Time filter

Source Type

Aš, Czech Republic

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.

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.

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.

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.

Discover hidden collaborations