Polyethylene/Polyhydroxyalkanoates-based Biocomposites and Bionanocomposites

The development of advanced polymer composite materials having superior mechanical properties has opened up new horizons in the field of science and engineering. Polyethylene (PE) is considered one of the most widely used thermoplastics in the world due to its excellent properties which have excellent chemical inertness, low coefficient of friction, toughness, near-zero moisture absorption, ease of processing and electrical properties. Polyhydroxyalkanoates (PHAs) are garnering increasing attention in the biodegradable polymer market because of their promising properties such as high biodegradability in different environments. This chapter covers polyethylene/polyhydroxyalkanoates-based biocomposites and bionanocomposites. It summarizes many of the recent research accomplishments in the area of PE/PHAs-based biocomposites and bionanocomposites such as state-of-the-art regarding different methods of their preparation. Also discussed are different characterization techniques and use of PE/PHAs-based biocomposites and bionanocomposites in biomedical, packaging, structural, military, coating, fire retardant, aerospace and optical applications, along with recycling and lifetime studies

Temperature effect on dielectric properties of carbon black filled epoxy polymer composites

The complex permittivity of carbon black/epoxy composites containing different amounts of conductive carbon black particles was reported in the frequency range 100 Hz-15 MHz and over the temperature range 23-80◦C. The shape of experimental spectra of these heterogeneous media gives evidence of a typical dielectric relaxation process below the threshold percolation. The temperature dependence of the dielectric response has been analysed below and at near the epoxy glass transition temperature (Tg∼=80◦C), for various carbon concentrations. Jonscher's phenomenological model has been used for modelling this relaxation process. The activation energy, deduced from Arrhenius equation, is found to be insensitive to the carbon black concentration. This behavior is discussed in term of the interfacial interaction between the carbon particles and the polymer. Besides, the increase of both parts of the complex permittivity with increasing the carbon black concentration and the temperature is compared to the recently proposed Shin's mixture law