Laminate film sample preparation

Sample Preparation. Polyethylene pellets were processed on a two-roll mill followed by pressing between clean aluminum sheets at 110°-125 °C for one minute. The resultant films were preoxidized to varying extents by initially exposing them in air to 5 Mrads of y-radiation from a C060 source followed by exposure to one atmosphere of oxygen gas in sealed vessels at 90°-100°C. The extent of oxidation was monitored by ir spectroscopy (see below). Two types of laminates were formed from 1.5 cm X 1.0 cm polyethylene films about 0.025 cm in thickness (a) a... 

Laminate samples are prepared by overlaying an ethylene vinyl alcohol polymer film, adhesive resin film and TPX film and are press-molded. 

The metallic layers were examined either by conventional or cross-section TEM in a Jeol 200 Cx microscope. For the cross section preparation a sandwich of two laminates is made, glued face to face with an epoxy, cut in small pieces, mechanically polished, and then ion milled to a final TEM observation thickness. The plane section TEM sample are prepared by dissolving the PET in trifluoroacetic acid for 5 to 10 mn. The area observed, on plane section TEM, for the grain size calculation is close to 0.2 urn. For the adhesion measurements, test pieces consist of aluminum support (1 mm thick) double sided tape (Permacel P-94) PET (12pm) / evaporated aluminum/ ethylene acrylic acid (EAA) copolymer film. These laminates are prepared for the peel test by compression under 1.3 105 N.m2 at 120°C for 10 seconds. The peel test is performed by peeling the EAA copolymer sheet from the laminate in an INSTRON tensile tester at 180° peel angle and 5 cm min peel rate. 

Tyvek 34g/m samples were prepared by cutting rectangular pieces of dimensions of 0.1524 m x 0.1524 m which were compression molded in varying layer placed biaxially and in a parallel manner and held together by tie layers of thin clear PE film. The laminates were molded at a temperature of 421.48°K, at a 2.2679 kg load for 720 s using a 45359.237 kg compression press machine. Tensile test strip specimens were prepared from the laminates cut at various angles of orientation 0,15,30,45,... 

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