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Acta Polymerica最新文献

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Degree of branching in hyperbranched polymers. 2. Enhancement of the db: Scope and limitations 超支化聚合物的支化程度。2. 增强数据库:范围和限制
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480802
H. Frey
{"title":"Degree of branching in hyperbranched polymers. 2. Enhancement of the db: Scope and limitations","authors":"H. Frey","doi":"10.1002/actp.1997.010480802","DOIUrl":"10.1002/actp.1997.010480802","url":null,"abstract":"<p>The degree of branching (DB) as well as the ANB (average number of branches) of polymers obtained from polycondensation of AB<sub>2</sub> and AB<i><sub>m</sub></i>-type monomers in general is analyzed in detail on the basis of kinetic considerations. Various possibilities for the enhancement of the DB of hyperbranched polymers beyond the limit for a random AB<i><sub>m</sub></i> polycondensation (0.5 for AB<sub>2</sub>, 0.44 for AB<sub>3</sub>) are considered, i.e., (i) enhanced reactivity of linear vs. terminal units; (ii) polymerization of prefabricated, perfect dendritic units and (iii) the slow addition technique. For AB<sub>2</sub> monomers, the formation of terminal (T), linear (L) and perfect dendritic (D) units in the course of the random one-pot polymerization is calculated. Furthermore, the evolution of the DB and ANB with conversion is calculated for AB<i><sub>m</sub></i> monomers. It is shown that the definition of the DB for AB<sub>2</sub> systems (DB = 2<i>D</i>/(2<i>D</i>+<i>L</i>)) derived in the first paper on the DB (<i>Acta Polym.</i> <b>1997</b>, <i>48</i>, 30) in the case of a random one-pot polycondensation exhibits the same conversion dependence as the branching parameter α = 1/2<i>P</i><sub>A</sub>, defined by Flory for AB<sub>2</sub> polycondensations. The dilution principle is introduced, which is based on slow addition of AB<i><sub>m</sub></i> monomers to a core molecule B<i><sub>f</sub></i> or an AB<i><sub>m</sub></i>-type hyperbranched molecule with an arbitrary DB. It is shown that the maximum DB value obtainable from such a dilution/slow addition process is 0.67 for AB<sub>2</sub> systems. Thus, the DB is considerably higher than in the case of a random one-step polymerization (0.5). The DB for AB<i><sub>m</sub></i>-type hyperbranched polymers prepared according to the dilution principle has been calculated to be <i>m</i>/(2<i>m</i>–1).</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 8","pages":"298-309"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84400105","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}
引用次数: 141
New polymeric metallomesogens: A potentially photorefractive side-chain polyacrylate containing a cyclopalladated azobenzene complex 一种含有环钯化偶氮苯配合物的潜在光折变侧链聚丙烯酸酯
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480908
M. Ghedini, I. Aiello, A. Roviello
{"title":"New polymeric metallomesogens: A potentially photorefractive side-chain polyacrylate containing a cyclopalladated azobenzene complex","authors":"M. Ghedini,&nbsp;I. Aiello,&nbsp;A. Roviello","doi":"10.1002/actp.1997.010480908","DOIUrl":"10.1002/actp.1997.010480908","url":null,"abstract":"","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 9","pages":"400-403"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480908","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89754977","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}
引用次数: 10
New synthesis, thermal properties and textures of cholesteric poly[oxy(1,2-butene)oxycarbonyl-1,4-phenyleneoxycarbonyl-1,4-phenylenecarbonyloxy-1,4-phenylenecarbonyl], PTOBEE 胆甾型聚[氧(1,2-丁烯)氧羰基-1,4-苯基氧羰基-1,4-苯基氧基-1,4-苯基羰基]PTOBEE的新合成、热性能和织构
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481106
M. Pérez-Méndez, C. Marco
{"title":"New synthesis, thermal properties and textures of cholesteric poly[oxy(1,2-butene)oxycarbonyl-1,4-phenyleneoxycarbonyl-1,4-phenylenecarbonyloxy-1,4-phenylenecarbonyl], PTOBEE","authors":"M. Pérez-Méndez,&nbsp;C. Marco","doi":"10.1002/actp.1997.010481106","DOIUrl":"https://doi.org/10.1002/actp.1997.010481106","url":null,"abstract":"<p>Liquid crystal poly[oxy(1,2-butene)oxycarbonyl-1,4-phenyleneoxycarbonyl-1,4-phenylenecarbonyloxy-1,4-phenylenecarbonyl], PTOBEE, has been synthesized in a different way than the previously reported nematic and it has been obtained as cholesteric, although synthesized from a racemic mixture of the 1,2-butanediol involved. Stereoselective solubilization of one enantiomer during its decantation in toluene, at the reaction temperature, explains why this chiral polymer phase appears. Evidence of this could be precisely obtained when a white solid recrystallized within the same toluene after the filtration of the polymer, being identified as (—) PTOBEE with a value of [α] = −2.33 [0.0056 mol/1, toluene].</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 11","pages":"502-506"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010481106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91827187","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}
引用次数: 7
New approaches to advanced polymers by selective cellulose functionalization 纤维素选择性功能化制备高级聚合物的新途径
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480801
D. Klemm, T. Heinze, B. Philipp, W. Wagenknecht
{"title":"New approaches to advanced polymers by selective cellulose functionalization","authors":"D. Klemm,&nbsp;T. Heinze,&nbsp;B. Philipp,&nbsp;W. Wagenknecht","doi":"10.1002/actp.1997.010480801","DOIUrl":"10.1002/actp.1997.010480801","url":null,"abstract":"<p>The uniform structure of cellulose, combined with its hydrophilicity, biocompatibility, chirality, and structure-forming capacity, as well as its broad synthetic potential, make the design of cellulose-based advanced materials a challenge for polysac-charide research. The synthesis of new cellulose products with regiocontrolled pattern of functionalization and of well defined supramolecular nanoscale architectures is a highlight in recent cellulose chemistry.</p><p>The present feature will discuss regioselective functionalization of cellulose and cellulose derivatives with respect to reactivity of the polymer depending on molecular and supramolecular structure. Experimental examples of functionalization via ester intermediates of controlled stability as well as via protecting or activating ether groups are described and the efficiency of the reaction routes and procedures is evaluated.</p><p>Moreover, problems and progress in techniques of product analysis and structure–property relationships as well as potential applications of regioselectively functionalized cellulosics are presented together with a discussion of possible future developments in cellulose chemistry.</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 8","pages":"277-297"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480801","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74344833","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}
引用次数: 90
Photochemical and photopolymerization study of 2,6-dihalogen derivatives of p-nitroaniline in the presence of N,N-dimethylaniline as a bimolecular photoinitiator system 以N,N-二甲基苯胺为双分子光引发剂体系，对硝基苯胺2,6-二卤衍生物的光化学和光聚合研究
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481002
A. Costela, I. Garcia-Moreno, F. Diaz, J. Dabrio, R. Sastre
{"title":"Photochemical and photopolymerization study of 2,6-dihalogen derivatives of p-nitroaniline in the presence of N,N-dimethylaniline as a bimolecular photoinitiator system","authors":"A. Costela,&nbsp;I. Garcia-Moreno,&nbsp;F. Diaz,&nbsp;J. Dabrio,&nbsp;R. Sastre","doi":"10.1002/actp.1997.010481002","DOIUrl":"10.1002/actp.1997.010481002","url":null,"abstract":"<p>Steady-state photolysis at 365 nm has been employed to carry out a structure—reactivity investigation of the 2,6-dihalogen derivatives of <i>p</i>-nitroaniline (<i>p</i>NA). Detailed studies of the spectroscopy of these molecules were accomplished. Photoreduction behavior of the 2,6-dihalogen derivatives of <i>p</i>-nitroaniline in the presence of <i>N,N</i>-dimethylaniline (DMA) has been analyzed. The efficiency of these compounds as photoinitiators was studied by following the polymerization kinetics of the lauryl acrylate (LA) monomer by differential scanning photo-calorimetry (Photo-DSC) under aerobic and anaerobic conditions. Using size exclusion chromatography (SEC) analysis of the polymers their number-average molecular weights, the number-average degree of polymerization, and the length of the kinetic chain were determined and information on the nature of the end-chain groups and the chain-transfer behavior of these photoinitiators systems were obtained. The polymerization activity of the 2,6-dihalogen derivatives of <i>p</i>NA proved to be higher than those obtained with conventional aromatic ketone photoinitiators.</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 10","pages":"423-431"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010481002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73352399","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}
引用次数: 4
Highly conjugated alternated poly(3-octylthiophene-co-thiophene) 高共轭交联聚(3-辛基噻吩-co-噻吩)
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481107
A. Bolognesi, F. Bertini, R. Consonni, R. Mendichi, A. Giacometti Schieroni, A. Provasoli
{"title":"Highly conjugated alternated poly(3-octylthiophene-co-thiophene)","authors":"A. Bolognesi,&nbsp;F. Bertini,&nbsp;R. Consonni,&nbsp;R. Mendichi,&nbsp;A. Giacometti Schieroni,&nbsp;A. Provasoli","doi":"10.1002/actp.1997.010481107","DOIUrl":"https://doi.org/10.1002/actp.1997.010481107","url":null,"abstract":"<p>A soluble copolymer formed by thiophene and 3-octylthiophene has been obtained by using nickel catalyst polymerization. The nearly alternated structure allows the formation of a highly conjugated system although the copolymer microstructure is not regioregular. <sup>1</sup>H-NMR, GPC characterization and pyrolysis experiments support the alternated structure of the copolymer. Moreover, theoretical calculations indicate that the average angle between adjacent monomeric units has been reduced, in agreement with the observed shift towards lower energy of the electronic spectra of this alternated structure.</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 11","pages":"507-512"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010481107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91827186","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}
引用次数: 2
In situ conductivity of a low band-gap conducting polymer: Measurement of intrinsic conductivity 低带隙导电聚合物的原位电导率:固有电导率的测量
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481007
H. Huang, P. G. Pickup
{"title":"In situ conductivity of a low band-gap conducting polymer: Measurement of intrinsic conductivity","authors":"H. Huang,&nbsp;P. G. Pickup","doi":"10.1002/actp.1997.010481007","DOIUrl":"10.1002/actp.1997.010481007","url":null,"abstract":"<p><i>In situ</i> conductivity measurements on the low band-gap polymer, poly-4-dicyanomethylene-4<i>H</i>-cyclopenta[2,1-b;3,4,b′]dithiophene have provided both p- and n-type conductivities as a function of the potential. A minimum in the conductivity, at a potential between the formal potentials for p- and n-doping, yields an intrinsic conductivity of 1.0 × 10<sup>−8</sup> S cm<sup>−1</sup>, consistent with the optical band-gap of ∼0.8 eV.</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 10","pages":"455-457"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010481007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87869075","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}
引用次数: 11
Trends in polymer chemistry 1996† 高分子化学趋势1996†
Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480401
H. Frey, J. Kressler, W. Richtering, R. Mülhaupt
{"title":"Trends in polymer chemistry 1996†","authors":"H. Frey,&nbsp;J. Kressler,&nbsp;W. Richtering,&nbsp;R. Mülhaupt","doi":"10.1002/actp.1997.010480401","DOIUrl":"10.1002/actp.1997.010480401","url":null,"abstract":"<p>Important advances have been made in controlled radical polymerization, particularly in the application of the new technique for the preparation of novel block copolymers. CO-copolymers are becoming increasingly popular. Increasing research efforts are also being devoted to discrete supermolecular structures as well as the preparation of nanometer-size noble metal clusters in polymer matrices. MALDI-TOF continues its triumph in synthetic polymer chemistry.</p>","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 4","pages":"107-115"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83114946","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}
引用次数: 1
Multilevel modelling of dispersed multiphase flows 分散多相流的多级建模
Acta Polymerica Pub Date : 2000-07-01 DOI: 10.2516/OGST:2000031
J. Kuipers
{"title":"Multilevel modelling of dispersed multiphase flows","authors":"J. Kuipers","doi":"10.2516/OGST:2000031","DOIUrl":"https://doi.org/10.2516/OGST:2000031","url":null,"abstract":"The disclosure relates to a process station to precisely control the electrochemical anodization of specially prepared silicon substrates. Remotely placed voltage probes are utilized to monitor changes in the potential drop across the wafer as the anodization proceeds. As the available anodilizable area changes, the voltage drop across the wafer and hence the anodization current density is maintained at the desired value by the computer through the use of active feedback provided by these probes. Any desired anodization conditions can be programmed into the system using the system software, thereby adding an even greater degree of control over the process.","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78990995","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}
引用次数: 6
Stereochemical configuration of 2‐hydroxyethyl methacrylate/styrene copolymers obtained in N,N′‐dimethylformamide solution over a whole range of conversion 在N,N ' -二甲基甲酰胺溶液中获得的2‐甲基丙烯酸羟乙酯/苯乙烯共聚物的立体化学构型
Acta Polymerica Pub Date : 1999-12-01 DOI: 10.1002/(SICI)1521-4044(19991201)50:11/12<408::AID-APOL408>3.0.CO;2-6
Carmen Fernández-Monreal, M. Sánchez-Chaves, G. Martínez, E. Madruga
{"title":"Stereochemical configuration of 2‐hydroxyethyl methacrylate/styrene copolymers obtained in N,N′‐dimethylformamide solution over a whole range of conversion","authors":"Carmen Fernández-Monreal, M. Sánchez-Chaves, G. Martínez, E. Madruga","doi":"10.1002/(SICI)1521-4044(19991201)50:11/12<408::AID-APOL408>3.0.CO;2-6","DOIUrl":"https://doi.org/10.1002/(SICI)1521-4044(19991201)50:11/12<408::AID-APOL408>3.0.CO;2-6","url":null,"abstract":"High resolution 1 H-NMR spectra of 2-hydroxyethyl methacrylate (HEMA)-styrene (S) copolymers prepared at low conversion by free radical copolymerization in N,N-dimethylformamide (DMF) solution at 50°C, have been analyzed in terms of sequence distribution and stereoregularity. The Bootstrap effect for the HEMA/S/DMF system was confirmed by comparison of the data obtained with those previously reported for the HEMA/S/bulk system. Reactivity ratios, statistical parameters, and the coisotacticity parameter σ HS = 0.40, estimated at low conversion, were used to describe the observed experimental changes in copolymer composition and triad fraction intensities over a wide range of conversions.","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"27 1","pages":"408-412"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74557294","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}
引用次数: 11
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