The transmittance, absorbance, and reflectance of polypropylene (PP), polyethylene (PE), and polypropylene/polyethylene (PP/PE) blends prepared by a hot pressing method are investigated. IR and UV spectra of PP, PE, and PP/PE blends (0-80%) in the wavelength range of 200-25000 nm were examined. The optical absorption spectra are presented and the determined values of energy gaps are listed. The results indicate that both direct and indirect transitions may exist. The analyses of the absorption peaks corresponding to oxygen groups for the PP/PE composite (80/20) show low optical density and, therefore, highly different optical behavior than for pure PP. The PP/PE composite is very promising with regard to optical stability

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The aim of this study is to show the applicability of artificial neural networks, which are getting more applications with the advancement of technology, to determine the mechanical properties of polymeric materials. Mechanical properties of pure polypropylene, polyethylene terephthalate and their blends are determined in this study and the effect of temperature (room temperature, 40• C and 60• C) on mechanical properties is investigated. The method of artificial neural networks is used to make a prediction for mechanical properties. Mechanical properties of samples are measured using Lloyd 250N capacity tension and compression apparatus at crosshead speed of 10 mm/min, 25 mm/min, and 50 mm/min. For artificial neural networks modelling, the tensile experiment results, temperature, percent ratio, and crosshead speed are used as the input and output parameters. Three-layered multilayer perceptron, feed-forward neural network architecture is used and trained with the error back propagation. The results obtained from the output of the network are compared with the experiment results. The suitability of the method is found to be satisfactory.

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