Thermally modified films, properties

Properties of thermally modified films. Thermally modified films produced in this work were found to be colourless, glassy materials with extremely strong adhesion to the metal substrate. Passivation tests have shown that the coated metals displayed excellent resistance to corrosive chemicals. Exposure of films to concentrated acids, such as ECt, HNO, H2S0i and H PO for several hours had no visible effect upon their surface. 

Considerable efforts have been directed, during the last few years, to grafting various vinyl and acrylic monomers on cellulosic fibers or films in order to modify their properties in a predetermined way. It was shown that one can graft large amounts of vinyl-type monomers, such as acrylonitrile or acrylic esters on rayon, cotton, cellophane, paper, and wood, thus modifying the properties of the base material in many respects, and improving, particularly, dimensional stability, water repellency, and resistance to thermal and chemical degradation. 

The most desirable properties for electrically conductive polymeric materials are film-forming ability and thermal and electrical properties. These properties are conveniently attained by chemical modification of polymers such as polycation-7, 7,8, 8-tetracyanoqninodimethane (TCNQ) radical anion salt formation (1-3). However, a major drawback of such a system is the brittle nature of the films and their poor stability (4,5) resulting from the polymeric ionicity. In recent years, polymeric composites (6-8) comprising TCNQ salt dispersions in non-ionic polymer matrices have been found to have better properties. In addition, the range of conductivities desired can be controlled by adjusting the TCNQ salt concentration, and other physical properties can be modified by choosing an appropriate polymer matrix. Thus, the composite systems are expected to have important advantages for use in electronic devices. 

Poly(ester-imide) resins have excellent thermal and mechanical properties, and wire enamels made from them are used in stressed electrical appliances. Other uses for imide modified polyesters are also known, where a balance between two thermal properties, cut through and soldering temperature, is required, e.g., in solderable poly(ester-imide)s and poly(ester-imide)s used in polyurethane wire enamels. A third application is in selfbonding wire enamels, where a softening of the film in a given temperature range is desired. 

Pax-Plus 3303. A rubber-modified film resin that exhibits good toughness and easy processing. Its major uses are for film requiring good odor and moisture barrier properties and superior thermal properties. 

To modify the properties of Sn02 films, different ways of their treatment are widely used. Of particular interest is the study on the influence of thermal and plasma treatments on optical and structural properties of the SnOx films, deposited by the sol-gel techniques. 

Film or sheet generally function as supports for other materials, as barriers or covers such as packaging, as insulation, or as materials of constmction. The uses depend on the unique combination of properties of the specific resins or plastic materials chosen. When multilayer films or sheets are made, the product properties can be varied to meet almost any need. Further modification of properties can be achieved by use of such additives or modifiers as plasticizers (qv), antistatic agents (qv), fire retardants, sHp agents, uv and thermal stabilizers, dyes (qv) or pigments (qv), and biodegradable activators. 

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