높은 온도에서, 후기에는 낮은 온도에서 우수하였다. 열지 가열육은 1$^{\circ}C$에서 12일, 5$^{\circ}C$에서 9일 염지하여 제조하면 기호성이 우수하였다. The effects of curing temperatures(1, 5 and 10$^{\circ}C$) and times on the chemical properties and palatability of cured pork loins which were cured in the 7% curing solution were investigated. The pork loins cured at 10$^{\circ}C$ curing temperature showed the decreased level of pH and water holding capacity up to 15 days of curing time. The growth of bacteria in the curing solution and surface region of cured loins, cured at 10$^{\circ}C$ were rapid after 12 days of curing. However, bacteria were not detected(<0.05${\times}$10$^2$ CFU/g) in the central region of cured loin until 15 days of curing. The penetration of salt into the central region of cured loins was faster at 10$^{\circ}C$ curing temperature than at lower curing temperatures for all curing times. The difference of salt contents between surface and central regions in the cured loins was less at higher temperature than at lower temperatures, and the difference decreased in boiling process for all curing times. The color fixation of the cured boiled loins was better at 5 and 10$^{\circ}C$ curing temperatures than at 1$^{\circ}C$. The sensory scores for saltiness and flavor of the cured boiled pork loins were higher at higher temperature than at lower temperatures until 9∼12 days of curing. Palatable cured boiled pork loins could be produced under the curing solution at low temperatures of 1 and 5$^{\circ}C$ for 12 and 9 days, respectively.

The epoxy resin system: function and role of curing agents

Aziz Tariq,Haq Fazal,Farid Arshad,Cheng Li,Chuah Lai Fatt,Bokhari Awais,Mubashir Muhammad,Tang Doris Ying Ying,Show Pau Loke 한국탄소학회 2024 Carbon Letters Vol.34 No.1

Curing agents are critical components of aqueous epoxy resin systems. Unfortunately, its uses and applications are restricted because of its low emulsifying yields. Epoxy resins are frequently used in electrical devices, castings, packaging, adhesive, corrosion resistance, and dip coating. In the presence of curing agents, epoxy resins become rigid and infusible. Eco-friendliness and mechanical functionality have emerged as vulcanization properties. Curing agents are used for surface modification, thermodynamic properties, functional approaches to therapeutic procedures, and recent advances in a variety of fields such as commercial and industrial levels. The curing agent has superior construction and mechanical properties when compared to the commercial one, which suggests that it has the potential for use as the architectural and industrial coatings. The thermal stability of cured products is good due to the presence of the imide group and the hydrogenated phenanthrene ring structure. Over the course of the projection period, it is anticipated that the global market for curing agents will continue to expand at a steady rate. The growth of the market is mainly driven by its expanding range in future applications such as adhesives, composites, construction, electrical, electronics, and wind energy. This review focused on the most recent advancements in curing techniques, emphasizing their thermal and mechanical properties. The review also presents a critical discussion of key aspects and bottleneck or research gap of the application of curing agents in the industrial areas. Similar content being viewed by others Curing agents are critical components of aqueous epoxy resin systems. Unfortunately, its uses and applications are restricted because of its low emulsifying yields. Epoxy resins are frequently used in electrical devices, castings, packaging, adhesive, corrosion resistance, and dip coating. In the presence of curing agents, epoxy resins become rigid and infusible. Eco-friendliness and mechanical functionality have emerged as vulcanization properties. Curing agents are used for surface modification, thermodynamic properties, functional approaches to therapeutic procedures, and recent advances in a variety of fields such as commercial and industrial levels. The curing agent has superior construction and mechanical properties when compared to the commercial one, which suggests that it has the potential for use as the architectural and industrial coatings. The thermal stability of cured products is good due to the presence of the imide group and the hydrogenated phenanthrene ring structure. Over the course of the projection period, it is anticipated that the global market for curing agents will continue to expand at a steady rate. The growth of the market is mainly driven by its expanding range in future applications such as adhesives, composites, construction, electrical, electronics, and wind energy. This review focused on the most recent advancements in curing techniques, emphasizing their thermal and mechanical properties. The review also presents a critical discussion of key aspects and bottleneck or research gap of the application of curing agents in the industrial areas. Similar content being viewed by others

황색종 Bulk건조시 송풍량 조절에 따른 건조엽의 물리성 변화

이철환,진정의,한철수 한국연초학회 1999 한국연초학회지 Vol.21 No.1

In recent years, the line of increase in policy on tobacco production triggered a rise in the loading volume per bulk curing barn, and manufacturers boosted the output of their blowers in order to prevent dirty leaves in the process of curing. for this reason, we studied the effect of the reducing air flow in bulk curing chamber from the color fixing stage to the stem drying stage of flue curing process on physical properties of cured leaves. The control of air flow was composed of the reducing air velocity of blower by means of a voltage regulator (slidac), and condition before color fixing stage was all the same with the conventional curing method. As a result, an effectiveness of improvement in the physical properties of cured leaves were observed. The leaves cured by this method were somewhat orange in color of upper stalk position, better bodied, and less brittle compared with the leaves produced by conventional curing. However, the leaves cured by this method had a little sharpness and harshness. As to the physical properties, there was decreased in occurrence of flat leaves than that of conventional ones. On the other hand, in case of reducing air flow during the curing process, increase of price per kg reached to about 5 % compared with those of conventional curing method.

Thermal Curing Behavior and Tensile Properties of Resole Phenol-Formaldehyde Resin/Clay/Cellulose Nanocomposite

Byung Dae Park,John F. Kadla 한국목재공학회 2012 목재공학 Vol.40 No.2

This study investigated the effects of layered clay on the thermal curing behavior and tensile properties of resole phenol-formaldehyde (PF) resin/clay/cellulose nanocomposites. The thermal curing behavior of the nanocomposite was characterized using conventional differential scanning calorimetry (DSC) and temperature modulated (TMDSC). The addition of clay was found to accelerate resin curing, as measured by peak temperature (Ta) and heat of reaction (AR) of the nanocomposite` curing reaction increasing clay addition decreased T with a minimum at 3-5% clay. However, the reversing heat flow and heat capacity showed that the clay addition up to 3% delayed the vitrification process of the resole PF resin in the nanocomposite, indicating an inhibition effect of the clay on curing in the later stages of the reaction. Three different methods were employed to determineactivation energies for the curing reaction of the nanocomposite. Both the Ozawa and Kissinger methods showed the lowest activation energy (K) at 3% clay content. Using the isoconversional method, the activation energy (K2) as a fttnction of the degree of conversion was measured and showed that as the degree of cure increased, the K2 showed a gradual decrease, and gave the lowest value at 3% nanoclay. The addition of clay improved the tensile strengths of the nanocomposites, although a slight decrease in the elongation at break was observed as the clay content increased, These results dcmonstrated that the addition of clay to resole PF resins accelerate the curing behavior of the nanocomposites with an optimum level of 3% clay based on the balance between the cure kinetics and tensile properties.

Preparation and Properties of the Fast-Curing γ-Ray-Shielding Materials Based on Polyurethane

Minxuan Ni,Xiaobin Tang,Hao Chai,Yun Zhang,Tuo Chen,Da Chen 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.6

In this study, fast-curing shielding materials were prepared with a two-component polyurethane matrix and a filler material of PbO through a one-step, laboratory-scale method. With an increase in the filler content, viscosity increased. However, the two components showed a small difference. Curing time decreased as the filler content increased. The minimum tack-free time of 27 s was obtained at a filler content of 70 wt%. Tensile strength and compressive strength initially increased and then decreased as the filler content increased. Even when the filler content reached 60 wt%, mechanical properties were still greater than those of the matrix. Cohesional strength decreased as the filler content increased. However, cohesional strength was still greater than 100 kPa at a filler content of 60 wt%. The γ-ray-shielding properties increased with the increase in the filler content, and composite thickness could be increased to improve the shielding performance when the energy of γ-rays was high. When the filler content was 60 wt%, the composite showed excellent comprehensive properties.

전자빔 조사에 의한 불포화 폴리에스터 수지 상온 경화물의 후경화

박상원(Sang-won Park),이병민(Byoung-Min Lee),권다솔(Da-Sol Kwon),최재학(Jae-Hak Choi) 한국고분자학회 2018 폴리머 Vol.42 No.5

불포화 폴리에스터 수지(unsaturated polyester resin, UPR)는 일반적으로 경화제 및 경화 촉진제의 산화-환원 반응을 이용한 상온 경화법이 사용되고 있으나, 상온 경화만으로는 최대 물성값을 단시간 내 구현하는 것이 어려워 적절한 후경화를 필요로 한다. 본 연구에서는 전자빔 조사를 이용한 UPR 상온 경화물의 후경화를 진행하였으며, 열에 의하여 후경화된 샘플과 물성을 비교하였다. 실험 결과, 전자빔 흡수선량이 증가함에 따라 UPR 상온 경화물의 물성이 향상됨을 확인할 수 있었으며, 기존 열경화 방법과 동일한 수준의 물성을 얻을 수 있음을 확인하였다. 따라서 전자빔 경화 방법은 기존 열경화 방법을 대체하여 UPR 제품의 대량 생산에 적용될 수 있을 것으로 판단된다. Unsaturated polyester resin (UPR) is generally cured by room temperature curing method using oxidationreduction reaction between curing agents and accelerators. However, it is difficult to realize the maximum physical properties within a short time only by room temperature curing process. Therefore, post-curing process should be carried out to improve physical properties. In this study, post-curing of room temperature-cured UPR was carried out by electron beam irradiation and the physical properties of the post-cured samples were compared with those of thermally post-cured samples. As a result, the physical properties of room temperature-cured UPR were increased with an increasing electron beam absorbed dose and were comparable to those of thermally post-cured UPR samples. Thus, electron beam curing method can be applied to the mass production of UPR-based products instead of conventional thermal curing method.

가류제와 가류온도에 따른 가류물 물성 효과

박병호 ( Byuog Ho Park ),고진환 ( Jid Hwan Go ) 조선대학교 공학기술연구원 2012 공학기술논문지 Vol.5 No.3

The push for increased productivity in the tire industry was obtained by raising cure temperatures. Conventional Vulcanization (CV) was widely used for NR based tread compounds which showed a good failure property and fatigue property. although exhibited problems again t blowout, reversion and aging properties under the conditions of high temperature and loads. CV cure system consist of high sulfur and low accelerator cure system in NR based compound that exhibited high reversion rate and low blow out properties etc. Heat build-up (HBU) and wear characteristics were showed large difference along with varying cure systems under conditions of similar modulus. KA-9188 imparts excellent reversion properties and blow-out performance without falling tensile properties and process characteristics. These results suggested that CV system might be replaced with hybrid cure system in the tire industry.

Pentaerytritol Triacrylate를 이용한 광경화용 6관능 우레탄 아크릴레이트 합성과 경화필름 물성에 관한 연구

문병준(Byoung Joon Moon),황석호(Seok Ho Hwang) 한국고분자학회 2011 폴리머 Vol.35 No.2

수산기를 함유한 3관능 아크릴레이트(PETA; pentaerytritol triacrylate)를 pentaerytritol과 acrylic acid의 축 합반응으로 합성하였다. 최적반응 조건이 용매로 heptane이 사용되고 pentaerytritol과 acrylic acid의 몰비가 1:4일 때, 최고수율의 3관능 아크릴레이트를 얻을 수 있었다. 그 후, 다양한 디이소시아네이트와 PETA간 축합반응을 통해 여러가지 6관능 우레탄 아크릴레이트(UA)를 합성하였다. 합성된 우레탄 아크릴레이트는 반응형 희석제를 광개시제와 함께 자외선 광경화한 후, 형성된 경화필름의 물성을 측정하였다. 방향족 벤젠고리를 포함하고 있는 우레탄 아크릴레이트는 지방족 분자를 포함하고 있는 우레탄 아크릴레이트에 비해 내후성이 취약하였으며, UA-2의 경우 연필경도 및 내스크레치성이 가장 우수하였고, 경화도가 가장 우수하였던 UA-1의 경우 내약품성이 가장 우수하였다. 밀착성의 경우 모든 조성에서 우수한 결과를 얻었으며, 경화도가 가장 낮은 UA-3의 경우 물리적 특성이 가장 낮았다. Pentaerytritol triacrylate (PETA) was synthesized by a condensation reaction between pentaerytritol and acrylic acid. The highest yield of PETA was obtained when heptane was used as a solvent under the 1:4 mole ratio of pentaerytritol and acrylic acid. The 6-functional urethane acrylates (UA) were also synthesized by a condensation reaction between PETA and diisocyanate. Cured films were prepared from the mixtures of UA oligomer, reactive diluents and UV initiator to investigate their physical properties. The thermal stability of the aliphatic urethane acrylate was better than that of the aromatic urethane acrylate. The UA-2 showed good hardness and scratch resistance properties while the UA-1 with a high degree of curing density exhibited a better chemical resistance. All the UA oligomers showed fairly good adhesion strengths but the other physical properties of UA-3 were poor due to its low curing density.

열기계적 분석법으로 측정된 레진 포뮬레이션의 경화 수축 특성

서안나 ( Ahn Na Seo ),이종현 ( Jong Hyun Lee ) 대한금속재료학회(구 대한금속학회) 2012 대한금속·재료학회지 Vol.50 No.9

Volume shrinkage behavior accompanying the cure of resin formulations might be a critical factor when assembly processes using polymer materials are considered. In this study, cure shrinkage behavior with respect to resin formulation type and heating method was measured on sandwich structure samples by a thermomechanical analyzer (TMA). Quartz, used as a cover material for the sandwich structure, indicated the coefficient of thermal expansion close to 0 ppm/℃. When a dynamic heating mode was conducted, a squeezeout region and a cross-linking region for each resin formulation could be separated clearly with overlapping differential scanning calorimeter results on the TMA results. In addition, a cure shrinkage dominant region and a thermal expansion dominant region in the cross-linking region were distinguished. Consequently, the degree of cure at the initiation of the thermal expansion dominant region was successfully measured. Measurement of all resin formulations indicated the thermal expansion behavior exceeded cure shrinkage before full cure.

Butyl고무와 EPDM고무 블렌드의 경화특성, 물리적 성질 및 내오존성

박찬영 ( Chan Young Park ),황영배 ( Young Bea Hwang ) 한국고무학회 2011 엘라스토머 및 콤포지트 Vol.46 No.4

일반적으로 butyl 고무(IIR : isobutylene isoprene rubber)는 우수한 내기체투과성 및 저반발 탄성체로서 우수한 충격흡수성을 갖는다. 본 실험에서는 butyl고무에 EPDM(ethylene propylene diene monomer)을 기계적 혼련법으로 blend 혼련물을 제조하여 이들의 가교 거동, 물리적 성질 및 내오존성 등을 측정하였다. EPDM 고무량이 증가할수록 최적 가황시간이 단축되는 경향을 보였다. 기체투과속도 테스트에 의한 내기체투과성 측정 결과 butyl고무량이 50 wt% 이상일 경우에는 기체투과도가 현저히 감소하였다. 한편 butyl rubber/EPDM 블렌드의 경우에 EPDM의 함량이 25 wt.% 이상 함유될 경우 내오존성이 향상되어 50 pphm, 50 ℃, 120시간 조건에서도 아무런 표면변화가 없었다. In general, butyl rubber(IIR : isobutylene isoprene rubber) has excellent gas permeability resistance and impact absorbance property as low resilience elastomer. In this experiment butyl rubber blends with EPDM(ethylene propylene diene monomer) were prepared by mechanical mixing method. Curing behavior, physical properties and ozone resistance etc. were subsequently examined. Measurement results of gas transmission rate test shows that butyl rubber contents above 50 wt% showed significant decrease in gas permeability resistant property. However, in butyl rubber/EPDM blend, EPDM contents above 25 wt% indicates no surface change due to improvement of ozone resistance under the condition of 50 pphm, 50 ℃, 120 hrs.