Acta Polymerica最新文献_第4页

A new approach to polymer crystallization used in an analysis of data of syndiotactic polypropylene 一种新的聚合物结晶方法应用于共规聚丙烯的数据分析

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481206

G. Strobl

引用次数: 14

Diffusion of polystyrene micronetwork spheres in melts of polyvinylmethylether 聚苯乙烯微网球在聚乙烯甲基醚熔体中的扩散

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480707

C. Pies, H. Sillescu

引用次数: 1

Block copolymers containing liquid crystalline segments 含有液晶段的嵌段共聚物

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481001

G. Mao, C. K. Ober

引用次数: 0

The influence of multivalent cations on negative thixotropy in aqueous glycerol solutions of partially hydrolyzed polyacrylamide 多价阳离子对部分水解聚丙烯酰胺在甘油水溶液中负触变性的影响

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481005

B. Bradna, O. Quadrat, L. Titkova, D. Dupuis

引用次数: 4

Impact of degradation mechanisms on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) during composting 堆肥过程中聚(3-羟基丁酸酯-co-3-羟基戊酸酯)降解机制的影响

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481103

C. Eldsäter, A.-C. Albertsson, S. Karlsson

{"title":"Impact of degradation mechanisms on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) during composting","authors":"C. Eldsäter, A.-C. Albertsson, S. Karlsson","doi":"10.1002/actp.1997.010481103","DOIUrl":"https://doi.org/10.1002/actp.1997.010481103","url":null,"abstract":"The individual impact of different degradation mechanisms occurring during composting on the degradation of poly(3-hydroxybutyrate-co-6%-3-hydroxyvalerate) [poly(3HB-co-6%-3HV)] have been assessed in simulated tests. Biotic hydrolysis with Aspergillus fumigatus had the largest impact on the breakdown of poly(3HB-co-6%-3HV) during composting conditions, with small changes in molecular weight and large weight loss. The major degradation products in the biotic environment were 3-hydroxy butyric acid and 3-hydroxy valeric acid. Abiotic hydrolysis during composting conditions (sterile water pH 7 at 60°C) has minor or no effect during such short times as 21 days. During abiotic hydrolysis both monomers and dimers were idientified while the abiotic thermo-oxidation of poly(3HB-co-6%-3HV) showed no degradation at all. The quantitation of degradation products and copolymer composition analysis by 1H NMR indicate that the abiotic hydrolysis is not random. Crotonic and 2-pentenoic acid which is produced at 100°C in air was not produced at 60°C during 298 days. We propose that this temperature is too low to promote the well-known six-member transition that produces crotonic acid, 2-pentenoic acid and oligomers with crotonyl or pentenoyl end groups.","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 11","pages":"478-483"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010481103","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91827188","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: 24

Anisotropic surface eruptions on polymerized diacetylene crystals† 聚合二乙炔晶体的各向异性表面喷发

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480302

V. Shivshankar, C. Sung, J. Kumar, S. K. Tripathy, D. J. Sandman

引用次数: 3

Rheology of diblock copolymer micellar systems 二嵌段共聚物胶束体系的流变学研究

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480701

H. Watanabe

{"title":"Rheology of diblock copolymer micellar systems","authors":"H. Watanabe","doi":"10.1002/actp.1997.010480701","DOIUrl":"10.1002/actp.1997.010480701","url":null,"abstract":"This article summarizes rheological features of moderately concentrated, diblock copolymer micellar solutions in selective solvents. In solvents of monomeric sizes, spherical micelles (with glassy cores) are arranged on cubic lattices to exhibit elasto-plastic responses. These lattices are formed due to an osmotic constraint for the conformation of solvated corona blocks of the micelles. In polymeric solvents (homopolymers) chemically identical to the corona blocks, this constraint is screened and the micelles are randomly dispersed in the systems. In this type of blends (micellar dispersions) in short, nonentangling matrices the micelles have no plasticity but exhibit two-step viscoelastic relaxation: The fast relaxation process corresponds to relaxation of individual corona blocks while the slow process is attributable to diffusion of the micelles. Corresponding to these molecular mechanisms, the fast process exhibits modest damping of the nonlinear relaxation modulus against large step strains while the slow process exhibits much stronger damping. Under steady flow, the micellar dispersion exhibits two-step shear-thinning with the molecular origin identical to that for the nonlinear damping. All these rheological features of the micellar lattices and dispersions are strikingly similar, in many aspects, to the features of colloidal crystals and hard-sphere suspensions of solid particles.","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 7","pages":"215-233"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480701","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82181483","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: 53

Poly(norbornene carboxylic acid ester)s: Synthesis and properties 聚降冰片烯羧酸酯的合成及性能研究

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480906

B. S. Heinz, W. Heitz, S. A. Krügel, F. Raubacher, J. H. Wendorff

引用次数: 37

Electrospray ionization mass spectrometry as an analytical tool for non-biological monomers, oligomers and polymers 电喷雾电离质谱法作为非生物单体、低聚物和聚合物的分析工具

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010481201

R. Saf, C. Mirtl, K. Hummel

引用次数: 30

Unique morphology of poly(azomethine ethers) sheared in the liquid crystalline state 聚亚甲醚在液晶状态下剪切的独特形态

Acta Polymerica Pub Date : 2003-03-11 DOI: 10.1002/actp.1997.010480404

D. Dean, P. H. Geil

{"title":"Unique morphology of poly(azomethine ethers) sheared in the liquid crystalline state","authors":"D. Dean, P. H. Geil","doi":"10.1002/actp.1997.010480404","DOIUrl":"10.1002/actp.1997.010480404","url":null,"abstract":"The morphology and electron diffraction patterns of sheared films of a series of aliphatic-aromatic poly(azomethine ethers) with n = 1,4 and 7–10 CH2 units in the aliphatic segment have been characterized by transmission electron microscopy. The films were prepared by shearing in the liquid crystalline (nematic) state. In all cases, lamellae ca. 400 Å thick and more or less perpendicular to the shear direction and perpendicular to the substrate were obtained. Annealing increases the lamellar thickness and overall order. Redrawing of annealed, sheared samples of n = 10 suggests they consist of chain folded lamellae. Electron diffraction (ED) yielded h0l single crystal patterns in all cases, except for n = 1, which yielded orthorhombic, fiber-like patterns. The h0l patterns suggest a planar, single crystal orientation over the entire sample. Annealing sheared samples above the crystal-liquid crystal transition temperature resulted in reorientation of the molecules (from parallel to perpendicular) with respect to the substrate. ED patterns changed accordingly from h0l to hk0. Sheared samples with n = 4 gave both orthorhombic and monoclinic diffraction patterns.","PeriodicalId":7162,"journal":{"name":"Acta Polymerica","volume":"48 4","pages":"149-163"},"PeriodicalIF":0.0,"publicationDate":"2003-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/actp.1997.010480404","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76904629","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: 3