A Study of Mechanical Properties of Polymer Composite Membranes with Various Ionic Liquids at Elevated Temperatures

This work was supported by Latvian Council of Science (Cooperation project No.666/2014.4).Ionic liquid/sulphonated poly(ether ether ketone) composite membranes were prepared using following ionic liquids: 1,2,3-trimethylimidazolium dimethylphosphate, 1-hexyl-3-methylimidazolium dimethylphosphate, 1-dodecyl-3-methylimidazolium dimethylphosphate. For each ionic liquid/polymer pair 4 composite membranes were prepared with 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.% ionic liquid content. Membranes were analyzed using strain-stress testing at various elevated temperatures up to 150 °C. Impact of temperature, ionic liquid content in membrane and structure of ionic liquids on mechanical properties of composite membrane were evaluated. It was found that temperature and ionic liquid content had highest impact on mechanical properties of composite membranes.Latvian Council of Science No.666/2014.4; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Nafion® and polyaniline composite modification with Li and Mg ions

Funding from European Union`s Horizon 2020 Research and Innovation Program project under grant agreement No 768789 is greatly acknowledged.Modification of Nafion®-based samples with polyaniline (PANI) and positive charged ions could potentially allow achieving good proton conductivity at higher working temperatures what is observed in typical polymer electrolyte membrane fuel cells. In this work Nafion® polymer was modified with 1% polyaniline emeraldine salt and Li and Mg ions containing solutions. The influence of activation process and the type of ions on composites' proton conductivity was investigated. To define the best composition the physiochemical properties of synthesized materials were determined by the means of thermogravimetric analysis, impedance spectroscopy, determination of water absorption and its kinetics, and FTIR. From the original samples the best results of σ=155 mS/cm were shown by Nafion®/PANI membrane what was modified by Li+ reduction solution. This membrane also had better thermal characteristic compared to other researched samples: membrane degradation starts on higher temperature interval.Horizon 2020 Research and Innovation Program project under grant agreement No 768789; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Modification of polyoxymethylene for increased thermal resistance

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 α-octene 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. POLYM. ENG. SCI., 57:772–778, 2017.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Potential uses of N-methylmorpholine N-oxide for the treatment of agricultural waste biomass

Lignocellulosic fibers have been used in polymer composites for a long time but their treatment process is still challenging due to insufficient efficiency and environmental impact. This research analyses the influence of N-methylmorpholine N-oxide (NMMO) on the structure and properties of three types of lignocellulosic fibers â sweet clover (SCS), buckwheat (BS) and rapeseed straws (RS). The fibers were treated with an NMMO solution at 90 °C for different periods of time (80 min, 180 min, 300 min and 30 h). It was detected that after treatment in a dilute NMMO solution, non-cellulosic substances were removed, the morphology and aspect ratio were affected and the fibers were characterized by higher thermal stability. However, the results show that before using NMMO for the production of microfibers, additional research on the pretreatment process will be necessary because an insufficient aspect ratio value and surface morphology were obtained. The current research shows that it is not economically feasible to process fibers using NMMO for the production of reinforcement for polymer composites

Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices

Slāņaino silikātus saturošu polioksimetilēna maisījumu ar etilēna-oktēna kopolimēru stiprības-deformatīvās īpašības

Darbs satur literatūras apskatu, metodisko daļu, eksperimentālo daļu, secinājumus un izmantotās literatūras sarakstu. Literatūras apskatā skatītas darba galveno komponentu, POM, EOK un nanopildvielu, mālu, kā arī kompatibilizatora struktūras īpatnības un ekspluatācijas īpašības. Darbā aprakstīti polimēru iegūšanas paņēmieni un principi, nanokompozītu iegūšanas svarīgākie aspekti, apkopoti iegūtie materiāli par POM un tā maisījumiem ar EOK; papildus vēl izvērtētas ar nanopildvielām modificētu POM kompozīciju īpašības. Darba eksperimentālajā daļā tika pētītas POM un dažāda sastāva POM/EOK maisījumu kalorimetriskās, termogravimetriskās, mehāniskās un struktūras īpašības. Papildus tam izvērtēta nanostrukturētas pildvielas (slāņaino silikātu) ietekme uz POM un POM/EOK maisījumu īpašībām, kā arī kompatibilizatora ietekme uz iegūto kompozītu saturošo komponentu savietojamību

Termoplastiskās cietes/slāņaino silikātu nanokompozītu struktūras, mehāniskās un ūdens tvaika sorbcijas īpašības

Literatūras apskatā apkopota informācija par cietes, poliolefīnu, savietošanas aģentu un slāņaino silikātu nanokompozītu iegūšanas metodēm, īpašībām un struktūru. Eksperimentālajā daļā analizētas termoplastiskās cietes nanokompozītu iegūšanas tehnoloģijas, kā arī pētītas kompozītu struktūras, mehāniskās, barjeras, termiskās īpašības