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Synpo, University of Pardubice and R.Ø.S.A. | Date: 2014-12-24

The invention relates to a method of preparation of a stabilized polyethylene (PE), in which the polyethylene (PE) is first plasma-treated, by which means hydroxyl and/or amine functional groups are formed on the surface of PE, to which in the following step is either bound methacryoyl chloride, capable of copolymerization with a polymerizable stabilizer, or to the hydroxyl and/or amine functional groups of the treated PE by its -NCO functional groups is bound an additive with reactive -NCO groups, to which at least one stabilizer is subsequently bound by its -OH, -NH or -NH_(2) groups.


Rehula M.,Charles University | Adamek R.,Charles University | Spacek V.,Synpo
Powder Technology | Year: 2012

It is possible to assess viscoelastic properties of materials by means of the stress relaxation test. This method records the decrease in pressing power in a tablet at its constant height. The cited method was used to evaluate the time-dependent deformation for six various materials: microcrystalline cellulose, cellulose powder, hydroxypropyl methylcellulose, mannitol, lactose monohydrate, and hydrogen phosphate monohydrate. The decrease in pressing powering of a tablet during a 180s period was described mathematically by the parameters of three exponential equations, where the whole course of the stress relaxation is divided into three individual processes (instant elastic deformation, retarded elastic deformation and permanent plastic deformation). Three values of the moduli of plasticity and elasticity were calculated for each compound. The values of elastic parameters A Ti have a strong relationship with bulk density. The plastic parameters P Ti represent particle tendency to form bonds. The values of plasticity in the third process P T3 ranged from 400 to 600MPas. Mannitol had higher plasticity and lactose monohydrate on the contrary reduced plasticity. A linear relation exists between A T3 and P T3 for the third process. No similar interpretation of moduli calculated on the basis of three exponential equations has been realized yet. © 2011 Elsevier B.V.


Cabulis U.,Latvian State Institute of Wood Chemistry | Fridrihsone A.,Latvian State Institute of Wood Chemistry | Andersons J.,University of Latvia | Vlcek T.,Synpo
AIP Conference Proceedings | Year: 2014

The biomass represents an abundant, renewable, competitive and low cost resource that can play an alternative role to petrochemical resources. The central topic of the research activity reported is the use of rape seed oil (RO) as a raw material for the production of rigid polyisocyanurate foams (PIR). The content of the renewable resource-derived polymers achieved in ready foams is up to 20%. By using biopolymers as a matrix, a prospective way is to reinforce them with nanoparticles, organically modified clays, for improvement of mechanical properties while, at the same time, replacing petrochemical raw materials. Organoclay Cloisite® 15A was tested as a filler of PIR foams. Three different techniques - ultrasonification, mixing by three-roll mills, and high-pressure homogenization were used for dispergation of nanoclays in polyols. Composite polyisocyanurate foams and solid polymer samples were produced and tested for stiffness and strength. This paper discusses the studies into the use of RO as a renewable source in rigid PIR foams filled with organomodified montmorillonite clay with loadings from 1 to 5% by weight. © 2014 American Institute of Physics.


Sustek S.,University of Pardubice | Svoboda L.,University of Pardubice | Zelenka J.,SYNPO | Zetkova K.,SYNPO
NANOCON 2011 - Conference Proceedings, 3rd International Conference | Year: 2011

Recently various eco-friendly products and technologies are developed in the world to replace environment threatening ones. In the field of superabsorbent materials the efforts are directed to substitute synthetic polymers for natural materials or a combination of these two groups of substances. Such products are used for example in agriculture, horticulture and forestry to improve soil water retention and nutrient utilization by plants. The presented work is focused on study of properties of polyacrylate hydrogel encapsulated in a mixture of collagen and nanostructured clay. In future, it allows to decrease content of synthetic component in the composite hydrogel and to reduce content of non-biodegradable residues in soil after using hydrogel as water and nutrient regulator in agricultural applications. Swelling capacity and the courses of water retention and release were studied. © 2011 TANGER Ltd., Ostrava.


Hochmannova L.,SYNPO | Vytrasova J.,University of Pardubice
Progress in Organic Coatings | Year: 2010

The interior paints investigated have been formulated on the basis of aqueous acrylic dispersion, rutile titanium dioxide, extenders and special additives as photocatalytic nano zinc oxide and different types of photocatalytic anatase titanium dioxide. Organic dye Orange II was used as an indicator for the reactivity of photocatalytic surfaces. The absorbance change of Orange II solution was measured by a photometer. An agar plate method was used for the evaluation of antimicrobial effect of the coatings. The effectiveness of coatings was demonstrated using the following bacteria relevant to hygiene: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, fungi Aspergillus niger and Penicillium chrysogenum. The nano-form of ZnO was found to be the best photocatalytic agent and also the best and broadest spectrum antimicrobial agent for these interior paints. Statistically significant differences between the control coatings and the coatings with nano-form of ZnO were found using Rank-sum test. © 2009 Elsevier B.V. All rights reserved.


Otahal R.,University of Pardubice | Vesely D.,University of Pardubice | Nasadova J.,Synpo | Zima V.,University of Pardubice | And 2 more authors.
Pigment and Resin Technology | Year: 2011

Purpose - The purpose of this paper is to study properties of intumescent coatings based on a silicone-epoxy hybrid resin (with an aminosilane as hardener). In the first part of this study, fire-resistance behaviour of the intumescent coating based on silicone-epoxy resin containing intumescent additives is evaluated. The second part assesses the effect of mineral fibres on fire-resistant properties of intumescent coatings based on the silicone-epoxy resin. Design/methodology/approach - Thermal degradation and char formation of coatings were investigated by Thermogravimetric analyses, X-ray diffraction and X-ray fluorescence and infrared spectroscopy (FTIR). The salt spray corrosion test was applied to study the resistance of intumescent coatings. Anticorrosion and fire-resistant properties after one, three and seven days of exposure were evaluated. Findings - It was shown that a silicone-epoxy hybrid resin is suitable for applications in the field of intumescent coatings. Intumescent coatings based on this resin form a thermally stable thin ceramic-like layer, which improves the thermal insulation properties of the char. Mineral fibres reinforced the char structure and thus improved fire-resistant properties of intumescent coating before as well as after the salt spray test. Mineral fibres also improved anticorrosion properties. Research limitations/implications - This paper discusses only the effect of mineral fibres on properties of intumescent coatings. Originality/value - A silicone-epoxy hybrid resin has not previously been used in intumescent coatings. This type of intumescent coating can be used as an effective passive fire protection system for steel constructions. © 2011 Emerald Group Publishing Limited. All rights reserved.


Podzimek S.,SYNPO | Podzimek S.,University of Pardubice | Machotova J.,University of Pardubice | Snuparek J.,University of Pardubice | And 2 more authors.
Journal of Applied Polymer Science | Year: 2014

The study is primarily focused on the possibility to utilize organic asymmetric flow field-flow fractionation (A4F) coupled to a multi-angle light scattering (MALS) detector for the characterization of copolymers of methyl methacrylate with various acrylates prepared by emulsion polymerization. The effects of acrylate monomer type and content on the molar mass distribution and degree of branching of acrylic copolymers have been studied by A4F-MALS using tetrahydrofuran as a carrier solvent. It has been found that the growing amount of acrylate results in the increase of molar mass, polydispersity, and branching degree as a result of chain transfer to polymer. Highly branched compact macromolecules with ultra-high molar mass were identified in all copolymers containing a high level of acrylate. In contrast to size traditionally used exclusion chromatography, organic A4F-MALS has been proved as a very efficient technique for the characterization of high molar mass acrylic emulsion copolymers. © 2014 Wiley Periodicals, Inc.


Podzimek S.,SYNPO | Podzimek S.,University of Pardubice
Journal of Applied Polymer Science | Year: 2014

This article discusses various aspects of the determination of molar mass distribution by means of size exclusion chromatography (SEC) in various application modes. The effects of erroneous specific refractive index increment (dn/dc), branching, column performance, and enthalpic interactions on the results obtained by different SEC techniques are discussed. Combination of SEC and a light scattering detector represents the most direct way to the molar mass distribution of all natural and synthetic polymers as it completely eliminates the need for column calibration and to a certain extent eliminates the dependence of the obtained results on some operational variables such as flow rate, temperature, or injected mass. A multiangle light scattering (MALS) photometer has become the most frequently used light scattering detector capable of determination of molecular size as another important polymer characteristic. This article contrasts SEC-MALS method with other application modes of SEC from the viewpoint of some frequent confusions and misunderstandings. © 2013 Wiley Periodicals, Inc.


Bretssnajdrova E.,University of Pardubice | Svoboda L.,University of Pardubice | Zelenka J.,Synpo
Journal of Electrical Engineering | Year: 2010

At present, great attention is given to study of preparation and properties of various nanomaterials usable in many applications. They are utilized in varied fields of human activity - eg in electronics, medicine, paint industry etc. Besides the detailed chemical structure, such nanoparticle properties as the shape and size distribution are fundamental to the given application. To measure these parameters various methods are used, e.g. transmission electron microscopy (TEM), atomic force microscopy (AFM), acoustic spectrometry, methods based on the light scattering and X-ray disc centrifuge system.

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