The addition of ethanol to isobutene in the vapour phase has been studied on four commercial macroporous resins. The acid group content of the resins used was about 5 meq g−1, and their degrees of crosslinking were 12, 16, 18 and 20%. Differential conversions were measured for ethanol-isobutene-nitrogen feeds at 53–78.5°C and atmospheric pressure, far from limitation by chemical equilibrium. The rate data showed that isobutene has an enhancing effect on the reaction, whereas ethanol has a strong inhibitory effect in the range studied. The four catalysts showed similar behaviour. At the lower temperatures explored all the resins have similar catalytic activity, but at the highest temperature the resin with 18% divinylbenzene showed the highest activity. This maximum activity can be explained by a greater accessibility to the acid groups, which is in agreement with the literature.
{"title":"Influence of resin structure on the addition of ethanol to isobutene in the vapour phase","authors":"M. Iborra, J. Tejero, J. Izquierdo, F. Cunill","doi":"10.1002/PI.4980230120","DOIUrl":"https://doi.org/10.1002/PI.4980230120","url":null,"abstract":"The addition of ethanol to isobutene in the vapour phase has been studied on four commercial macroporous resins. The acid group content of the resins used was about 5 meq g−1, and their degrees of crosslinking were 12, 16, 18 and 20%. Differential conversions were measured for ethanol-isobutene-nitrogen feeds at 53–78.5°C and atmospheric pressure, far from limitation by chemical equilibrium. The rate data showed that isobutene has an enhancing effect on the reaction, whereas ethanol has a strong inhibitory effect in the range studied. The four catalysts showed similar behaviour. At the lower temperatures explored all the resins have similar catalytic activity, but at the highest temperature the resin with 18% divinylbenzene showed the highest activity. This maximum activity can be explained by a greater accessibility to the acid groups, which is in agreement with the literature.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81456694","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}
{"title":"Microelectronic polymers. Edited by Maung S. Htoo, Marcel Dekker Inc., New York, 1989. pp. v + 407, price £108.00. ISBN 0‐8247‐79908","authors":"R. A. Pethric","doi":"10.1002/PI.4980220415","DOIUrl":"https://doi.org/10.1002/PI.4980220415","url":null,"abstract":"","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83981495","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}
Several classes of organosilicon polymers are effective precursors for silicon carbide ceramic compositions. These include polydimethylsilane (via a two-step process), ‘polysilastyrene’, polycarbosilazanes or polysilazanes, and certain siloxanes, plus the branched polycarbosilanes, branched polysilahydrocarbons, and vinylic polysilanes developed at Union Carbide. The latter three classes are prepared by active metal dechlorinations of appropriate chlorosilane blends, leading to recognition of branching at backbone silicon atoms (either as prepared or during processing) as a prerequisite for obtaining useful ceramic yields. Fundamental reactivity differences between the active metals (potassium and sodium) allow the preparation of sodium-derived vinylic polysilanes. The latter offer certain economic and performance advantages as ceramic precursors.
{"title":"Polymeric routes to silicon carbide","authors":"C. L. Schilling","doi":"10.1002/PI.4980180602","DOIUrl":"https://doi.org/10.1002/PI.4980180602","url":null,"abstract":"Several classes of organosilicon polymers are effective precursors for silicon carbide ceramic compositions. These include polydimethylsilane (via a two-step process), ‘polysilastyrene’, polycarbosilazanes or polysilazanes, and certain siloxanes, plus the branched polycarbosilanes, branched polysilahydrocarbons, and vinylic polysilanes developed at Union Carbide. The latter three classes are prepared by active metal dechlorinations of appropriate chlorosilane blends, leading to recognition of branching at backbone silicon atoms (either as prepared or during processing) as a prerequisite for obtaining useful ceramic yields. Fundamental reactivity differences between the active metals (potassium and sodium) allow the preparation of sodium-derived vinylic polysilanes. The latter offer certain economic and performance advantages as ceramic precursors.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76822976","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}
{"title":"Cationic ring‐opening polymerization, Part 2: Synthetic applications (Advances in Polymer Science, Volumes 68/69). By S. Penczek, P. Kubisa and K. Matyjaszewski, Springer‐ Verlag, Berlin Heidelberg, 1985. pp. 300, price DM 188.00. ISBN 3‐540‐13781‐5","authors":"D. Pepper","doi":"10.1002/PI.4980180613","DOIUrl":"https://doi.org/10.1002/PI.4980180613","url":null,"abstract":"","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90981051","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}
A general survey is presented of the preparation, physical and chemical properties, and structural patterns of transition metal borides and silicides. The appropriateness of their description as inorganic homopolymers stabilised by electron transfer from metal centres is discussed. Finally, applications are outlined, with particular reference to the fabrication of thin films and their use in advanced microelectronic devices.
{"title":"Borides and Silicides ‐ New Chemistry and Applications","authors":"B. J. Aylett","doi":"10.1002/PI.4980180603","DOIUrl":"https://doi.org/10.1002/PI.4980180603","url":null,"abstract":"A general survey is presented of the preparation, physical and chemical properties, and structural patterns of transition metal borides and silicides. The appropriateness of their description as inorganic homopolymers stabilised by electron transfer from metal centres is discussed. Finally, applications are outlined, with particular reference to the fabrication of thin films and their use in advanced microelectronic devices.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77660778","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}
{"title":"Kirk‐Othmer ‘Concise encyclopedia of chemical technology’. Edited by M. Grayson, Wiley‐Interscience, New York, 1985. pp. xxxii+1318, price £123.45. ISBN 0‐471‐86977‐5","authors":"C. Finch","doi":"10.1002/PI.4980180615","DOIUrl":"https://doi.org/10.1002/PI.4980180615","url":null,"abstract":"","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73336824","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}
Three polymers based upon p-hydroxybenzoic acid have been studied by thermogravimetry to ascertain their relative thermal stabilities in both inert and oxidising atmospheres. Experiments have been carried out at a rate of temperature rise of 2°C min−1 and isothermally at a number of temperatures. The polymers have good thermal stability. They have also been examined by pyrolysis gas chromatography mass spectrometry using two different procedures. In the first, fresh samples were pyrolysed at a number of increasing temperatures, whereas in the second, the same sample was subjected to successive pyrolyses at the same temperature intervals. The results are compared with those of other authors derived using different techniques.
{"title":"The Thermal Degradation of Some Polymers Based Upon p-Hydroxybenzoic Acid","authors":"G. J. Knight, W. W. Wright","doi":"10.1002/PI.4980180605","DOIUrl":"https://doi.org/10.1002/PI.4980180605","url":null,"abstract":"Three polymers based upon p-hydroxybenzoic acid have been studied by thermogravimetry to ascertain their relative thermal stabilities in both inert and oxidising atmospheres. Experiments have been carried out at a rate of temperature rise of 2°C min−1 and isothermally at a number of temperatures. The polymers have good thermal stability. They have also been examined by pyrolysis gas chromatography mass spectrometry using two different procedures. In the first, fresh samples were pyrolysed at a number of increasing temperatures, whereas in the second, the same sample was subjected to successive pyrolyses at the same temperature intervals. The results are compared with those of other authors derived using different techniques.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83834827","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}
Cloud point curves for several narrow fractions of polystyrene dissolved in cycloheptane, in cyclooctane and in cyclodecane have been established, and the critical solution temperatures extrapolated to give the respective temperatures. All three cycloalkanes are good solvents for the polymer. A comparison is made between the phase behaviour of polystyrene dissolved in cyclic alkanes and in n-alkanes using free volume polymer solution theory.
{"title":"A Comparison of the Phase Behaviour of Polystyrene in Cycloalkanes and n‐Alkanes","authors":"J. Cowie, I. McEwen","doi":"10.1002/PI.4980180608","DOIUrl":"https://doi.org/10.1002/PI.4980180608","url":null,"abstract":"Cloud point curves for several narrow fractions of polystyrene dissolved in cycloheptane, in cyclooctane and in cyclodecane have been established, and the critical solution temperatures extrapolated to give the respective temperatures. All three cycloalkanes are good solvents for the polymer. A comparison is made between the phase behaviour of polystyrene dissolved in cyclic alkanes and in n-alkanes using free volume polymer solution theory.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77257177","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}
{"title":"Molecular semiconductors. Edited by J. M. Lehn and C. W. Rees, Springer-Verlag, Berlin, Heidelberg, New York, Tokyo, 1985. pp. 350, price DM 174.00. ISBN 3-540-13754-8","authors":"R. Pethrick","doi":"10.1002/PI.4980180623","DOIUrl":"https://doi.org/10.1002/PI.4980180623","url":null,"abstract":"","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90095495","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}
Size exclusion chromatography calibrations for polystyrene and poly(ethylene glycol) standard samples in the molecular weight range of (600-11000) have been obtained in tetrahydrofuran. The Kuhn-Mark-Houwink-Sakurada constants of poly(ethylene glycol) in tetrahydrofuran were determined, and poly(ethylene glycol) chromatograms were evaluated according to primary and universal calibration methods. The molecular weights determined from universal curves were substantially lower than those obtained from primary curves. The Coll and Prusinowski universal calibration procedure gave better results than the calibration of Benoit et al.
{"title":"Size Exclusion Chromatography of Poly(ethylene glycol)","authors":"O. Güven","doi":"10.1002/PI.4980180609","DOIUrl":"https://doi.org/10.1002/PI.4980180609","url":null,"abstract":"Size exclusion chromatography calibrations for polystyrene and poly(ethylene glycol) standard samples in the molecular weight range of (600-11000) have been obtained in tetrahydrofuran. The Kuhn-Mark-Houwink-Sakurada constants of poly(ethylene glycol) in tetrahydrofuran were determined, and poly(ethylene glycol) chromatograms were evaluated according to primary and universal calibration methods. The molecular weights determined from universal curves were substantially lower than those obtained from primary curves. The Coll and Prusinowski universal calibration procedure gave better results than the calibration of Benoit et al.","PeriodicalId":9298,"journal":{"name":"British Polymer Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82367653","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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