Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of chemically bonded poly(vinyl alcohol)-starch compositeResults published in this paper were extracted from the Ph.D. Thesis to be submitted by M. M. Hashem to Cairo Univ./Egypt. (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 230 (1995), S. 189-204 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zur Entwicklung neuartiger, ökologisch verträglicher makromolekularer Schlichtemittel wurden Copolymerisationsreaktionen zwischen Polyvinylalkohol (PVA) und Stärke unter Verwendung von chemisch reaktiven, bifunktionellen Verbindungen wie N-Methylolacrylamid (N-MAm) untersucht. Die Copolymerisationsreaktion wurde in zwei Schritten durchgeführt. Im ersten Reaktionsschritt erfolgt eine Additionsreaktion von N-MAm mit PVA unter alkalischen Bedingungen. Im Rahmen der Untersuchungen wurde der Einfluß verschiedener Reaktionsparameter wie Alkali-Konzentration, Temperatur, Reaktionszeit sowie der N-MAm-Konzentration geprüft. Die zweite Reaktionsstufe besteht in einer Pfropfcopolymerisationsreaktion von substituiertem Polyvinylalkohol (N-MAm-PVA) mit hydrolytisch abgebauter Stärke in Anwesenheit von NH4Cl. Auch hier wurde der Einfluß unterschiedlicher Reaktionsbedingungen wie Temperatur, Reaktionszeit sowie Konzentrationen der eingesetzten Katalysatoren und Reaktanden untersucht. Mit Hilfe der Gelpermeationschromatographie wurde nachgewiesen, daß die Molekulargewichtsverteilung und die Viskosität von PVA-Stärke-Copolymeren von den Molekulargewichten der Ausgangspolymeren (PVA, Stärke) abhängt.
    Notes: Poly(vinyl alcohol) (PVA) was grafted on hydrolysed starch through introduction of the chemically reactive bifunctional compound N-methylolacrylamid (N-MAm). The grafting reaction was carried out in two separate reaction steps. The first step was the reaction of PVA with N-MAm in alkaline medium. The reaction mechanism and reaction conditions such as alkali concentration, temperature, reaction time as well as N-MAm concentration were studied. According to the results obtained, the most appropriate conditions for the preparation of this reactive PVA are: treating PVA with N-MAm (1.25 mol/mol PVA) in the presence of NaOH (6% based on solution volume) at 20°C for 8 h. Second step was the reaction of this reactive PVA (N-MAm-PVA) with hydrolysed starch in the presence of NH4Cl. The latter was carried out under different conditions including temperature, reaction time, catalyst concentration as well as N-MAm-PVA/hydrolysed starch ratio. The results obtained show that the extent of the grafting reaction is governed by each of these factors. Furthermore, GPC data showed that the molecular weight distribution and the apparent viscosity of PVA-N-MAm-starch composite depend on the initial molecular weight of both PVA and hydrolysed starch used.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052300114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Characterization of N,N-dimethylacrylamide/2-methoxyethylacrylate copolymers and phase behaviour of their thermotropic aqueous solutions (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 39 (1996), S. 113-119 
    Details
    ISSN: 0959-8103
    Keywords: dimethylacrylamide ; 2-methoxyethylacrylate ; copolymer ; reactivity ratios ; lower critical solution temperature ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Dimethylacrylamide (DMA) has been copolymerized with 2-methoxyethylacrylate (MOEA) and solutions of the products were analysed by FTIR to yield derived reactivity ratios rDMA = 1.11 ± 0.13 and rMOEA = 0.63 + 0.10. The measured glass transition temperatures Tg of PDMA and PMOEA were 395 K, and 242 K, respectively. These and the values of Tg for the copolymers accorded well with the Fox relationship. Cloud point curves for copolymers in water were established over a wide range of concentration, solubility decreasing with increase in temperature. For these reversibly thermotropic solutions, the lower critical solution temperature (LCST) increased from 9°C to 80°C with decrease in content of MOEA in the copolymer from 91.1 mol% to 38.6 mol%.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Characterization and application of poly(vinyl alcohol)/starch composite as a sizing agentResults published in this paper were extracted from the Ph. D. Thesis to be submitted by M. M. Hashem to Cairo University, Egypt. (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 241 (1996), S. 149-163 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zur Entwicklung neuartiger ökologisch verträglicher makromolekularer Schlichtemittel wurden in früheren Arbeiten Copolymerisationsreaktionen zwischen Polyvinylalkohol (PVA) und Stärke unter Verwendung von chemisch reaktiven bifunktionellen Verbindungen wie N-Methylolacrylamid beschrieben. Im Rahmen dieser Arbeit werden die physikochemischen Eigenschaften des resultierenden Copolymeren untersucht. Von Bedeutung sind hierbei insbesondere Merkmale wie Molekulargewichtsverteilung, Klebekraft, Stabilität, Löslichkeit sowie rheologische Eigenschaften. Derartige Kenntnisse über die physikochemische Beschaffenheit der PVA-Ausgangsverbindung sowie des makromolekularen Endproduktes sind eine wesentliche Voraussetzung für die Entwicklung von neuen Produkten, die als wasserlösliche, recycelbare Schlichtemittel zur Anwendung in der Textilindustrie kommen können.
    Notes: A macromolecular sizing agent based on the copolymerization of poly(vinyl alcohol) (PVA) with hydrolysed starch was prepared using the chemically reactive bifunctional compound N-methylolacrylamide. Detailed characteristics of the resultant PVA/N-methylolcarbamoylethylated starch copolymer were studied where emphasis has been placed on solubility, rheological properties, molecular weight distribution, adhesive power and stability. Elucidation of the nature of the macromolecular segments of both N-methylolcarbamoylethylated PVA as well as PVA/N-methylolcarbamoylethylated starch copolymer fulfilled the prerequisite to tailor PVA/starch copolymer which is appropriate for application as a water-soluble recyclable sizing agent by ultrafiltration.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052410112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Easy-care properties of simultaneously grafted and crosslinked cotton fabrics (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 2165-2176 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The Concurrent grafting of acrylic acid (AA) and crosslinking of dimethylodihydroxyethyleneurea (DMDHEU) with cotton fabric in the presence of ammonium persulfate [(NH4)2S2O8)], magnesium chloride hexahydrate (MgCl2 · 6H2O), and ammonium chloride (NH4Cl) catalysts were studied. These salts were separately used or as a binary mixture of (NH4)2S2O8/MgCl2 · 6H2O or (NH4)2S2O8/NH4Cl. The pad-dry-cure method was employed for the fabric treatment under a variety of conditions. The latter include the nature and kind of the single catalyst as well as pair-mixed catalysts, the concentrations of the catalyst and AA, and temperature and duration of curing. The effects of these conditions on the values of the carboxyl content and crease recovery angle (CRA) of the treated fabrics were evaluted. The tensile strength, elongation at break, dyeability, aqueous and nonaqueous oily soiling, and soil-release properties of the treated fabrics were also examined. Results obtained indicated that all treated fabrics have superior properties, except tensile strength and elongation at break, as compared with the untreated fabric (control). However, beside the AA-grafting and DMDHEU-crosslinking reactions, there are other types of reactions catalyzed by the salts used, viz., the addition reactions between AA molecules and the cellulosic hydroxyls The tentative mechanisms for these reactions are suggested. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...