Solvent casting of film

Ester interchange between the additive and polymer would be expected if the mixture were held for an excessive time in the melt. In order to avoid the potential for interchange, the blendings were conducted in solution and heated only for a time necessary to melt press films for flammability testing. An alternative method of film preparation by solvent casting of films was discarded due to difficulties in preparing uniform, sufficiently thick, solvent free films for evaluation. 

Figure 5.18 schematizes the principle of solvent casting of film. 

To perform addition and condensation polymerization and solvent casting of films. 

Mechanical Properties. The mechanical properties of thin, solvent-cast polymer films were measured on an Instron Tensile Tester according to ASTM standard D882-83. In all cases, tensile values were calculated from the average of at least four measurements obtained from four separate specimens per polymer sample. 

Incorporating small amounts of plasticizer during the manufacture of solvent-cast polycarbonate films results in films with a higher modulus of elasticity, a higher stiffness, and higher heat distortion temperatures than films cast from unplasticized polymer. 

Compare the appearance of the solvent-cast nylon film with that of the polystyrene. 

Fig. 5. Tapping Mode pictures of a thin solvent-cast copolymer film with 20 (left) and 30 (right) wt% of a siloxane macromonomer. Clearly seen is the transition fi om a segregated domain stmeture to an interpenetrating sponge morphology.

Measurement of the influence of different micellar environments on proton transfer from excited states of 3-hydroxyflavone allows estimates to be made of micelle concentrations from measurement of the tautomer emission yield. Proton transfer reactions of benzimidazole excited singlet states have also been studied in ionic micelles. Magnetic fields are found to affect the behaviour of radicals generated by the photodissociation of benzil in micellar media. The starburst dendrites which are formed by anionic macromolecules in interaction with both anionic and cationic surfactants have been examined by pyrene fluorescence. Benzo[k]fluoranthrene fluorescence has served as a probe of the effects of metal salts on bile salt aggregation. The incorporation and distribution of benzoquinone into liposomes containing amphilic Zn(II) porphyrin has been followed by its effect on the quenching of the excited state °. A comparison of the photochromism of spirobenzpyran derivatives in unilamellar surfactant vesicles and solvent cast surfactant films has also been reported. ... 

Solvent casting of polymer mixmres (usually with additives) may affect the density, porosity, mechanical properties, mode of failure, etc. These effects are particularly pronounced in films of immiscible polymers. Before discussing these effects, it is appropriate to consider the intermediate step — solvent casting of copolymers Table 9.20 provides few examples. 

Machell, J. S., Greener, J., and Contestable, B. A. (1990). Optical properties of solvent cast pol3mier films, Macromnlecules. 23,186-194. 

Greener, J., Lei. H., Elman, ]., and Chen, J. (2005). Optical properties of solvent-cast polarizer films for liquid-crystal displa5rs A viscoelastic modeling framework,/. SID., 13,835-839. 

Polyphosphazene films, prepared by solvent casting of either polyphosphazene polymers or polyphosphazene blends, have been actively studied for periodontal or bone tissue engineering. Duan et al. prepared poly[(ethyl... 

Plastic films are manufactured by several completely different methods. Casting of films from solutions or dispersions is carried out on an appreciable scale. The solution or dispersion is cast on an endless belt of polished stainless steel or other suitable materials. The solvent is evaporated and the film is stripped from the belt, trimmed and wound up. This method is used for films from cellulose derivatives, rubber hydrochloride, etc., and can produce very uniform and clear films, virtually without orientation effects. 

Solution casting of films such as cellulose acetate uses solvents such as acetone and methylene chloride (e.g. for photographic film). Most solvent is recovered for reuse in the process. 

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