Kohei Saito, Liqian Huang, Y. Kadowaki, Takashi Inoue
Poly(ethylene-co-vinylacetate) (EVA) was mixed with sodium montmorillonite (MMT) at 90/10 wt. ratio. EVA was also mixed with an organophilic montmorillonite (o-MMT) prepared by replacing Na+ in MMT with trimethylstearylammonium cation. The structure and mechanical properties of the composites were studied by scanning electron microscopy (SEM), transmission electron microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, and dynamic mechanical analysis. In the EVA/MMT composite, MMT particles were poorly dispersed in the order of a few µm. The composite was opaque. By contrast, in the EVA/o-MMT composite, the exfoliated silicate layers were nicely dispersed in EVA matrix. It was a transparent material. The composite showed an interesting reinforcing effect; i.e., the rubbery plateau modulus was retained even above the melting point of EVA. The rubbery modulus seems to originate from a formation of the “house-of-cards” structure of silicate layers.
{"title":"Evolution of Rubbery Plateau Region above the Melting Point of Poly(ethylene-co-vinylacetate) by the Incorporation of Montmorillonite","authors":"Kohei Saito, Liqian Huang, Y. Kadowaki, Takashi Inoue","doi":"10.2324/EJSM.1.20","DOIUrl":"https://doi.org/10.2324/EJSM.1.20","url":null,"abstract":"Poly(ethylene-co-vinylacetate) (EVA) was mixed with sodium montmorillonite (MMT) at 90/10 wt. ratio. EVA was also mixed with an organophilic montmorillonite (o-MMT) prepared by replacing Na+ in MMT with trimethylstearylammonium cation. The structure and mechanical properties of the composites were studied by scanning electron microscopy (SEM), transmission electron microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, and dynamic mechanical analysis. In the EVA/MMT composite, MMT particles were poorly dispersed in the order of a few µm. The composite was opaque. By contrast, in the EVA/o-MMT composite, the exfoliated silicate layers were nicely dispersed in EVA matrix. It was a transparent material. The composite showed an interesting reinforcing effect; i.e., the rubbery plateau modulus was retained even above the melting point of EVA. The rubbery modulus seems to originate from a formation of the “house-of-cards” structure of silicate layers.","PeriodicalId":11628,"journal":{"name":"E-journal of Soft Materials","volume":"195 1","pages":"20-25"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75891121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Maebayashi, M. Endo, T. Matsuoka, S. Koda, Yoshinobu Isono
A carbon black (CB) filled styrene-butadiene rubber (SBR) compound was investigated by acoustic techniques, scanning acoustic microscopy and longitudinal wave velocitometry.The CB agglomerates of larger than 5 µm dispersed in the compound mixed by two-roll mill were observed as black spots in acoustic micrographs. On the other hand, the CB agglomerates in the compound mixed by oil-pressure kneader were not observed in the acoustic micrograph, since the particle size of the agglomerates was less than 5 µm.The density and the longitudinal wave velocity of the compound were measured as a function of the weight percentage of the CB. The density and the velocity increased linearly with the content of the CB. The mass ratio of the bound rubber to the CB in the unvulcanized sample was determined by using toluene extraction and thermo gravimetric analysis. The partial specific adiabatic compressibility of the CB was estimated as (−0.5±0.5)×10−10 Pa−1 on the basis of the three states model. The adiabatic compressibility of the bound rubber was (2.2±0.5)×10−10 Pa−1, and it is half of that of the SBR matrix.
{"title":"Acoustic Analysis of Composite Soft Materials IV.Evaluation of Compressibility of Bound Rubber in Carbon Black Filled SBR","authors":"M. Maebayashi, M. Endo, T. Matsuoka, S. Koda, Yoshinobu Isono","doi":"10.2324/EJSM.1.26","DOIUrl":"https://doi.org/10.2324/EJSM.1.26","url":null,"abstract":"A carbon black (CB) filled styrene-butadiene rubber (SBR) compound was investigated by acoustic techniques, scanning acoustic microscopy and longitudinal wave velocitometry.The CB agglomerates of larger than 5 µm dispersed in the compound mixed by two-roll mill were observed as black spots in acoustic micrographs. On the other hand, the CB agglomerates in the compound mixed by oil-pressure kneader were not observed in the acoustic micrograph, since the particle size of the agglomerates was less than 5 µm.The density and the longitudinal wave velocity of the compound were measured as a function of the weight percentage of the CB. The density and the velocity increased linearly with the content of the CB. The mass ratio of the bound rubber to the CB in the unvulcanized sample was determined by using toluene extraction and thermo gravimetric analysis. The partial specific adiabatic compressibility of the CB was estimated as (−0.5±0.5)×10−10 Pa−1 on the basis of the three states model. The adiabatic compressibility of the bound rubber was (2.2±0.5)×10−10 Pa−1, and it is half of that of the SBR matrix.","PeriodicalId":11628,"journal":{"name":"E-journal of Soft Materials","volume":"1 1","pages":"26-32"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86465765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Effects of interfacial interactions between rubber matrix and filler surface on the structural changes of rubber matrix upon a tensile deformation of filled styrene-butadiene rubber (SBR) vulcanizates were studied by ESR and pulsed NMR. The interfacial interactions were controlled by using several kinds of surface modified silicas and carbon blacks. For silica filled systems, the degree of chain scission during tensile deformation of the samples could be evaluated from ESR results. Information on the structural changes of rubber matrix upon a tensile deformation for both carbon black filled and silica filled SBR vulcanizates could be obtained from the results of pulsed NMR. The combination of ESR and NMR results revealed that the degree of chain scission was dependent on the strength of interfacial bondings between filler and rubber molecules and the chain scissions are suggested to occur in the interfacial regions between rubber molecules and fillers.
{"title":"Chain Scissions of Rubber Molecules by a Tensile Force in Filled Rubber Systems","authors":"N. Suzuki, Masayoshi Ito","doi":"10.2324/EJSM.1.1","DOIUrl":"https://doi.org/10.2324/EJSM.1.1","url":null,"abstract":"Effects of interfacial interactions between rubber matrix and filler surface on the structural changes of rubber matrix upon a tensile deformation of filled styrene-butadiene rubber (SBR) vulcanizates were studied by ESR and pulsed NMR. The interfacial interactions were controlled by using several kinds of surface modified silicas and carbon blacks. For silica filled systems, the degree of chain scission during tensile deformation of the samples could be evaluated from ESR results. Information on the structural changes of rubber matrix upon a tensile deformation for both carbon black filled and silica filled SBR vulcanizates could be obtained from the results of pulsed NMR. The combination of ESR and NMR results revealed that the degree of chain scission was dependent on the strength of interfacial bondings between filler and rubber molecules and the chain scissions are suggested to occur in the interfacial regions between rubber molecules and fillers.","PeriodicalId":11628,"journal":{"name":"E-journal of Soft Materials","volume":"21 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2005-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87355396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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