This research aims to improve the tensile properties of the polyethylene (PE) film deposited with a multilayer graphene membrane, in order to establish the understanding of the influence of the methane to hydrogen ratio on the tensile properties of the MLG membrane, providing insight into design of a new generation of body armour system with better protection level and light weight.
Two types of specimens are prepared to investigate the tensile properties, denoted by G1 and G2. G1 is the PE film deposited with a MLG membrane and G2 is produced by coating MLG membrane on one side of the PE film which is then backed up by an uncoated PE film. It is referred to as a sandwich structure. In addition, one-layer pure PE (P1) and two layers pure PE (P2) are prepared under the same conditions respectively for comparison purposes.
In this study, the specimens are cut into a rectangular shape as illustrated in Fig. 5. The gauge length and the effective width are set to 50 mm and 10 mm to ensure the effective grip. The constant tensile speed of 200 mm/min is used. Each specimen is tested five times to determine the tensile properties. Scanning Electron Microscopy (SEM) is used for the analysis of the morphology of samples by Hitachi S3000.
In order to further analyse the influence of the ratio of methane to hydrogen, the flow of methane is increased from 25 to 40 sccm at the flow of 100 sccm hydrogen and the changes in tensile properties are investigated. It has been shown in Fig. 7 and Fig. 8. The morphology of the MLG sheet is also characterized by SEM images which is showed in Fig. 9. The Raman spectrum of sample G1 and G4 are showed in Fig. 10 (Table 1).
ASTM D882 is a widely used testing standard for tensile properties of thin plastic sheet films. It is commonly used for in-line quality control. Thin plastic films and sheeting are surprisingly durable, making them an excellent choice for packaging. Not only are they strong enough to withstand shipping or transportation, but also provides an effective barrier against moisture, oxygen, light, and bacteria.
ASTM D882 is a common method of examining the mechanical properties of thin plastic films of less than 1 mm (0.040 in). In this test, a sample of film is mounted between two grips that are 250 mm (10 in) apart at the beginning of the test (gage length) distance which are then pulled by applying a tensile load. The elongation (or extension) produced in the sample is registered as the load increases.
Test samples for thin films or plastic sheeting consist of a rectangular strip of consistent width as opposed to a dumbbell shape, which is required for ASTM D638 tensile tests. The absence of a reduced sample section increases the stress concentration where the jaws grab the specimen. The test goal is to reduce these stress concentrations and enable the specimen to break in the center of the gage length.
The tensile test on plastics according to ASTM D638 helps determine essential mechanical properties, including tensile stress, strain, tensile modulus, tensile strength, tensile strength at yield and tensile strength at break. The ASTM D638 standard is not identical to its counterparts ISO 527-1 and ISO 527-2. These standards differ in many aspects, including the shape and dimensions of the specimens, the definition of test results, and the test procedure itself. While ASTM D638 presents a pragmatic characterization of tensile properties, the guiding principle of the ISO 527 standard is the high level of reproducibility of test results across laboratories, companies and national borders.
In the ASTM D638 standard test method for tensile properties of plastics, essential mechanical properties of a molding material or a specimen machined from a defined area on a component are determined.
Tensile test on plastics in the new ZwickRoell temperature chamber. The temperature range can be adjusted from -80 °C to +250 °C (-112 °F to 480 °F). The fully integrated system ensures efficient, reliable and easy operation during the performance of tensile tests. With the door-in-door solution, nitrogen consumption and ice formation are significantly reduced while testing at cold temperatures, so that the tests can be performed more cost effectively.
The tensile strength of plastics is essentially determined by measuring the stress that is required to cause a plastic specimen to break or to yield. The standard, therefore, makes a differentiation between the yield point and the break resistance. This defining characteristic of plastic materials is commonly used in research and development and for quality control purposes. The tensile strength of plastics is determined using a tensile testing machine, which pulls the specimen apart until it breaks, while critical values are measured and calculated. Most commonly these tests are performed according to standard ASTM D638, which specifies the shape and dimensions of the specimen to be tested, provides machine specifications, and describes the test procedure.
The ASTM D638 standard describes tensile testing on plastics. It is applied to measure tensile properties including the tensile modulus, yield stress, yield strain, tensile strength and strain at break. These properties are important for the determination and comparison of plastics and plastic compounds, as well as for quality assurance purposes.
The ASTM D882 standard is used for tensile tests on plastic films and sheet material with a thickness up to 1 mm. For this, there are special specimens and a test method that addresses the particular requirements for testing of film.
Long fiber reinforced plastics such as GRC or CRC are measured in the tensile test to ASTM D3039. These materials can have very different properties depending on the direction and structure of the laminate or fabric. They, therefore, often require special specimens and test methods.
The ASTM D638 standard covers the determination of tensile properties including the tensile strength of unreinforced and reinforced plastics. Other common standards used to test tensile strength are ASTM E8/ASTM E8M for metals, ASTM D412 for rubber and elastomers, and ASTM D3039 fiber-reinforced composites
ASTM D882 is a standard test method for analyzing the tensile characteristics of thin plastic sheeting. In this test, the plastic sheet is pulled until it breaks for measuring the elongation, tensile yield strength, tensile modulus, and tensile strength at break.
1.3 The permanent set is in accordance with the definition of claim 1 to be measured per ASTM D882-97 after recovery of the film being initially stretched to 100% of its original size. This standard test method per se is a method for determining tensile properties of plastic films, but not the permanent residual deformation of films held under tension. Considering the indication in paragraph  of the specification (page 3, lines 47-48) that the test method used to determine the permanent set is based upon ASTM D882-97 with some modifications defined in said paragraph, the skilled person understands as acknowledged by the parties during the oral proceedings that the test method used to determine the permanent set is a method using some aspects of the methodology of ASTM D882-97.
4.4 As to the experimental part of D3, its Example 5 illustrates the tensile properties of plastoelastic film materials formed with an elastomeric component (i.e. a V1100 film-grade VISTAMAXX elastomeric polypropylene), various polyolefin-based plastic components and an optional opacifier (paragraph bridging pages 31 and 32). One of these plastoelastic materials, whose compositions are shown in Table 5A, on page 32, is referred to as "Sample 5E". It is a mixture of 85 wt.% of said elastomeric polypropylene (V1100 VISTAMAXX) and 15 wt.% of a linear low density polyethylene (LL6201). The unactivated samples, i.e. the inactivated films made out of the compositions shown in Table 5A, were tested to determine their tensile properties and subjected to a hysteresis test (page 32, lines 2-5).
4.4.1 The results of the tests are provided in Tables 5B and 5C, each of the tables showing the results obtained with a "Sample 5E". Table 5B and Table 5C show the results of the tensile test and those of the hysteresis test, respectively, on the basis of which it is concluded that these plastoelastic films have favorable mechanical properties that make them suitable for inclusion into a SOC (page 33, lines 1-3). 2b1af7f3a8