• 한국염색가공학회지
• /
• 제20권2호
• /
• pp.29-37
• /
• 2008

Polar amino groups of the waste SS(silk-sericin) were modified by two isocyanate compounds of MOI[2-(methacryloyloxy)ethyl isocyanate] and AOI [2-(acryloyloxy)ethyl isocyanate]. When the MOISS (MOI-modified silk sericin) or AOISS(AOI-modified silk sericin) was pressed hot, vinyl groups in the MOI or AOI were polymerized and then the flexible and transparent films were obtained. Tensile moduli and strengths of the MOISS films were significantly improved as the MOI contents increased. By the addition of the isocyanate compounds, silk sericin films exhibited lower solubility to the distilled water($80^{\circ}C$) and also lower swell ratio to the distilled water(room temperature). In the effect of tensile properties and restraining the water swelling, MOI was better than AOI. BOD(biochemical oxygen demand)/TOD(theoretical oxygen demand) of the pure sericin film was almost 100% perfect level after 10 days immersion into the activated sludge. With increasing isocyanate content reacted with polar amino groups, BOD/TOD decreased. When more than 50 mol% of polar amino groups remained unreacted, sericin films could retain more biodegradability. Comparing with MOI from the viewpoint of biodegradability, AOI was more effective.

• Elastomers and Composites
• /
• 제52권2호
• /
• pp.105-113
• /
• 2017

The curing behavior, mechanical properties, hot-air aging resistance, abrasion properties,thermal properties, etc., of EVM/EPM/APP (ammonium polyphosphate)/DPER (dipentaerythritol)/EG (expandable graphite) and EVM/EPM/ATH (aluminium trihydroxide) flame retarding systems in ethylene vinyl acetate rubber (EVM) blends with EPM (ethylene propylene rubber) were sequentially examined. For both flame retarding systems, the torque values increased with the content of EPM rubber and with the vulcanization time. As the content of EPM rubber increased, the scorch time became shorter, whereas the optimum cure time followed an increasing trend. For the EVM/EPM/APP/DPER/EG flameretarding system, as the content of EPM rubber increased, the hardness did not change,whereas the tensile strength and elongation at break decreased. A hot-air aging resistance test at $150^{\circ}C$ showed that the heat resistance decreased with the EPM content regardless of the kinds and contents of flame retardants. As the EPM content increased, the abrasion rate became higher and the abrasion resistance of the EVM/EPM/APP/DPER/EG flame retarding systems exceeded that of the EVM/EPM/ATH flame retarding counterparts. In comparison with the EVM/EPM/ATH flame retarding systems, the thermal stability of the EVM/EPM/APP/DPER/EG flame retarding system showed an increasing tendency.

• 한국응용과학기술학회지
• /
• 제26권3호
• /
• pp.288-296
• /
• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• 한국농공학회논문집
• /
• 제57권4호
• /
• pp.11-19
• /
• 2015

The important properties of EVA (ethylene vinyl acetate) redispersible polymer was waterproof, densification of internal pore space of concrete and ball bearing and micro filler. Also, the significant role of polypropylene(PP) fiber was crack control and blockade of movement for deterioration factors. The most studies for EVA were limited in the field of mortar and PP fiber reinforced concrete had been studied in the state of being restricted unit water content, rich mix and mixing much of the fiber without considering construction site. Therefore, the control mix design were applied in ready mixed concrete using 10 % fly ash of total cement weight used in batch plant. On the basis of control mix design, EVA contents ranging from 0 % to 10 % of total cement weight and PP fiber contents ranging from 0 % to 0.5 % of EVA concrete volume were used in the mix designs. The results showed the maximum compressive strength value was measured at EVA 5.0 % and PP fiber 0.1 %, the minimum water absorption ratio was at EVA 10 % and PP fiber 0 %, the durability factor for freezing and thawing resistance was at EVA 5.0 % and PP fiber 0.3 % and the minimum weight reduction ratio of resistance to sulfuric acid attack was at EVA 10 % and PP fiber 0.5 % after curing age 42days. Meanwhile, From these results, PP fiber reinforced EVA concrete would be very benefit, if each optimal mix types were used in hydraulic structures, underground utilities and agricultural structures.

• 한국염색가공학회지
• /
• 제20권3호
• /
• pp.31-38
• /
• 2008

Regenerated composite fibers were prepared from solution of styela clava tunics(SC) and poly vinyl alchol(PVA) using N-methylmorpholine-N-oxide(NMMO)/water(87/13)(wt%/wt%) as a solvent by dry jet-wet spinning. Structure and physical properties of regenerated composite fibers were investigated through birefrngence, x-ray diffratograms, tenacity, fibrillation and SEM. Optimal blend ratio of SC/PVA for mechanical properties of composite fibers was 70/30 and total weight was 4wt% concentrations in NMMO/$H_2O$ solvent system. Crystallinity index of composite fibers were decreased as the PVA contents increased. Fibrillation of $10{\sim}20wt%$ PVA blended fibers were occurred less than pure SC fiber. Shape of composite fibers were a circle cross section within 10wt% PVA content. But the cross section of fibers were changed as crushed flat with the PVA contents increased.

• 한국식품과학회지
• /
• 제26권5호
• /
• pp.512-519
• /
• 1994

박하를 대상으로 재배조건 및 수확시기에 빠른 방향 성분의 함량변화를 조사한 결과 박하의 생육은 비닐보온시험구에서 초기에 왕성한 생육을 보였지만, 수확기가 가까와 짐에 따라 다른 시험구와 유사하게 성장하였으며, 강유량과 일조시간에 따라 줄기와 잎의 성장속도에서 매우 많은 차이를 보였다. 수확시기에 따른 조성분의 변화는 l-menthone의 l-menthol로의 환원과정이 일조시간의 차이에 따라 그 진행속도가 빨라졌으며, 수확말기에 가서는 특히 menthofuran의 함량이 급속히 증가하는 현상을 보였다. 따라서 전체적으로 정유 조성분의 비율이 가장 양호한 시험구는 7월 5일과 7월 7일 수확분으로서, 이 시기가 수확 적기임을 알 수 있었고 정유의 우율도 이 시기에 가장 높게 확인되었다.

• Elastomers and Composites
• /
• 제33권5호
• /
• pp.345-354
• /
• 1998

폴리아미드 수지가 첨가된 PVC졸 실란트의 유변학적 물성에 대해 연구하였다. PVC졸은 디옥틸프탈레이트로 PVC를 가소화시켜 제조된 것이다. 아민가가 달라 점도가 다른 두 종류의 폴리아미드를 사용하였는데 PVC졸의 점도, 틱소트로피 및 비중에 미치는 폴리아미드 수지 종류와 함량의 영향을 고찰하였다. 폴리아미드가 첨가된 PVC졸 실란트의 점도는 폴리아미드의 종류에 관계없이 시간에 따라 증가되었으나 폴리아미드 함량의 영향에 관해서는 아민가가 낮은 폴리아미드 수지 A가 첨가된 PVC졸 실란트의 점도는 폴리아미드 A함량에 따라 증가되고, 반면 아민가가 높은 폴리아미드B가 첨가된 PVC졸 실란트의 점도는 폴리아미드 B함량에 따라 감소되었다. 폴리아미드가 첨가된 PVC졸 실란트의 틱소트로피는 폴리아미드의 종류에 관계없이 그 함량에 따라 다른 거동을 보였다. $45^{\circ}C$의 수조에서 숙성한 후의 폴리아미드가 첨가된 PVC졸 실란트의 점도거동과 충진제인 $CaCO_3$ 함량의 영향도 고찰하였다.

• 한국축산시설환경학회지
• /
• 제7권1호
• /
• pp.33-38
• /
• 2001

육계의 분 배설량과 그 특성을 알아보고자 축산기술연구소 시험계사에서 육계 120수를 이용하여 시험을 실시하였으며 그 결과는 다음과 같다. 1. 육계는 6주령시 수당 일일 160.1~165.2g의 사료를 섭취했으며 암텃, 213.0$m\ell$,수컷 252.9$m\ell$의 물을 섭취하였다. 2. 육계 1수당 1일 암수 평균 배설량은 6주령시 생분기눙으로 90.5g이며 육계 1수가 42일령까지 배설하는 누적배설량은 암수 평균 3,800g이었고 이때 계분중의 수분 함량은 79.4%였다. 3. 육계분의 평균 N 함량ㅇㄴ 건물기준으로 N 1.19%, $P_2O_5 1.28%, K_2O$ 2.02%였다. 4. 무창육계사의 여름철 깔짚 중의 수분 함량은 18.3%로 자연환기식 개방계사 계분의 수분함량 29.7%, 간이계사 30.1%보다 낮았다.

• 접착 및 계면
• /
• 제11권4호
• /
• pp.155-161
• /
• 2010

점착부여수지의 종류와 함량을 달리하여 에틸렌비닐아세테이트 공중합체(Ethylene Vinyl Acetate Copolymer, EVA)를 베이스 폴리머로 하는 핫멜트 접착제를 제조하고, 그것들의 유변학적 거동과 폴리우레탄 기재에 대한 T-peel 접착력을 평가하였다. C5 지방족 석유수지, C9 방향족 석유수지, 수소가 첨가된 디사이클로펜타디엔 석유수지 그리고, 디사이클로펜타디엔/아크릴 모노머 공중합 석유수지가 각각 핫멜트 접착제의 점착부여수지로 사용되었다. 점착부여수지의 산소 함량을 분석하여 점착부여수지의 극성도를 측정하였는데, 디사이클로펜타디엔/아크릴 모노머 공중합 석유수지가 다른 점착부여수지보다 산소 함량이 높은 것을 확인하였다. 디사이클로펜타디엔/아크릴 모노머 공중합 석유수지만이 EVA와 완전한 혼화성을 보였고, 핫멜트 접착제는 모든 조성에서 균일상을 나타내었다. 핫멜트 접착제와 폴리우레탄 기재와의 T-peel 접착력은 핫멜트 접착제 자체의 저장탄성계수(G')보다는 핫멜트 접착제에 첨가된 점착부여수지의 극성도에 의해서 좌우됨이 확인되었다.

• 한국환경보건학회지
• /
• 제4권1호
• /
• pp.26-33
• /
• 1977

A bacteriological research of the school desks, bags and indoor-shoes was made from Oct. 2, 197 through May 28, 1976. The research included one girl's middle school, two boy's middle schools, two boy's high schools and 15 girl's high schools, alltogether 244 students from 28 schools, The research was analyzed and the results are as follows: 1) The research showed that 95% of the indoor-shoes materials were of cloth. Only 13% of the students carried the indoor-shoes in shoes sacks and 84.8% of them kept the shoes in schoolbags with books and lunchbox. 2) Only 5% of them cleaned their shoes every week and 79% cleaned every six. 3) 49.3% of the students kept the indoor-shoes in the school bag with other contents at home. 4) 88% of the bag was made of vinyl and 24.8% of the students carried their lunch in their bag without lunch box. 5) The research showed that 79.1% of the students never cleaned their bags. 6) In using the desk drawer, 58.2% of the students put their out-door shoes into the drawer, 18.9% of them kept their lunch in it, 11.9% used it keeping books alone and 11% keeping school bags with books. 7) 30.4% of the students had an experience of having cleaned their desks and 69.6% were unconcerned wirh desk-cleaning. 8) 34.4% of the indoor-shoes using school showed fecal coliform positive, 40.2% showed non-fecal coliform positive and 25.4% showed no reaction to IMViC. 9) The 34.4% of the fecal coliform positive showing schools, equivalant to 77 students, was composed of zero percents of girl's middle school, 18.2% of girl's high school, 36.4% of boy's middle school and 45.4% of boy's high school. 10) Among the 77 students, whose shoes showed fecal coliform positive, only 6.5% of them cleaned their shoes once in a week or a month and 62.3% of them cleaned them once in a six month. 11) The fccal coliform positive rate was higher in the cloth shoes materials than the vinyl materials. 12) The concrete-bottomed building higher positive rate (40.2%) than the wood-bottomed building (7.5%). 13) Even among the student's who frequently cleaned their desk drawer, 2.3% were in the positive, and among those who were unconcerned with drawer cleaning, 48.9% were involved in the positive. 14) In the fecal coliform positive rate of bags, 38.5% of the positive rate belonged to using indoor shoes while cleaning their class bottom with water, 53.8% belonged to using outdoor shoes while cleaning their class bottom with water, 7.7% belonged to using outdoor shoes while cleaning their class with oil.