불포화 폴리에스테르 수지의 물성이 폴리머 콘크리트의 강도에 미치는 영향

이필호,박재근,황보 영,이정우 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-

본 연구에서는 폴리머 콘크리트의 결합재인 불포화 폴리에스테르 수지(UPR)의 물리적 성질을 조사하였다. 그 결과는 비중 1.1 g/mL, 점도 3.0 poise, styrene의 함량은 40% 내외이고 산값은 약 20이었다. 본 실험에서 제조된 폴리머 콘크리트의 압축강도는 평균 1,056 Kg/cm², 휨강도는 216 Kg/cm², 인장강도는 110 Kg/cm²이었는데, 이는 시멘트 콘크리트에 비해 비교적 좋은 역학적 성질을 나타낸 것이다. 변동계수는 압축강도의 경우 약 3%, 휨강도의 경우 5%, 인장강도의 경우 6% 내외로서 매우 양호하다. 강도비를 산출하여 본 바 압축강도와 휨강도의 비가 4.9, 압축강도와 인장강도의 비가 9.7, 휨강도와 인장강도가 1.97로서 나타났는데 이는 폴리머 콘크리트의 압축강도는 1000 Kg/cm²를 상회함을 감안할 때 휨 및 인장강도가 상대적으로 큼을 보여주는 결과이다. In this study, effect on the strength of polymer concrete of unsaturated polyester Resin's(UPR) property was investigated. The physical property of UPR was as follows; density 1.1 g/mL, viscosity 3.0 poise, the content of styrene 40%, and acid value 20. The mechanical property of Polymer Concrete was relatively good; compressive strength 1,056 Kg/cm², flexural strength 216 Kg/cm², splitting tensile strength 110 Kg/cm², The coefficient of fluctuation was 3% of compressive strength, 5% of flexural strength, and 6% of splitting tensile strength. The ratios of respective strength were 4.9(compressive strength to splitting tensile strength), and 1.97(flexural strength to splitting strength). Therefore, flexural strength and splitting tensile strength of polymer concrete was relatively big under consideration of compressive strength(1,000 Kg/cm²).

導入羅王材와 國産材를 混用한 合板의 材質改善에 關한 硏究

李弼宇 서울大學校 農科大學 1977 서울대농학연구지 Vol.2 No.1

This study was planned to substitute the impoerted logs by American Sycamore (Platanus occidentalis), Italian poplar (Populus eurmericana), Korean White Oak (Quercus acutissima) and Korean Red Pine (Pinus densiflora) growing as major economical timber species in our country to relieve dem and for domestic plywood industry, which depends upon entirely foreign timber resources at present. Until present, our country has imported and utilized expensive lauan (Shorea, Parashorea and Pentacme of Dipterocarpaceae) logs producted in Indonesia, Malaysia, and Philippines of southern pacific region to supply the demand for domestic plywood industry. However because of the unfavourable conditions of rising cost and buying competition in log producing countries, at a first step of research to exploit the domestic timber products into veneer logs, this study was carried out to develope the plywood manufacturing process composing of imported lauan logs and cheap domestic timber products. Accordingly the study has important meanings for the promotion of plywood manufacture using domestic log products and the decrease of imported log quantities even a little, and also it has advantage for the cost down in plywood manufacture, and saves dollars. At this study the advantageous properties of upgrading plywood qualities were compared and discussed between plywood composed of sole lauan veneers, and plywood constructed by imported lauan and domestic timber species. Important items dealt with in this study were dry and wet shear strength, specific gravities, moisture contents, and bending strength. They were experimented as accordance with A.S.T.M. Standards as general, and analyzed statistically. By the analysis and discussions of the results, this study may be conclyded as follows: 1) In dry shear strength of plywoods composed of two species, most excellent results were shown by Lauan-Oak construction plywoods and strength values were decresed in following orders; Lauan-Sycamore, Lauan-Popar. The worst results were given by Lauan-Pine constructions. In plywoods composed of three species, high strength values were obtained from the plywoods constructed by Lauan, Oak and Sycamore, but comparatively low strength values were obtained from plywoods constructed with pine veneers. 2) In wet shear strength of plywood composed of two species, most excellent results were obtained from Lauan-Sycamore construction plywoods, and Lauan-Poplar constructions next order. Worse strength values were obtained from the plywoods constructed by Lauan-Oak with Lauan-Pine. In plywoods composed of three species, comparatively high strength values were obtained from the plywoods properly constructed by Lauan, Poplar and Sycamore, of Lauan, Oak and Sycamore. The decreasing tendency of wet shear strength as dry shear strength was obtained from plywoods constructed with pine veneers. 3) In dry shear strength of the plywoods constructed by thin 0.7∼0.9mm veneers, the recognizable, more excellent constructions of two species than all lauan veneer construction were Oak-Oak-Lauan(Q-Q-L), Lauan-Sycamore-Lauan (L-S-L), Lauan-Oak-Lauan(L-Q-L), Oak-Lauan-Oak(Q-L-Q), and Sycamore-Sycamore-Lauan(S-S-L) types, and in thick 1.3∼1.5mm veneer construction, they were Oak-Oak-Lauan(Q-Q-L), Lauan-Sycamore-Lauan(L-S-L), Lauan-Oak-Lauan (L-Q-L), Lauan-Poplar-Lauan(L-P-L), Lauan-Sycamore-Sycamore(L-S-S), and Lauan-Lauan-Oak(L-L-Q) types. In plywoods constructed by thin veneers of three species, the recognizable, more excellent con-structions were Oak-Poplar-Lauan(Q-P-L), Oak-Sycamore-Lauan (Q-S-L), Sycamore-Poplar-Lauan(S-P-L), Oak-Pine-Lauan (Q-P-L), and Sycamore-Oak-Lauan (S-Q-L) types, and in thick veneer constructions, they were Oak-Poplar-Lauan (Q-P-L), Oak-Sycamore-Lauan (Q-S-L), Sycamore-poplar-Lauan (S-P-L), Oak-Pine-Lauan(Q-N-L), and Sycamore-Oak-Lauan(S-Q-L) types. 4) In wet sheat strength of the plywoods constructed by thin 0.7∼0.9mm veneers, the recognizedable, more excellent constructions of two species than all lauan veneer construction were Sycamore-Sycamore-Lauan(S-S-L), Lauan-Sycamore-Lauan (L-S-L), Lauan-Poplar-Lauan(L-P-L), and Poplar-Poplar-Lauan(P-P-L), types, and in thick 1.3∼1.5mm veneer constru-ction, they were Sycamore-Sycamore-Lauan(S-S-L), Lauan-Sycamore-Lauan(L-S-L), Sycamore-Lauan-Sycamore(S-L-S), Lauan-Poplar-Lauan(L-P-L), and Lauan-Poplar-Poplar(L-P-P), types. In plywoods constructed by thin veneers of three species, the recognizable, more excellent constructions than all lauan veneer construction were Sycamore-poplar-Lauan (S-P-L), Poplar-Oak-Lauan (P-Q-L), Sycamore-Oak-Lauan(S-Q-L), Oak-Sycamore-Lauan (Q-S-L), and Poplar-Sycamore-Lauan(P-S-L), types. and in thick 1.3∼1.5mm veneer constru-ction, they were Oak-Sycamore-Lauan (Q-S-L), Lauan-Sycamore-Poplar (L-S-P), Sycamore-Oak-Lauan(S-Q-L), Sycamore-poplar-Lauan (S-P-L), Poplar-Oak-Lauan (P-Q-L) types. 5) In shear strength according to the thickness of veneers, the plywoods constructed by thick veneers showed higher values than plywoods constructed by thin veneers. Wet shear strength compared with dry shear strength considerably lowered under the same plywood construction. 6) Wood failures of all plywoods at dry test which composed of different species showed higher values than all lauan veneer plywood. In the wet test, they did not showed a definite tendency, and the avlue considerable lowered in comparison with the results at dry test. 7) In Wood failures according to the thickness of veneers, the plywoods constructed by thin veneers showed higher values than plywoods constructed by thick veneers. 8) In the phenol resined plywoods composed of different species, proper manufacturing condit-joins were considered as 150∼165℃ in plate temperature, 150∼210 1bs/in.²in press pressure, and 180∼240 seconds in pressing time in manufacture of plywood constructed by three sheets veneers of thickness 1.0∼1.2mm, and in the urea resined plywoods considered as 100-120℃ in plate tempertature, 150∼180 1bs/in.²in press pressure, and 90∼120 seconds in pressing time. 9) In the specific gravities of plywoods composed of two species, most excellent high values were obtained from the plywoods constructed by Lauan and Oak, and worst results from Lauan and Poplar construction. Also in the plywood composed of three species, the constructions comp-osed of above these species were remarkably affected by specific gravities of species. Especially all the plywoods composed of Sycamore and Oak showed higher values than all lauan veneer plywoods. 10) In the moisture contents of plywood, wide variation and significant differences were shown among the plywood construction types composed of different species, but its mositure contents differed from those of plywood constructed by single veneer species. 11) In the bending strength of plywood, all the plywoods compsed of different species showed higher values than all lauan veneer plywoods, and the strength decrease was shown prominently according to the increase of lauan veneer sheets which were constructed with veneers from domestic timber species.

리기다소나무 (Pinus rigida Miller) 판재의 압축이상재 (壓縮異常材) , 대응재 (對應材) 및 측면재 특성에 관한 주사전자현미경적인 연구

이필우,엄영근 한국목재공학회 1985 목재공학 Vol.13 No.1

In Korea, a study on the anatomical features of pitch pine(pinus rigida Miller) branch wood through photo-microscopical method was reported in 1972 by Lee. Therefore, as a further study of Lee's on the anatomical features in branch wood of pinus rigida miller that grows in Korea, compression wood, opposite wood, and side wood were selected and treated for the purpose of comparing their structures revealed on cross and radial surface through scanning electron microscope in this study. The obtained results in this study were summarized as follows: 1. The trachied transition from earlywood to latewoad is very gradual and the tracheids are nearly regular in both arrangement and size in compression wood but this transition in opposite wood and side wood is abrupt and the tracheids in opposite wood and side wood are less regular than those in compression wood. Also, the annual ring width of opposite wood is narrower than that of compression wood or side wood and the rays revealed on cross surface of side wood are more distinct than compression wood and apposite wood rays. 2. The tracheids of compression wood show roundish trends especially in earlywood but those of apposite wood and side wood show same angular trends. And intercellular space, helical cavity, and spiral chock are present in both earlywood and latewood of compression wood but not present in opposite wood and side wood irrespective of earlywood and latewood. 3. The wall thickness of latewood tracheid is similar to that of earlywood tracheid in compression wood whereas the wall thickness of latewood tracheid is by far thicker than that of earlywood tracheid in opposite wood and side wood and the S₃ layer of secondary wall is lack in comgression wood tracheid unlike opposite wood and side wood traeheid. 4. The tracheids in compression wood are often distorted at their tips unlike those in opposite wood and side wood and the bordered pit in compression wood tracheid is located at the bottom of helical groove unlike that in opposite wood and side wood tracheid. 5. The bordered pits in radial wall of apposite wood and side wood tracheids are oval in shape but those of compression wood tracheids show some modified oval shape. 6. in earlywood of side wood, the small apertures of cross-field pits are roundish triangle to rectangle and the large one are fenestriform through the caalition of two small ones. However, the small apertures of cross-field pits are upright oval and the large ones are procumbent oval shape in earlywood of opposite wood and the apertures of cross-field pits in compression wood are tilted bifacial convex lens shape in earlywood and slit in latewood because of the border on tracheid side.

전처리한 목섬유로 제조한 섬유판의 물리적 및 기계적 성질

李弼宇,辛榕洙 서울大學校 農業生命科學大學 農業開發硏究所 1996 서울대농학연구지 Vol.21 No.2

This paper reports on dimensional stability of the composites made from acetylated wood-fibers. The fiberboards at this study were made by different face-layer formulation ratios(10, 20, 30, 40 and 50%) of acetylated wood-fibers. In this experiment, acetylation of wood-fiber was reacted with liquid acetic anhydride in stainless steel cylinder. The WPG(weight percent gain) as a result of acetylation was calculated based on the weight of oven-dry untreated wood-fiber, and the 17% WPG could be achieved in reaction time from 2 hours. In physical properties of fiberbodards made from acetylated wood-fiber, thickness swelling and water absorption were more reduced than control fiberboards, but mechanical properties(MOR, MOE and IB) decreased with increasing of face-layer formulation ration of acetylated wood-fibers, which was probably due to poor adhesion and uncontinuous mat forming between acetylated fiberboards and control fiberboards. In the IB test on acetylated fiberboards most failure occurred in the boundary between acetylated face-layer and untreated core-layer. In the acetylated fiberboards, the failure was due to adhesive penetration and compressibility problems associated with acetylated fiber.

MDI(methylene diphenyl diisocyanate) 樹脂를 利用한 톱밥보드의 物性(Ⅱ) : 열압온도, 열압시간에 관하여 On the press temperature and press time

李弼宇,尹炯雲 서울大學校 農業生命科學大學 農業開發硏究所 1995 서울대농학연구지 Vol.20 No.1

韓紙 슬러지ㆍ 木材 파티클 複合보드의 製造硏究 : II.韓紙 슬러지ㆍ 木材 파티클 複合보드의 機械的 性質 II.Mechanical Properties of Hanji(Korean Paper)SludgeㆍWood Particles Composite

이학래,손정일,김현중,이필우 한국목재공학회 2002 목재공학 Vol.30 No.2

韓紙製造工程 中에서 發生하는 백색 슬러지와 흑색 슬러지를 각각 일정비율(10, 20, 30, 40%)로 木材 파티클과 混合하고 PMDI, 요소 및 페놀수지를 이용하여 目標比重 0.60, 0.75, 0.90 별로 複合모드를 製造하여 機械的 性質을 측정한 결과 파티클보드에 韓紙 슬러지를 약 20%까지는 混合하여 複合材를 제조하여도 충분히 可能하리라 믿어진다. This research was carried out to develop the Hanji(Korean paper) sludge ·wood particle composite utilizing the waste sludges occurring from the making process of Hanji(Korean paper). At the research, four mixing ratios of white or black sludge to wood particle(10:90, 20:80, 30:70 and 40:60), three types of the resin adhesives(PMDI, urea and phenol resin) and three levels of the densities(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Hanji(Korean paper) sludge ·wood particle composite. In the white and black sludge ·wood particle composites, bending properties(MOR, MOE) showed the decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Also tensile strength had the same tendency as in these bending properties. The internal bond strength of white sludge ·wood particle composite had no tendency, but that of black sludge ·wood particle composite was decreased as an increase of Hanji sludge additive.

제지 슬러지-합성 섬유-목섬유 복합재의 개발

이필우,이영규,김현중 한국목재공학회 2002 목재공학 Vol.30 No.1

제지 공정중에서 발생하는 슬러지의 효율적인 활용 방안중의 하나로써 목질보드 원료 대체 재료로써의 그 가능성을 평가하기 위하여 제지 슬러지, 합성 섬유, 목섬유의 혼합비를 각각 5:5:90, 15:15:90, 25:25:50으로 PMDI와 요소수지 접착제를 사용하여 목표비중 0.7, 0.8, 0.9인 복합재를 제작하여 물리적 및 기계적 성질을 측정한 결과 제지 슬러지와 합성 섬유를 30%∼50%를 혼합하여 복합재를 제조하여도 기존의 보드와 비교하여 손색이 없는 제품을 생산할 수 있다고 판단되었다. The aim of this research was to investigate the manufacturing possibility of the paper sludge-synthetic fiber-wood fiber composite. Three levels of the formulation of paper sludge, synthetic fiber and wood fiber (5:5:90, 15:15:70, 25:25:50), two types of adhesive (PMDI, urea-formaldehyde resin) and three levels of density(0.7, 0.8, 0.9) were designed. From the test result, composites with similar or better properties, when compared with commercial fiberboard, appeared to be possible by the addition of up to 30∼50% paper sludge and synthetic fiber into wood fiber.

PMDI(Polymeric Methylene Diphenyl Diisocyanate)樹脂를 利用한 新聞古紙纖維-木纖維 混合 하드보드의 物理的 및 機械的 性質

李弼宇,李喆周 서울大學校 農業生命科學大學 農業開發硏究所 1996 서울대농학연구지 Vol.21 No.2

Conventional researches have reported that ONP(Old Newspaper) fiber mixed hardboard is inferior to wood fiber hardboard on physical and mechanical properties, specially, internal bond strength and dimensional stability are very poor. It is thought that wetted ONP fiber by using water soluble resin results in poor uniformity of resin distribution. Actually internal bond strength, to a large extent, depends upon the uniformity of resin distribution. The objective of this research was to compare the results from ONP fiber mixed hardboard using water soluble phenol resin with those from ONP fiber mixed hardboard using PMDI(Polymeric Methylene Diphenyl Diisocyanate) which get fiber less wet relatively. Boards were fabricated with ratios of ONP fiber to wood fiber of 0 to 100, 30 to 70, 50 to 50, 70 to 30 and 100 to 0, and tested for static bending strength, internal bond strength, tensile strength, water absorption and thickness swelling. As expected, ONP fiber mixed hardboard using water soluble phenol resin showed that physical and mechanical properties decreased with increasing of ONP fiber mixed level. However, those using PMDI showed opposite results, specially internal bond strength increased, and water absorption and thickness swelling decreased with ONP fiber mixed level ranging from 30% to 70%.

數種의 增量劑 粒度와 增量比率에 따른 尿素樹脂合板의 接着 特性

楊翰承,尹炯雲,李弼宇 서울대학교 농과대학 농업개발연구소 1993 서울대농학연구지 Vol.18 No.2

The purpose of this research was to evaluate and to examine the substitutional feasibility of paper sludge extender instead of wheat flour. As the extending materials, taro flour, paper sludge, wood flour and wheat were selected and dried at 103±2℃ during 24 hours in the drying oven and pulverized into three levels(-50∼+100, -100∼+200, -200∼mesh). The extenders were mixed with urea formaldehyde resin in the ratio of 10, 20 and 30%. After plywoods were manufactured by the above extended ratios, dry and wet shear strength were examined. The results obtained at this research were summarized as follows : 1) In 10% extionsion on -50∼+100 mesh particle size, paper sludge showed the highest dry and wet shear strength among the extenders. 2) As 20% extension, wheat showed the highest value. 3) the shear strength was affected by the particle size and extending ratios, and the shear strength extended by paper sludge powder was sensitively varied with particle sizes and extending ratios. 4) The shear strength extended by taro and wheat flour were less affected by the particle size of extender. Therefore, the particle size of extender would be considered along the extention ratios and extender types.

경사판 시험에 의한 내화도료 처리가 목질판상재료의 내화성능 및 열저항변화에 미치는 영향

金顯中,尹榮基,李弼宇 서울대학교 농과대학 농업개발연구소 1991 서울대농학연구지 Vol.16 No.2

In this study the inclined panel test was used to compare the relative effectiveness in fire resistance among plywood. particleboard and medium density fiberboard which was treated with fire-retardant of chlorinated resin and non-coated ones. The results obtained were summarized as follows: 1. The medium density fiberboard ranked first in flammablility followed in turn by particleboard and plywood in non-coated treatments. 2. The rate of weight loss decreased with increasing level of coating quantity. 3. The highest fire-retardant effectiveness was found in plywood with C treated level. This effectiveness was mostly found in particleboard with C treated level. 4. The temperature of back in non-treated and treated board decreased with increasing level of coating quantity. 5. The weight loss of the tested samples which had high value of temperature decreasing showed low values. 6. The time that reached 99℃ on the back of plywood, PB and MDF in nontreated-board was 300sec, 180sec and 150sec, respectively but time that reached 99℃ on the back of PB, MDF in treated-board was 210sec, l50sec, and plywood did not reach 99℃.