H. Harada

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Relationships between Chemical Structures of Crosslink Sites and Physical Properties of Vulcanized Rubbers. Part V. Analysis of Chemical Structures of Combined Sulfur in Crosslink Sites for Various EPDM Vulcanizates

Rubber Chemistry and Technology (1970)

Minoru Imoto Yuji Minoura Kunio Gotō H. Harada K. Nishihira

Abstract Various EPDM vulcanizates with different chemical structures of crosslink sites, such as C—C, C—R—C and C—Sz—C linkage, were obtained by using a variety of curing agents. C—Sz—C linkage was separated into polysulfide linkage and monosulfide linkage by using the LiAlH4 method which was confirmed beforehand with model compounds. The relationships between the chemical structure of combined sulfur in the crosslink sites and the type of curing agents used were clarified. For example, the mole ratios of polysulfide linkage to all the combined sulfurs in the vulcanizates by using DCP—S8, TMTD, S8—TMTD and S8-zinc dimethyldithiocarbamate curing system were respectively 0.35, 0.25, 0.53 and 0.82 at 160° C for 45 minutes. But in DCP—S8 curing system considerable C—C linkages seemed to be formed in addition to the C—Sz—C linkage.

Polysulfide

Chemical structure

Disulfide Linkage

10.5254/1.3547264

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Citations (1)

Synthesis and Evaluation of Potassium Hexatitanate Fibers with Negligible Leachability

Journal of the Ceramic Society of Japan (1995)

H. Harada Yukitsugu Kudoh Yasuo Inoue Hiromi Shima

A conversion process from potassium tetratitanate fibers into potassium hexatitanate was investigated to develop potassium hexatitanate fibers with negligible leachability which are usable as a filler for fiber-rein-forced polyester thermoplastic resins. Calcined potassium tetratitanate fibers were dispersed in water. By titrating the above mentioned suspension with an aqueous HCI solution to adjust the value of ([K+]/[H3O+])2/3=5.71×105 at 60°C, the fibers with TiO2/K2O=5.95 was obtained. The product thus obtained was heated at 1000°C for 30min, then potassium hexatitanate fibers having a tunnel structure were obtained. Then, the water soluble potassium was further removed with an aqueous HCI solution. Potassium hexatitanate fibers having a tunnel structure whose molar ratio of TiO2/K2O was 6.0 was obtainable. Water soluble potassium thus prepared was only 4 mass ppm. The potassium hexatitanate fibers prepared by the novel method developed by the present authors were found useful as a reinforcing material for polycarbonate which has been known to be vulnerable to soluble potassium.

10.2109/jcersj.103.155

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Citations (9)

Fabrication of Potassium Titanate Whisker Reinforced Aluminum Alloy (AC4C) Composite and Their Some Properties

Tetsu-to-Hagane (1989)

Isao Tsuchitori Akira Nitta Nobuhiko Hara H. Harada

The modified potassium titanate whisker being stabler at higher temperature was developed recently. This whisker was only composed of K2O· 6TiO2 which free from other chemical constitutions and, was used to make the preform with addition of small amount of inorganic binder. This preform was infiltrated aluminum alloy(AC4C) by squeeze casting, and the dimentional change of the composite was very small. Therefore, the K2O· 6TiO2 whisker reinforced aluminum alloy composite with lower volume fraction of the whisker could be fabricated without large deformation and distortion. Some properties of the composites were investigated. Tensile and hardness tests, measurment of elastic modulus, damping capacity, thermal expansion and thermal analysis were carried out. In particular, it was found that this whisker began to react with aluminum over about 1 123 K.

10.2355/tetsutohagane1955.75.9_1526

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Citations (2)

Preparation and Mechanical Properties of AC8A Aluminum Alloy Composite Reinforced with Potassium Titanate Whisker

Journal of the Japan Institute of Metals and Materials (1994)

H. Harada Yukitsugu Kudoh Yasuo Inoue Isao Tsuchitori

An AC8A aluminum alloy matrix composite reinforced with highly crystallized potassium titanate whisker having a crystallite size of 76 nm was fabricated by squeeze casting. Heat hardening behavior and mechanical properties were examined on the obtained composites whose Mg contents in the matrix were from 0.7 to 1.9 mass%.The Mg content and hardness of the composite were uniform at any locations. The composite whose Mg content in the matrix were 1.7 mass% solutionized at 803 K showed the highest strength value at room temperature and 573 K, respectively. And the Young’s modulus was as high as 138 GPa. The decrease in strength during exposure at up to 573 K was not observed. In particular, the properties of the obtained composite were found to be useful for the elevated temperature materials.

Mass fraction

10.2320/jinstmet1952.58.1_69

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Citations (7)

247 Development of a combined tilt-angle and acceleration sensor for evaluation of structural

The Proceedings of the Dynamics & Design Conference (2010)

Hiroyuki Furukawa Hajime OOURA Yosuke Masui Satoru Koshimizu H. Harada

It is thought that it is effective to measure the change in the tilt-angle and the change in the intrinsic period for evaluation of structure. The field test with the bridge was executed by using a combined tilt-angle and acceleration sensor, and the control panel that had been developed this time. It is thought that the measurement of a steady tilt-angle and the measurement of the intrinsic period by the acceleration are possible as a result of the test.

Tilt sensor

10.1299/jsmedmc.2010._247-1_

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Citations (0)

CCDC 2067452: Experimental Crystal Structure Determination

The Cambridge Structural Database (2021)

Yuka Hashimoto Sasuga Hosokawa Fengying Liang Yuto Suzuki Namin Dai

10.5517/ccdc.csd.cc27dc01

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Photo-on-Demand Base-Catalyzed Phosgenation Reactions with Chloroform: Synthesis of Arylcarbonate and Halocarbonate Esters

The Journal of Organic Chemistry (2021)

Yuka Hashimoto Sasuga Hosokawa Fengying Liang Yuto Suzuki Namin Dai

Carbonate esters are utilized as solvents and reagents for C1 building blocks in organic synthesis. This study reports a novel photo-on-demand in situ synthesis of carbonate esters with CHCl3 solutions containing a mixture of an aromatic or haloalkyl alcohol having relatively high acidity, and an organic base. We found that the acid–base interaction of the alcohol and base in the CHCl3 solution plays a key role in enabling the photochemical reaction. This reaction allows practical syntheses of diphenyl carbonate derivatives, haloalkyl carbonates, and polycarbonates, which are important chemicals and materials in industry.

Base (topology)

Organic base

Organic Synthesis

Propylene carbonate

10.1021/acs.joc.1c01210

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Citations (17)

Effect of Si Content and Heat Treatment on Hardness and Bending Strength of 2024 Alloy Reinforced with Potassium Hexatitanate Fibers

Journal of the Japan Society for Composite Materials (1996)

H. Harada Yasuo Inoue Hiromi Shima

10.6089/jscm.22.214

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THE PEROXIDE OF EPDM AND EPM IN THE PRESENCE OF C=C UNSATURATED ORGANIC COMPOUNDS (II)

NIPPON GOMU KYOKAISHI (1970)

M. Imote Yuji Minoura K. Goto H. Harada K. Nishihira

EPDMおよびEPMのペルオキシド加硫におけるジエン系液状ポリマー, 液状ポリクロロプレン (以下液状CRとする) および液状ポリスルフィド (以下液状TKとする) の添加効果を求めた.ジエン系液状ポリマーとして主鎖にオレフィン性二重結合を含んだ1.4ジエンポリマー (液状SBR, 液状NBR) と側鎖にビニル基をもった1.2ジエンポリマー (液状1.2BR) を用いた.EPDMおよびEPMのペルオキシド加硫におけるムーニスコーチレートはジエン系液状ポリマーの添加により遅延され, 液状CRの添加により促進された. また液状TKはEPDMに対してはスコーチを速める効果があり, EPMに対しては遅らせる効果が認められた. しかしEPDMのイオウ加硫の場合には液状1.4ジエンポリマー (SBR, NBR) はムーニスコーチレートを促進し, 液状1.2ジエンポリマー (1.2BR) は逆に遅らした.加硫物の橋かけ密度 (νs), 引張応力, 引張強さおよびかたさは, 液状SBR, 液状NBRおよび液状TKの添加により減少し, 液状1.2BRおよび液状CRの添加により増大した. また上記液状ポリマーはいずれもEPMのペルオキシド加硫物の耐熱老化性を大きく改善することが認められた.

Peroxide

EPDM rubber

10.2324/gomu.43.29

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Citations (3)

THE EFFECTS OF C=C UNSATURATED COMPOUNDS ON THE PEROXIDE CURE OF EPDM AND EPM

NIPPON GOMU KYOKAISHI (1969)

Minoru Imoto Yuji Minoura K. Goto H. Harada K. Nishihira

ポリマーとビニルモノマーの混合物をジクミルペルオキシドを用いて重合と架橋を同時に行ない, 得られた加硫物の物性とポリマー/ビニルモノマー混合比の関係を求めた. 使用したポリマーはEPDM, EPM, エチレン-酢ビ共重合体 (EVAC), BR, IRでビニルモノマーはトリデシルメタクリレート (TDMA), エチレングリコールジメタクリレート (EGDMA), トリメチロールプロパントリメタクリレート (TPTMA) および混合モノマー (TDMA/EGDMA, TDMA/TPTMA) であった.EPDM/TDMA (50/50) のペルオキシド加硫物を溶剤を用いて抽出分別し, 抽出分および抽出残分をIRで確認した結果, 加硫中にTDMAのホモポリマーとグラフト重合物が同時に生成することが明らかにされた. また, 位相差顕微鏡による観察の結果, ポリマー/ビニルモノマーブレンド系の方がポリマー/ビニルポリマーブレンド系よりも分散状態が良好であることがわかった.

Peroxide

10.2324/gomu.42.921

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Citations (4)