Compression molded films

Sample 250-pm compression-molded films of Teflon PFA 340 from G.E. resonance transformer 2 MeV capacity, at a current of 1 m A. 

Amine-terminated siloxane oligomers have also been utilized in the synthesis of various siloxane-amide and siloxane-imide copolymers, High molecular weight siloxane-amide copolymers have been synthesized by the solution or interfacial co-polymerization of siloxane oligomers with sebacoyl chloride or terephthaloyl chloride respectively 1S5,165). In some reactions diamine chain extenders have also been utilized. Thermal and dynamic mechanical characterization of these copolymers have shown the formation of multiphase systems160). Compression molded films displayed very good elastomeric properties. 

The release of steroids such as progesterone from films of PCL and its copolymers with lactic acid has been shown to be rapid (Fig. 10) and to exhibit the expected (time)l/2 kinetics when corrected for the contribution of an aqueous boundary layer (68). The kinetics were consistent with phase separation of the steroid in the polymer and a Fickian diffusion process. The release rates, reflecting the permeability coefficient, depended on the method of film preparation and were greater with compression molded films than solution cast films. In vivo release rates from films implanted in rabbits was very rapid, being essentially identical to the rate of excretion of a bolus injection of progesterone, i. e., the rate of excretion rather than the rate of release from the polymer was rate determining. 

A comparison of the dynamic mechanical properties of our HB at 35 Hz has been made to that of LDPE in Figures 14 A and B. The thermal and sample preparative history affects the mechanical properties of HB films to such an extent that in order to make a meaningful comparison one has to describe the exact history of the samples. Such a thermal history dependence has been examined for LDPE(54,57) and recently for HB.(12) Shown in Figures A and B are the mechanical spectra for HB-PQ, HB-Tol, and LDPE-PQ films. The compression molded films were prepared 1 to 2 days prior to the test. The solution cast film (from toluene), HB-Tol, was annealed at 80°C for 2-3 days and stored at room temperature for 1 week... 

Infrared spectra of the polymer, before and after photolysis, were run on a Perkin Elmer 521 double-beam grating spectrophotometer, using compression-molded films. Film thicknesses were determined by a micrometer. 

The 1% ethylene-carbon monoxide copolymer was also irradiated in the solid phase (thin film). Compression-molded films were fixed on plates which fitted into the Perkin Elmer 521 infrared spectrophotometer. An infrared spectrum of the polymer could thus be obtained after each period of photolysis without disturbing the film. For photolyses at room temperature and above the plates were mounted in a solid brass cell through which a stream of inert gas could be passed while the cell was being heated. 

Harwood, R. J., and Schwartz, J. B. (1982), Drug release from compression molded films Preliminary studies with pilocarpine, Drug Dev. Ind. Pharm., 8(5), 663-682. 

Gohen EM, Grim WM, Harwood RJ, Mehta GN. Solid state ophthalmic medication. United States Patent No. 4,179,497 1979. Harwood RJ, Schwartz JB. Drug release from compression molded films preliminary studies with pilocarpine. Drug Dev Ind Pharm 1982 8 663-682. 

Blends were prepared by solution blending the copolymers with a Dow general purpose molding grade (667) polystyrene, casting from solution and then compression molding film as for the copolymer. 

Fig. 34 Images of clear compression molded films made with linear PS (MW = 280kg mol ) blended with PS-y-CD 12-arm star molecules, (a) PS3.4-y-CD, (b) PS32-y-CD, (c) PS52-y-CD, and (d) PS90-y-CD...

Figure 1. FTIR spectra of compression molded films of A) Polystyrene B) H-SPS (7.6 mole %) C) Na-SPS (1.7 mole %).

Tensile strengths were determined on microdumbbells from about 20-mil thick compression-molded films with an Instron table model instrument at the rate of 2 in./min. 

Compression molded film Extrusion cast film Biaxially oriented - 2.5 x 2.5... 

Fig. 46 Remaining surface potential of fluorinated PEIs after 24 h at 90 °C. The fluorine content in wt% of each polymer is given in parentheses below. The compression molded films of 100 pm thickness were corona charged to +400 V for 20 s [84]. Published by permission of WILEY-VCH...

Dynamic Mechanical Analysis. The modulus loss tangent data for FPE-2 and -3 are shown In Figures 7 and 8. The data for FPE-2 were obtained from a compression molded film and those for FPE-3 were obtained from a film cast from methylene chloride. 

Hydrolytic Stability Data of Compression Molded Films... 

The glass transition temperatures (T ) were measured on compression-molded films by using a Perkin-cimer DSC-2 differential scanning calorimeter with a Data Station at a heating rate of lOK/ min. under a nitrogen atmosphere. Transreaction of the binary polymer blends was also carried out directly in the DSC-2, by holding blends at 250°C for up to 16 hours. The transreaction was monitored by DSC, CPC and C NMR. 

Figure 22.14 Stress-strain curves, recorded at room temperature of melt-compression-molded films of poly(butyloxy-pora-meftl-phenylene) (PBmP) (55) (high-molar-mass part). For reference purposes, corresponding curves of a-PS, PMMA, and PC are also shown, illustrating the excellent mechanical properties of...

Minature dumbbell-shaped specimens of each polymer and blend were molded from pieces of compression molded films by means of a Mini-Max Injection Molder (Custom Scientific Instruments) whose operation and mixing characteristics have been reviewed by Maxwell (12), Gauge length of the molded dumbbells was 8.9 mm at a cross-sectional diameter of 0.157 cm. 

It is noted that the specific phase morphology of the injected molded tensile specimens used in the present study may differ from the compression molded film morphology. In the case of extruded samples of polymer blends displaying macrophase separation. Van Oene (25) indicates that the dispersed phase may appear as either ribbons (stratification) or droplets independent of shear strain rate but dependent of the post-extrusion thermal history. A study of the effect of morphology and phase inversion on the mechanical properties of the incompatible PPO blends is presently in progress. 

Pig. 7. First Run DSC Curves for Sample El (I) Powder, (II) Compression Molded Film Cooled Under Pressure. (Ill) Compression Molded Film Cooled Without Pressure (Ref. 2). 

This technique is suitable for amorphous materials, such as waxes, tarry solids, hot melt adhesives, and some low-melting solids. Rubbery materials often have a tendency to retract, since the applied pressure is normally only by hand, and the assembly may need to be clamped. For rubbers it is probably better to prepare a thin film by the melt method described in the section Hot compression molded films. This melt approach is not recommended for materials which will crystallize on solidification, since scatter and molecular orientation effects will lead to both poor spectral contrast and irreproduci-bility. 

Hot compression molded films Hot compression molding is one of the most effective and satisfactory means of preparing films from many thermoplastic resin samples for infrared presentation, particularly for quantitative compositional analyses. The polymer must of course be thermally stable at the pressing temperature. 

Eor certain analyses it may be desirable to ensure that the hot pressed compression molded film is frozen into an amorphous state. This may be achieved by melting a few milligrams between a pair of thin press plates or aluminum sheet, leaving part of the plates exposed from the press platens. This may be... 

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