Department of Synthesis and Characterization of Polymers

The aim of the department is to cover completely the expertise in synthesis of polymers using various polymerization techniques including free radical, reversible-deactivation radical and anionic polymerizations. The second object of synthesis represents preparation, spectral characterization and mainly utilization of different fluorescence probes for characterization of polymer microstructure and for polymerization study mechanism. Modification of polymers by grafting, crosslinking and functionalizations and preparation of polymeric and inorganic nanoparticles and hybrids represents another part of synthetic direction. Prepared as well as comercial polymers are characterised by spectral methods (UV-VIS, FTIR, Fluorescence and Raman spectroscopy), thermal analysis (DSC, TGA, chemiluminescence, thermal and photo stability, flammability) and their molar characteristics by advanced HPLC techniques. Electron spin resonance (ESR) and positron annihilation lifetime spectroscopy (PALS) techniques are used for the microscopic structural-dynamic characterization of various pure and composed organic materials.

Research Topics:

1. Study and development of reversible-deactivation radical polymerizations and synthesis of functional polymers
2. Inorganic and carbon (nano)particles and hybrids
3. Polymeric (nano)particles, (hydro)gels and (nano)fibres
4. Synthesis and properties of photoactive compounds
5. Synthesis of polymers and polymeric materials from renewable monomers
6. Degradation, stabilization and flammability of polymers
7. Liquid chromatography research for effective separation of macromolecules
8. Structure and physico - chemical properties of polymers

6. Degradation, stabilization and flammability of polymers

Expertise includes:

  1. Thermal oxidation and ageing of materials
  2. Prediction of the remaining service life of the industrially produced polymers based on investigation of the life trajectory of the polymer material
  3. Synthesis and testing of photo- and thermostabilizers
  4. Ignitability a burning of polymers, characterization studies on cone calorimeter, model of ignition, burning and extinction of burning material

Tests of oxidation stability and of extent of degradation

Oxidation stability tests follow from Bolland Gee scheme: time or temperature evolution of concentration of hydroperoxides, DSC, thermogravimetry, chemiluminiscence, analytical determination of carbonyls.
Life trajectory of the polymer product polymers utilised practically have unknown residual stability due to unknown concentration of additives and modification procedure, points A,B,C and D represent the examples picture
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Example of the development of non-isothermal chemiluminescence (in oxygen) and thermogravimetry (in nitrogen) runs with the polyester urethane shoe ageing under laboratory conditions. The rate of heating 5°C/min.

Related recent publications:

  • J. Rychlý, L. Matisová-Rychlá, K. Csomorová, „Degradation of plastics from the ResinKit as a model for the selection of polymers for artworks. Assessment by nonisothermal thermogravimetric analysis and chemiluminometry“, Polym. Degrad. Stab., Vol. 102, p. 105 – 111 (2014).
  • J. Rychlý, L. Rychlá, A. Fiedlerová, S. Chmela, M. Hronec, „Thermally and UV initiated degradation of polypropylene in the presence of 2,5 bis(2-furylmethylene) cyclopentanone and heterogeneous distribution of hydroxides assessed by non-isothermal chemiluminescence in nitrogen“. Polym. Degrad. Stab., Vol. 108, p. 41-47 (2014).
  • J. Rychlý, L. Matisová-Rychlá, K. Csomorová, „Reprint of degradation of plastics from the ResinKit as a model for the selection of polymers for artworks. Assessment by nonisothermal thermogravimetric analysis and chemiluminometry“. Polym. Degrad. Stab., 2014, vol. 107, p. 191-197.

Thermostability of phase change materials based on linear low-density polyethylene, paraffin wax and expanded graphite

PCMs with improved thermal conductivity, based on linear low-density polyethylene (LLDPE), paraffin wax with a melting point of approximately 42°C and expanded graphite are prepared and their physical behavior is investigated.
Heat transport is usually enhanced in PCMs by incorporating thermally conductive fillers. However, problems arise when attempting to minimize the filler content and maximize the paraffin content to optimize the functionality and maintain a compact form. Thus, these three components must be optimized. Expanded graphite (EG) has been extensively used over the past few years to improve thermal conductivity of particularly paraffin-based PCMs.
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DSC heating curves of LLDPE, wax and their blend.
An estimate of the total heat energy that can be reversibly absorbed or released by the designed materials was determined using Differential Scanning Calorimetry (DSC). The improvement in the thermal conductivity of the polymeric materials was obtained by incorporating expanded graphite into the blends. Significant amounts of wax are leached from the samples, and higher wax content also results in more wax leaching. Graphite significantly reduces the wax loss from the samples.

Related recent publications:

  • I. Krupa, Z. Nogellova, Z. Špitalský, M. Malíková, P. Sobolčiak, H. Abdelrazeq, M. Ouederni, M. Karkri, I. Janigova, M. AlMaadeed „Positive influence of expanded graphite on the physical behavior of phase change materials based on linear low-density polyethylene and paraffin wax“, Thermochim. Acta, doi:10.1016/j.tca.2015.06.028
  • L. F. Cabeza, C. Barreneche, I. Martorell, L. Miró, S. Sari-Bey, M. Fois, H. Paksoy, N. Sahan, R. Weber, M. Constantinescu , E. Anghel, M. Malikova, I. Krupa, M. Delgado, P. Dolado, P. Furmanski, M. Jaworski, T. Haussmann, S. Gschwander, A. Fernández, „Unconventional technologies available for phase change materials (PCM) characterization. Part 1. Thermophysical properties.” Renew. Sustain. Energy Rev., Vol. 43, p. 1399–1414 (2015).
  • A. Fernández, A. Solé, J. Giró-Paloma, M. Martínez, M. Hadjieva, A. Boudenne, M. Constantinescu, El. Anghel, M. Malikova, I. Krupa, C. Peñalosa, A. Lázaro, H. Paksoy, K. Cellat, J. Vecstaudž, D. Bajare, B. Sumiga, B. Boh, T. Haussmann, S. Gschwander, R. Weber, P. Furmanski, M. Jaworski, L. Cabeza „Unconventional technologies used for phase change materials (PCM) characterization. Part 2. Morphological and structural characterization, physico-chemical stability and mechanical properties“, Renew. Sustain. Energy Rev., Vol. 43, p. 1415–1426 (2015).

Study of photochemical, hydrolytic and enzymatic degradation of polymers

Photochemical, hydrolytic and enzymatic degradation of biodegradable polymeric materials, such as polylactide-based blends and composites applicable in food packaging and agriculture is studied under laboratory as well as real agricultural conditions. Extent of degradation is investigated by UV-vis, FT IR, Raman spectroscopies, GPC, mechanical properties, DSC, TGA, mass decrease and carbon dioxide production.

Related recent publications:

Synthesis and testing of thermal and photochemical stabilizers

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DSC heating curves of LLDPE, wax and their blend.
New types of thermal and photochemical stabilizers based on hindered phenols and hindered amines derivatives are synthesized and their stabilization efficiency is investigated. Special attention is paid to synthesis of higher molecular weight stabilizers and combined phenols / amines stabilizers with synergistic effect. Hyperbranched macrostabilizers with decreased leakage from the polymers also investigated in polyolefins as well as various types degradable polyesters. Comercially available antioxidants and UV absorbers are investigated in new types of polymers polymeric materials as well.

Related recent publications:

  • G. Kasza, K. Mosnackova, A. Nador, Z. Osvath, T. Stumphauser, G. Szarka, K. Czanikova, J. Rychly, Š. Chmela, B. Ivan, J. Mosnacek „Synthesis of hyperbranched poly(ethyleneimine) based macromolecular antioxidants and investigation of their efficiency in stabilization of polyolefins”, Eur. Polym. J., Vol. 68, p. 609–617 (2015).
    doi:10.1016/j.eurpolymj.2015.03.037
  • J. Rychlý, K. Mosnáčková, L. Rychlá, Fiedlerová A., G. Kasza, A. Nádor, Z. Osváth, T. Stumphauser, G. Szarka, K. Czaniková, Š. Chmela, B. Iván, J. Mosnáček „Comparison of the UV stabilisation effect of commercially available processing stabilizer Irganox HP 136 with Irganox 1010 and synthesized hyperbranched phenolic antioxidants”, Polym. Degrad. Stab., Vol. 118, p. 10-16 (2015).
    doi:10.1016/j.polymdegradstab.2015.04.007
  • J. Rychly, L. Rychla, A. Fiedlerova, S. Chmela, M. Hronec, „Thermally and UV initiated degradation of polypropylene in the presence of 2,5 bis(2-furylmethylene) cyclopentanone and heterogeneous distribution of hydroperoxides assessed by non-isothermal chemiluminescence in nitrogen”, Polym. Degrad. Stab., Vol. 108, p. 41-47 (2014).
    doi:10.1016/j.polymdegradstab.2014.05.022

Cone Calorimeter and Burning of Polymers

Determination of Heat Release Rate (HRR), ignition time, mass loss during combustion, quantitative determination of smoke density and other parameters
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Related recent publications:

  • J. Rychlý, M. Hudáková, L. Rychlá, I. Janigová, K. Csomorová, I. Chodák, „Magnesium hydroxide and magnesium oxide in oxidation and burning of polypropylene“, J. Sci. Res. Rep., Vol. 3 (6), p. 772-776 (2014).
  • J. Rychlý, M. Hudáková, L. Rychlá, „Burning of thermally thin polyethylene mixtures. Cone calorimeter study“, J. Therm. Anal. Calorim., Vol. 115, p. 527 – 535 (2014).

Flammability of Smart Textiles Based on Expanded Graphite-Polymeric Nanocomposites

Smart textiles including electrically conducting textiles are developed in last decades due to many applications in medical, military, and sports, as well as in the industrial textile areas. Many of methods and coating techniques were used for manufacturing of conductive textiles, including conducting polymers, metals fibers incorporation, etc.
Conductive textiles prepared by surface coating with polymer composites containing expanded graphite were studied in our lab. The flammability, conductivity, thermostability, and contact angles were measured before and after washing of coated textiles with detergents.

Electrical conductivity of all untreated textiles was about 10-14 S/cm. The surface treatment with conducting suspension of graphite led to substantially higher values of conductivity. SEM pictures demonstrated the quality of surface treatment by polymeric matrix Axilat containing graphite. The coating remains preserved also after series of 5 cycle washing.

Flammability of textiles was investigated by the cone calorimeter. Parameters characterizing the burning processes as heat release rate, time to ignition, total oxygen consumed, total smoke released, effective heat of combustion as well as calculated value of maximum rate of heat emission (MARHE) were obtained. We can notice that the time to ignition increases in the order cotton = Co/PES < PES (Fig.). After ignition HRR increased to its maximal value for PES and Co/PES, between 290 and 500 kW/m2. The decay of the HRR which precedes the total consumption of the sample is rather fast. Burning behavior of cotton is different, it decreases less abrupt and is accompanied by long-term char glowing.
TGA results showed that washing lowered the onset temperature, the first step of degradation of washed samples probably due to using detergent SDS. The second step of TGA curves depended on the textile type. Textile treatment with polymeric matrices has an impact on thermal stability of washed samples – it lowers the onset of degradation, depending on the textile type. From studied textile treated PES samples showed the best thermostability. picture
Heat release rate lines for samples of different textiles – cotton (thick line), PES (straigth line) and cotton/PES (dashed line). The cone radiance 25 kW/m2 (temperature of the regulator on the cone heater 680°C).