Water absorption by acrylic-based latex blend films and its effect on their properties

✍ Scribed by N. Agarwal; R. J. Farris

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 574 KB
• Volume: 72
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990613)72:11<1407::aid-app4>3.0.co;2-5

✦ Synopsis

The absorption of moisture, from liquid as well as gaseous states of water, is known to strongly influence the properties of many polymeric materials. In this article, we examine the unusually high affinity for water of acrylic-based latex blend films, which lose their transparency and turn white upon water absorption. Composed of rubbery and glassy phases at room temperature, these blends absorb significant amounts of water, which results in only a minor plasticization of the glassy component. When redried at elevated temperatures, the blend films return to their original transparent state but remain white and opaque when freeze-dried at Ϫ70°C. Scanning electron micrographs of the freeze-fractured surfaces of wet samples exhibit micronsized holes that suggest clusters of water inside the bulk of the films. A qualitative model associates these water clusters to residual surfactant inside the samples that is left behind after the drying of original latices.