Studies on the stability of styrene-acrylonitrile copolymer latex dispersions

Ono, Hiroshi; Satô, Fumihiko; Jidai, E.; Shibayama, Kyōichi

doi:10.1007/bf01753957

Cited by 4 publications

(2 citation statements)

References 12 publications

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“…where A is the Hamaker constant. According to the calculation of A eff , it is clear that both PMMA and SAN films on the substrate are stable (A PMMA = 2 Â 10 À20 J, A SAN = 0.8 Â 10 À20 J, A SiO = 2.2 Â 10 À20 J, and A air = 0 J 42,43 ). In the PMMA/SAN blend ultrathin film, however, it dewets the substrate by means of composition fluctuation.…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…To assess the stability of polymer films on the substrate, we can calculate the effective Hamaker constant ( A eff ) by eq : A eff = false( A substrate − A polymer false) false( A air − A polymer false) where A is the Hamaker constant. According to the calculation of A eff , it is clear that both PMMA and SAN films on the substrate are stable ( A PMMA = 2 × 10 –20 J, A SAN = 0.8 × 10 –20 J, A SiO = 2.2 × 10 –20 J, and A air = 0 J , ). In the PMMA/SAN blend ultrathin film, however, it dewets the substrate by means of composition fluctuation.…”

Section: Resultsmentioning

confidence: 99%

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Composition Effect on Interplay between Phase Separation and Dewetting in PMMA/SAN Blend Ultrathin Films

et al. 2011

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Using in situ atomic force microscopy (AFM) and grazing incidence ultrasmall-angle X-ray scattering (GIUSAX), the composition dependence of phase separation, dewetting, and interplay between them in blend [poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN)] ultrathin films (∼1R g, radius of gyration) on silicon oxide substrate was investigated. It was found that phase behaviors depended crucially on the composition in blend. First, dewetting morphologies in SAN50 and SAN70 were still under the control of U q0/E, which was introduced in our previous work [Polymer2009504456] to distinguish different dewetting pathways. Here, U q0 and E described the initial amplitude of the surface undulation and original thickness of film, respectively; second, composition produced significant influences on its gradient in composition fluctuation, resulting in the accelerated (or suppressed) dewetting; last, this kind of acceleration or suppression affected the following interplay between phase separation and dewetting so much. Using two samples of “dewetting/wetting–phase separation” and “wetting–dewetting/phase separation” with different components, we discussed the interplay mechanism of them in detail. In conclusion, our results indicate that dewetting, phase separation, and the following interplay between them are sensitive to composition in blend. Furthermore, composition gradient plays an important role in them.

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Section: ' Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Composition Effect on Interplay between Phase Separation and Dewetting in PMMA/SAN Blend Ultrathin Films

et al. 2011

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Cationic latex interaction with pulp fibers. I. Deposition of styrene‐butadiene latex having quaternized amino groups

Alinče

Inoue

Robertson

1979

J of Applied Polymer Sci

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SynopsisFour experimental latexes of different styrene-butadiene ratios stabilized with quaternized amino groups were employed in deposition studies on unbeaten kraft pulp fibers. The attraction between the oppositely charged latex and fibers facilitates a ready latex deposition in the pH region between the points of zero charge of the latex and of the fibers. The rate of deposition appears to be controlled by latex diffusion and convection up to the fiber surface. The distribution of latex particles deposited on the fiber surface is related to the butadiene content and the latex stability. Polystyrene latex is the most stable and covers the fibers uniformly as individual particles. With increased butadiene content, the coagulation region of the latex is more extended and the tendency to deposit as aggregates is promoted.Wet-end addition of latex is the most convenient way of introducing polymer into paper, but because most conventional latexes are anionic they do not deposit on negative pulp fibers without some kind of deposition aid. The potential advantage of using cationic latex is in the natural attraction between oppositely charged latex particles and fibers. It has been shown' that latex stabilized with built-in tertiary amino groups not only readily deposits on fibers, but offers an opportunity to regulate the latex distribution on fibers by controlling the pH and salt concentration. A uniform coverage of fibers by individual particles of film-forming latex was found to be most effective for paper reinforcement. However, the latex with tertiary amino groups has certain shortcomings, because the uniform latex deposition is achieved only at very low pH and above neutral pH the latex does not deposit due to the reversal of its charge.In the present study, latex stabilized with built-in quaternized amino groups was employed. Such latex is expected to be less sensitive to pH and the range over which it deposits should be extended. The stability and deposition characteristics of four experimental latexes with different styrene-butadiene ratio were examined. EXPERIMENTAL MaterialsPulp Fibers. Bleached, unbeaten kraft fibers, washed three times with distilled water in order to remove fines, were used.Latex. Four experimental cationic latexes of different softness (styrenebutadiene ratio) were prepared in the absence of emulsifier by a procedure described elsewhere.' The cationic charge was supplied by 1% %(diethy1 amino) ethyl methacrylate quaternized by dimethylsulfate and added to the reaction

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The coagulation mechanism of heat sensitive latices

Goossens

Vogt

1990

Colloids and Surfaces

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Studies on the stability of styrene-acrylonitrile copolymer latex dispersions

Cited by 4 publications

References 12 publications

Composition Effect on Interplay between Phase Separation and Dewetting in PMMA/SAN Blend Ultrathin Films

Composition Effect on Interplay between Phase Separation and Dewetting in PMMA/SAN Blend Ultrathin Films

Cationic latex interaction with pulp fibers. I. Deposition of styrene‐butadiene latex having quaternized amino groups

The coagulation mechanism of heat sensitive latices

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