ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Conventional film casting methods have proved unsuitable for the preparation of thin (10-100 μ) films from surfactant-free polymer latices. A flash casting technique has been devised and successfully employed to cast films from a wide range of surfactant-free homopolymer, copolymer and core-shell polymer latices. Essentially, the method involves spraying the latex at a specially designed hotplate, the surface of which is coated with a thin layer of PTFE. The hotplate is maintained at a temperature between 393 and 473 K. When sufficient thickness of film has been built up, the hotplate is switched off and allowed to cool to the temperature at which the film is to be removed. For homogeneous latex films, the optimum temperature range for removal lies in the region of the glass transition temperature of the polymer concerned. Where this is below ambient, the appropriate cooling mixture is placed in a slush bath, situated to the rear of the hotplate, thereby cooling the hotplate to the correct temperature. The film is removed by gently peeling it from the surface. The surfaces of the films appeared smooth to the naked eye, but the sprayed surfaces of freshly prepared poly(n-butyl methacrylate) films were rough when examined by scanning electron microscopy. The surfaces smoothed out on ageing, resembling those of solvent-cast films after one months storage.
Zusätzliches Material:
10 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1985.070301106
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