In this work, polypropylene/volcanic basalt rock (PP/VBR) thick film composites with different VBR powder mass ratio varying from 0.5 wt.% to 20.0 wt.% were prepared by using the hot press technique. The effects of VBR powder doping on mechanical, structural and dielectric properties of PP were investigated by stress-strain measurements, Fourier transform infrared analysis, thermal gravimetric analysis, scanning electron microscopy and dielectric spectroscopy methods. The highest tensile strength, percentage strain and energy at break were achieved for 0.5 wt.% VBR powder doped PP composite. According to the stress-percentage strain curves of the samples, it was observed that 0.5 wt.% VBR powder doping increases the mechanical performance of PP polymer. In addition, regardless of the doping concentration level of basalt powder, the real part of complex dielectric function (ε′) of all PP composites display approximately frequency independent behavior between 100 Hz and 1 MHz. On the other hand, 0.5 wt.% VBR powder doped PP composite has also the lowest dielectric constant at the vicinity of 2.7 between 100 Hz and 1 MHz. The composite also has considerably low dielectric loss which has a crucial importance for technological applications. For these reasons, PP/0.5 wt.% VBR composite with the highest tensile strength can be considered as a suitable candidate for microelectronic devices. Furthermore, the alternative current conductivity mechanism was determined as nearly constant loss due to approximately constant dielectric loss between 10 Hz and 1 MHz.

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Poly(lactic) acid (PLA), is a compostable thermoplastic which degrades fast under composting conditions of microorganisms, high humidity, and temperatures. However, PLA degrades slowly below its glass transition temperature and in low humidity, hence, when used as short-shelf life product containers and not disposed to composting systems, PLA may cause environmental pollution. Therefore, when not disposed to proper waste management systems, the effect of long incubation time at room temperature on mechanical and thermal properties of PLA is the main concern of this study. To determine the effect of room temperature on semi-crystalline PLA degradation at a low humidity percentage, PLA films (PLA2) were kept at room temperature for 5 years at 40?10% humidity. Some PLA films (PLA3) were pre-treated at 55?C under dry conditions for one year and then kept at room temperature for four years. Influence of incubation time and temperature on PLA degradation was evaluated by mechanical, thermal analyses and by FTIR spectroscopy analysis and compared with the initial PLA samples (PLA1). Mainly mechanical properties of PLA were affected by incubation temperature and time since 68% tensile strength loss was observed in PLA3 samples which were pre-treated at 55?C and 34% decrease in tensile strength was observed in PLA2 samples. Ther?mal behavior of PLA was also influenced by incubation time and temperature as degree of crystallinity decreased 5% and 3% in PLA2 and PLA3 samples, respectively. Deformation of CH bonds and amorphous phase degradation were revealed by FTIR analyses in PLA2 and PLA3 samples.

Abstract-In the present study, the dielectric permittivity change of basalt (two type basalt; CM-1, KYZ-13) reinforced PANI composites were studied to determine the effects of PANI additivities (10.0, 25.0, 50.0 wt.%) at several frequencies from 100 Hz to 17.5 MHz by a dielectric spectroscopy method at the room temperature and artificial neural networks (ANNs) simulation. Also, the dielectric permittivity at 30.0 wt.% of PANI additivity was obtained by ANNs without experimental process. That process, a significant predictive instrument was produced which allows optimization of dielectric properties for numerous composites without substantial experimentation. It has been observed that PANI additivities decreased to dielectric constant of composites at low frequencies. Furthermore, the ANNs method have satisfactory accuracy for prediction of dielectric parameters.