Films test specimens

Film and sheeting materials test methods have been standardized by ASTM, DIN, and others. As with all materials, the test specimens must be carefiiUy prepared and conditioned. Thin-film specimens are vulnerable to nicks and tears which mar the results. Moisture and temperature can affect some materials. Common test methods are Hsted in Table 1. 

Fig. 7. Test specimens illustrate the nonwettable surface produced by a filming amine (381) compared with an untreated surface (380).

ISO 1346 2004 Fibre ropes - Polypropylene split film, monofilament and multifilament (PP2) and polypropylene high tenacity multifilament (PP3) - 3-, 4- and 8-strand ropes ISO 1873-1 1995 Plastics - Polypropylene (PP) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1873-2 1997 Plastics - Polypropylene (PP) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 3213 1996 Polypropylene (PP) pipes - Effect of time and temperature on expected strength... 

ISO 1874-2 1995 Plastics - Polyamide (PA) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 15987 2003 Plastics - Film and sheeting - Biaxially oriented polyamide (nylon) films. 

F-BDAF Tg for various blend compositions, see Fig. 14. The microphase-separated morphology further manifests itself in the self-adhesion behavior of polyimide films derived from such mixtures. For mixture containing at least 25 wt% of the flexible component, peel tests of polyimide bilayer samples prepared by solution casting, bulk failure of the test specimens was observed. Since the flexible component contained fluorine, the samples could be examined by X-ray photoelectron spectroscopy to determine the surface composition. At only 10% loading, the flexible component comprised 100% of the top 75 A of the sample. The surface segregation of the flexible component is believed to be responsible for the adhesion improvements. 

Since it is difficult to control processes for making plastic films in order to limit variability in their physical properties to one percent or less we find that material inhomogeneity is an obstacle to the development of better SRM s. It is also difficult to use such materials as transfer standards because their characteristics often drift with time and test specimens often do not tolerate abuse suffered during the measuring process. 

Regarding the spatial aspects of the enzymatic degradation of CA-g-PLLA, a surface characterization [30] was carried out for melt-molded films by atomic force microscopy (AFM) and attenuated total-reflection Fourier-transform infrared spectroscopy (ATR-FTIR) before and after the hydrolysis test with proteinase K. As exemplified in Fig. 3 for a copolymer of MS = 22, the AFM study showed that hydrolysis for a few weeks caused a transformation of the original smooth surface of the test specimen (Fig. 3a) into a more undulated surface with a number of protuberances of 50-300 nm in height and less than a few micrometers in width (Fig. 3b). The ATR-FTIR measurements proved a selective release of lactyl units in the surface region of the hydrolyzed films, and the absorption intensity data monitored as a function of time was explicable in accordance with the AFM result. 

The static immersed test specimens are prepared by heating them in oil formulations with additives, film is formed on oxide contaminated surfaces load is not involved in specimen preparation, only temperature can be a comparable parameter very different compounds are formed from the same additives solution. 

Figure 1. Schematic diagram of test specimen Ni film of thickness, t, on PET substrate of width w strained in direction of arrows. Dotted lines represent brittle cracking. The x-coordinate is measured in the direction of strain from the edge of a film segment.

The test specimen was a PET substrate 6 pm or 12 pm thick, 2.5 mm wide and about 1.5 cm long with a 3 mm long strip of evaporated metal, 0.2 pm to 1.2 pm thick, deposited near its center. The film thickness was monitored, during evaporation, with a quartz crystal thickness monitor, and the substrate temperature was measured with a thermocouple. The substrate temperature always remained within within 10 C of room temperature. An ion gun could be used to treat the substrate surface before deposition to modify the film adhesion. After deposition, the specimen was removed from the deposition... 

The retardation of the migration of silicone oligomers from the silicone tubing after being coated indicates that the plasma polymer coating applied to the tube substrate is in a form of continuous film with barrier characteristics instead of some other physical forms (e.g., powder). Direct evidence of this aspect can also be seen from the fact that all test specimens prepared had passed the dye penetration test. 

Fig. 28a, b. A schematic of a typical fragility test specimen a. The ductile copper grid subdivides the polymer film into ca. 50 independent grid squares. Shown in b is a schematic of the dependence of stress CT on strain e (or time) for an individual film square... 

Licari tested specimens with water droplets bridging the gap between the two conductors as well as with other specimens exposed to relative humidities up to 100% at a constant 80°C. He showed that even with applied voltages over 20 volts, and time periods up to two weeks, silver migriation did not occur unless there was a film of liquid water on the surface. 

The oriented film specimens were mounted on aluminum frames and exposed on an Atlas Weather-Ometer, Model 65WR. An 18 minute spray cycle together with an 102 minute cycle at 55% relative humidity and approximately 65°C was used. At regular intervals, the test specimens were removed from exposure and their tensile strength measured on an Instron Model 1102. A decrease in tensile strength, expressed as tenacity, over the tensile strength of the same formulation before exposure, is a measure of the deterioration of the physical properties of the polymer. "Failure" in this test is defined as a loss of 50% or more of the initial sample tenacity. 

A specimen may be in the form of pellets, powder, sheet, film, plastic cellular, or composite materials, with a specimen weight of 3.0 0.2 g. The ASTM procedure describes in detail cutting or folding sheet or film materials and conditioning test specimens. 

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