Igor Novak | Slovak Academy of Sciences (original) (raw)

Papers by Igor Novak

Archives of Materials Science, 2008

Hybrid ethylene-propylene-diene-monomer (EPDM) nanocomposite foams were produced via compression ... more Hybrid ethylene-propylene-diene-monomer (EPDM) nanocomposite foams were produced via compression molding with enhanced electromagnetic wave absorption efficiency. The hybrid filler, consisting of 20 phr ferroelectric barium titanate (BT) and various loading fractions of multi-wall carbon nanotubes (MWCNTs), synergistically increased the electromagnetic (EM) wave absorption characteristics of the EPDM foam. Accordingly, while the EPDM foam filled with 20 phr BT was transparent to the EM wave within the frequency range of 8.2-12.4 GHz (X-band), the hybrid EPDM nanocomposite foam loaded with 20 phr BT and 10 phr MWCNTs presented a total shielding effectiveness (SE) of~22.3 dB compared to~16.0 dB of the MWCNTs (10 phr). This synergistic effect is suggested to be due to the segregation of MWCNT networks within the cellular structure of EPDM, resulting in enhanced electrical conductivity, and also high dielectric permittivity of the foam imparted by the BT particles. Moreover, the total SE of the BT/MWCNTs loaded foam samples remained almost unchanged when subjected to repeated bending due to the elastic recovery behavior of the crosslinked EPDM foamed nanocomposites.

Apple Academic Press eBooks, Feb 14, 2014

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2013

Adhesive and surface behaviour of polyimide-polysiloxane elastomers. The poly(imide-siloxane) (PI... more Adhesive and surface behaviour of polyimide-polysiloxane elastomers. The poly(imide-siloxane) (PIS) block copolymers containing siloxane blocks are suitable for industrial application, e.g. in microelectronics, and this kind of the block copolymers are used as high-performance adhesives and coatings. PIS block copolymers were studied with respect to their structure surface and adhesive properties relationship. The study of the morphology of PIS copolymers characterized by Atomic Force Microscopy (AFM) shows a growth of the surface roughness by increase of the content of siloxane. The relatively small amount of siloxane in PIS block copolymer, 10-20 wt. %, decreased significantly the surface energy of the PIS copolymer, as well as the polar component of surface energy. The increase of PIS the surface hydrophobicity reduced the peel strength of adhesive joints.

Materials in engineering, 2014

Low density polyethylene (LDPE) was blended with date palm wood powder (DPW) to prepare composite... more Low density polyethylene (LDPE) was blended with date palm wood powder (DPW) to prepare composites with concentrations of filler ranging from 10 to 70 wt.%. The Young´s modulus of the composites significantly increased with an increase in the filler content in the entire concentration range. The maximum value of 1933 MPa for the composite filled with 70 wt.% of the filler is approximately 13 times higher than that for the neat LDPE. The presence of the filler improved the flexural strength, which was represented by the flexural stress at peak. The flexural strength of 17.8 MPa for the composite filled with 70 wt.% of the filler was two-times greater than that for the neat LDPE. The water absorption test revealed that the composites had a strong tendency to absorb water, which was dependent on the filler content. The experimental data were compared with several theoretical models.

Coatings

The wax leakage from shape-stabilized phase change materials (SSPCMs) is a limitation because it ... more The wax leakage from shape-stabilized phase change materials (SSPCMs) is a limitation because it reduces their functionality. In this work, an enhancement of the compositional stability of SSPCMs formed by high-density polyethylene (HDPE) and paraffin wax blends through a lamination by aluminum (Al) foil was studied. The materials’ thermal conductivity was enhanced by adding expanded graphite (EG). The lamination of SSPCMs is the simplest method of reducing leakage, but it suffers from poor adhesion between polymer-based blends and protecting layers. The improved adhesion between SSPCMs and Al foil was achieved by adding 2 wt.% of maleated polyethylene (PE) acting as an adhesion promoter into SSPCMs or by plasma treatment of both SSPCMs and Al surfaces. Microscopic, spectroscopic, and optical techniques were used to analyze the surface and adhesion properties of SSPCMs. The peel resistance of SSPCMs after plasma treatment or modification by maleated PE increased from 2.2 N/m to 7.2 ...

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2013

Influence of modified collagen on parameters of adhesive mixtures. Part: I. Influence of collagen... more Influence of modified collagen on parameters of adhesive mixtures. Part: I. Influence of collagen modifications on adhesion, biodegradability and formaldehyde emission. The work describes possibility to lower formaldehyde emission in wood products glued with urea-formaldehyde (UF) adhesives at keeping of required strength of glued joints. Results of laboratory and industrial tests confirmed, that collagen biodegradable additive modified with urea is suitable modifier for lowering of formaldehyde emission from hardened UF adhesive mixtures. Increased efficiency of collagen was reached by modification of standard hardener with di-aldehyde. Industrial tests at plywood production confirmed lowering of formaldehyde emission in comparison with standard production down to 30 %, stated according to EN 120.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2015

Lowering of formaldehyde emission from modified UF resin with collagen polymers. Presented work d... more Lowering of formaldehyde emission from modified UF resin with collagen polymers. Presented work describes the possibility of lowering the formaldehyde emission from wood products glued with ureaformaldehyde (UF) adhesive. Results of laboratory tests confirmed, that collagen prepared from leather waste is suitable additive for lowering of formaldehyde emission from wood products glued with UF adhesive. Increased efficiency of collagen was obtained by modification with urea and di-aldehyde. Tests confirmed the decrease of formaldehyde content in comparison with the standard down to 50 % stated by perforator method.

Journal of Applied Polymer Science, 2017

ABSTRACTBacterial contamination is one of the biggest drawbacks of implanted biomaterials, which ... more ABSTRACTBacterial contamination is one of the biggest drawbacks of implanted biomaterials, which may cause nosocomial infection. Avoiding bacterial adhesion onto the biomaterial surface by preparing active antibacterial biomaterials is an accurate solution. In this study, three of the fluoroquinolones: sparfloxacin, enrofloxacin, and lomefloxacin were selected due to their broad bactericidal effect and immobilized onto low‐density polyethylene surface at two different pH values (pH 3 and pH 6), after tailoring the surface by plasma treatment followed by grafting of polymer brush of N‐allylmethylamine. Surface wettability test and morphological investigations were carried out by water contact angle measurement and scanning electron microscopy analysis, respectively. Chemical characterizations were carried out by Fourier transform infrared spectra and X‐ray photoelectron spectroscopy. Antibacterial activity was checked against Staphylococcus aureus and Escherichia coli strains and res...

Development of new types of nanocomposite hot-melt adhesives. The paper deals with adhesive and m... more Development of new types of nanocomposite hot-melt adhesives. The paper deals with adhesive and mechanical properties study of nanocomposites based on ethylene-acrylic acid copolymer during aluminium bonding. The main objective was to describe the changes of co-polymer properties during increasing of the nanofiller's concentration. Based on executed experiments it was found out, that the properties of tested nanocomposite system were mostly improved depending on the contents of the nanofiller in the system. The optimum concentration of nanofiller Aerosil 130 SLP in the composite was 2.5 weight % for cohesive mechanical properties of the system and 3.5 weight % for adhesive ones. Thermal properties of the composite system showed their maximum within concentration of 4.5 weight % of nanofiller.

Polymer Composites, 2012

High-density polyethylene (HDPE)/graphite nanocomposites containing up to 30 vol% of graphite pow... more High-density polyethylene (HDPE)/graphite nanocomposites containing up to 30 vol% of graphite powder filler were prepared by melt mixing in a Brabender Plasticorder at 1808C for 15 min. The nanocomposites were characterized for their rheological, dynamic mechanical, crystallographic, and electrical properties as a function of graphite loading. The results indicated that graphite loading affects storage modulus, loss modulus, complex viscosity, and conductivity of HDPE matrix. The storage modulus increases while the graphite loading increases in the studied concentration range (up to 30%). When the graphite loading was increased to 30%, storage modulus at room temperature was about 300% higher than that of pure HDPE. Also, the composites containing 20 and 30% graphite shows more conductivity than the others. POLYM. COM

Polymer-plastics Technology and Engineering, Dec 27, 2017

In this paper, a diffuse coplanar surface barrier discharge plasma at atmospheric pressure has be... more In this paper, a diffuse coplanar surface barrier discharge plasma at atmospheric pressure has been used to surface modification of polyester/cotton (PESc) fabric, tghat was subsequently modified by sol-gel process using suitable organofunctional silanes to enhance its hydrophobicity. Modified PESc fabric surfaces were conditioned during the gelling process to obtain the permanent hydrophobicity. The contact angle of water before washing of plasma and sol gel pre-treated PESc fabric was found to be of 154°, and 151° after standardized washings. It was also demonstrated that the process is applicable at the industrial scale.

Composites Part A-applied Science and Manufacturing, Mar 1, 2016

This study aims to investigate experimentally the effects of aspect ratio (length/diameter ratio)... more This study aims to investigate experimentally the effects of aspect ratio (length/diameter ratio) and concentration of multiwalled carbon nanotubes (MWCNTs) on thermal properties of high density polyethylene (HDPE) based composites. The aspect ratios of two types of MWCNT fillers are in the range of 200-400 and 500-3000. Composite samples were prepared by melt mixing up to weight fraction of 19% filler content, followed by a compression molding. Measurements of density, specific heat and thermal diffusivity (by modulated photothermal radiometry, PTR) were performed and effective thermal conductivities k e of nanocomposites were calculated using these values. The results show that the composites containing MWCNTs with higher aspect ratio have higher thermal conductivities than the ones with lower aspect ratio. In terms of conductivity enhancement k e /k m À 1, the results indicate that MWCNTs with higher aspect ratio provide three to fourfold larger enhancement than the ones with lower aspect ratio, at low filler concentrations.

Archives of materials science and engineering, 2008

Wood research, Dec 16, 2020

The hydrothermal treatment of maple (Acer pseudoplatanus L.) wood by steam represents the modific... more The hydrothermal treatment of maple (Acer pseudoplatanus L.) wood by steam represents the modification method with the effective heat transfer, which can improve industrially significant properties of wood, i.e. its color, hydrophobicity and subsequently dimensional stability. The maple wood was modified by steam at 125°C during 8 hours, and at pressure of 0.18 MPa. The water contact angle of steam-treated maple wood increased from 44.9° (for untreated maple wood) to 55.3° (for steam-treated maple wood), and the stability of water drop on steam-treated maple wood surface increased. FTIR spectra show an increase in C=O and glycoside bonds concentration on the surface of steam-treated maple wood, but the concentration of CO -C groups decreased. SEM micro photos confirmed the deformation and shrinking of maple wood cells due to steam treatment. XPS measurements confirmed, that the concentration of oxygen as well as C=O and CO -O groups on the surface of steam-treated maple wood showed a slight decrease in comparison with pristine wood sample.

Apple Academic Press eBooks, Aug 27, 2015

Currently the reinforcement of steel surface treatment is widely used in various industries, espe... more Currently the reinforcement of steel surface treatment is widely used in various industries, especially in the automobile. The paper discusses the new economical methods of processing the steel surface, which can significantly improve the properties of the metal.

Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1, 2014

Limiting factor of PE application in healthcare is high susceptibilit y of pol yethylene towards ... more Limiting factor of PE application in healthcare is high susceptibilit y of pol yethylene towards bacterial growth. For this reason, antibacterial treatment of PE foils using appropriate antibacterial agents was used in this work. Benzalkonium chloride and bronopol were selected due to their satisfactor y antibacterial effect confirmed by applications in medical and cosmetic industr y. These antibacterial agents were immobiliz ed onto PE surface by a multistage approach via pol yacr ylic acid br ushes graf ting onto the PE surface pre-treated by low-temperature plasma. Measurements of surface energ y, X-ray P hotoelectron S pectroscopy (XPS), Fourier Transform Infrared S pectroscopy with Attenuated Total Reflectance (F TIR-ATR), S canning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) were used for investigation of surface changes af ter antibacterial modification of PE. Moreover, the antibacterial effect was evaluated by inhibition z one measurements of S taphylococcus aureus and Escherichia coli bacterial strains. Health and Biomedical

Plastics Rubber and Composites, Jun 19, 2015

ABSTRACT In this work, a radio frequency discharged plasma generated in air atmosphere by pressur... more ABSTRACT In this work, a radio frequency discharged plasma generated in air atmosphere by pressure has been used to modify polylactic acid (PLA) surface. The results were evaluated through nanoindentation testing. Contact angle measurements revealed a gradual transition to a more hydrophilic state with increasing polarity after plasma treatment, while partial recovery to their untreated state during 10 day storage in air was evidenced. The results were evaluated through nanoindentation testing. All PLA samples exhibited an almost hard-like surface area where hardness and elastic modulus are enhanced. The activity of the plasma creates a higher cross-linking density within the material in the surface region. For higher displacements, both H and E tend to reach pristine PLA's values. Hardness values reveal surface hardening due to plasma treatment except for 180 s etching time, where hardness is slightly decreased possibly due to surface deformation. The change of H/E slope reveals the strengthening of oxygen plasma etched PLA with 180 s of etching time with increasing displacement. Keywords: Plasma treating, Polylactic acid, Nanomechanical properties References 1. Suhr H.: ‘Applications of nonequilibrium plasmas to organic chemistry’, in ‘Techniques and applications of plasma chemistry’, (ed. Hollahan J. and Bell A. T.., 2nd edn, 57; 1974, New York, J. Wiley and Sons. 2. Yasuda H.: ‘Plasma for modification of polymers’, J. Macromol. Sci. Chem. A, 1976, 10A, 383–420. 3. Liston E. M., Martinu L. and Wertheimer M. R.: ‘Plasma surface modification of polymers for improved adhesion: a critical review’, J. Adhes. Sci. Technol., 1993, 7, (10), 1091–1127. 4. Chan C. M.: ‘Polymer surface modification and characterization’, 225–263; 1994, Munich, Hanser Publishers. 5. Piskin E.: ‘Plasma processing of biomaterials’, J. Biomater. Sci. Polym. Ed., 1992, 4, 45–60. 6. Gombotz W. R. and Hoffman A. S.: ‘Gas-discharge techniques for biomaterial modification’, CRC Crit. Rev. Biocompat., 1987, 4, 1–42. 7. Ratner B. D., Chilkoti A. and Lopez G. P.: ‘Plasma deposition and treatment for biomaterial applications’, in ‘Plasma deposition, treatment and etching of polymers’, (ed. d'Agostino R.., 463–516; 1990, San Diego, CA, Academic Press. 8. Favia P. and d'Agostino R.: ‘Plasma treatments and plasma deposition of polymers for biomedical applications’, Surf. Coat. Technol., 1998, 98, 1102. 9. Loh I.-H.: ‘Plasma surface modification in biomedical applications’, Med. Device Technol., 1999, 10, 24–30. 10. Terlingen J. G. A.: ‘Introduction of functional groups at polymer surfaces by glow discharge techniques’, ‘PhD thesis’; 1993, Enschede, The Netherlands, University of Twente. 11. Groenewoud L. M. H.: ‘Transparent and conductive polymer layers by gas plasma techniques’, 2000, Enschede, The Netherlands, University of Twente. 12. Takens G. A.: ‘Functionalization of polymeric surfaces by oxidative gas plasma treatment’, 1997, Enschede, The Netherlands, University of Twente. 13. Lens J. P.: ‘Gas plasma immobilization of surfactants to improve the blood compatibility of polymeric surfaces’, 1996, Enschede, The Netherlands, University of Twente. 14. Klomp A. J. A.: ‘Design of surface modified poly(ethylene terephthalate) non-wovens for the removal of leukocytes from platelet concentrates’, 1998, Enschede, The Netherlands, University of Twente. 15. Chou S. Y., Krauss P. R. and Renstrom P. J.: ‘Imprint lithography with 25-nanometer resolution’, Science, 1996, 272, 85–87. 16. Mansky P., Harrison C. K., Chaikin P. M., Register R. A. and Yao N.: ‘Nanolithographic templates from diblock copolymer thin films’, Appl. Phys. Lett., 1996, 68, (18), 2586–2588. 17. Mansky P., DeRouchey J., Russell T. P., Mays J., Pitsikalis M., Morkved T. and Jaeger H.: ‘Large-area domain alignment in block copolymer thin films using electric fields’, Macromolecules, 1998, 31, 4399–4401. 18. Morkved T. L., Lu M., Urbas A. M., Ehrichs E. E., Jaeger H. M., Mansky P. and Russell T. P.: ‘Local control of microdomain orientation in diblock copolymer thin films with electric fields’, Science, 1996, 273, (5277), 931–933. 19. Park M., Harrison C., Chaikin P. M., Register R. A. and Adamson D. H.: ‘Block copolymer lithography: periodic arrays of ∼1011 holes in 1 square centimeter’, Science, 1997, 276, (5317), 1401–1404. 20. Mansky P., Chaikin P. and Thomas E. L.: ‘Monolayer films of diblock copolymer microdomains for nanolithographic applications’, J. Mater. Sci., 1995, 30, 1987–1992. 21. Harrison C., Park M., Chaikin P. M., Register R. A. and Adamson D. H.: ‘Lithography with a mask of block copolymer microstructures’, J. Vac. Sci. Technol. B, 1998, 16B, 544–552. 22. Spatz J. P., Eibeck P., Mossmer S., Moller M., Herzog T. and Ziemann P.: ‘Ultrathin diblock copolymer/titanium laminates – a tool for nanolithography’, Adv. Mater., 1998, 10, (11), 849–852. 23. Lammertink R. G. H., Hempenius M. A., van den Enk J. E., Chan V. Z. H., Thomas E. L. and Vancso G. J.:…

An investigation was made of wood of the species oak (Quercus petraea), beech (Fagus sylvatica L.... more An investigation was made of wood of the species oak (Quercus petraea), beech (Fagus sylvatica L.), maple (Acer pseudoplatanus) and ash (Fraxinus excelsior) pre-treated using radio-frequency (RF) plasma in air at reduced pressure. Physical and chemical changes for all of the wood species were determined using measurements of water contact angles and FTIR-ATR spectroscopy. The results confirmed an increase in the wood’s hydrophilicity/polarity in all cases, caused by an increase in –OH group concentration due to irradiation by RF plasma. The content of oxygen-containing functional groups after treatment by RF plasma significantly increased, and the water contact angles were diminished. FTIR-ATR spectroscopy confirmed that RF plasma modification of the surfaces of all investigated wood samples led to certain changes, which were also dependent on the time of plasma exposure.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2015

Oak wood modification using cold plasma. The contact angles of water on oak wood surface showed a... more Oak wood modification using cold plasma. The contact angles of water on oak wood surface showed a steep decrease after activation by cold plasma in air. The surface energy and its polar component of oak wood increased with time of activation by plasma. The surface energy of oak wood treated by radio-frequency (RF) plasma in air increased from 62 mJ.m-2 (pristine wood) to 74 mJ.m-2 (plasma-modified wood), and the polar component of the surface energy increased from 17.0 mJ.m-2 to 27.8 mJ.m-2. The shear strength of adhesive joint of oak wood with epoxy adhesive increases non-linearly with activation time from 5.6 MPa to 8.8 MPa.

Archives of Materials Science, 2008

Apple Academic Press eBooks, Feb 14, 2014

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2013

Materials in engineering, 2014

Coatings

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2013

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2015

Journal of Applied Polymer Science, 2017

Polymer Composites, 2012

Polymer-plastics Technology and Engineering, Dec 27, 2017

Composites Part A-applied Science and Manufacturing, Mar 1, 2016

Archives of materials science and engineering, 2008

Wood research, Dec 16, 2020

Apple Academic Press eBooks, Aug 27, 2015

Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1, 2014

Plastics Rubber and Composites, Jun 19, 2015

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2015

The trend in food packaging technology consists from research and development of new material tha... more The trend in food packaging technology consists from research and development of new material that exhibits significantly improved barrier properties against gases and vapors. Low-permeable materials can decrease the total amount of packaging materials required, as they are made of thin or lightweight materials with high-barrier properties. A significant trend in food packaging technology today is convenience, especially with regard to manufacturing, distribution, transportation,
sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne
illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect current food processing technologies, lifestyle changes, and scientific research.

In all fields of food science, there is an increasing interest in utilizing nanostructures for im... more In all fields of food science, there is an increasing interest in utilizing nanostructures for improving the performance of food products and processes. Many structures in
foods are within 100 nm size range, and because of their unique physical properties, take a significant task in the delivery of nutrients or more in general, show enhanced
bioactivity. By manufacturing foods using particular processing or environmental conditions, it is possible to obtain nanostructures. The small size affects their
functional properties, when compared to structures with similar composition, but larger in size. In foods, these structures are usually dispersed in solution, and they
are not biologically persistent, i.e., they are digested and hydrolyzed, and they do not accumulate in organs or in the environment. Because of their physical properties
and especially their enhanced surface area, these structures tend to be more efficacious in encapsulating bioactive and improving texture and structures or more in
general show some improved processing and nutritional functionality. The low-temperature discharge plasma treatment of polymers is used for surface sterilization
of food packaging foils. The bulk and mass transport properties of discharge plasma-treated films must be explored and quantified. These properties are
important for packages, and they are suitable for both respiring and non-respiring foods and also for safety product assessment. The use of discharge plasma to aid in the deposition of biologically actives and antimicrobials can help expand the emerging field of edible films and active food packaging. Future studies should focus on study of antimicrobial efficiency after their immobilization on low-temperature plasma-grafted polyolefin surfaces. The use of natural antimicrobial
agents is a very promising alternative because of their appeal as natural The food security is a big issue in the world, and antimicrobial packaging could play a role in
food security assurance, comprehensively agreed with industrial sectors, farmers, producers, wholesalers, retailers, governments, and consumers. A following trend in food packaging technology consists from research and
development of new material that exhibits significantly improved barrier properties against gases and vapors. Low-permeable materials can decrease the total amount
of packaging materials required, as they are made of thin or lightweight materials with high-barrier properties. A significant trend in food packaging technology today
is convenience, especially with regard to manufacturing, distribution, transportation, sales, marketing, consumption, and waste disposal. Another important trend is safety as it relates to public health and security against bioterrorism. The Foodborne illnesses and the malicious alteration of foods must be eliminated from the food chain. The food safety will become a major active food packaging application. Food packaging technologies are linked also to consumer studies. Consumers tend to seek out new materials with new functions, and new food packaging systems reflect
current food processing technologies, lifestyle changes, and scientific research.