Anna Boczkowska - Academia.edu (original) (raw)

Papers by Anna Boczkowska

IOP Conference Series: Materials Science and Engineering, 2018

The goal of the present study was to implement thermoplastic nonwoven fabrics containing multi-wa... more The goal of the present study was to implement thermoplastic nonwoven fabrics containing multi-walled carbon nanotubes as interlayers in Carbon Fiber Reinforced Polymers. These functional nonwovens were fabricated by a half-industrial scale melt-blown technique, starting with nanocomposite pellets of copolyamides doped with 3.5wt% of multi-walled carbon nanotubes. Three types of composite panels were fabricated using an out-of-autoclave technique (OoA): one without nonwovens and two with nonwovens. Incorporation of thermoplastic nonwovens doped with 3.5wt% of multi-walled carbon nanotubes increased the surface and volume electrical conductivity in direction Kz by about 2 and 3 orders of magnitude, respectively. Based on the images obtained from a Scanning Electron Microscope, it was found that melted nonwovens adhere well to the carbon fibers. It was also confirmed that carbon nanotubes are well dispersed in nonwovens, which results in an improvement of the overall electrical conductivity of the composite panels. The lack of homogenous layers of nonwovens between the carbon fiber layers decreased the interlaminar shear strength of the composite panels and affected the level of their electrical conductivity. Moreover, thermo-mechanical analysis showed an increase of the glass transition temperature of the resin in the presence of thermoplastic nonwovens and the appearance of an additional peak on the loss modulus curve caused by the polyamide 6 segments present in the copolyamides used.

KOMPOZYTY ( …, 2004

Page 1. KOMPOZYTY (COMPOSITES) 4(2004)9 Anna Boczkowska1, Katarzyna Konopka2, Jerzy Schmidt3, Krz... more Page 1. KOMPOZYTY (COMPOSITES) 4(2004)9 Anna Boczkowska1, Katarzyna Konopka2, Jerzy Schmidt3, Krzysztof J. Kurzydłowski4 Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. ... [4] Szafran M., Konopka K, Rokicki G, Lipiec W., Kurzydłow-ski KJ, Porowata ...

Kompozyty ( …, 2002

Page 1. KOMPOZYTY (COMPOSITES) 2(2002)3 Katarzyna Konopka1, Anna Boczkowska2, Krzysztof Batorski3... more Page 1. KOMPOZYTY (COMPOSITES) 2(2002)3 Katarzyna Konopka1, Anna Boczkowska2, Krzysztof Batorski3, Krzysztof Kurzydłowski4 Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. ... W wyniku tych procesów wzrasta odporność ceramiki na kruche pękanie [1, ...

Polymers

For the bonding of the lightweight composite parts, it is desired to apply electrically conductiv... more For the bonding of the lightweight composite parts, it is desired to apply electrically conductive adhesive to maintain the ability to shield electromagnetic interference. Among various solvent-based adhesives, there is a new group of thermoplastic hot melt adhesives that are easy to use, solidify quickly, and are environment-friendly. To make them electrically conductive, a copolyamide-based hot melt adhesive was mixed with 5 and 10 wt% of carbon nanotubes using a melt-blending process. Well-dispersed nanotubes, observed by a high-resolution scanning microscope, led to the formation of a percolated network at both concentrations. It resulted in the electrical conductivity of 3.38 S/m achieved for 10 wt% with a bonding strength of 4.8 MPa examined by a lap shear test. Compared to neat copolyamide, Young’s modulus increased up to 0.6 GPa and tensile strength up to 30.4 MPa. The carbon nanotubes improved the thermal stability of 20 °C and shifted the glass transition of 10 °C to a hig...

accepted for inclusion in Articles by an authorized administrator of

Chemical Physics Letters, 2018

The paper describes modification of carbon nanotubes surface by attaching the grains of NiP , NiB... more The paper describes modification of carbon nanotubes surface by attaching the grains of NiP , NiB , CoB and Fe-B. The modification was obtained by electroless metallization using sodium hypophosphite (NaH 2 PO 2). We have investigated the parameters of electroless metallization process of CNTs. The uniformity of the coating on the carbon nanotubes was related to proper surface activation. While optimizing the electroless deposition, a range of catalyst concentrations from 0.1 to 1.0 gPd/l were tested. Deposition was used to improve the electrical properties of the later composite materials CNT-Ni-P/epoxy. The best results of electroless deposition were obtained for NiP and NiB coatings.

Acta Physica Polonica A, 2011

In the paper we present results of the research on polarization mode dispersion changes inside th... more In the paper we present results of the research on polarization mode dispersion changes inside the polarimetric optical fiber sensors based on highly birefringent optical fibers embedded into composite materials with different angular orientations of the optical axes. Based on measurements made for different types of highly birefringent optical fiber sensors we have shown that strain sensitivities after lamination process are different in comparison to the data obtained before lamination. Our results indicate that polarization mode dispersion in side-hole highly birefringent fibers under axial stress strongly depends on fiber orientation in the composite material suggesting that orientation of the polarization axes of the highly birefringent fiber can be responsible for behavior of the fiber inside the composite material.

Journal of Materials Engineering and Performance, 2016

To develop an optimised manufacturing method of fly ash-reinforced metal matrix composites, the p... more To develop an optimised manufacturing method of fly ash-reinforced metal matrix composites, the preliminary tests were performed on the cenospheres selected from fly ash (FACS) with halloysite nanotubes (HNTs) addition. The preform made out of FACS with and without the addition of HNT (with 5 and 10 wt.%) has been infiltrated by the pure aluminium (Al) via adapted gas pressure infiltration process. This paper reveals the influence of HNT addition on the microstructure (analysis was done by computed tomography and scanning electron microscopy combined with energy-dispersive x-ray spectroscopy), thermal properties (thermal expansion coefficient, thermal conductivity and specific heat) and the mechanical properties (hardness and compression test) of manufactured composites. The analysis of structure-property relationships for Al/FACS-HNT composites produced shows that the addition of 5 wt.% of HNT to FACS preform contributes to receiving of the best mechanical and structural properties of investigated composites.

Springer Series on Polymer and Composite Materials, 2015

The aim of this chapter is to promote the usage of polyamide (PA) thermoplastic elastomers and it... more The aim of this chapter is to promote the usage of polyamide (PA) thermoplastic elastomers and its composites in the electronic sector. General knowledge about this group of materials and their applications will be presented in Sect. 1. The structure and synthesis methods will be briefly described in Sect. 2 as there are few books focusing on these issues. Properties of PA thermoplastic elastomers—especially from the perspective of electronic applications—are discussed in Sect. 3. The small market for PA elastomers including manufacturers, commercial products, and the properties of some of the grades of PA elastomers is described in Sect. 4. Finally, the application of PA elastomers in general sectors and in the electronic industry is included in Sect. 5, which is divided into 5 subsections. Such topic as cable insulating, antistatic blends, conductive composites and nanocomposites, sensors, and textile composites will be described as thermoplastic PA elastomers which are commonly used there.

Polymers

The lack of resistance of plastic objects to various pathogens and their increasing activity in o... more The lack of resistance of plastic objects to various pathogens and their increasing activity in our daily life have made researchers develop polymeric materials with biocidal properties. Hence, this paper describes the thermoplastic composites of Polyamide 12 mixed with 1–5 wt % of the nanoparticles of zinc, copper, and titanium oxides prepared by a twin-screw extrusion process and injection moulding. A satisfactory biocidal activity of polyamide 12 nanocomposites was obtained thanks to homogenously dispersed metal oxides in the polymer matrix and the wettability of the metal oxides by PA12. At 4 wt % of the metal oxides, the contact angles were the lowest and it resulted in obtaining the highest reduction rate of the Escherichia coli (87%), Candida albicans (53%), and Herpes simplex 1 (90%). The interactions of the nanocomposites with the fibroblasts show early apoptosis (11.85–27.79%), late apoptosis (0.81–5.04%), and necrosis (0.18–0.31%), which confirms the lack of toxicity of u...

Polymers

This work is devoted to evaluating the effectiveness of the recovery of carbon fibers from end-of... more This work is devoted to evaluating the effectiveness of the recovery of carbon fibers from end-of-life wind turbine blades in the pyrolysis process, and the use of those fibers in the production of flat composite panels. The recovery of carbon fibers from wind turbine blades uses a pyrolysis process at 500–600 °C in a non-oxidizing atmosphere, in such a way that makes it possible to preserve the shape and dimensions of the fibers. Using recycled carbon fibers, flat CFRP sheets with epoxy resin matrix were produced by pressing. Seven different series of samples were tested, which differed in fiber length, fiber orientation, and pressure holding time. The results obtained on the recycled fibers were compared to the original carbon fibers, cut to corresponding lengths. Additionally, one of the series was reinforced with a biaxial fabric. The most favorable pressing parameters are empirically found to be pre-pressing 2 MPa (10 min), and further pressing at a pressure of 7 MPa until the ...

Smart self-healing epoxides have attracted immense interest in the industry due to their capabili... more Smart self-healing epoxides have attracted immense interest in the industry due to their capability to prevent crack propagation and increase material service life. Self-healing can be achieved via a number of approaches, where microcapsulebased systems are deemed to be the closest to market implementation. The work presented here demonstrates the effect of polymeric microcapsules made of poly(urea-formaldehyde) on the Charpy impact resistance of a standard epoxy matrix. Poly(urea-formaldehyde) microcapsules containing epoxy resin (EPIDIAN 52) and organic solvent (Ethyl phenylacetate) were prepared using in-situ polymerisation in an oil-in-water emulsion as described in the literature. The Charpy impact tests were performed on specimens made of neat epoxy resin (EPIDIAN 52) amine hardener (Z1) as well as for the epoxy filled with microcapsules with 1, 2.5, 5, 10 and 25 wt.%. The test results have shown that the presence of brittle and spherical additives has a detrimental effect on ...

Journal of Industrial Textiles, 2020

Thermoplastic nonwovens containing 2.5 wt% of multi-walled carbon nanotubes were manufactured by ... more Thermoplastic nonwovens containing 2.5 wt% of multi-walled carbon nanotubes were manufactured by half-industrial melt-blowing process from two copolyamides belonging to the group of hot melt adhesives having different melt-viscosities. The initial masterbatches have been analyzed by their rheological and thermal properties to adjust the appropriate conditions of melt-blowing process which allowed to manufacture the nonwovens without structural defects. It was found using a scanning electron microscope that in 10 wt% masterbatches fewer agglomerates of the multi-walled carbon nanotubes occurred in less viscous coPA2 and their average diameter measured by ImageJ was 60 mm. For more viscous coPA1 some oval agglomerates with even 270 mm diameters have been detected but during the extrusion they were destroyed. Microstructural observations of the nonwovens showed that fibers occur in the

Journal of Composite Materials, 2020

The main goal of this work was the increasing electrical conductivity of carbon-epoxy composites ... more The main goal of this work was the increasing electrical conductivity of carbon-epoxy composites due to implementation of thermoplastic nonwoven veils doped with carbon nanotubes into the composite structure. Nonwovens which differ in areal weight were produced by extrusion of fibers and their thermal pressing. Laminates were fabricated using an out-of-autoclave method and nonwovens were incorporated between each layer of carbon-epoxy unidirectional prepreg. The applied conductive nonwovens improved surface and volume electrical conductivity of carbon fibre reinforced polymer in all directions. Microstructure observations proved a very high quality of the fabricated composites. The implementation of nonwovens affected the crack propagation under loading.

ABSTRACT The aim of the study was to develop an innovative processing method of magnetorheologica... more ABSTRACT The aim of the study was to develop an innovative processing method of magnetorheological elastomers (MRE). This method comprises optimization of the MRE structure in the context of their performance in the magnetic field. The influence of the amount of ferromagnetic particles and their arrangement in relation to the external magnetic field was investigated. As matrixes various elastomers, with different stiffness, were used. Their properties were compared with commercially available silicone rubbers. It was found that the structure of the MRE produced depends on the viscosity of the matrix before curing and the magnetic field strength applied. Two different magnetic field strengths were used: 100 and 300 mT. The amount of the carbonyl iron particles was equal to 1.5, 11.5 and 33.0 vol. %. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The influence of curing conditions on the thermal properties of the MRE was investigated. To evaluate the external magnetic field effect on the magnetorheological properties a deflection under magnetic field was measured. The experiment showed that application of the magnetic field increases stiffness of the material.

IOP Conference Series: Materials Science and Engineering, 2018

The goal of the present study was to implement thermoplastic nonwoven fabrics containing multi-wa... more The goal of the present study was to implement thermoplastic nonwoven fabrics containing multi-walled carbon nanotubes as interlayers in Carbon Fiber Reinforced Polymers. These functional nonwovens were fabricated by a half-industrial scale melt-blown technique, starting with nanocomposite pellets of copolyamides doped with 3.5wt% of multi-walled carbon nanotubes. Three types of composite panels were fabricated using an out-of-autoclave technique (OoA): one without nonwovens and two with nonwovens. Incorporation of thermoplastic nonwovens doped with 3.5wt% of multi-walled carbon nanotubes increased the surface and volume electrical conductivity in direction Kz by about 2 and 3 orders of magnitude, respectively. Based on the images obtained from a Scanning Electron Microscope, it was found that melted nonwovens adhere well to the carbon fibers. It was also confirmed that carbon nanotubes are well dispersed in nonwovens, which results in an improvement of the overall electrical conductivity of the composite panels. The lack of homogenous layers of nonwovens between the carbon fiber layers decreased the interlaminar shear strength of the composite panels and affected the level of their electrical conductivity. Moreover, thermo-mechanical analysis showed an increase of the glass transition temperature of the resin in the presence of thermoplastic nonwovens and the appearance of an additional peak on the loss modulus curve caused by the polyamide 6 segments present in the copolyamides used.

KOMPOZYTY ( …, 2004

Page 1. KOMPOZYTY (COMPOSITES) 4(2004)9 Anna Boczkowska1, Katarzyna Konopka2, Jerzy Schmidt3, Krz... more Page 1. KOMPOZYTY (COMPOSITES) 4(2004)9 Anna Boczkowska1, Katarzyna Konopka2, Jerzy Schmidt3, Krzysztof J. Kurzydłowski4 Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. ... [4] Szafran M., Konopka K, Rokicki G, Lipiec W., Kurzydłow-ski KJ, Porowata ...

Kompozyty ( …, 2002

Page 1. KOMPOZYTY (COMPOSITES) 2(2002)3 Katarzyna Konopka1, Anna Boczkowska2, Krzysztof Batorski3... more Page 1. KOMPOZYTY (COMPOSITES) 2(2002)3 Katarzyna Konopka1, Anna Boczkowska2, Krzysztof Batorski3, Krzysztof Kurzydłowski4 Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. ... W wyniku tych procesów wzrasta odporność ceramiki na kruche pękanie [1, ...

Polymers

For the bonding of the lightweight composite parts, it is desired to apply electrically conductiv... more For the bonding of the lightweight composite parts, it is desired to apply electrically conductive adhesive to maintain the ability to shield electromagnetic interference. Among various solvent-based adhesives, there is a new group of thermoplastic hot melt adhesives that are easy to use, solidify quickly, and are environment-friendly. To make them electrically conductive, a copolyamide-based hot melt adhesive was mixed with 5 and 10 wt% of carbon nanotubes using a melt-blending process. Well-dispersed nanotubes, observed by a high-resolution scanning microscope, led to the formation of a percolated network at both concentrations. It resulted in the electrical conductivity of 3.38 S/m achieved for 10 wt% with a bonding strength of 4.8 MPa examined by a lap shear test. Compared to neat copolyamide, Young’s modulus increased up to 0.6 GPa and tensile strength up to 30.4 MPa. The carbon nanotubes improved the thermal stability of 20 °C and shifted the glass transition of 10 °C to a hig...

accepted for inclusion in Articles by an authorized administrator of

Chemical Physics Letters, 2018

The paper describes modification of carbon nanotubes surface by attaching the grains of NiP , NiB... more The paper describes modification of carbon nanotubes surface by attaching the grains of NiP , NiB , CoB and Fe-B. The modification was obtained by electroless metallization using sodium hypophosphite (NaH 2 PO 2). We have investigated the parameters of electroless metallization process of CNTs. The uniformity of the coating on the carbon nanotubes was related to proper surface activation. While optimizing the electroless deposition, a range of catalyst concentrations from 0.1 to 1.0 gPd/l were tested. Deposition was used to improve the electrical properties of the later composite materials CNT-Ni-P/epoxy. The best results of electroless deposition were obtained for NiP and NiB coatings.

Acta Physica Polonica A, 2011

In the paper we present results of the research on polarization mode dispersion changes inside th... more In the paper we present results of the research on polarization mode dispersion changes inside the polarimetric optical fiber sensors based on highly birefringent optical fibers embedded into composite materials with different angular orientations of the optical axes. Based on measurements made for different types of highly birefringent optical fiber sensors we have shown that strain sensitivities after lamination process are different in comparison to the data obtained before lamination. Our results indicate that polarization mode dispersion in side-hole highly birefringent fibers under axial stress strongly depends on fiber orientation in the composite material suggesting that orientation of the polarization axes of the highly birefringent fiber can be responsible for behavior of the fiber inside the composite material.

Journal of Materials Engineering and Performance, 2016

To develop an optimised manufacturing method of fly ash-reinforced metal matrix composites, the p... more To develop an optimised manufacturing method of fly ash-reinforced metal matrix composites, the preliminary tests were performed on the cenospheres selected from fly ash (FACS) with halloysite nanotubes (HNTs) addition. The preform made out of FACS with and without the addition of HNT (with 5 and 10 wt.%) has been infiltrated by the pure aluminium (Al) via adapted gas pressure infiltration process. This paper reveals the influence of HNT addition on the microstructure (analysis was done by computed tomography and scanning electron microscopy combined with energy-dispersive x-ray spectroscopy), thermal properties (thermal expansion coefficient, thermal conductivity and specific heat) and the mechanical properties (hardness and compression test) of manufactured composites. The analysis of structure-property relationships for Al/FACS-HNT composites produced shows that the addition of 5 wt.% of HNT to FACS preform contributes to receiving of the best mechanical and structural properties of investigated composites.

Springer Series on Polymer and Composite Materials, 2015

The aim of this chapter is to promote the usage of polyamide (PA) thermoplastic elastomers and it... more The aim of this chapter is to promote the usage of polyamide (PA) thermoplastic elastomers and its composites in the electronic sector. General knowledge about this group of materials and their applications will be presented in Sect. 1. The structure and synthesis methods will be briefly described in Sect. 2 as there are few books focusing on these issues. Properties of PA thermoplastic elastomers—especially from the perspective of electronic applications—are discussed in Sect. 3. The small market for PA elastomers including manufacturers, commercial products, and the properties of some of the grades of PA elastomers is described in Sect. 4. Finally, the application of PA elastomers in general sectors and in the electronic industry is included in Sect. 5, which is divided into 5 subsections. Such topic as cable insulating, antistatic blends, conductive composites and nanocomposites, sensors, and textile composites will be described as thermoplastic PA elastomers which are commonly used there.

Polymers

The lack of resistance of plastic objects to various pathogens and their increasing activity in o... more The lack of resistance of plastic objects to various pathogens and their increasing activity in our daily life have made researchers develop polymeric materials with biocidal properties. Hence, this paper describes the thermoplastic composites of Polyamide 12 mixed with 1–5 wt % of the nanoparticles of zinc, copper, and titanium oxides prepared by a twin-screw extrusion process and injection moulding. A satisfactory biocidal activity of polyamide 12 nanocomposites was obtained thanks to homogenously dispersed metal oxides in the polymer matrix and the wettability of the metal oxides by PA12. At 4 wt % of the metal oxides, the contact angles were the lowest and it resulted in obtaining the highest reduction rate of the Escherichia coli (87%), Candida albicans (53%), and Herpes simplex 1 (90%). The interactions of the nanocomposites with the fibroblasts show early apoptosis (11.85–27.79%), late apoptosis (0.81–5.04%), and necrosis (0.18–0.31%), which confirms the lack of toxicity of u...

Polymers

This work is devoted to evaluating the effectiveness of the recovery of carbon fibers from end-of... more This work is devoted to evaluating the effectiveness of the recovery of carbon fibers from end-of-life wind turbine blades in the pyrolysis process, and the use of those fibers in the production of flat composite panels. The recovery of carbon fibers from wind turbine blades uses a pyrolysis process at 500–600 °C in a non-oxidizing atmosphere, in such a way that makes it possible to preserve the shape and dimensions of the fibers. Using recycled carbon fibers, flat CFRP sheets with epoxy resin matrix were produced by pressing. Seven different series of samples were tested, which differed in fiber length, fiber orientation, and pressure holding time. The results obtained on the recycled fibers were compared to the original carbon fibers, cut to corresponding lengths. Additionally, one of the series was reinforced with a biaxial fabric. The most favorable pressing parameters are empirically found to be pre-pressing 2 MPa (10 min), and further pressing at a pressure of 7 MPa until the ...

Smart self-healing epoxides have attracted immense interest in the industry due to their capabili... more Smart self-healing epoxides have attracted immense interest in the industry due to their capability to prevent crack propagation and increase material service life. Self-healing can be achieved via a number of approaches, where microcapsulebased systems are deemed to be the closest to market implementation. The work presented here demonstrates the effect of polymeric microcapsules made of poly(urea-formaldehyde) on the Charpy impact resistance of a standard epoxy matrix. Poly(urea-formaldehyde) microcapsules containing epoxy resin (EPIDIAN 52) and organic solvent (Ethyl phenylacetate) were prepared using in-situ polymerisation in an oil-in-water emulsion as described in the literature. The Charpy impact tests were performed on specimens made of neat epoxy resin (EPIDIAN 52) amine hardener (Z1) as well as for the epoxy filled with microcapsules with 1, 2.5, 5, 10 and 25 wt.%. The test results have shown that the presence of brittle and spherical additives has a detrimental effect on ...

Journal of Industrial Textiles, 2020

Thermoplastic nonwovens containing 2.5 wt% of multi-walled carbon nanotubes were manufactured by ... more Thermoplastic nonwovens containing 2.5 wt% of multi-walled carbon nanotubes were manufactured by half-industrial melt-blowing process from two copolyamides belonging to the group of hot melt adhesives having different melt-viscosities. The initial masterbatches have been analyzed by their rheological and thermal properties to adjust the appropriate conditions of melt-blowing process which allowed to manufacture the nonwovens without structural defects. It was found using a scanning electron microscope that in 10 wt% masterbatches fewer agglomerates of the multi-walled carbon nanotubes occurred in less viscous coPA2 and their average diameter measured by ImageJ was 60 mm. For more viscous coPA1 some oval agglomerates with even 270 mm diameters have been detected but during the extrusion they were destroyed. Microstructural observations of the nonwovens showed that fibers occur in the

Journal of Composite Materials, 2020

The main goal of this work was the increasing electrical conductivity of carbon-epoxy composites ... more The main goal of this work was the increasing electrical conductivity of carbon-epoxy composites due to implementation of thermoplastic nonwoven veils doped with carbon nanotubes into the composite structure. Nonwovens which differ in areal weight were produced by extrusion of fibers and their thermal pressing. Laminates were fabricated using an out-of-autoclave method and nonwovens were incorporated between each layer of carbon-epoxy unidirectional prepreg. The applied conductive nonwovens improved surface and volume electrical conductivity of carbon fibre reinforced polymer in all directions. Microstructure observations proved a very high quality of the fabricated composites. The implementation of nonwovens affected the crack propagation under loading.

ABSTRACT The aim of the study was to develop an innovative processing method of magnetorheologica... more ABSTRACT The aim of the study was to develop an innovative processing method of magnetorheological elastomers (MRE). This method comprises optimization of the MRE structure in the context of their performance in the magnetic field. The influence of the amount of ferromagnetic particles and their arrangement in relation to the external magnetic field was investigated. As matrixes various elastomers, with different stiffness, were used. Their properties were compared with commercially available silicone rubbers. It was found that the structure of the MRE produced depends on the viscosity of the matrix before curing and the magnetic field strength applied. Two different magnetic field strengths were used: 100 and 300 mT. The amount of the carbonyl iron particles was equal to 1.5, 11.5 and 33.0 vol. %. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The influence of curing conditions on the thermal properties of the MRE was investigated. To evaluate the external magnetic field effect on the magnetorheological properties a deflection under magnetic field was measured. The experiment showed that application of the magnetic field increases stiffness of the material.