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2 Archives of Materials Science and Engineering

2 2007

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Ultrasonic methods in diagnostics of polyethylene

Wróbel G., Wierzbicki Ł.

Archives of Materials Science and Engineering

2007

Vol. 28, nr 7

413-416

Purpose: The aim of the work was to find relationship between the ultrasonic wave velocity and the strenght and stess in a polyethylene specimens. Design/methodology/approach: The experiments have been performed in three distinct phases. During the first phase, typical polyethylene was ageing to get different mechanical properties. In the second phase, strength and ultrasonic properties of composite was testing. In the last of phases we compare changes of properties. Findings: The experimental results showed relationship between velocity of ultrasonic wave and strength and stress in a polyethylene specimens. Research limitations/implications: In the future test will be necessary to use more precise testing equipment. Perhaps we will use other ultrasonic probes of lower frequency. In this experiment we used 2 Mhz probes. It is necessary to run an experiment with more specimens. Further work is needed in the correlations between ultrasound and stress area. Practical implications: The results of the investigation have shown possibility of using ultrasonic method to diagnosis of strength changes in polymers materials. This method allowed to test working parts of machines or buildings, without destruction. Originality/value: The results of the investigations allow to confirm, that ultrasonics can be used to nondestructive testing of the strength and Young's modulus changes.

The examination of the structure of PP composites with the glass fibre

Kwiatkowski D., Nabiałek J., Gnatowski A.

Archives of Materials Science and Engineering

2007

Vol. 28, nr 7

405-408

Purpose: of the examination is determination of selected physical properties: melting and crystallization temperature for polypropylene PP and its composites with glass fiber during observation the melting and congealing process by means of optical microscope in white light. Design/methodology/approach: Examination of melting and crystallization temperature of polypropylene composites with glass fibre became carried out by means of the set for the microscopic observation of phase transformations. The set consist of polarized microscope and computer system recording. By means of the set the crystal objects were tested during melting and crystallization process of polymer plastic going through the sample in normal light. The melting and crystallization temperatures were determined visuallily. Examination were carried out registering by means of the microphotography at the definite temperature occurring transformations during heating polymer samples and composites with speed of 200 °C /min, and also during cooling with speed of 50 °C/min in white light. Findings: Fibrous filler in the form of the glass fibre nucleation and modifies the process of the crystallization of the polypropylene composites. Research limitations/implications: The influence of other fillers on crystallization process of polypropylene composites will be defined in future. Practical implications: The carried out tests of structure are useful especially for determination how the used filler nucleates and modifies the crystallization process of polypropylene and its composites. Originality/value: The computer system of recording of the picture enables the carrying out of proceeding processes on-screen of the computer monitor and the recording of single frames and sequences the video, what enables more precise analysis of processes occurring at the high speed.