Abstract
The effects of plasticizer, physical aging, and film-forming temperature on the mechanical and transport properties of films formed from aqueous dispersions of ethylcellulose latex were investigated. The water vapor permeability of latex films was found to decrease with diethyl phthalate to a minimum value and then to increase with diethyl phthalate at higher concentrations. Because of the decrease in free volume and the further coalescence of particles of latex polymer films in the physical aging range, the creep compliance of latex films decreased with physical aging time. Within 60 to 100°C, the film-forming temperature was found to have no effect on the mechanical and transport properties of Aquacoat films. However, since many pinholes formed in the latex films when the film-forming temperature was above 100°C, the water vapor permeability of latex films was higher than that of latex films formed between 60 and 100°C. The formation of films from aqueous latex dispersions is suggested to proceed gradually from the top to the bottom of the latex dispersion in this study.
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REFERENCES
G. S. Banker and G. E. Peck. The new, water-based colloidal dispersions. Pharm. Tech. April 55–61 (1981).
K. Lehmann and D. Dreher. The use of aqueous synthetic-polymer dispersions for coating pharmaceutical dosage forms. Drug Made in Germany 19:126–136 (1973).
S. L. Bertha and R. M. Ikeda. Film formation from polymer dispersions. J. Appl. Polym. Sci. 15:105–109 (1971).
J. G. Brodnyan and T. Konen. Experimental study of the mechanism of film formation. J. Appl. Polym. Sci. 8:687–697 (1964).
K. L. Hoy. Estimating the effectiveness of latex coalescing aids. J. Paint Tech. 45:51–56 (1973).
R. Patella. Minimum film forming temperatures of emulsion vehicles and latex paints. J. Coat. Tech. 48:60–61 (1976).
T. F. Protzman and G. L. Brown. An apparatus for the determination of the minimum film temperature of polymer emulsions. J. Appl. Polym. Sci. 10:81–85 (1960).
C. Ho and H. Suryakusuma. The effects of plasticizer and polymer ratio on the permeation of chlorpheniramine maleate through aqueous dispersion Eudragit RS30D and RL30D films. Pharm. Res. 5:S-55 (1988).
R. J. Wald, R. A. Opdycke, S. L. Saddler, M. E. Houghton, and G. E. Amidon. Diffusion cell testing of the permeation properties of aqueous based ethycellulose dispersions used for controlled released. Pharm. Res. 5:S-55 (1988).
S. C. Porter. The effect of additives on the properties of an aqueous film coating. Pharm. Tech. 4:67–75 (1980).
C. Bindschaedler, R. Gurny, and E. Doelker. Osmotic water transport through cellulose acetate membranes produced from a latex system. J. Pharm. Sci. 76:455–460 (1987).
Jian-Hwa Guo, R. E. Robertson, and G. L. Amidon. Influence of physical aging on mechanical properties of polymer free films: The prediction of long-term aging effects on the water permeability and dissolution rate of polymer film-coated tablets. Pharm. Res. 8:000–000 (1991).
E. B. Bradford and J. W. Vanderhoff. Additional studied of morphological changes in latex films. J. Macromol. Sci. 6:671–694 (1972).
E. B. Bradford and J. W. Vanderhoff. Morphological changes in latex films. J. Macromol. Sci. 1:335–360 (1966).
L. C. E. Struik. Physical Aging in Amorphous Polymers and Other Materials, Elsevier, Amsterdam, 1978.
N. G. McCrum, C. P. Buckley, and C. B. Bucknall. Principles of Polymer Engineering, Oxford University Press, New York, 1988.
R. Simha, J. G. Curro, and R. E. Robertson. Molecular dynamics of physical aging in the glassy state. Polym. Eng. Sci. 24:1071–1078 (1984).
R. E. Robertson. Effect of free-volume fluctuations on polymer relaxation in the glassy state. J. Polym. Sci. Polym. Symp. 63:173–183 (1978).
J. G. Curro, R. R. Lagasse, and R. Simha. Use of a theoretical equation of state to interpret time-dependent free volume in polymer glasses. J. Appl. Phys. 52:5892–5897 (1981).
R. E. Robertson, R. Simha, and J. G. Curro. Free volume and the kinetics of aging of polymer glasses. Macromolecules 17:911–919 (1984).
D. Distler and G. Kanig. Feinstruktur von Polymeren aus wäßriger Dispersion. Colloid Polym. Sci. 256:1052–1060 (1978).
G. Kanig and H. Neff. Ein neues Kontrastierverfahren für die elektronenmikroskopische Untersuchung vonsäure-und estergruppenhaltigen Polymersystemen. Colloid Polym. Sci. 253:29–31 (1975).
B. J. Roulstone, M. C. Wilkinson, J. Hearn, and A. J. Wilson. Studies on polymer latex films: I. A study of latex film morphology. Polym. Int. 24:87–91 (1991).
M. Chainey. Council for National Academic Awards (CNAA), Ph.D. thesis, Trent Polytechnic, Nottingham, UK, 1984.
H. Arwidsson, O. Hjelstuen, D. Ingason, and C. Graffner. Properties of ethyl cellulose film for extended release. II. Influence of plasticizer content and coalescence condition when using aqueous dispersions. Acta Pharm. Nord. 3:65–70 (1991).
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Guo, JH., Robertson, R.E. & Amidon, G.L. An Investigation into the Mechanical and Transport Properties of Aqueous Latex Films: A New Hypothesis for the Film-Forming Mechanism of Aqueous Dispersion System. Pharm Res 10, 405–410 (1993). https://doi.org/10.1023/A:1018992423232
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DOI: https://doi.org/10.1023/A:1018992423232