Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Polymer and Materials Science  (20)
  • latex films  (2)
  • particle morphology  (2)
Datenquelle
Materialart
Erscheinungszeitraum
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Characterization of particle surface and morphology in vinyl acetate-butyl acrylate emulsion copolymers — Influence of the copolymerization pathway (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 791-802 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Vmyl acetate-butyl acrylate emulsion copolymers ; surface end-groups ; soap titration method ; particle morphology ; emulsion process
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Surface characterization was investigated in vinyl acetate (VAc) butyl acrylate (BuA) copolymer latexes of various compositions and prepared with four different emulsion polymerization processes: conventionnal batch, composition-controlled batch, core-shell, emulsifier-free semi-continuous. Surface end-groups (sulfate or carboxylic) titration results were first compared and discussed according to the type of process and as a function of conversion. As previously shown [1], it was confirmed that batch latex particles present a heterogeneous structure with a rich VAc outlayer, as in core-shell particles. As expected, semi-continuous and composition-controlled batch particles exhibit surface end-group characteristics revealing a more homogeneous distribution of both monomers within the particles. These differences in particle morphology were corroborated by analyzing water-polymer interface in these latexes using the soap titration method, with the sodium dodecyl sulfate (SDS) or sodium hexadecyl sulfate (SHS) as emulsifier probes. When the BuA was batch-polymerized onto PVAc seed particles, the estimated surface composition seemed to show that probably phase rearrangement occurs in the particle during the synthesis or upon aging. It was also confirmed that SDS displays an abnormal adsorption due to complexation and solubilization in the rich-VAc shell of the particles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01418455
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Polystyrene(1)/poly(butyl acrylate-methacrylic acid)(2) core-shell emulsion polymers. Part II: Thermomechanical properties of latex films (1992)
    Springer
    Colloid & polymer science 270 (1992), S. 1208-1221 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Polystyrene(1)/poly(butyl acrylate-methacrylic acid)(2) ; core-shell ; morphology ; latex films ; phase arrangement ; mechanical properties ; differential thermal analysis ; scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Polystyrene(1)/poly(n-butyl acrylate-methacrylic acid)(2) structured latex particles were prepared through a two-stage emulsion polymerization procedure, using a polystyrene (PS) latex seed (118 nm), and differentn-butyl acrylate (BA)/methacrylic acid (MAA) ratios. Polymerization kinetics, particle morphology, and MAA location have already been discussed in the first part of this series. In this second part the thermomechanical behavior of films cast from these latexes was studied. Differential Thermal Analysis and Dynamic Mechanical Analysis (DMA) were employed as characterization techniques for the films. Two polymer phases corresponding to polystyrene and a poly(BA-MAA) copolymer were distinguished. Comparison was made to analogous unfunctionalized PS/PBA systems, as a result of which an effect of MAA upon the phase arrangement in the film was found. Scanning Electron Microscopy of film samples and DMA showed that the evolution of the phase arrangement as a result of annealing was strongly dependent on the type of mechanical and heat treatments being applied to functionalized systems. Finally, the thermomechanical behavior of films was related to the structural features of the corresponding latexes, and computer simulation techniques wer eemployed to establish a mechanistic support for these relationships.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01095062
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Emulsifier-free emulsion copolymerization of styrene and butyl acrylate. II. Kinetic studies in the presence of ionogenic comonomers (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1937-1959 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Batch emulsifier-free copolymerizations of styrene (S) and butyl acrylate (BuA) have been performed for a S/BuA weight ratio = 50/50 in the presence of two types of functional comonomers [methacrylic acid (MAA) at different pHs] or potassium sulfopropylmethacrylate (SPM) and two initiators [potassium persulfate or 4-4′azobiscyanopentanoic acid (AZO)]. The use of AZO/MAA system results in the formation of polymer particles with only surface carboxylic end groups. The particle size of the final latexes can be adjusted with the MAA concentration, provided the polymerization is carried out at pH 〉 6.5. However, the higher the MAA concentration, the sooner the polymerization levels off in conversion. With the K2S2O8/SPM system, particles bearing only sulfate and sulfonate groups are produced and the polymerization is complete. In that case, the particle size of the final latexes is smaller than with the previous system and 30% of the SPM is fixed on the particle surface, instead of 10% with MAA. Using SPM, a too high functional monomer concentration results in the latex destabilization caused by the formation of a large amount of polyelectrolytes. Kinetic studies indicate that most of the functional monomer is incorporated onto the particle surface during the last 30% conversion of the polymerization. A tentative explanation of such a behavior is discussed, based on the existence of two polymerization loci in the latex system.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1988.080260719
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Emulsifier-free emulsion copolymerization of styrene and butyl acrylate. I.Part II of this series has been published in the Journal of Polymer Science Part A: Polymer Chemistry, Volume 26, Number 7, 1988 on page 1937. Kinetic studies in the absence of surfactant (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 119-136 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Soapless emulsion copolymerization of styrene (S) and n-butyl acrylate (BuA) has been investigated using two types of initiator and different comonomer feed mixtures. When using K2S2O8 as initiator, the particle size and size distribution of the final latexes (500 nm and 1.003, respectively) is not significantly affected by the comonomer feed composition, whereas the molecular weight and surface characteristics were found to sharply change at high butyl acrylate content. Based on the most probable particle nucleation mechanism and type of chain termination in the monomer swollen particles, a tentative explanation of these results has been proposed. Replacing persulfate by a carboxylic initiator (4-4′-azobiscyanopentanoic acid) results in the formation of stable particles as α observed with the persulfate, provided the aqueous phase pH is fixed in between 6 and 7. Results on the initiator residue location as a function of the conversion point out that the particle flocculation mechanism is strongly significant in the preparation of such latexes.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1990.080280109
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Study of the thermal decomposition of potassium persulfate by potentiometry and capillary electrophoresis (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1271-1281 
    Details
    ISSN: 0887-624X
    Schlagwort(e): potassium persulfate ; decomposition ; soap-emulsified systems ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two methods of analysis, potentiometry and capillary electrophoresis, were used to study the decomposition of potassium persulfate (KPS) in aqueous solutions. The experiments were carried out in a glass reactor equipped with continuous control of temperature and pH during the reaction. The effect of the pH on the decomposition of KPS was investigated. The rate of KPS decomposition in the presence of a variety of additives (surfactants, inhibitor, monomer-like molecules, and monomers), which are used in emulsion polymerization recipes, was also studied over the temperature range of interest. The rate of disappearance of the persulfate ion was greatly increased in the presence of hydroquinone, but changed very little in the presence of surfactants. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
  • 6
    Digitale Medien
    Digitale Medien
    Consistent values of rate parameters in free radical polymerization systems (1988)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 26 (1988), S. 293-297 
    Details
    ISSN: 0887-6258
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1988.140260704
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Emulsifier-free emulsion copolymerization of styrene and butyl acrylate. III. Kinetic studies in the presence of a surface active comonomer, the sodium acrylamido undecanoate (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 137-152 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Emulsion terpolymerization of styrene (S), butylacrylate (BuA) and sodium acrylamido undecanoate (AUNa), a surface active functional monomer have been carried out using a batch process in the presence of sodium 4-4′-azobiscyanopentanoate as initiator. Varying the AUNa concentration, stable particles bearing only carboxylic charges have been produced with diameters ranging from 200 to 500 nm at solids content as high as 40%. However a low AUNa yield at the particle surface has been found (30-35%), which could be explained by very unfavorable reactivity ratios of AUNa with S and BuA. Most of the AUNa seems to be wasted in the water phase (unpolymerized and forming hydrosoluble chains). Furthermore, a concentration of AUNa higher than 10-2 mol L-1 results in the latex destabilization, presumably caused by the formation of a large amount of polyelectrolytes. Kinetic studies of the AUNa consumption show that the AUNa is mainly fixed at the particle surface between 90 and 100% conversion, which indicates that the AUNa is mainly polymerized in the water phase and not at the particle surface. An attempt has been made to increase the surface charge density by polymerizing a shell of AUNa/S/BuA on a seed latex. It turned out to be unsuccessful (low surface yield, formation of new particles).
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1990.080280110
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Efficiency of mercaptan chain transfer agents in emulsion copolymerizations. I. Influence on kinetics and microstructure. Modeling of radical desorption (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 157-168 
    Details
    ISSN: 0887-624X
    Schlagwort(e): emulsion polymerization ; reaction calorimetry ; chain transfer agents ; kinetics ; radical desorption ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effect of chain transfer agents (CTA) on the emulsion copolymerization of styrene and butyl acrylate was studied in a bench scale 7 L reactor. On-line estimates of conversion were obtained through the joint use of calorimetric measurements and fast gravimetric data. Off-line measurements of partial conversions, molecular weight distribution (MWD), glass transition temperature (Tg), and particle diameter were also performed in order to investigate the effect of two mercaptans (tert-butanethiol and n-dodecanethiol) on both the kinetics of the polymerization process and the microstructure-dependent properties of the copolymer. The obtained experimental results were interpreted in terms of radical desorption and diffusive limitations of the CTA between the oil droplets and the particles. A model has been derived to compute the kinetic constants, the number of radicals per particle, and both the GPC/SEC diagrams and DSC thermograms related to MWD and Tg measurements, respectively. Several batch and semibatch examples are proposed to show that these important variables are satisfactorily fit by the model. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 157-168, 1998
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
  • 9
    Digitale Medien
    Digitale Medien
    Emulsion copolymerization of styrene with a nonionic styrenic polymerizable surfactant (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 465-472 
    Details
    ISSN: 1042-7147
    Schlagwort(e): polystyrene, emulsion polymerization ; styrenic nonionic surfactant ; latex stability ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Among the variety of possible structures for polymerizable surfactants, it seems clear that the most interesting should be those with the reactive group located in the hydrophobic part of the molecule. We report here a study based on such a surfactant. Its general formula is \documentclass{article}\pagestyle{empty}\begin{document}$$ CH_2d\hbox{---}CH\hbox{---}C_6 H_4\hbox{---}CH_2\hbox{---}O(CH_2)_n\hbox{---}O(CH_2CH_2\hbox{---}O)_m\hbox{---}H $$\end{document}A set of surfactants has been produced with m varying from 23 to 48 and n = 6 or 12. The compounds have been characterised by 1H-NMR (nuclear magnetic resonance), size exclusion chromatography, surface tension measurements and turbidimetry.These surfactants have been copolymerized with styrene in emulsion polymerization. The coagulum is rather important, except if m is large enough. Although the incorporation of the surfactant in the latex is rather high. Most of the anchored surfactant remains at the surface and is not too buried inside. The particle size decreases with both the amount of surfactant and the length of its hydrophilic part. The use of these polymerizable surfactants leads to an excellent stability of the latex against the addition of electrolytes, and also against freeze-thawing constraints.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pat.1995.220060707
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Steric stabilization of polystyrene colloids using thiol-ended polyethylene oxide (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 473-479 
    Details
    ISSN: 1042-7147
    Schlagwort(e): emulsion polymerization ; steric stabilization ; polymeric transfer agent ; redox system ; polystyrene colloids ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Thiol-ended polyethylene oxide (I) has been prepared from the esterification of thioglycolic acid with monomethylether of polyoxyethylene glycol. Emulsion polymerization of styrene (and, in a few cases, methylmethacrylate as comonomer) was carried out in the presence of I using either water-soluble azo initiator or t-butylhydroperoxide. In the former case, bimodal particle size distribution was obtained while monodisperse latexes could be prepared in the latter case. Then a redox system was formed from I and t-BuOOH so that I was both an initiator and a transfer agent. Good steric stabilization of the latexes was observed. The polyethylene oxide sequence of I was partly incorporated at the surface of the latex particles, but the incorporation yield remained limited (between 7 and 18%). Most of the resdue of I remained in the serum.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pat.1995.220060708
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...