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Anna Hrynowiecka and Artur Szymczyk

Abstract

The environmental variability during the Mazovian/Holsteinian interglacial is better understood thanks to the results of multidisciplinary palaeobotanical studies. The perfectly preserved and abundant material from Nowiny Żukowskie in SE Poland has been the subject of numerous palaeobotanical analyses. The results both of initial pollen analysis and of the examination of plant macroremains provide a detailed view of changes in the palaeoenvironment of this area during the Mazovian/Holsteinian interglacial. Originally, the water basin was mostly the habitat of plants indicative of low trophy. The frequent occurence of swamp plants evidences a change in hydrological and climatic conditions consistent with the intra-interglacial climatic oscillation. In the subsequent part of the optimum, an expansion of swamps with Aracites interglacialis and Dulichium arundinaceum was recorded. The development of a peat bog overgrown by i.a. Sphagnum sp., Eriophorum vaginatum, and Andromeda polifolia was also observed. The growth of swamp and peat vegetation resulted in the nearly complete disappearance of aquatic vegetation, apart from species typical of the climatic optimum of the Mazovian/Holsteinian interglacial: Brasenia borysthenica and Aldrovanda dokturovskyi. The close of the interglacial was marked by the intensive development of peat bog and swamp communities with Carex rostrata, Menyanthes trifoliata, and A. interglacialis. The intensive increase in the number of A. interglacialis during the period described as the “birch oscillation” supports the hypothesis of noticeable changes in hydrological conditions at that time. The end of the described period is typified by a deterioration of climatic conditions, indicated by the increase in values for Betula humilis, B. nana, and Juniperus communis.

Open access

Katarzyna Szymczyka and Anna Tarabab

Abstract

Activity coefficients at infinite dilution of the aqueous solutions of nonionic hydrocarbon surfactants, p-(1,1,3,3- tetramethylbutyl) phenoxypoly(ethylene glycols), Triton X-100 (TX100) and Triton X-165 (TX165), fluorocarbon surfactants, Zonyl FSN-100 (FSN100) and Zonyl FSO-100 (FSO100) and their ternary mixtures were determined from the Gracia-Fadrique et al. method for non-volatile compounds. The values of activity coefficients were calculated taking into account the surface tension data of the studied systems at 293K and compared to those determined on the basis of the values of the contact angle of solutions on the polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA) surfaces and the solid-liquid interface tension.

Open access

Sandra Paszkiewicz, Iwona Pawelec, Anna Szymczyk and Zbigniew Rosłaniec

Abstract

This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO) based nanocomposites with 0.5 wt.% of clay (MMT), graphene nanoplatelets (GNP) and graphene oxide (GO) have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM) in order to present good dispersion without large aggregates. It was indicated that PTT-PTMO/GNP composite shows the highest crystallization temperature. Unlike the addition of GNP and GO, the introduction of MMT does not have great effect on the glass transition temperature of PTMO-rich soft phase. An addition of all three types of nanoplatelets in the nanocomposites caused the enhancement in tensile modulus and yield stress. Additionally, the cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than neat PTT-PTMO.

Open access

Sandra Paszkiewicz, Małgorzata Nachman, Anna Szymczyk, Zdeno Špitalský, Jaroslav Mosnáček and Zbigniew Rosłaniec

Abstract

This work is the continuation and refinement of already published communications based on PET/EG nanocomposites prepared by in situ polymerization1, 2. In this study, nanocomposites based on poly(ethylene terephthalate) with expanded graphite were compared to those with functionalized graphite sheets (GO). The results suggest that the degree of dispersion of nanoparticles in the PET matrix has important effect on the structure and physical properties of the nanocomposites. The existence of graphene sheets nanoparticles enhances the crystallization rate of PET. It has been confirmed that in situ polymerization is the effective method for preparation nanocomposites which can avoid the agglomeration of nanoparticles in polymer matrices and improve the interfacial interaction between nanofiller and polymer matrix. The obtained results have shown also that due to the presence of functional groups on GO surface the interactions with PET matrix can be stronger than in the case of exfoliated graphene (EG) and matrix.

Open access

Janusz Typek, Kamil Wardal, Grzegorz Zolnierkiewicz, Anna Szymczyk, Nikos Guskos, Urszula Narkiewicz and Elzbieta Piesowicz

Abstract

Magnetic properties of 0.7(Fe2O3)/0.3(ZnO) nanocomposite synthesized by traditional wet chemistry method and containing only two phases: ZnO (nonmagnetic) and ZnFe2O4 (magnetic, with nanocrystallites of average size 12 nm, but forming large agglomerates, up to 100 nm in size) were studied by DC magnetization and ferromagnetic resonance (FMR). The investigated nanocomposite was either in a form of nanopowder or dispersed at concentration of 0.1 wt.% in poly(ethylene naphthalate-block-tetramethylene oxide) PTMO-b-PEN polymer matrix. Similarities and differences in magnetic behavior of these two samples revealed by the study of static magnetization and FMR spectra have been discussed relative to different morphologies and the associated variation of interparticle interactions. Moreover, thermal and thermo-oxidative stability of the nanocomposite and the neat polymer have been studied by thermogravimetric method.