• Elastomers and Composites
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• v.32 no.5
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• pp.302-308
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• 1997

Over 1953/54 Karl Ziegler and Giulio Natta independently discovered new types of catalyst. Thus it was able to produce synthetic cis-polyisoprene rubber which has same properties like natural rubber, since then the amount of consumption was increased rapidly. The problem of disposing of used rubbers has become acute in recent years. cis-Polyisoprene was degraded in supercritical tetrahydrofuran and degree of degradation and product were observed by GPC, FT-IR, GC-MS analyses. As a result, degradation of cis-polyisoprene had small dependency upon the operating pressure, and was inhibited in concentration increase. And cis-polyisoprene was degraded into narrow molecular weight distribution oligomer in 3 hours, and more than 10 organic compounds were produced.

• Elastomers and Composites
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• v.18 no.4
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• pp.140-147
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• 1983

The purpose of this dissertation is to increase oxidation resistance for Polybutadiene & Polyisoprene, and to investigate the energetics of inhibited oxidation of Polybutadiene & Polyisoprene stabilized with various types of antioxidants using DSC. The results of the study are as fellows: 1. In the DSC SCREEN for the onset temperature of oxidation, Polybutadiene was faster than Polyisoprene for the samples containing no antioxidant in air. 2. In the DSC evaluation for Polybutadiene, Recipe BG-4 with 2.0phr compounds of antioxidant was the best effective, and Recipe BS-4 with 2.0phr compounds of antioxidant was the worst effective, and the degrees of effect of antioxidant were exhibited in the ranking of G-1, D, BHT, and SP, roughly. 3. In the DSC evaluation for the Polyisoprene, Recipe IG-4 with 2.0phr compounds of antioxidant was the best effective, and Recipe ID-4 with 2.0phr compounds of antioxidant was the worst effective, and the degrees of effect of antioxidant were exhibited in the ranking of G-1, SP, BHT, and D roughly. 4. In the study on enthalpy which depends on exothermal reaction, the enthalpy of Polyisoprene was gloater than that of Polybutadiene. However, the problem was not solved completely, and it needs further studies.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1853-1855
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• 2005

• Elastomers and Composites
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• v.55 no.3
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• pp.199-204
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• 2020

Considering the immense applicability of isoprene rubbers, such as natural rubber (NR) and synthetic polyisoprene rubber (IR), attempts are being made to introduce more functionality within the rubber structure, e.g. epoxidation, to widen their technological viability. Epoxidation introduces polar epoxy bonds into the rubber molecular chain, resulting in enhanced intermolecular interactions among the rubber chains, increasing the oil resistance and air impermeability. Although there have been many reports on the epoxidation of NR in its latex form, there has been no such report using its solid form (or gum), which limits the epoxidation in terms of portability. Furthermore, the gum form has longer lifetime, while the latex form has limited lifetime for its efficient use. In this study, the epoxidation of natural rubber and polyisoprene rubber (using meta-chloroperoxybenzoic acid (mCPBA) as the epoxidizing agent) by dissolving their gum in hexane (i.e., the solution method) have been studied and compared. The effects of the amount of mCPBA, reaction time, and reaction temperature were investigated. The present process is easy and facilitates the epoxidation of rubbers in their solid form; therefore, it can be used for industrial upscaling of epoxidized rubber production.

• Elastomers and Composites
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• v.12 no.1
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• pp.9-19
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• 1977

• Elastomers and Composites
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• v.8 no.1
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• pp.81-91
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• 1973

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.115-121
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• 1963

Aliphatic hydrocarbon gases from rubber pyrolysis have been identified by gas chromatography with tetraethyleneglycol dimethylether column. Rubbers used in this work are polyisoprene, SBR, NBR, polybutadiene, buthyl rubber, polychloroprene and polyurethane rubber. The chromatogram is characteristic for each polymer. Author proposes a method of identification of synthetic rubbers by gas chromatograph of pyrolyzed gas. Sample is pyrolyzed at $450^{\circ}C$ under nitrogen or more effectively helium and gaseous portion, which eliminated liquid condensate, is passed to the column. The appearance of exclusively large peak of isoprene, isobutylene and carbon dioxide shows the presence of polyisoprene, polyisobutylene and polyurethane, respectively. Large peak of butadiene will appear in case of polybutadiene, SBR and NBR, but SBR can be identified through the styrene peak in gas chromatogram of liquid pyrolyzate and NBR can be identified by the evolution of hydrogen cyanide during pyrolysis. Polychloroprene is identified by the evolution of hydrogen chloride. This method could be applied to the identification of copolymer or polymer blend.

• 보존과학연구
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• s.27
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• pp.215-226
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• 2006

In the field conservation treatment, it is important that the method chosen to lift an object out of the ground depends on its surrounding weather, strength, size, composition, and condition. This paper describes a physical support(Urethane bandage, De naturation - polyisoprene resin) created for lifting delicate relics in this field. The advantage of Urethane bandage method is of conveniently portable size, and it's convenient for use, while curing time is very fast.(approx. 5~10minute)Denaturation -polyisoprene resin is able to be soft by the hot water(approx. $60^{\circ}C$ ). so it's good to stick to the relic surface of an indeterminate form. The results of use of these reinforcement methods are of utility value.

• Elastomers and Composites
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• v.3 no.1
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• pp.62-74
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• 1968

천연(天然)고무 및 합성(合成) 고(高) cis 1 : 4 polyisoprene, 대표적(代表的)으로 'Natsyn 400'의 가공(加工), 배합(配合) 또는 가황체(加黃體)의 성질(性質)들의 차이점(差異點)들에 대(對)하여 설명(說明)하였다. 합성중합체(合成重合體)는 미리 소연(素鍊)함이 없이 충전제(充塡劑)를 첨가(添加)함으로서 가공(加工)이 용역(容易)하였으며 CV형(形) 천연(天然)고무에 있어서도 이점(利點)이 나타났다. 천연(天然)고무 배합물(配合物)은 점착성(粘着性)이 좋으며, 특(特)히 미가황물(未加黃物)의 강도(强度)가 현저(顯著)하게 우수(優秀)하다. 가황과정(加黃過程) 및 몇몇가황체(加黃體)의 성질(性質)에 있어서의 차이(差異)는 비(非)고무질(質)을 함유(含有)하지 않는 Natsyn으로 나타난다. 기타(其他)의 가황체성질(加黃體性質)의 차이(差異)는 천연(天然)고무에 있어서 그 가황체(加黃體)가 인장시(引張時)에 결정(結晶)하는 경향(傾向)을 크게 나타내고 있고 특(特)히 고온(高溫)에서 이들 차이(差異)가 현저(顯著)하다.

• Bulletin of the Korean Chemical Society
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• v.20 no.7
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• pp.853-856
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• 1999