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Volume 49, Issue 3
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[in Japanese]1976 Volume 49 Issue 3 Pages 161
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSDownload PDF (133K) -
Shinzo Yamashita, Shinzo KOHJIYA, Katsumi SANDO, Masayuki TAMURA1976 Volume 49 Issue 3 Pages 162-168
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSCopolymerizations of 1-chlorobutadiene and butadiene were carried out by emulsion polymerization techniques to produce 1-chlorobutadiene-butadiene rubber (CB-BR).Both low-temperature (5°C) and high-temperature (50°C) polymerizations gave high molecular-weight CB-BR's.The obtained CB-BR was found to contain hydroxyl group which appeared to be produced by the hydrolysis of active chlorine attached to CB-BR.The hydroxyl content in CB-BR was determined by ultraviolet spectroscopy.Heating of the CBBR latex it was found to raise the hydroxyl content in CB-BR.Thus, the novel butadiene rubber containing three kinds of chemically functional groups, i. e., -C=C-, -Cl and -OH, permitted various chemical modifications.As for non-sulfur vulcanization, the following chemicals were found to be effective curatives; 2-mercaptoimidazoline, diamines, ethanolamines, diisocyanates, acid anhydride-diepoxy systems, and acid anhydride-zinc oxide system.Amine antioxidants having tertiary amino group were shown to act as reactive antioxidants upon CB-BR.View full abstractDownload PDF (937K) -
Akihiro KAWASAKI, Tsuyoshi MATUMOTO, Masanobu TANIGUCHI, Isao MARUYAMA ...1976 Volume 49 Issue 3 Pages 169-178
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThe process for preparing propylene-butadiene alternating copolymer rubber (PBR) was invented by us for first time.The production cost of PBR is now estimated to be quite comparable to that of solution SBR.
As a result of our laboratory test, PBR was found to be a possible tire rubber or general purpose rubber with overall properties intermediate between natural rubber (NR) and SBR.
The most possible advantage of PBR is a better retention of physicals on heat-aging than general purpose rubbers now available such as NR, polycisisoprene (IR), polycisbutadiene (BR) and SBR.A crosslinked structure is formed and hardening-type degradation occurs on heat-aging of SBR and BR.On the other hand, PBR vulcanizate shows breakdown-type degradation on heat-aging as can be seen in the case of NR and IR. However, the degradation rate of PBR is remarkably lower than that of NR and IR under the conditions described in this paper.View full abstractDownload PDF (1146K) -
Masanori KAKEI, Hiroshi NAMIZASHI, Kyoichi MISHIMA, Satoshi MASHIMO, T ...1976 Volume 49 Issue 3 Pages 178-182
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSSulfur vulcanizable acrylic elastomers were prepared by the copolymerization of ethylacrylate and ethylidenenorbornene with suspension polymerization system.Redox system was used as radical polymerization initiator. Minimum value was observed at around 6°C in tensile strength and elongation of the vulcanizates when the reaction temperatures were varied from2 to 21°C. The polymer prepared at 2°C gave the best result in physical properties of the vulcanizate.When vulcanized with polysulfide cure system they showed better heat resistance than those of monosulfide cure system even after14days of heat aging at150°C.View full abstractDownload PDF (515K) -
Hiromi TANNO, Hiroshi SAMESHIMA, Yoshitaka TAKANO, Katuhiro ONO, Kenic ...1976 Volume 49 Issue 3 Pages 182-189
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSWe blended poly bd R-45HT to PPG-2000andcured by one shot methodusing diisocyanate and we examined the change of physical properties on the other hand the PPG-2000blended poly bd R-45HT cured 40minutes at 120°C and take sample out of the mold easily.It seemed that the curing time was influenced by the highreactivity of poly bd R-45HT to diisocynate. Low temperature property and insulating property of blended product were improved by poly bd R-45HT.On the thermal resistance it was improved by increasing the curing time.
Then we blended poly bd prepalymer to ester or ether type poly urethane prepolymer and cured by prepolymer method.By blending poly bd prepolymer lower tensile strength was obtained but owing to the low palarity of paly butadiene water rasistance low temperature property and insulating property were imperoved.As the sametime permanent set at high temperature was remarkably improved.We shoud think that the high reactivity of poly bd prepolymer tend to take part not only in the chain extending but also in the closslinking effocoemcu greatly.View full abstractDownload PDF (1024K) -
Yutaka OBATA, Masaru IKEYAMA, Masahiro NIINOMI1976 Volume 49 Issue 3 Pages 190-194
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSIn order to investigate the relationship between the molecular configuration and the bulk properties of syndiotactic 1, 2-polybutadiene, a series of samples with different degrees of crystallinity (below 46%) were prepared by the method reported previouly by Takeuchi et al.
Infrared and C13-NMR spectra indicated that the content of 1, 2 unit with syndiotactic configuration is mainly responsible for the degree of crystallinity.
Morphological observation of the samples was made by means of electron microscope using the ultrathin sections stained by OsO4. It was found that the crystal is composed of radiating fibrils whose diameter is about 30±5 Å in all cases, which is five to seven times as large as the length of c axis. DSC thermogram of the samples indicated that the melting behavior is very similar to that of copolymers with crystallizable and non-crystallizable components, in the following points. 1) The thermogram has a wide melting temperature range. 2) The melting temperature depends greatly on the content of syndiotactic 1, 2 unit.
By applying Flory's theory concerning the melting temperature of a copolymer, the following fact was made clear, that is, the propagation probability of the crystallizable unit (synd. 1, 2) is expected to be much larger than the content of the component and nearly unity.
The above results conclude that the polymer chain propagates in a manner similar to that of a block copolymer.View full abstractDownload PDF (3211K) -
Yasuyuki TANAKA, Hisaya SATO1976 Volume 49 Issue 3 Pages 195-201
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESS13C-NMR spectra were investigated on1, 4-polyisoprenes containing various ratios of cis and trans structures and fon hydrogenated polyisoprenes prepared with various kinds of catalysts. Signals were assigned as diad or triad sequences of cis and trans units or of 1, 4 and 3, 4 units. Distributions of isomeric structures were studied on these polyisoprenes.It is revealed that cis and trans units were randomly distributed in cis trans isomerized1, 4-polyisoprenes and that chicle was a mixture of cis and tram homopolyisoprenes. It is disclosed that 1, 4 and 3, 4 units were randomly distributed in n-BuLi/Et2O, CoI2-ROH-PhMgBr, and radical catalyzed polyisoprenes, rather alternatingly in Ti (OBu) 4-AlEt3 catalyzed polyisoprene, and slightly blocky in alfin polyisoprene. It is also confirmed that significant amounts of head-to-head and tail-to-tail linkages of 1, 4 and 3, 4 units were present in alfin, radical, and cobalt catalyzed polyisoprenes.View full abstractDownload PDF (753K) -
Masayuki YAMADA, Masaki OHARA, Yusuke SAKURAMOTO, Takashi WATANABE1976 Volume 49 Issue 3 Pages 202-210
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSWe synthesized2, 6-substituted-4-dimethylaminomethyl phenols and studied the effect of these reagents on the vulcanization of CR.In the presence of zinc oxide and magnesium oxide, 2, 6-substituted-4-dimethylaminomethyl phenols acted as accelerators in the vulcanization of CR, delayed scorch action and gave rapid cure rate.In the extracts of vulcanizates with2, 6-di-tert-butyl-4-dimethylaminomethyl phenol, phenol derivatives without N-atoms were identified.And by analysis of generating gas, dimethyl amine could be found.
We can conclude that dimethyl amine acts as an effective accelerator of CR and2, 6-substituted-4-dimethylaminomethyl phenols, dimethyl amine salts such as those of3, 5-dinitrobenzoic acid, hydrochloric acid are new powerful accelerators in the vulcanization of CR.View full abstractDownload PDF (987K) -
Masashi UMENO, Junji FURUKAWA, Shinzo YAMASHITA1976 Volume 49 Issue 3 Pages 210-217
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSApparent dynamic moduli S and loss moduli S of various raw diene rubbers were determined on the basis of measured torque S* and loss angleδat6cpm of frequency and±3degrees of amplitude, using the Curelastometer, i. e., oscillating die curemeter.The experiments yielded the characteristic relationship between S and S for the respective rubbers.
The moduli S, S and stress relaxations of cis-1, 4-polybutadiene stocks were also determined continuously in the process of vulcanization. Curing systems used were dicumyl peroxide (DCP), tetramethylthiuramdisulfide-zinocx ide (TT-ZnO) and diphenylguanidine-suefur (DPG-S). The moduli S increased with an increasing crosslink densityνdetermined by equilibrium swelling measurements. The values of S also increased with the progress of vulcanization, but gave maximum value at definit ν, beyond which S decreased with an increasing the crosslink density.The relation was influenced by the type of curing system, and S increased in the order of DPG-S>TT-ZnO>DCP at the same νvalues in the range of S≤20 kg-cm.
The DCP vulcanizate showed the lowest relaxation, but relaxed to some extent at lower range of ν.
Some discussions were made on these results in connection with the structure of the crosslinks.View full abstractDownload PDF (855K) -
Yutaka KAWAOKA, Hideo ODA, Hideo KAWAOKA1976 Volume 49 Issue 3 Pages 217-222
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESS2-Cyclohexyldithiobenzimidazole (CDTB) react with2-mercaptobenzothiazole (MBT) immediately to give2-cyclohexyldithiobenzothiazole (CDB) which is a fairly delayed action accelerator and 2-mercaptobenzimidazole (MBI) which is a good retarder to CDB.
The reaction products of CDTB with dibenzothiazyl disulfide (MBTS) were CDB and dibenzimidazyl disulfide (DBID).
The reactions of CDTB with sulfenamide accelerators did not occur so fast as those with MBT or MBTS, but DBID, CDB and moderately active accelerators, i.e., cyclohexylthioamines were obtained.
The reaction products of CDTB with various thiuram disulfides were cyclohexylthiocarbamyl disulfides (CTDS) which are effective retarding action accelerators and DBID which is a good retarder to CTDS.
The function of CDTB as a good prevulcanization inhibitor in a sulfur curing system may be due to the removal of accelerators, forming MBI, DBID, CDB, CTDS or cyclohexylthioamines.View full abstractDownload PDF (716K) -
Kumakazu OHKITA, Norio TSUBOKAWA, Naomitsu TAKASHINA1976 Volume 49 Issue 3 Pages 223-230
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThe polymerization of vinyl monomers has been carried out in the presence of carbon using initiators such as benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) in nitrogen or oxygen atmosphere. The results indicate that free radicals formed by the decomposition of initiators, beside the inherent unpaired electrons of carbon black, react with carbon blacks to give active sites on their surface which then capture either the free radicals or the growing polymer radicals.Using the monomers with negative e values, such as styrene and vinyl acetate, a marked retardation was observed in BPO-initiated polymerizations in the presence of furnace black.On the contrary, using the monomers with positive e values, such as methyl methacrylate and acrylonitrile, carbon black-BPO system acted initially as an inhibitor and then as an accelerator. The phenomena may be responsible for the newly formed unpaired spins having an electron acceptability. On the other hand, it was shown that furnace black-AIBN system is almost independent of the e values of monomers.
Furthermore, it was found that the reaction of BPO with furnace black in the presence of oxygen gives a newly quinonic oxygen on the surface. As the result, the polymerization reactions using BPO in oxygen were found to promote grafting of the growing polymer radicals onto the surface of furnace black, consequently giving polymer-grafted particles while hindering the formation of homopolymers.View full abstractDownload PDF (1093K) -
Tokuzo NUKUI, Kazuhiko KAIDA, Yonemasa FURUSAWA, Masafumi ARAKAWA, Eij ...1976 Volume 49 Issue 3 Pages 230-235
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThe properties of the dry ground clays and the SBR compounded with them were examined.It was shown that the changes in particle surface properties as well as the changes in specific surface area by grinding were related to the physical properties of rubber.
The immersion heat had a good correlation with the rubber properties. Mooney viscosity was related to the immersion heat in water, and scorch time was related to the immersion heat in ethyl benzene.Tensile strength increased with the specific surface area of filler;there was a maximum at which the tensile strength began to decrease abruptly as the specific surface area increased.In the rubber compounded with high ground clay, the filler particles were not well dispersed and could be found as agglomerate.It seems that a decrease of tensile strength of the rubber compounded with the high ground clay causes the difficulty of dispersion of filler.View full abstractDownload PDF (3154K) -
Kenjiro HASHIMOTO, Minoru MIURA, Shinichi TAKAGI, Harunori OKAMOTO1976 Volume 49 Issue 3 Pages 236-241
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThe co-curing of EPDM and diene rubbers has been discussed about cure rate, compatibility and preferential reaction of curatives between each polymer.We studied on the co-curing of EPDM and NR whose cure rates are largely different.We attempted to make the degree of crosslink equal by blending NR with the pendent sulfur EPDM which was reacted with sulfur and accelerator without zinc oxide.
According to the result, the values of tensile strength and elongation at break of P-EPDM/NR blends were higher than those of EPDM/NR blends.It is shown that a marked improvement in their compatibility is accomplished by P-EPDM and that the pendent sulfur groups combined with EPDM plays an important role for the co-curing of EPDM and NR.View full abstractDownload PDF (656K) -
Kenjiro HASHIMOTO, Minoru MIURA, Yasuo SUMIYOSHI, Masayoshi NAKAJIMA1976 Volume 49 Issue 3 Pages 241-245
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThere were many studies on the co-curing in dissimilar elastomer blends and the problems of the interfacial crosslink in blend have received recent attention.
In order to resolve these problems, we attempted to measure the average distance between vulcanization points and to analyze the photograph of electron microscope in EPDM/NR blend. As a result, it was found that the crosslink of EPDM phase in EPDM/NR blend gradually increased with progress of cure time but the co-curing could not be achieved because of no forming of the interfacial crosslink between EPDM and NR phase. On the other hand, it was found that the network chain of P-EPDM phase in blend was not formed sufficiently, although much improvement was made over EPDM/NR blend, but the co-curing could be achieved because of forming of the interfacial crosslink in blending NR with the pendent sulfur EPDM which was reacted with sulfur and accelerator without zinc oxide.View full abstractDownload PDF (3194K) -
Kenjiro HASHIMOTO, Minoru MIURA, Takahide MIZUNO, Harunori OKAMOTO1976 Volume 49 Issue 3 Pages 246-250
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSIn our previous paper, it was reported that the covulcanization of EPDM with NR was much improved by addition reaction of sulfur compounds to EPDM under heating before blending it with NR. In this paper, the covulcanization was discussed by measuring hysteresis loss, strain energy and constant stress fatigue life. Practical application to the side-wall of bicycle tire was evaluated.
It was found that vulcanizate of P-EPDM (EPDM with pendent sulfur) with NR showed good covulcanization behavior. But the blend of EPDM with NR did not covulcanize satisfactorily and EPDM portion worked as flaws in constant stress fatigue life test. Mechanical crack was observed on the tire of EPDM-NR blend in the early stage of field test, but no crack on one of P-EPDM-NR blend even after 2-year field test.View full abstractDownload PDF (2937K) -
Yuichi INUKAI, Syobu MINATONO, Takashi KAGEYAMA, Hiroshi HARIMA1976 Volume 49 Issue 3 Pages 251-256
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSAlthough Ziegler catalized synthetic cis-1, 4-polyisoprene resembles natural rubber, the latter shows a marked superiority in green strength.The purpose of this paper, therefore, is to investigate why natural rubber shows such superiority in green strength, and thus the relationship between stress-strain curve and linear viscoelastic properties has been investigated.Moreover, molecular characteristics of natural rubber and synthetic cis-1, 4-polyisoprene and interactions between rubber molecuies and fillers have been studied in order to analyze differences in above-mentioned relationships between natural rubber and synthetic rubbers.
The superiority of natural rubber in green strength may be caused by higher mean molecular weight and broader distribution of molecular weight in case of unfilled rubber, and by higher crystallizability and stronger interaction between rubber molecules and fillers in addition to higher mean molecular weight and and broader distribution of molecular weight in case of filled rubber.View full abstractDownload PDF (651K) -
Yoshiteru KAZAMA, Yuzo SUMIDA, Hiroko OGAWA, Setsuyo OKAI1976 Volume 49 Issue 3 Pages 256-263
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSSome basic stress-strain behaviors of plasticized PVC have been investigated in terms of the Mooney-Rivlin equation as a function of temperature, strain-rate and the sort and concentration of plasticizer.From these results, it was found that the pattern of the Mooney-Rivlin isotherm is parabolic below Tg, and turns out convex above TgA linear isotherm can be observed both around Tg and well above Tg.
In order to elucidate this behavior theoretically, the three-elements modle comprising an ideal rubber element (ER) combined in parallel with a Maxwell unit (EH, η;η/EH=τH) was presented as the simplest system manifesting the simultaneous reaction of the entropy tension and the energgy tension thermodynamically not in eguilibruim.
On the bas is of the present model, the two constants in the Mooney-Rivlin equation are related with the mechanical parameters as follows: 2C1=ER, 2C2=EH/3 and 2C2=ηγ. The theoretical Mooney Rivlin isotherm in accordance with the experiments reveals the change of the pattern from parabolic to convex with an increasing value of reduced relaxation time, τHγ
Some experimental verifications of the theory were made in comparison with the data obtained from the capillary-flow and the stress relaxation measurements.View full abstractDownload PDF (771K) -
Junji FURUKAWA, Hiroshi OKAMOTO, Shinji INAGAKI1976 Volume 49 Issue 3 Pages 263-270
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThe equation of rubber elasticity proposed by the authors on the basis of the average network chain principle is applicable to explanation of uniaxial stress-strain behavior of rubber vulcanizates at large defor-mation for both the extension and the retraction curve of hysteresis cycle.But the plotted line is usually observed to deviate some what from a straight line at the point of small deformation region.The suthors considered this deviation as due to the internal viscosity of rubber vulcanizates and carried out to analyzed this problem molecularly by means of the three element viscoelastic and the pseudo crosslink network model. As a result of the analysis by means of the three element viscoelastic model, the parameter b or b which is introduced in the presented equation as a correction term is recognized as a value depending on the internal viscosity coefficient of vulcanized rubber and the strain rate of deformation. These dependencies were confirmed experimentally.
The correction terms b and b were also recognized experimentally to be proportional with the C2 term of the Mooney-Rivlin plot.
Then, the molecular meaning of the C2 term became more definite.
These experimental tendencies were also recognized in the case of a higher oil extended SBR vulcanizate. On the other hand, the difference between the values of b and b, and thixotropical properties as an example of hysteresis phenomenon cannot be explained by means of the viscoelastic model.
Then, the authors assumed an entanglement of network chain due to the intermolecular force as the secondary crosslink, and analyzed its change kinetically and could successfully explain the hysteresis phenomenon.View full abstractDownload PDF (904K) -
Yoshihiro TODANI, Shizuye SAGAYE, Hirokatsu SEYA, Nagatoshi SUGI1976 Volume 49 Issue 3 Pages 270-275
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSTensile properties of pure rubber, precipitated CaCO3 filled and carbon black-reinforced SBR vulcanizates under biaxial extension were measured.Observation by electron-microscope under extension was done. In the case of biaxial extension, it is observed that the average extension ratio of rubber chains at break is proportional to the crosslink density to the minus one-half power and it is assumed that a fracture of speciman occurs when rubber chains are fully extended.In the same case, there are low-density, plane-like structures which are1000A thick and run parallel to the extension direction.Those low density structures may be related to the generation of energy elasticity of reinforced rubber.View full abstractDownload PDF (3435K) -
Tasuku SAITO, Tadatoshi YAMADA, Tsutomu MATSUNAGA1976 Volume 49 Issue 3 Pages 276-280
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSVery few techniques are known which are applicable to the three dimensional stress analysis of rubber products under large deformation.
In this paper a new method of three dimensional stress analysis under large deformation will be demonstrated. This method is based on the new findings about photo-plastic properties of segmented polyurethane (PUR).It was shown that a segmented PUR makes a progressive change in the birefringence from positive to negative when it is heated at high temperature under constant deformation.The negative birefringence as well as positive one relates linearly to the elastic strain.The photo-plasticity in this study may be applied to the three dimensional problems under large deformation.View full abstractDownload PDF (2988K) -
Setsuo FUKUHARA, Yasuo SUZUKI, Shigeo OMOTE, Chozou KUWAYAMA1976 Volume 49 Issue 3 Pages 281-287
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSTire cords have to survive the effects of heat encountered in a heat set oven and during the vulcanization process of tire, but they do suffer degradation under certain conditions. This paper presents a study on the relationship between the decrease of tensile strength and the change in the fine structure of nylon 6 tire cords induced by heat treatment.
The following results were obtained.
(1) The effects of steam-heat treatment on the fine structure and tensile strength of nylon 6 were stronger than those of dry-heat treatment.
(2) Degradation in the degree of polymerization and distinct change in fine structure of nylon 6 by steamheat treatment cause a distinct decrease in the tensile strength of nylon 6 tire cords.
(3) The decrease in the strength in nylon 6 tire cords which were heated at high temperatures above 150°C under tension and rapidly shrunk was attributable to its rapid shrinkage at high temperatures.
The decrease in the strength of nylon 6 tire cords with heat treatment is mainly attributable to (a) dry heat-treatment (b) steam-heat treatment, and also (c) its rapid shrinkage in length immediately after the vulcanization process at high temperatures.View full abstractDownload PDF (9976K) -
Yukio MAEDA, Hiroshi KAGA, Yoshihiro MATSUSHITA1976 Volume 49 Issue 3 Pages 287-292
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThis paper describes a newly developed tire traction test vehicle and several fundamental results of measured by the test vehicle. Using this test vehicle, one can obtain the relationships between tractive force coefficient and slip ratio on actual road surface under steady state conditions ranging from free rolling to locked wheel, between laleral force coefficient and slip angle, between aligning torque and slip angle, and between rolling resistance and slip angle. The test results described here show the influence of road surfaces to tire traction, the influence of the number of circumferential grooves in a tire on wet asphalt, and the influence of fundamental tread patterns on snow covered road surface.View full abstractDownload PDF (5253K) -
Tadao OHKITA, Kazuyoshi AOKI, Mituo SAKURAI, Shinichi OZIKA, Kohzi SHI ...1976 Volume 49 Issue 3 Pages 293-298
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSPowdered rubbers of scrap passenger tires(20mesh)were heated at300-330°C without oxygen in an autoclave to give carbon black and oil.The properties of the recovered carbon black were almost the same as those of SRF carbon.The results of analysis of the oil showed that some unsaturated hydrocarbon existed.
On the other hand, BR or SBR was heated to examine the thermal degradation process in an autoclave in the same manner as powdered rubber. Both BR and SBR hardened at 200-250°C and degraded at 300°C. As a whole, vulcanized rubber tended to degrade at lower temperature than unvulcanized one.The results of analysis of the degraded oil of BR showed that some unsaturated parts and cyclized parts existed in it.In the case of the thermal degradation process of BR, isomerization from cis-1, 4to trans-1, 4, cross-linkage, and degradation seem to occur with increasing temperature.The cyclized parts seem to form at the step of crosslinkage and degradation.The thermal degradation process of powdered rubber also seem to be the same as the case of BR.View full abstractDownload PDF (740K) -
Nariyoshi KAWABATA, Shinzo YAMASHITA, Kimio MORI, Toshihiro FUJII1976 Volume 49 Issue 3 Pages 298-305
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL FREE ACCESSThis report describes a new simple method of reclaiming scrap tire by a phenylhydrazine-ferrous chloride system, which was presented at the International Rubber Conference held in Tokyo, October 14-17, 1975. The phenylhydrazine-ferrous chloride system considerably softened not only the truck tire scrap mainly composed of natural rubber but also the scrap tire of passenger cars mainly composed of SBR at room temperature in several hours. Vulcanization of these reclaims gave useful elastomers. The system was shown to be a very effective reagent for the reclamation of various types of synthetic rubber vulcanizates having C=C double bond at room temperature.The crosslink chain of vulcanized synthetic isoprene rubber was found to undergo the severance reaction by the system in the following order of easiness: polysulfide linkage>monosulfide linkage>carbon-carbon crosslink.Both the scission of main chain and the severance of crosslinks were found to be included in the degradation of sulfur vulcanizate of synthetic isoprene rubber by the system. Atmospheric oxygen was shown to be necessary for the above degradation reaction.View full abstractDownload PDF (957K) -
1976 Volume 49 Issue 3 Pages 306-307
Published: March 15, 1976
Released on J-STAGE: March 05, 2013
JOURNAL RESTRICTED ACCESSDownload PDF (248K)
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