• Elastomers and Composites
• /
• 제55권4호
• /
• pp.289-299
• /
• 2020

Highly aromatic (HA) oils are common processing aids used in tire tread compounds. However, they often bleed and evaporate from the vulcanizates during tire use. Thus, the mechanical and dynamical properties of the tire decrease. To overcome this problem, we investigated nonfunctionalized liquid butadiene rubber (LBR-305, Kuraray) and center-functionalized liquid butadiene rubber (C-LqBR), polymerized by anionic polymerization. In addition to the liquid butadiene rubbers, p-tert-octylphenol (P-Resin) and C5 hydrocarbon (H-Resin) tackifier resins, which can induce entanglement of rubber compounds, were researched as a processing aid to solve the bleeding problem. Liquid butadiene rubbers have significantly reduced extraction loss by crosslinking with the main rubber chain. They have also increased the abrasion resistance and showed similar or better mechanical and dynamical properties against HA oils. However, resin compounds did not show differences in extraction loss compared to HA oil compounds; instead, they showed increased wet traction.

• Elastomers and Composites
• /
• 제57권4호
• /
• pp.129-137
• /
• 2022

Low molecular weight liquid butadiene rubber (LqBR) is a processing aid that can resolve the migration problem of tire tread compounds. Various studies are being conducted to replace the petroleum-based processing oil with LqBR. However, the effect of the loading time of LqBR in the compounding process on silica dispersion and vulcanizate properties is not well known. In this study, we analyzed silica dispersion, vulcanizate properties, and viscoelastic properties of silica-filled tire tread compound according to the processing aid type (TDAE oil, non-functional LqBR) and, silane terminated LqBR) and input timing. In the non-functional LqBR compounds, the 'with TESPT' mixing procedure showed excellent dynamic viscoelastic properties while silane-terminated LqBR compounds showed that the 'after TESPT' mixing procedure was good for 300% modulus and abrasion resistance.

• Elastomers and Composites
• /
• 제56권3호
• /
• pp.152-163
• /
• 2021

Liquid butadiene rubber (LqBR) is used as a processing aid and plays a vital role in the manufacture of high-performance tire tread compounds. In this study, center-functionalized LqBR (C-LqBR) was polymerized with different vinyl content via anionic polymerization. The effects of the vinyl content on the properties of the compounds were investigated by partially replacing the treated distillate aromatic extract (TDAE) oil with C-LqBR in silica-filled rubber compounds. C-LqBR compounds showed a low Payne effect and Mooney viscosity regardless of the vinyl content, because of improved silica dispersion due to the ethoxysilyl group. As the vinyl content of C-LqBR increased, the optimum cure time (t₉₀) increased owing to a decrease in the number of allylic hydrogen. Moreover, the glass transition temperature (T_g) of the compound increased, and snow traction and abrasion resistance performance decreased, whereas wet grip improved. The energy loss characteristics revealed that the hysteresis attributed to the free chain ends of C-LqBR was dominant.

• Elastomers and Composites
• /
• 제43권2호
• /
• pp.113-123
• /
• 2008

에폭시 수지는 우수한 접착력, 높은 강도, 내크리프성, 내열성, 내화학성을 나타내는 열경화성 고분자이지만, 매우 깨지기 쉬우며 균열성장에 대한 낮은 저항성을 보여 낮은 충격강도를 보인다. 그러므로 본 연구에서는 에폭시 수지에 carboxyl-terminated butadiene acrylonitrile (CTBN) 및 amine-terminated butadiene acrylonitrile(ATBN)을 변량 첨가하여 에폭시 수지의 낮은 충격강도를 향상시키고자 한다. 에폭시/CTBN, 에폭시/ATBN복합체의 충격강도(impact strength)가 큰 값을 나타낼 때 표면자유에너지(surface free energy)의 비극성 값 또한 가장 큰 값을 보였으며, 반면에 인장강도와 유리전이온도는 감소함을 보였다. CTBN 및 ATBN을 각각 15 phr 첨가한 에폭시 복합체가 높은 표면자유에너지와 충격강도를 보였다. 결론적으로 액상고무의 첨가로 에폭시 수지의 취성을 향상시켰으며, 에폭시/CTBN보다는 에폭시/ATBN복합체의 물성이 더 우수하다고 사료된다.

• Journal of Electrical Engineering and Technology
• /
• 제13권2호
• /
• pp.918-927
• /
• 2018

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at $70^{\circ}C$ under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at $25^{\circ}C$ was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

• Elastomers and Composites
• /
• 제38권1호
• /
• pp.65-71
• /
• 2003

저분자량 SBR (액상 SBR)이 실리카로 보강된 SBR 배합물의 특성에 미치는 영향에 대해 연구하였다. 액상 SBR을 실리카로 보강된 SBR 배합물에 첨가하면 점도가 낮아졌다. 가교밀도는 액상 SBR의 함량이 증가함에 따라 감소하였고 가창속도는 느려졌다. 모듈러스와 인장강도는 액상 SBR의 함량이 증가할수록 낮아졌고 신율은 증가하였다. 마모 특성은 액상 SBR의 함량에 따라 큰 차이를 보이지 않았다. 이는 액상 SBR의 첨가에 의해 실리카 분산이 향상되었기 때문으로 여겨진다. 실험결과를 종합해 볼 때, 5 phr 이하의 적은 양의 액상 SBR을 사용하는 것이 실리카로 보강된 SBR 배합물의 특성을 향상시키는데 바람직할 것으로 판단된다.

• Elastomers and Composites
• /
• 제25권3호
• /
• pp.195-202
• /
• 1990

Rubber-modified polyurethane resin which was prepolymer type terminated with NCO, was synthesized by reacting isocyanate groups[NCO] and hydroxyl groups[OH]. Polybutadiene rubbers which had OH groups in the side of rubber chains, were charged at ratio $0%{\sim}40%$ of solid component in reactants. For products, physical properties were investigated experimentally. The results abtained in experiment were as follows. 1. Liquid resin and dried film was good solubility and clearity at less than 25%, 20% of rubber without being related to sort. 2. G-1000 showed better properties than R-45HT in solubility, dring time and adhesive strength. 3. Dring time and adhesive strength were considerably influenced by molecular weigh and structure of rubber. 4. In using 25% of mixed rubber(G-1000/R-45HT=50/50), It represented best properties in dring time(10 minute) and adhesive strength($23Kg/cm^2$).

• Elastomers and Composites
• /
• 제31권1호
• /
• pp.13-22
• /
• 1996

In order to Improve the fracture toughness of epoxy resin system, liquid chloroprene rubber(LCR) and liquid butadiene rubber (LBR) which have hydroxy group were used in the brittle epoxy system. Mechanical and toughness characterization of the modified epoxy resins were investigated as a function of liquid rubbers content. Epoxy resins modified with both of the liquid rubbers showed complete phase-separation microstructure : In all of the LCR content, it was observed that the domain size of LCR dispersed in the epoxy matrix ranging from $2{\mu}m\;to\;5{\mu}m$. It was found that fracture toughness, $K_{ic}$, of the modified LCR system was enhanced continuously as increasing LCR content. However around 10phr of LBR system showed maximum fracture toughness. Specifically, when BPA add to the modified LCR system, thermal and mechanical properties increased than neat epoxy. At the same time, fracture toughness was enhanced.

• Elastomers and Composites
• /
• 제28권1호
• /
• pp.13-21
• /
• 1993

Polyurethane resin was especially mixed with polybutadiene rubbers which had each other different molecular structures and functional groups. Liquid and cure properties were tested experimentally for mixtures. Viscosity of mixtures and drying time were influenced by solubility of thinner and reactivity of rubber. Adhesive strength represented maxium at rubber content $15{\times}22%$ (Wt. % ), and rapidly decreased over 25%. DBTDL(di-n-butyltindilaurate) showed the longest stroage stability.

• 대한화학회지
• /
• 제7권2호
• /
• pp.115-121
• /
• 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.