Curcumin is a natural polyphenolic phytochemical, which has a number of potential benefits in biological activities. However, curcumin has extremely low water solubility and low bioavailability, which makes it difficult to incorporate into many food products. In this study, we investigated the effects of biopolymer emulsifier type and environmental stress on the physical stability of nanoemulsions containing curcumin. Nanoemulsion containing curcumin stabilized by sodium caseinate (SC), whey protein isolate (WPI), modified starch (MS), and gum arabic (GA) were prepared using microfludizer. The droplet size of nanoemulsions decreased significantly from 1028 nm to 169 nm as emulsifier concentration increased (p<0.05). The optimum concentration of emulsifiers for stable curcumin nanoemulsions were determined to be 1% of SC and 1% of WPI, respectively. The storage study showed that the nanoemulsions were physically stable for 5 weeks at 25oC. In addition, nanoemulsions were physically stable against heat, freeze-thaw, pH, and NaCl solution. However, extensive droplet aggregation occurred in protein-stabilized nanoemulsions at CaCl2 solution, which was attributed to hydrophobic interaction between droplets.

PURPOSES : The objective of this study is to evaluate the environmental resistance of bio-polymer concrete for use of pavement materials developed for reducing the carbon-dioxide. METHODS : The compression, tension, and bending strength tests were conducted on the bio-polymer concrete specimens with and without environmental conditioning. The specimens were conditioned using the freezing-thaw and accelerated weathering process for long period of time. To assess the resistance against chloride, the chloride ion penetration resistance tests were carried out on the bio-polymer concrete specimens. RESULTS : Test results show that the maximum difference in strength between specimens with and without conditioning is about 2.6MPa indicating that the effect of environmental conditioning on specimen strength is negligible. Based on the chloride ion penetration resistance test, the penetration quantity of electric charge of the specimens is zero and there is no ion penetration within the bio-polymer concrete. CONCLUSIONS : It is found from this study that there is slight change in strength of bio-polymer concretes before and after environmental conditioning process and no chloride ion penetration observed in these specimens. Therefore, the developed bio-polymer concretes can be applied effectively as pavement materials due to the small change of physical properties with environment change.

전 세계적으로 산업의 고도화로 인하여 환경오염이 급속도로 진행되고 있으며, CO2 발생의 증가로 지 구 온난화 현상이 급속도로 진행되고 있다. 기존의 일반 아스팔트포장은 약 160℃의 고온에서 생산 및 시공되기 때문에 CO2가 크게 발생되며, 시멘트포장 또한 시멘트 생산 시 CO2가 발생되고 있다. 최근 강상판 장대교량(케이블교)의 건설이 증가하고 있으며, 사하중을 절감하기 위한 박층 폴리머 콘크리트가 개발되고 있다. 그러나 폴리머 수지도 석유계 재료로 생산되기 때문에 CO2가 발생되며 석유자원 의 고갈로 인한 폴리머 수지의 가격 상승 등이 문제점으로 부각되고 있다. 이러한 문제점의 대안으로 식물성 수지를 사용한 바이오 폴리머 수지를 개발하는 연구가 지속적으로 수행되고 있다. 그러나 식물성 재 료를 사용하게 되면 기존 석유계 수지에 비하여 강도 및 환경 영향에 대한 물리적 특성이 감소하는 문제 가 발생하여 차량하중의 영향이 작은 주차장, 보도, 자전거 도로 등에 적용되고 있는 실정이다. 본 연구에서는 기존 석유계수지의 약 30~50%를 식물성 재료로 대체한 도로포장용 바이오 폴리머 수지를 개발하고자 한다. 식물성 재료는 콩유(Soybean Oil), 피마자유(Castor Oil), 야자수유(Palm Oil) 등 그 종류가 다양하지만 폴리올(Polyol)공정을 거치지 않고 생산이 가능한 피마자유를 이용하여 생산비용을 절감하였으며, 환경 영향 저항성과 관련된 시험을 수행하여 도로포장에 대한 적용성을 평가하였다. 식물 성 재료가 약 30% 첨가된 수지(906-3)와 50% 첨가된 수지(2I)를 대상으로 무처리 상태의 강도와 처리 후(동결융해, 자외선)의 강도를 측정하여 비교·평가하고 염화물에 대한 저항성을 시험하였다. 그 결과 기 존 석유계 폴리머 수지에 식물성 재료를 50% 대체하여도 강도변화가 미미한 결과를 도출하여 바이오 폴리머 수지를 도로포장에 적용하여도 문제가 없음을 확인하였다.

PURPOSES : The objective of this study is to evaluate the mechanical characteristics of castor oil based bio-polymer concrete for use of ultra thin overlays. METHODS : To evaluate the mechanical properties of bio-polymer concrete, the various laboratory tests including compressive, tensile, and flexural strength, and elongation tests were conducted on bio-polymer concrete specimens in this study. The mechanical characteristics of bio-polymer concretes were examined by changing the content of hardener and polymer binder to determine the optimum content for ultra-thin overlays. The bio-polymer concrete developed in this study was used for field trial test of the ultra-thin bridge deck pavement for verifying the workability and monitoring the long-term performance of materials. RESULTS : Test results showed that tensile and the flexural strength of bio-polymer concretes increase and the elongation of bio-polymer concrete decreases with increase of binder content. A field adhesive strength tests conducted on bridge deck pavement indicates the bio-polymer concrete has more than 2MPa of adhesive strength satisfy with the design criteria. CONCLUSIONS : The bio-polymer concrete with more than 20% content of castor oil was developed for ultra-thin overlays in this study. It is found from this study that the 35% of hardener content is most appropriate for maintaining the strength characteristics and flexibility.

Recently, a great social damage has been caused by the sargassum homeri, which has flowed from China in the Jeju and Namhae coasts. In this study, biopolymer was prepared by using sargassum homeri and applied to bridge pavement concrete. The performance of chloride ion penetration resistance of the bridge pavement concrete made of biopolymer was evaluated. As a result, excellent penetration resistance performance was shown.

최근 남해안과 제주도 연안에는 5,000톤 이상의 괭생이 모자반이 유입되어 양식장과 조업에 큰 피해를 주고 있으며, 환경훼손 등 사회적 문제로 부각되고 있다. 괭생이 모자반에 존재하는 알긴산은 주로 의약품, 식품 등으로 활용되는 천연 고분자 물질이다. 하지만, 대량으로 활용할 수 있는 수요처가 확보되지 않아 본 연구에서는 괭생이 모자반을 활용한 바이오 폴리머를 구조물 보수용 폴리머 모르타르에 활용하기 위한 연구를 수행하였다. 응결특성 평가 시험에서는 바이오 폴리머가 12% 혼입된 L0BP12 배합은 합성폴리머만 혼입된 L12BP0 배합보다 종결시간이 최대 20%증가하는 것을 확인하였다. 흡수율 시험에서는 LOBP12 배합이 초속경 시멘트 배합인 Plain-URHC보다 0.36% 감소하는 것으로 나타나 바이오 폴리머 혼입으로 모르타르의 수밀성이 증가하는 것을 확인하였다. 압축 및 휨강도 시험에서는 바이오 폴리머의 혼입이 증가할수록 강도가 감소하는 경향을 나타내었고, KS F 4042 기준을 만족하는 최대 바이오 폴리머의 혼입률은 12%로 결정되었다. 또한, 재령 4시간 기준 부착강도는 Plain-URHC시험체 보다 모두 향상되었으며, 1 MPa 이상을 확보하여 바이오 폴리머의 혼입이 모르타르의 부착강도를 향상 시킬 수 있는 것을 확인하였다.

Resently, sargassum honeri, which has flown into the Korean coast, has become a serious problem due to the serious damage to domestic aquaculture and fishery. The purpose of this study is to utilize sargassum honeri containing alginic acid as a natural polymer material in cement mortar for repairing structures. The experimental results show that the flow of mortar tends to decrease as the incorporation rate of biopolymer increases.

In this study, the setting times of mortar using the biopolymer in seaweed was evaluated by penetration resistance. The evaluation was based on the method presented in KS F 2436. Test results show that the biopolymer was used instead of the synthetic polymer, the termination time was delayed.

In order to develop bacterial cellulose (BC) with antimicrobial activity against pathogenic microorganisms, silver and chitosan were incorporated into BC, respectively. Experiment results showed that antimicrobial activity against pathogenic microorganisms was improved with increasing silver concentration. Chitosan also showed a direct proportion between its concentration and antimicrobial activity. These results suggest that antimicrobial effects of BC using silver and chitosan are well proven to be effective. We also tested the stainability of BC with natural colorant for the application of food industry. Stainability of BC was enhanced with increasing natural colorant concentration. Decolorization of BC stained was observed by dipping it into distilled water with one hour-intervals. As a result, there was no significant difference. Combination of natural colorant-stainability and antibiosis of BC is expected to be useful in making colored antibiotic BC in various industrial application areas, considering its antimicrobial activity, high stainability and low decolorization tendency.