GTR 및 미발포 Expancel이 경질우레탄폼의 열전도특성에 미치는 영향

안원술(Ahn, Won-Sool) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.6

미세하게 분쇄된 폐타이어 분말(GTR)과 미발포 Expancel^® 분말이 경질 폴리우레탄 발포체(PUF)의 열전도 특성에 미치는 영향을 연구하였다. 마이크론 크기로 분쇄된 GTR과 100℃ 이상의 온도 영역에서 약 40배 부피로 팽 창 가능한 Expancel^® 미세분말을 사용하였고 이들이 경질 PUF 생성 시의 발포 기핵제 역할에 의한 기포크기 감소효 과 및 이로 인한 PUF의 열전도특성 개선 효과를 집중적으로 살펴보았다. 연구의 결과로서, GTR이 충전된 PUF 샘플 들의 열전도도는 GTR 함량이 증가함에 따라 선형적으로 증가하는 현상을 나타내는 반면, Expancel^®이 도입된 샘플 들은 농도에 따라 약간 감소하는 특성을 보여 주었다. 이러한 결과로부터 GTR은 PUF 생성에서 증량제의 역할이 상 대적으로 우세하여 단열 특성에 기여하지 못하는 반면, Expancel^®은 분말의 표면극성으로 인한 발포 기핵 작용에 의 하여 셀 크기를 감소시킴으로서 단열효과에 기여할 수 있는 것으로 생각되었다. Effects of ground tire rubber(GTR) and unexpanded Expancel^® powders on the thermal conducting characteristics of rigid polyurethane foams(PUFs) were studied. Sub-micron sized GTR powders and Expancel^® powders were used as the foam nucleating agents to improve the thermal insulating properties of the rigid PUFs. As the results, while the thermal conductivities of the GTR filled-PUF samples were increased linearly with GTR contents, those of Expancel^® filled-PUF samples were decreased a little bit. It was considered from the results that GTR powders might predominantly play a role as the extending fillers. On the other hand, Expancel^® powders could act as the foam nucleating agents based on the polar surface, showing smaller cell sized PUF with improved insulating characteristics.

폐타이어 고무분말(GTR)이 니트릴고무(NBR) 발포체의 난연 및 발포 특성에 미치는 영향

문성철 ( Mun Seong Cheol ),이재철 ( Lee Jae Cheol ),최재곤 ( Choe Jae Gon ),조병욱 ( Jo Byeong Ug ) 한국고무학회 2003 엘라스토머 및 콤포지트 Vol.38 No.3

본 연구에서는 폐타이어 고무분말 (GTR)과 일부 난연제를 포함한 acrylonitrile-butadiene rubber(NBR) 발포체를 제조하고, 난연 및 발포특성에 GTR이 미치는 영향을 조사하였다. 그 결과 고무/난연제의 조성비가 1/1.95∼3.70wt%이며, GTR의 함량이 20wt% 범위 이내에서 원활한 핵의 생성 및 cell의 성장으로 인해 높은 발포율(215∼300%)과 균일한 닫힌/반 닫힌 셀(closed/semi-closed cell)을 보여주었으며, 높은 LOI(29.4∼40.0)와 낮은 (A)-HRR을 보임을 확인하였다. 또한 GTR의 함량이 증가함에 따라 자체적인 난연 특성으로 인해 LOI가 증가하고, HRR이 감소하는 반면에 (A)-COY는 증가함을 확인하였다. The flame retardancy and foaming properties of NBR foams containing waste ground tire rubber (GTR) were studied. When the composition rations of NBR/GTR were ranged in 100/0∼80/20 (w/w) and rubbers/flame retardants were in the range of 1/1.95∼3.70 wt%, the considerably optimized foam for flame retardancy was obtained with high limiting oxygen indices (LOI, 29.4∼40.0), low heat release rate(HRR),closed/semi-closed cell of uniformity, and reasonable expandability (215∼300%). The LOI was increased and the heat release rate was decreased with increasing the amount of GTR content.

치과 임상에서 조직유도재생술의 의미

장현선 대한구강악안면병리학회 2018 대한구강악안면병리학회지 Vol.42 No.4

Guided tissue regeneration(GTR) is regenerative operating technique at dental clinic. The vertical bone defect can be treated by GTR. The purpose of this study is to present the importance of GTR at dental clinic. The vertical bone defect was observed on distal side of mandibular right 2nd molar. The patient had been treated scaling, root planing and GTR. Both nonresorbable occluding membrane and resorbable occluding membrane can be used as GTR operation. The former was used in this study. Nonresorbable occluding membrane can exclude epithelial cells from healing defect. The Bio-Oss bone graft used at GTR operation. A radiograph demonstrates that the regenerative part was observed by GTR. In conclusion, GTR operating effect has importance on vertical defect at dental clinic.

3D Printing of Ground Tire Rubber Composites

Faez Alkadi,Jeongwoo Lee,Jun-Seok Yeo,Seok-Ho Hwang,Jae-Won Choi 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.2

Recycled tire rubber is an environmentally and economically beneficial material. Ground tire rubber (GTR) as a filler in a polymer matrix was used as an ink material (composite material) for material extrusion in a 3D printing process. The maximum allowable amount of GTR incorporated into the mixture without significantly altering the rheological behavior of the ink was set. Printability investigations revealed that pressure and speed show linear and power relationships, respectively, to the line width for three different amounts of GTR. Moreover, the post-curing time of 30 min at 115 °C was set as the full-cure condition to achieve polymerization of 80% or more for the 3D printed parts. Unidirectional tensile testing demonstrated that 3D printed specimens exhibit no degradation in tensile strength when compared to molded specimens. Moreover, printability and mechanical properties of functionalized GTR were investigated to determine if this material exhibits enhanced mechanical strength. Unidirectional tensile tests show that the maximum tensile strength for specimens with functionalized GTR was 20% higher than in specimens with non-functionalized GTR. In conclusion, 3D printing of GTR composites shows promise for using recycled GTR to create 3D structures with rubber-like properties.

An experimental study on gtr technique using lyodura and microfilter in rat s osseous defects

조세인(Se In Cho),여환호(Hwan Ho Yeo),김영균(Young Kyun Kim),임석균(Seok Kyun Lim) 대한구강악안면외과학회 1995 대한구강악안면외과학회지 Vol.21 No.4

구강악안면외과 영역에서 골 결손부에 대한 골재생유도에 관한 많은 연구를 통해 GTR technique에 이용되고 있는 Gore-tex membrane의 생물학적 친화성이나 골 결손부의 재생시 유도능력에 관한 확신올 제공하고 있다. 최근에는 치주치료에 이용되는 GTR과 구분을 위하여 골 조직의 선택적인 재생을 유도한다는 의미로 GBR(Guided bone regeneration)과 osteopromotion이라는 용어가 주로 사용이 되고 있고 협의의 치료개념이 아닌 광범위한 악안면의 결손부의 재건에 응용이 기대되고 있다. 그러나 재료의 값이 비싸고 비흡수성으로 제거가 필요하다는 단점을 갖고 있다. 이에 저자 등운 값이 싸며 흡수성을 갖는 lyodura와 비흡수성의 microfilter를 GTR에 이용하여 Gore-tex membrane을 대치하는 효과를 살펴보고자 하였다. 실험군은 lyodura와 microfilter group으로 나누어 백서의 좌측 하악 우각부에 인위적인 8×8mm의 전층골결손부를 형성하고 각기 lyodura와 microfiliter를 골결손부위에 기개하고 봉합하였으며 반대측은 각 실험군의 대조군으로 골 결손부를 피개하지 않고 방치하였다. 술후 1주, 3주, 5주, 8주 후에 각기 실험동물을 희생시키고 골결손부의 조직학적 검사를 시행하였다. 양 실험군은 대조군에 비해 골결손부에 새로운 골의 형성이 더 많이 되었고, Lyodura 군이 Micro filter꾼에 비하여 골형성이 더 이루어졌다. 본 실혐의 결과로 흡수성의 Lyodura가 GTR technique에 이용되는 Gore-Tex를 대치할 수 있는 매우 유용한 재료로 사료되었다. Many reports confirmed excellent biocompatibility and ability of bony regeneration of e-PTEE (Gore-tex membrane) in the Oral & maxillofacial field. At present, the term「Guided bone regeneration」and osteopromotion are mainly used in the literature for this membrane technique. Biologically membrane coverage of bone defects create a suitable environment for bone regeneration. However, disadvantages of high cost and necessity of membrane removal still remained. Recently, biodegradable membranes have been studied and used The present study was designed to consider the effect of lyodura and microfilter for replacement of Gore-tex membrane in rat s osseous defects. The experimental groups were divided into 2 groups. Group 1 is the lyodura group, Group 2 is the microfilter group. The control group was the contralateral angle defect without membrane coverage. Fullthickness bony defects to expose the marrow 8×8 mm in size were created in the right and left mandible angle of rats, and then lyodura and microfilter were covered on the left side and not covered in the right side as a control. Each group was sacrificed after 1 week, 3 weeks, 5 weeks, and 8 weeks after surgery and histologic examination was performed. Both experimental groups had earlier and more bone formation than the control group. The Lyodura group seemed to have more bone formation than the Microfilter group. These results suggest that Lyodura may be very useful in GTR for replacement of Gore-tex material.

유도조직재생술에 의한 발치창의 골치유 및 즉시 임프란트 매식에 대한 임상적 연구

박광호 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.2

Early implantation before sufficient ossification has taken place usually results in osseointegartion failure due to reduced bone-fixture interface area. However, various studies have shown successful osseointegration results following immediate implants concurrently with GTR. The clinical trends have been to shorten the patients' edentulous state by immediate implantation, and reduce the alveolar bone resorption. However, it may be difficult to attain the complete soft tissue coverage of the sites, increasing the chance of infection. Furthermore, there may be more studies needed on the clinical behaviors of e-PTFE membranes, various modofications in the membrane materials and bone graft materials. Various animal and clinical studies have been reported on the successful osseointagration following immediate implantation, but the long-term follow-up studies are limited. The present study investigated 16 immediately-implanted implants with GTR therapy with or without calcium carbonate grafting on 11 patients 3 years after installation and 24-30 months after functional loading. Based on the clinical, radiographic and histologic findings, the following results have been attained. 1. Clinically, stability has been shown on all 16 implants throughout the investigated periods. 2. Radiologically, the alveolar bone loss has progressed up to the polished neck portion but not beyond it, suggesting the progressive osseointegration from the GTR therapy. 3. The GTR method used in the present study is easy to use clinically, and may be appied in the regeneration of ossoeous defects around implants and in the immediate implantation. 4. The difficulty in complete tissue coverage may be avoided by delaying the installation for 2 to 3 weeks after the extraction allowing certain degree of soft tissue healing.

수종의 흡수성 차단막의 생체 분해도와 조직학적 반응

석헌주,권석훈,김창성,최성호,전동원,김종관,Suk, Hun-Joo,Kwon, Suk-Hoon,Kim, Chang-Sung,Choi, Seong-Ho,Jeon, Dong-Won,Kim, Chong-Kwan 대한치주과학회 2002 Journal of Periodontal & Implant Science Vol.32 No.4

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. With the development of non-resorbable membrane, GTR has proved to be the representive technique of periodontal regeneration. However, due to various clinical problems of non-resorbable membrane, resorbable membrane was developed and it showed to be clinically effective. The newly developed Para-Dioxanone membrane has a characteristic of non-woven fabric structures which is different from the generally used membranes with structure of mesh form. In addition, Chitosan membrane has been developed to apply its adventage maximally in GTR. Although a number of different types of membranes had been clinically used, researches on absorption rate of membranes were inadequate and limited to subjective opinions. However, since long term period of resorption and space maintenance are required in implant or ridge augmentation, accurate verification of resorption rate is clinically important. In this study, we had implanted Resolut(R), Biomesh(R), Para-Dioxanone membrane and Chitosan membrane (Size : 4mm ${\times}$ 4mm) on dorsal side of Sprague Dawley rat, and sacrified them after 4 weeks, 8 weeks, 12 weeks respectively. Histologic observation was carried out, and the following results were obtained by calculating the objective resorption rate. 1. In case of Resolut(R), external resorption took place initially, followed by internal resorption. Surface area are 5.76${\pm}$2.37$mm^2$, 4.90${\pm}$l.06$mm^2$, 4.90${\pm}$0.98$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.6${\pm}$4.5%, 52.8${\pm}$9.4%, 56.4${\pm}$5.1% respectively. 2. Biomesh(R) showed a pattern of folding, relatively slow resorption rate with small size of membrane. Surface area are 3.62${\pm}$0.82$mm^2$, 3.63${\pm}$0.76$mm^2$, 4.07${\pm}$1.14$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 26.1${\pm}$5.8%, 30.9${\pm}$3.4%, 29.2${\pm}$3.6%, respectively. 3. Para-Dioxanone membrane was surrounded by fibrous conncetive tissue externally, and resorption took place internally and externally. Surface area are 5.96${\pm}$1.05$mm^2$, 4.77${\pm}$10.76$mm^2$, 3.86${\pm}$0.84$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 30.7${\pm}$5.1%, 53.3${\pm}$4.4%, 69.5${\pm}$3.1%, respectively. 4. Each fiber of Chitosan membrane was surrounded by connective tissue and showed external resorption pattern. It showed little invasion of inflammatory cells and excellent biocompatability. The resorption rate was relatively slow. Surface area are 6.01${\pm}$2.01$mm^2$, 5.49${\pm}$1.3$mm^2$, 5.06${\pm}$1.38$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.3${\pm}$3.6%, 38.4${\pm}$3.80%, 39.7${\pm}$5.6%, respectively. Consequently, Para-Dioxanone membrane and Chitosan membrane are found to be clinically effective for their excellent tissue reaction and biocompatibility. Futhermore, the advantage of bone regenerating ability as well as the relatively long resorption period of Chitosan membrane, it might be widely used in implant or ridge augmentation.

니트릴고무/타이어고무분말(GTR)을 이용한 발포체의 발포 및 난연 특성에 관한 연구

문성철 ( Sung Chul Moon ),최재곤 ( Jae Kon Choi ),조병욱 ( Byung Wook Jo ) 한국고무학회 2002 엘라스토머 및 콤포지트 Vol.37 No.3

본 연구에서는 acrylonitrile-butadiene rubber(NBR)/타이어고무분말(Ground Tire Rubber, GTR) 블렌드계의 발포체를 제조하고, 이들의 난연성을 증진시키고자 하였다. 그 결과 난연제 중 유기인 화합물 및 무기금속 수산화물의 함량 증가에 따라 난연성이 증진됨을 확인할 수 있었다. 유기인 화합물의 경우 함량 증가에 따라 한계산소지수(LOI)가 증가하고, 열 방출 속도(HRR) 및 유효 연소열(EHC)이 감소하는 반면에 CO 방출률(량) 및 연기밀도가 증가함을 확인할 수 있었다. 무기금속 수산화물은 함량 증가에 따라 난연효과뿐 만 아니라 연기발생 억제효과를 동시에 가짐으로써 LOI, HRR, EHC가 유기인 화합물 첨가에서와 같은 경향성을 보여주었지만 CO 방출률(량) 및 연기밀도에 있어서는 유기인 화합물 첨가에서와 상이하게 감소하였다. 그리고 난연성을 판단함에 있어 중요한 변수들인 열 방출속도, 유효 연소열, 무게감소, 한계산소지수간의 상관관계를 확인하였는데, A-HRR과 LOI가 증가함에 따라 질량손실이 각각 증가 혹은 감소하는 뚜렷한 경향성을 확인하였다. 이로써 NBR/GTR의 조성비가 100~80/0~20 wt.%이고 고무/난연제의 조성비가 1/1.55~3.60 wt.%일 때, 원활한 핵의 생성 및 cell의 성장으로 인해 균일한 closed cell 및 semi-closed cell을 보여주었다. 또한 225~250 %의 발포율을 보이며, 낮은 HRR과 높은 LOI(28.0~39.3)를 갖는 난연성 및 발포성이 우수한 발포체를 얻을 수 있었다. The improvement of flame retardancy of the foams based on NBR/GTR compounds was conducted by formulating various materials i.e. NBR, GTR, inorganic and phosphorus containing flame retardants, foaming agent, cross-linking agent and activator. The foaming properties, morphology, smoke density and flame retardancy of the specimens were investigated using SEM, LOI tester, smoke density control system and cone calorimeter. The phosphorus containing flame retardant reduces heat release rate, increases the limiting oxygen index and a char formation. The inorganic flame increases the limiting oxygen index and reduces heat release rate with an increased CO yield by char formation, and smoke suppressing effect. The formed char seemed to intercept the oxygen transport and heat transfer into the core area. When the composition ratios of the compounds of NBR/GTR were 100~80/0~20 wt.%, and the ratios of the rubbers/flame retardants were 1/1.55~3.60 wt,%, we could developed foams with low heat release rate, high limiting oxygen index(28.0~39.3), closed or semi-closed cell of uniformity and reasonable expandability(225~250 %).

Halogen-free flame retarding NBR/GTR foams

최유성,최수경,Sung Chul Moon,Byung Wook Jo 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.3

The effectiveness of some halogen-free flame retardants (i.e. aluminium trihydroxide, red phosphorus, ammonium polyphosphate, di-melamine pyrophosphate and expandable graphite) in flame retardancy of acrylonitrile butadiene rubber (NBR)/ground tire rubber (GTR) foams, blown with azodicarbonamide has been investigated by means of cone calorimetry and limiting oxygen index tests. The GTR itself was effective to reduce flammability of NBR/GTR foams. The charring behavior and synergistic effect in flame retardancy of NBR/GTR foams filled with the flame retardants have also been considered. The results showed that the introduction of phosphorus compound and expandable graphite into the foam containing aluminium trihydroxide as a base flame retardant results in a processable and considerable flame retarding products. P and N containing flame retardant such as di-melamine pyrophosphate gave the highest flame retardancy in limiting oxygen index (LOI) test and in heat release rate of the NBR/GTR foams. The results also indicated that the P-N synergistic action was not only dependent on the component proportion of flame retardants used, but was also influenced to a great degree by the P₂O5/N ratios.

Halogen-free flame retarding NBR/GTR foams

Choi, Y.S.,Choi, S.K.,Moon, S.C.,Jo, B.W. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.3

The effectiveness of some halogen-free flame retardants (i.e. aluminium trihydroxide, red phosphorus, ammonium polyphosphate, di-melamine pyrophosphate and expandable graphite) in flame retardancy of acrylonitrile butadiene rubber (NBR)/ground tire rubber (GTR) foams, blown with azodicarbonamide has been investigated by means of cone calorimetry and limiting oxygen index tests. The GTR itself was effective to reduce flammability of NBR/GTR foams. The charring behavior and synergistic effect in flame retardancy of NBR/GTR foams filled with the flame retardants have also been considered. The results showed that the introduction of phosphorus compound and expandable graphite into the foam containing aluminium trihydroxide as a base flame retardant results in a processable and considerable flame retarding products. P and N containing flame retardant such as di-melamine pyrophosphate gave the highest flame retardancy in limiting oxygen index (LOI) test and in heat release rate of the NBR/GTR foams. The results also indicated that the P-N synergistic action was not only dependent on the component proportion of flame retardants used, but was also influenced to a great degree by the P<SUB>2</SUB>O<SUB>5</SUB>/N ratios.