ASTM D5477-2018 pdf free download

ASTM D5477-2018 pdf free download.Standard Practice for Identification of Polymer Layers or Inclusions by Fourier Transform Infrared Microspectroscopy (FT-IR)
1. Scope
1.1 This practice describes the techniques used for detecting two different polymer entities such as: 1.1.1 Abnormal specks or spots on a surface or in the film that are objectionable as defects and 1.1.2 Layers of different polymeric sheets commonly used as barrier films made by coextrusion. 1.2 This practice utilizes through-transmittance optical and infrared techniques. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7. N OTE 1—There is no known ISO equivalent to this standard. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions: 3.1.1 For definitions of the terms used in this practice, refer to Terminologies D883 and D1600. 3.1.2 For units, symbols, and abbreviations used in this practice, refer to Terminology E131 or IEEE/ASTM SI-10.
4. Significance and Use
4.1 Aspeck will ultimately cause a failure to occur by virtue of its appearance in a film or by the decrease in electrical or mechanical properties in the polymer substrate (see Specifica- tion D1248). 4.2 The analysis of composite layers for barrier purposes by microscopic Fourier transform infrared spectroscopy (FT-IR) can indicate the adequacy of the barrier tape or indicate why a barrier may be defective (a missing layer or hole in the layer or poor coextrusion practice). Fig. 1 represents a typical multi- layer film.
5. Apparatus
5.1 FT-IR Spectrophotometer, with nominal 4-cm −1 resolu- tion (see Practices E168). 5.2 Microsampling Accessory, accommodated into the FT-IR for microscopic infrared analysis, with nominal 6.25-µm resolution in the infrared mode. 5.3 Optical Microscope, equipped with cross-polarized light and phase contrast accessories. May be incorporated into the infrared microsampling accessory. 5.4 Hot-Stage, with temperature readout, is accommodated into the optical microscope or microsampling accessory. 5.5 Microtome, capable of <25 µm slices 62.5 µm.
8. Specimen Preparation
8.1 It is necessary to microtome a thin cross section at right angles to the surface of the film or sample in order to conveniently observe the individual layers or the interior of the speck. 8.2 Samples that do not deflect can be microtomed into the required thin sections as received. 8.3 Flexible samples must be supported during sectioning. Two common support techniques are shown, for flexible samples, in Fig. 2. On the left, a stiff, flat plastic is used for the support. A cyano-acrylate adhesive quickly bonds the flexible sample to the flat plastic support. On the right of Fig. 2, the sample is supported and cured inside a thermoset compound, such as a two-part epoxy. (See Guide E2015.) 8.4 The entire sandwich is then microtomed in a direction normal to the sample surface. Slice thickness typically of25-50 µm provide satisfactory transmission of optical and infrared light.
9. Procedure
9.1 Optical Microscopy 9.1.1 The first step is to observe the sample visually in an optical microscope. The fundamentals of optical microscopy and sample preparation have been discussed in detail else- where. 3 9.1.2 The key to optical microscopy analysis is the sample preparation. A 25 to 50-µm thick section allows the visible and IR radiation to go through the section. A section with very few knife marks is required. A knife mark is a gouge created in the section by a defect in the microtome knife. Under cross- polarized light, knife marks will confuse and distort the boundaries of an inhomogeneity or layers in a multilayer specimen. 9.1.3 Once suitable sections have been collected, they are viewed in the optical microscope under cross-polarized light. In pigmented materials, it is also necessary to view the materials in uncrossed polarized light. Differences in contrast between inhomogeneities of layers develop in these situations due to differences in the intrinsic birefringence of the resins, thermal and stress history, and pigment concentration. The differences in contrast generally define material boundaries. The areas of interest may then be photographed and measure- ments made to quantify the dimensions of inhomogeneities or layers.