engleski

Investigation of thermal behaviour and ageing of thermoplastic polymers used for protective textiles

The influence of ageing behaviour on tensile strength and other properties needed for protection is very important during the expected lifetime of protective textiles. Tensile strength loss by degradation caused by environmental stress is a critical parameter which has to be determined for the expected lifetime of the protective textiles. At present, commonly used materials in protective textiles besides many others are Polyethylene (PE), Polypropylene (PP) and Polyester (PET). Polymeric molecules are very large on the molecular scale, and their unique and useful properties are mainly a result of their structure. Any loss in chain length lowers tensile strength and it is a primary cause of structural weakness. In this paper, thermal behaviour and ageing of thermoplastic polymers were investigated with the aim of understanding their mechanisms of degradation. One part of the tested specimens was aged under natural conditions, while the other specimens were aged artificially with a UV-tester. Thermal behaviour of both specimens was investigated by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA), while the ageing effect was determined with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The DSC curves show a significant change of the cooling behaviour of aged samples. TGA confirmed changes in structure during the ageing procedure leading to an increased resistance against degradation. SEM method is a viable tool for visualization of ageing behaviour but it gives no quantitative data of the material behaviour changes. Thermal behaviour of new and aged polymers is one of the most important parameters for the determination of the product quality that provides the crucial information used for the decision of products prospective usage.

protective textiles; thermoplastic polymers; ageing; DSC; TGA; FTIR; SEM

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