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Oat and spelt husks (OH and SH, respectively) lignocellulosic biomass derived fillers have been compared with commercial wood flour (WF) in respects to their morphology, chemical composition, bulk density, aspect ratio, and thermal stability. OH and SH have been obtained by both mechanical milling and steam explosion auto-hydrolysis treatment at various processing conditions. Reinforcement efficiency of OH and SH derived lignocellulosic biomass fillers on the flexural properties of maleic acid-grafted polypropylene (PPgMA) compatibilized polypropylene (PP) composites is compared with that of WF. The compatibilized PP composites have been manufactured by melt compounding. Flexural test specimens of the compatibilized PP composites have been manufactured by injection molding. It has been demonstrated that both the husks derived lignocellulose fillers can be used to improve flexural modulus and maximal flexural strength of PP, although its modifying effect is somewhat smaller in comparison to WF reinforcement, most probably due to higher cellulose content of the latter. Husks derived lignocellulose filler-reinforced PP composites, however, demonstrate increased flexibility in comparison to WF-filled systems., INTRODUCTION The concept of bio-based materials is becoming increasingly important by considering deficiency of fossil resources. EU has declared the bio-based products sector to be a priority area with high [...]

Ternary nanocomposites, composed of polyoxymethylene (POM), ethylene octene copolymer and zinc oxide (ZnO), are prepared by melt compounding. The effects of two types of ethylene-octene copolymers, differing with aoctene content (38% for EOC38 and 17% for EOC17), as well as nanostructured ZnO on thermal behavior of POM are investigated. The content of EOC in the POM based composites is varied between 10 and 50 wt%, while the content of ZnO is 2 wt%. Thermal behavior of POM based systems are studied by using differential scanning calorimetry and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. Results of thermogravimetric analysis show that, by rising either the elastomer or ZnO content, thermal stability of the investigated POM composites can be increased. The modifying effect of EOC17 in respect of thermal resistance is somewhat greater than that of EOC38. Simultaneous addition of EOC and ZnO to POM is synergistic with respect to thermal stability of the composite material., INTRODUCTION Development of the composites as perspective substitutes of traditional materials becomes increasingly popular in new material design. Over the last years polymer nanocomposites have attracted much interest because addition [...]

This work is devoted to the fabrication of p-type polyvinyl alcohol (PVA)-based flexible thermoelectric composites using multiwall carbon nanotubes-antimony telluride (MWCNT-Sb2Te3) hybrid filler, the study of the thermoelectrical and mechanical properties of these composites, and the application of these composites in two types (planar and radial) of thermoelectric generators (TEG) in combination with the previously reported PVA/MWCNT-Bi2Se3 flexible thermoelectric composites. While the power factors of PVA/MWCNT-Sb2Te3 and PVA/MWCNT-Bi2Se3 composites with 15 wt.% filler were found to be similar, the PVA/MWCNT-Sb2Te3 composite with 25 wt.% filler showed a ~2 times higher power factor in comparison with the PVA/MWCNT-Bi2Se3 composites with 30 wt.% filler, which is attributed to its reduced electrical resistivity. In addition, developed PVA/MWCNT-Sb2Te3 composites showed a superior mechanical, electrical, and thermoelectric stability during 100 consequent bending cycles down to a 3 mm radius, with insignificant fluctuations of the resistance within 0.01% of the initial resistance value of the not bent sample. Demonstrated for the first time, 2-leg TEGs composed from p-type PVA/MWCNT-Sb2Te3 and n-type PVA/MWCNT-Bi2Se3 composites showed a stable performance under different external loads and showed their potential for applications involving low temperature gradients and power requirements in the range of nW. [ABSTRACT FROM AUTHOR]

The results of investigation of gamma irradiated blends of high-density polyethylene (PE) with thermotropic polymer liquid crystal (PLC) are presented. The PLC used was a copolyester of 40% poly(ethylene terephthalate) with 60% p-(hydroxybenzoic acid). The PLC content in the blends was 0, 5, and 10 wt%. The constituents were blended with the use of a single screw extruder. The specimens were prepared by compression molding. The irradiation of the samples was performed by a [Co.sup.60] [Gamma]-radiation source in inert atmosphere (argon) up to absorbed relatively low doses (up to 200 kGy; 1 Mrad = 10 kGy). The morphological, thermal, and mechanical properties were investigated for irradiated and unirradiated samples. The influence of gamma irradiation and addition of PLC on the temperature dependence of the elastic modulus as well as the effect of a 'form memory' of the materials examined are discussed. It was found that an addition of the PLC affects substantially the stress-strain relationship in tension at temperatures above the melting point of PE for the irradiated samples. The features of thermomechanical behavior of the PE + PLC blends, previously irradiated and oriented, at isometrical heating and cooling were also established. The results obtained testify that the addition of PLC to PE makes it possible to improve considerably the thermosetting properties of the heat-shrinkable polymeric products., INTRODUCTION High energy irradiation (gamma or electron beams) is the well-known technique for the modification of polymers (1-5). The radiation processing of polymers can successfully compete with the chemical processing [...]

Copyright of Proceedings of the Estonian Academy of Sciences is the property of Teaduste Akadeemia Kirjastus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modification of multi-walled carbon nanotubes (MWCNTs) by means of imidazolium ionic liquid (IL) was performed. Structural characterization of funtionalized nanofillers (IL-f-MWCNTs) was made by means of Raman spectroscopy and transmission electron microscopy. MWCNTs and IL-f-MWCNTs were introduced within ethylene octane copolymer (EOC) with octene co-monomer content of 17% by using the masterbatch approach. The efficiency of the carbonaceous nanofiller distribution within the polymer matrix was characterized by means of scanning electron microscopy. It was shown that MWCNTs and IL-f-MWCNTs were both effective in rising storage modulus, tensile modulus, stress-at break, and electrical conductivity of EOC-based nanocomposites along with the increasing nanofiller content. Besides, it was observed that the modification efficiency of the investigated EOC matrix composites by IL-f-MWCNTs was greater in comparison to pristine MWCNTs. [ABSTRACT FROM AUTHOR]

Copyright of Proceedings of the Estonian Academy of Sciences is the property of Teaduste Akadeemia Kirjastus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)