As the first step of study on fabrication of ceramic powders from phytoliths in rice, especially in rice husks, pulverization method of rice husks and the properties of milled rice husks were investigated. Impact methods, such as ball milling, were not meaningful for pulverizing elastic and thin fabric structure of rice husks. The most effective one was cutting method. In the present work, a rotating knife cutting method was applied to pulverizing rice husks. A 40-mesh screen was inserted under the rotating knives. The most portion of the milled powder was found in -50/+100 mesh section. Morphology of the milled rice husks revealed that the husks larger than 70 mesh were flake-like shape, at -70/+100 mesh section relatively equi-axed shape, at -170/+325 mesh section rod-like shape, and below 325 mesh section dust-like shape. Tap density of raw rice husks was about 0.1 , while those of milled rice husks were over . This meant that, for a given volume of reactor, raw material charge can be increased more that 4 times when using milled rice husks than unmilled one. True densities of unmilled and milled rice husks were higher than , and increased with decreasing milled sizes.

지난 수십년간 부직포 산업에 대한 관심이 증대되고 있고, 정부차원에서 환경문제에 관심이 고조되면서 부직포를 이용한 FILTER의 수요는 꾸준히늘고 있다. 특히 대구의 페놀사건 및 리우회담 개최 등으로 환경문제에 전국민이 적극적으로 대응하고 관심의 영역이 급속히 넓어짐으로 인하여 공해방지용 각종 FILTER와 집진기용 FILTER의 수용가 상당히 증가되고 있는 실정이다. 또한 리우회담을 계기로 정부의 공해방지 및 환경에 대한 규제도 대폭 강화되었다. 이에 따라 기존의 직물을 소재로 한 여과매체보다 형태의 안정성, 다양성, FILTERING 효과에서 앞서고 있는 부직포의 여과매체에 대한 관심이 점차 높아지고 있는 실정이다. 따라서 아질 개발하지 못한 부직포를 이용한 FILTER의 개발이 시급하고, 미개척 분야에서의 부직포 사용을 위한 연구가 꾸준히 이루어져야 하겠다. 그리고 환경규제가 강화됨에 따른 고서능 여과포의 개발 또한 시급한 실정이다. 본 장에서는 부직포를 이용한 여과매체, 즌 BAG FILTER의 제조 및 선정 등에 대하여 간략하게 소개하고 추후 부직포 산업의 활성화에 미약하나마 보탬이 되길 바란다.

To prepare a O/W type durable softner(OESA), octadecamidoethylaminoethyl dodecate and tetra (2-dodecamidoethyl) urea synthesized as the main components of softner, were blended with polyoxyethylene(20) oleyl ether, sorbitan sesquioleate, and polyoxyethylene(7) stearyl ether in various compositions. Emulsion stability of OESA was good, and mixed HLB value was 9.7, OESA was found was to be good durable softner for nylon through the examination of softness, lubriation, antistatic property, bending resistance, and color fastness.

Oil dispersants using polyoxyethylene monooleate, polyoxyethylene oleylether, and poly(oxypropylene-oxyethylene)glycol block copolymer were prepared, and oil dispersant efficiency was measured using vertical shaking flask method to 4 kinds of Bunker B oil with different physical properties by appling the prepared dispersants. Although the dispersant efficiency was differed according to the differences of physical properties of Bunker B oil, the dispersant prepared using polyoxyethylene oleylether was the most effective to disperse the oil into water. The impurities like surfur contained in sample oil have to be removed by filteration to obtain the correct degree of absorption using UV spectrophotometer.

The 2-packaged polyurethane coatings were synthesized, blending pheylmodified polyesters(of which synthetic methods were reported in the previous paper), Desmodur L-75(polyisocyanate wide1y used for coatings), wetting-dispersing agent, white pigment. etc. A variety of coating properties were tested for the coating treatment polyurethane coationgs. Compared with conventional 2-packaged polyure-thane coating, abrasion resistance and lightness index difference of the ones synthesized in the present work were somewhat decreased, but the coating properties such as hardness, gloss specular, cross hatch adhesion. etc. were improved. Especially, resistance against chemical reagents and salt were strikingly improved. In addition. the coationgs had short drying time and long pot-life. This shows that the coationgs are appropriate for rapid drying coatings.

비정질 PEEK 필름의 self-bonding강도는 접합시의 공정변수(시간, 온도, 그리고 압력)와 밀접한 관계가 있다. 본 연구에서는 이러한 공정변수의 효과를 규명하기 위하여 각기 다른 접합조건하에서 개발된 시편들의 self-bonding강도를 single lap-shear test를 통하여 측정된 각각의 전단 응력(shear strength)으로 나타내었다. 개발된 self-bonding강도는 접합온도가 증가함에 따라 증가하였으며, 접합시간의 1/4승에 일차함수적으로 비례증가하였다. 접합공정 중의 압력의 효과는 단지 초기 접합단계인 wetting에 기여하였을 뿐 self-bonding강도 자체에는 거의 영향을 미치지 않는 것으로 사려되었다. 결론적으로 비정질 PEEK 필름의 self-bonding현상은 현장에서의 실제 접합공정에서 어떠한 접착재료의 사용없이도 모재와 같은 강도를 개발하는데 무한한 가능성이 있는 것으로 판단되었다.

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, ) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 50, whereas it was very rough due to tearing at . It was found that the tensile strength and elongation of the composites extruded at are greater than those of composites extruded at This is due to the easier plastic deformation of composite extruded at , compared with the composites extruded at . The effect of die angle was examined under 20=60, 120, die angles at extrusion temperature of under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=approved to be higher than that of the composties extruded with 28 : 120 and This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.