Rafał Oliwa - Academia.edu (original) (raw)

Papers by Rafał Oliwa

Research paper thumbnail of A new method to electrical parameters identification of carbon fiber reinforced composites using lightning disturbances corresponding to subsequent return strokes

Research paper thumbnail of Methods for Enhancing the Electrical Properties of Epoxy Matrix Composites

Energies

This paper presents ways to modify epoxy resin matrix composites to increase their electrical con... more This paper presents ways to modify epoxy resin matrix composites to increase their electrical conductivity. Good electrical properties are particularly important for materials used in the construction of vehicles (cars, trains, airplanes) and other objects exposed to lightning (e.g., wind turbines). When the hull plating is made of an electrical conductor (e.g., metal alloys) it acts as a Faraday cage and upon lightning discharge the electrical charge does not cause damage to the structure. Epoxy-resin-based composites have recently been frequently used to reduce the weight of structures, but due to the insulating properties of the resin, various modifications must be applied to improve the conductivity of the composite. The methods to improve the conductivity have been categorized into three groups: modification of the matrix with conductive fillers, modification of the composite reinforcement, and addition of layers with increased electrical conductivity to the composite.

Research paper thumbnail of The Place of 3D Printing in the Manufacturing and Operational Process Based on the Industry 4.0 Structure

Tehnički glasnik

The article presents the place of 3D printing in the manufacturing and operational process. It an... more The article presents the place of 3D printing in the manufacturing and operational process. It analyzes selected incremental technologies in the product life cycle. It describes selected processes for testing the properties of materials used in 3D printing, including accelerated aging tests and simulation of operating conditions. Areas of application of 3D printing were defined, starting from design and prototype development through manufacturing of technological tools and finally finished products. Design criteria of additivelymanufactured elements in relation to the exploitation process are discussed. A methodology for the development of 3D-CAD models of manufactured elements, software processing of data and data storage format for manufacturing products and spare parts is presented. The assumptions of repair procedures based on the production of spare parts by means of 3D printing in relation to data circulation compatible with the idea of Industry 4.0 structure have been adopted.

Research paper thumbnail of Polymer Composites Based on Glycol-Modified Poly(Ethylene Terephthalate) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing Technology

Polymers

As part of the work, innovative polymer composites dedicated to 3D printing applications were dev... more As part of the work, innovative polymer composites dedicated to 3D printing applications were developed. For this purpose, the influence of modified fillers, such as silica modified with alumina, bentonite modified with quaternary ammonium salt, and hybrid filler lignin/silicon dioxide, on the functional properties of composites based on glycol-modified poly(ethylene terephthalate) (PET-G) was investigated. In the first part of the work, using the proprietary technological line, filaments from unfilled polymer and its composites were obtained, which contained modified fillers in an amount from 1.5% to 3.0% by weight. The fittings for the testing of functional properties were obtained using the 3D printing technique in the Melted and Extruded Manufacturing (MEM) technology and the injection molding technique. In a later part of the work, rheological properties such as mass melt flow rate (MFR) and viscosity, and mechanical properties such as Rockwell hardness, Charpy impact strength,...

Research paper thumbnail of Torsional strength tests of spline connections made of polymer materials (Rapid communication)

This work is a continuation of the publication [1], in which the torsional strength tests of samp... more This work is a continuation of the publication [1], in which the torsional strength tests of samples made of polymer materials, loaded with torsional moment, which more and more often can be made with the use of incremental technologies, were carried out. The designed proprietary test stand, which was described in the publication [1], was used. A series of preliminary studies on the torsion of fittings with spline connections obtained using additive techniques were carried out. It was found, that a additive technologies have a clear impact on the torsional strength of the tested machine components, including the placement of the prototype relative to the 3D printing plane or the method of processing polymer material.

Research paper thumbnail of Kompozyty zywicy epoksydowej z modyfikowanymi bentonitami dla potrzeb przemyslu lotniczego

Research paper thumbnail of Polyurethane compositions for rapid prototyping containing bentonites modified with silsesquioxanes

Research paper thumbnail of Mechanical strength of epoxy/organoclay/carbon fiber hybrid composites

Polimery, 2017

The influence of organoclay (bentonite BS) modified with quaternary ammonium (QAS) and phosphoniu... more The influence of organoclay (bentonite BS) modified with quaternary ammonium (QAS) and phosphonium salts (QPS) on the mechanical properties of epoxy/organoclay/carbon fiber hybrid composites was investigated. The longitudinal flexural strength of the composites containing 1 wt % BSQAS and BSQPS increased by 4 and 10 %, respectively, compared to the reference sample (epoxy resin/carbon fiber). Moreover, there was also a significant improvement, up to 13 %, of Young's modulus and transverse elastic modulus for the composites with modified bentonites. On the basis of the atomic force microscopy cross-section analysis (AFM), it was found that the composites with matrix containing the modified bentonites were characterized with larger interfacial surface, about 50 %, than that of unmodified matrix (epoxy resin/carbon fiber).

Research paper thumbnail of Article Epoxy Resin Composite Based on Functional Hybrid Fillers

A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modi... more A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS). The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS) curves, and an exfoliated structure observed by TEM.

Research paper thumbnail of Testing of Conductive Carbon Fiber Reinforced Polymer Composites Using Current Impulses Simulating Lightning Effects

Energies

Carbon fiber reinforced polymer (CFRP) composites are lightweight and an increasingly used materi... more Carbon fiber reinforced polymer (CFRP) composites are lightweight and an increasingly used material with good mechanical properties. In the aviation industry, they are also required to have specific electrical properties that guarantee resistance to the direct and indirect lightning effects. The paper is focused on the description of a test stand and development of a method used to determine the electrical characteristics of conductive CFRP laminate samples with the use of high current impulses of lightning nature. Samples of three laminates (square format with side 30 × 30 cm) with a different composition were tested on the constructed stand, confirming the possibility of characterizing this type of laminate sample in terms of electrical conductivity and resistance to the effects of lightning current. It was possible to observe the impulse current flow (with a peak value up to 15 kA and a rise time above 6 µs) from the high voltage electrode placed in the center of the sample in al...

Research paper thumbnail of Poly(vinyl chloride) Composites with Raspberry Pomace Filler

Polymers, 2021

This study examined, the effect of chemically extracted raspberry pomace on the thermal stability... more This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing of poly(vinyl chloride). It was observed that the pomace in this study was used to extract naphtha, thereby permitting the removal of bio-oil as a factor preventing the obtaining of homogeneous composites. Furthermore, adding 20% raspberry pomace filler after extraction extended the thermal stability time for the composites by about 30%. It was observed that composite density, impact strength, and tensile strength values decreased significantly with increasing concentrations of filler in the PVC matrix. At the same time, their modulus of elasticity and Shore hardness increased. All tested composites were characterized by a good burning resistance with a flammability rating of V0 according to the UL94 test. Adding 20 to 40% of a natural filler to the PVC matrix made it possible to obtain composites for the production...

Research paper thumbnail of Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials, 2021

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant po... more We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this compos...

Research paper thumbnail of Polymer Composites Used in Rapid Prototyping Technology

Advances in Manufacturing Science and Technology, 2020

New materials and filaments dedicated to 3D printing were obtained using the fused deposition mod... more New materials and filaments dedicated to 3D printing were obtained using the fused deposition modeling method, and the properties of the produced materials were investigated. Polylactide was used as a polymer base for the assays because of the desired properties of the polymer, mainly biodegradability, and the matrix was refilled by the addition of metallic nanofillers, such as bronze, copper, brass, and steel. For the composites obtained, mechanical properties were investigated to determine the dependence of the obtained results on the content and type of filler used and on the method of fabrication of the fittings. It was found that the additives present in the polymer matrix increased the fluidity of the material. The best results were obtained for the compositions with bronze and steel in which the mass flow rate was 72.97 and 79.99 g/10 min, respectively. The filled material that had lower hardness was measured by Rockwell and the impact strength was measured by Charpy. In addi...

Research paper thumbnail of Composites of Poly(vinyl chloride) with Residual Hops after Supercritical Extraction in CO2

Polymers, 2021

The common applications of poly(vinyl chloride) (PVC) in many industries mean that the topic of r... more The common applications of poly(vinyl chloride) (PVC) in many industries mean that the topic of recycling and disposal of post-consumer waste is still very important. One of the methods of reducing the negative impact of PVC waste on the natural environment is to use technological or post-consumer waste of this polymer to produce new composite materials with favorable utility properties, with the addition of natural fillers, among which agro-waste, including hop residue, is deserving of special attention. In this study, the effect of the addition of residual hops (H) on the mechanical and physicochemical properties of poly(vinyl chloride) was investigated. PVC blends containing 10, 20 and 30 wt % of hop residue were mixed in an extruder, while the specimens were obtained by the injection molding method. It was observed that the addition of H increased their thermostability, as shown by a Congo red test. Furthermore, thermogravimetric analysis showed that the degradation rate of PVC/...

Research paper thumbnail of Carbon fabric reinforced hybrid epoxy composites

Advances in Manufacturing Science and Technology, 2015

Address: Rafał OLIWA, PhD Eng., Maciej HENECZKOWSKI, DSc Eng., Mariusz OLEKSY, DSc Eng., Rzeszow ... more Address: Rafał OLIWA, PhD Eng., Maciej HENECZKOWSKI, DSc Eng., Mariusz OLEKSY, DSc Eng., Rzeszow University of Technology, The Faculty of Chemistry, 6 Powsta ńców Warszawy Av., 35-959 Rzeszów, email: oliwa@prz.edu.p l, Grzegorz BUDZIK, DSc Eng., Olimpia MARKOWSKA, PhD Eng., Rzeszow University of Technology, Department of Mechanical Engineering, 8 Powsta ńców Warszawy Av., 35-959 Rzeszów CARBON FABRIC REINFORCED HYBRID EPOXY COMPOSITES

Research paper thumbnail of Hybrid Polymer Composites Used in the Arms Industry: A Review

Polymer fiber composites are increasingly being used in many industries, including the defense in... more Polymer fiber composites are increasingly being used in many industries, including the defense industry. However, for protective applications, in addition to high specific strength and stiffness, polymer composites are also required to have a high energy absorption capacity. To improve the performance of fiber-reinforced composites, many researchers have modified them using multiple methods, such as the introduction of nanofillers into the polymer matrix, the modification of fibers with nanofillers, the impregnation of fabrics using a shear thickening fluid (STF) or a shear thickening gel (STG), or a combination of these techniques. In addition, the physical structures of composites have been modified through reinforcement hybridization; the appropriate design of roving, weave, and cross-orientation of fabric layers; and the development of 3D structures. This review focuses on the effects of modifying composites on their impact energy absorption capacity and other mechanical propert...

Research paper thumbnail of Polymer Composites Based on Polycarbonate (PC) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing (MEM) Technology

Polymers

As part of the present work, polymer composites used in 3D printing technology, especially in Mel... more As part of the present work, polymer composites used in 3D printing technology, especially in Melted and Extruded Manufacturing (MEM) technology, were obtained. The influence of modified fillers such as alumina modified silica, quaternary ammonium bentonite, lignin/silicon dioxide hybrid filler and unmodified multiwalled carbon nanotubes on the properties of polycarbonate (PC) composites was investigated. In the first part of the work, the polymer and its composites containing 0.5–3 wt.% filler were used to obtain a filament using the proprietary technological line. The moldings for testing functional properties were obtained with the use of 3D printing and injection molding techniques. In the next part of the work, the rheological properties—mass flow rate (MFR) and mechanical properties—Rockwell hardness, Charpy impact strength and static tensile strength with Young’s modulus were examined. The structure of the obtained composites was also described and determined using scanning e...

Research paper thumbnail of Compositions of unsaturated polyester resins used for facing layers of laminates

Polimery

Hybrid composites of unsaturated polyester resin with the addition of glass microspheres and bent... more Hybrid composites of unsaturated polyester resin with the addition of glass microspheres and bentonite modified with a quaternary ammonium salt were obtained. The content of bentonite in composites was 3 wt %, while glass microspheres varied in the range of 5-15 wt %. The effect of the addition of glass microspheres on the rheological and mechanical properties of unsaturated polyester resin composites containing modified bentonite was investigated. On the basis of the obtained results, it was found that the optimum content of glass microspheres in polyester composites at which a clear increase in the value of most mechanical parameters was achieved, is 15 wt %. The Young's modulus, flexural modulus, tensile strength, and Charpy impact strength increased by 14.7, 38.7, 17.7 and 25%, respectively, compared to the unmodified resin. On the other hand, with relation to the sample containing 3 wt % of bentonite, a significant improvement was achieved only in the case of the flexural modulus and impact strength, amounting to 16.5 and 36.0%, respectively. In addition, composite with 15 wt % of glass microspheres was characterized by a smaller, by about 25%, flexural strength in relation to the unfilled resin and resin with 3 wt % of bentonite. In turn, rheological studies have shown that as the content of glass microspheres increased, there was an increase in viscosity and a decrease in gelation time in relation to the reference sample and the sample with 3 wt % of bentonite.

Research paper thumbnail of Epoxy resin compositions containing liquid phosphorus flame retardants used in infusion technology

Polimery

This study investigates the impact of the type and amount of liquid phosphorus flame retardant ad... more This study investigates the impact of the type and amount of liquid phosphorus flame retardant additive on the flammability and mechanical properties of epoxy compositions dedicated to the infusion process. To this purpose, epoxy resin (EP) compositions containing 10 and 20 wt % of liquid ammonium polyphosphate (APPL) and dimethyl methylphosphonate (DMMP) were obtained. Mechanical properties and flame resistance of obtained epoxy compositions were determined in terms of their use as a matrix in laminate infusion technology. Based on the results obtained, it was found, that the flame resistance increases, while the mechanical properties decreases with flame retardant loading. The best flame resistance results were obtained for a composite containing 20 wt % APPL: limiting oxygen index LOI = 23.9% instead of 19.8%-EP, peak of heat release rate pHRR = 427.3 kW/m 2 instead of 1046.3 kW/m 2-EP.

Research paper thumbnail of The Mechanical Properties of Kevlar Fabric/Epoxy Composites Containing Aluminosilicates Modified with Quaternary Ammonium and Phosphonium Salts

Materials

We investigated the effect of modified aluminosilicates, including bentonite from Armenia (BA) mo... more We investigated the effect of modified aluminosilicates, including bentonite from Armenia (BA) modified with quaternary ammonium salts (BAQAS) and phosphonium salts (BAQPS), on the mechanical properties and morphology of Kevlar/epoxy composites. The Kevlar/epoxy composites containing 1.0 or 3.0 wt.% modified bentonites were fabricated using the hand lay-up technique. The mechanical properties, including the tensile, flexural, and in-plane shear strength, were tested. Based on the obtained results, we found that the mechanical properties increased with modified bentonite loading. The best results were obtained for composites containing 3 wt.% BAQAS, as most of the mechanical properties were significantly improved (tensile strength 302.9 MPa (+30%), Young’s modulus 16.3 GPa (+17%), flexural modulus 23.4 GPa (+12.5%), in-plane shear strength 22.8 MPa (+24.5%), and in-plane shear modulus 677.2 MPa (+42%)). The obtained improvements in the mechanical properties are attributed to the unif...

Research paper thumbnail of A new method to electrical parameters identification of carbon fiber reinforced composites using lightning disturbances corresponding to subsequent return strokes

Research paper thumbnail of Methods for Enhancing the Electrical Properties of Epoxy Matrix Composites

Energies

This paper presents ways to modify epoxy resin matrix composites to increase their electrical con... more This paper presents ways to modify epoxy resin matrix composites to increase their electrical conductivity. Good electrical properties are particularly important for materials used in the construction of vehicles (cars, trains, airplanes) and other objects exposed to lightning (e.g., wind turbines). When the hull plating is made of an electrical conductor (e.g., metal alloys) it acts as a Faraday cage and upon lightning discharge the electrical charge does not cause damage to the structure. Epoxy-resin-based composites have recently been frequently used to reduce the weight of structures, but due to the insulating properties of the resin, various modifications must be applied to improve the conductivity of the composite. The methods to improve the conductivity have been categorized into three groups: modification of the matrix with conductive fillers, modification of the composite reinforcement, and addition of layers with increased electrical conductivity to the composite.

Research paper thumbnail of The Place of 3D Printing in the Manufacturing and Operational Process Based on the Industry 4.0 Structure

Tehnički glasnik

The article presents the place of 3D printing in the manufacturing and operational process. It an... more The article presents the place of 3D printing in the manufacturing and operational process. It analyzes selected incremental technologies in the product life cycle. It describes selected processes for testing the properties of materials used in 3D printing, including accelerated aging tests and simulation of operating conditions. Areas of application of 3D printing were defined, starting from design and prototype development through manufacturing of technological tools and finally finished products. Design criteria of additivelymanufactured elements in relation to the exploitation process are discussed. A methodology for the development of 3D-CAD models of manufactured elements, software processing of data and data storage format for manufacturing products and spare parts is presented. The assumptions of repair procedures based on the production of spare parts by means of 3D printing in relation to data circulation compatible with the idea of Industry 4.0 structure have been adopted.

Research paper thumbnail of Polymer Composites Based on Glycol-Modified Poly(Ethylene Terephthalate) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing Technology

Polymers

As part of the work, innovative polymer composites dedicated to 3D printing applications were dev... more As part of the work, innovative polymer composites dedicated to 3D printing applications were developed. For this purpose, the influence of modified fillers, such as silica modified with alumina, bentonite modified with quaternary ammonium salt, and hybrid filler lignin/silicon dioxide, on the functional properties of composites based on glycol-modified poly(ethylene terephthalate) (PET-G) was investigated. In the first part of the work, using the proprietary technological line, filaments from unfilled polymer and its composites were obtained, which contained modified fillers in an amount from 1.5% to 3.0% by weight. The fittings for the testing of functional properties were obtained using the 3D printing technique in the Melted and Extruded Manufacturing (MEM) technology and the injection molding technique. In a later part of the work, rheological properties such as mass melt flow rate (MFR) and viscosity, and mechanical properties such as Rockwell hardness, Charpy impact strength,...

Research paper thumbnail of Torsional strength tests of spline connections made of polymer materials (Rapid communication)

This work is a continuation of the publication [1], in which the torsional strength tests of samp... more This work is a continuation of the publication [1], in which the torsional strength tests of samples made of polymer materials, loaded with torsional moment, which more and more often can be made with the use of incremental technologies, were carried out. The designed proprietary test stand, which was described in the publication [1], was used. A series of preliminary studies on the torsion of fittings with spline connections obtained using additive techniques were carried out. It was found, that a additive technologies have a clear impact on the torsional strength of the tested machine components, including the placement of the prototype relative to the 3D printing plane or the method of processing polymer material.

Research paper thumbnail of Kompozyty zywicy epoksydowej z modyfikowanymi bentonitami dla potrzeb przemyslu lotniczego

Research paper thumbnail of Polyurethane compositions for rapid prototyping containing bentonites modified with silsesquioxanes

Research paper thumbnail of Mechanical strength of epoxy/organoclay/carbon fiber hybrid composites

Polimery, 2017

The influence of organoclay (bentonite BS) modified with quaternary ammonium (QAS) and phosphoniu... more The influence of organoclay (bentonite BS) modified with quaternary ammonium (QAS) and phosphonium salts (QPS) on the mechanical properties of epoxy/organoclay/carbon fiber hybrid composites was investigated. The longitudinal flexural strength of the composites containing 1 wt % BSQAS and BSQPS increased by 4 and 10 %, respectively, compared to the reference sample (epoxy resin/carbon fiber). Moreover, there was also a significant improvement, up to 13 %, of Young's modulus and transverse elastic modulus for the composites with modified bentonites. On the basis of the atomic force microscopy cross-section analysis (AFM), it was found that the composites with matrix containing the modified bentonites were characterized with larger interfacial surface, about 50 %, than that of unmodified matrix (epoxy resin/carbon fiber).

Research paper thumbnail of Article Epoxy Resin Composite Based on Functional Hybrid Fillers

A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modi... more A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS). The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS) curves, and an exfoliated structure observed by TEM.

Research paper thumbnail of Testing of Conductive Carbon Fiber Reinforced Polymer Composites Using Current Impulses Simulating Lightning Effects

Energies

Carbon fiber reinforced polymer (CFRP) composites are lightweight and an increasingly used materi... more Carbon fiber reinforced polymer (CFRP) composites are lightweight and an increasingly used material with good mechanical properties. In the aviation industry, they are also required to have specific electrical properties that guarantee resistance to the direct and indirect lightning effects. The paper is focused on the description of a test stand and development of a method used to determine the electrical characteristics of conductive CFRP laminate samples with the use of high current impulses of lightning nature. Samples of three laminates (square format with side 30 × 30 cm) with a different composition were tested on the constructed stand, confirming the possibility of characterizing this type of laminate sample in terms of electrical conductivity and resistance to the effects of lightning current. It was possible to observe the impulse current flow (with a peak value up to 15 kA and a rise time above 6 µs) from the high voltage electrode placed in the center of the sample in al...

Research paper thumbnail of Poly(vinyl chloride) Composites with Raspberry Pomace Filler

Polymers, 2021

This study examined, the effect of chemically extracted raspberry pomace on the thermal stability... more This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing of poly(vinyl chloride). It was observed that the pomace in this study was used to extract naphtha, thereby permitting the removal of bio-oil as a factor preventing the obtaining of homogeneous composites. Furthermore, adding 20% raspberry pomace filler after extraction extended the thermal stability time for the composites by about 30%. It was observed that composite density, impact strength, and tensile strength values decreased significantly with increasing concentrations of filler in the PVC matrix. At the same time, their modulus of elasticity and Shore hardness increased. All tested composites were characterized by a good burning resistance with a flammability rating of V0 according to the UL94 test. Adding 20 to 40% of a natural filler to the PVC matrix made it possible to obtain composites for the production...

Research paper thumbnail of Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials, 2021

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant po... more We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this compos...

Research paper thumbnail of Polymer Composites Used in Rapid Prototyping Technology

Advances in Manufacturing Science and Technology, 2020

New materials and filaments dedicated to 3D printing were obtained using the fused deposition mod... more New materials and filaments dedicated to 3D printing were obtained using the fused deposition modeling method, and the properties of the produced materials were investigated. Polylactide was used as a polymer base for the assays because of the desired properties of the polymer, mainly biodegradability, and the matrix was refilled by the addition of metallic nanofillers, such as bronze, copper, brass, and steel. For the composites obtained, mechanical properties were investigated to determine the dependence of the obtained results on the content and type of filler used and on the method of fabrication of the fittings. It was found that the additives present in the polymer matrix increased the fluidity of the material. The best results were obtained for the compositions with bronze and steel in which the mass flow rate was 72.97 and 79.99 g/10 min, respectively. The filled material that had lower hardness was measured by Rockwell and the impact strength was measured by Charpy. In addi...

Research paper thumbnail of Composites of Poly(vinyl chloride) with Residual Hops after Supercritical Extraction in CO2

Polymers, 2021

The common applications of poly(vinyl chloride) (PVC) in many industries mean that the topic of r... more The common applications of poly(vinyl chloride) (PVC) in many industries mean that the topic of recycling and disposal of post-consumer waste is still very important. One of the methods of reducing the negative impact of PVC waste on the natural environment is to use technological or post-consumer waste of this polymer to produce new composite materials with favorable utility properties, with the addition of natural fillers, among which agro-waste, including hop residue, is deserving of special attention. In this study, the effect of the addition of residual hops (H) on the mechanical and physicochemical properties of poly(vinyl chloride) was investigated. PVC blends containing 10, 20 and 30 wt % of hop residue were mixed in an extruder, while the specimens were obtained by the injection molding method. It was observed that the addition of H increased their thermostability, as shown by a Congo red test. Furthermore, thermogravimetric analysis showed that the degradation rate of PVC/...

Research paper thumbnail of Carbon fabric reinforced hybrid epoxy composites

Advances in Manufacturing Science and Technology, 2015

Address: Rafał OLIWA, PhD Eng., Maciej HENECZKOWSKI, DSc Eng., Mariusz OLEKSY, DSc Eng., Rzeszow ... more Address: Rafał OLIWA, PhD Eng., Maciej HENECZKOWSKI, DSc Eng., Mariusz OLEKSY, DSc Eng., Rzeszow University of Technology, The Faculty of Chemistry, 6 Powsta ńców Warszawy Av., 35-959 Rzeszów, email: oliwa@prz.edu.p l, Grzegorz BUDZIK, DSc Eng., Olimpia MARKOWSKA, PhD Eng., Rzeszow University of Technology, Department of Mechanical Engineering, 8 Powsta ńców Warszawy Av., 35-959 Rzeszów CARBON FABRIC REINFORCED HYBRID EPOXY COMPOSITES

Research paper thumbnail of Hybrid Polymer Composites Used in the Arms Industry: A Review

Polymer fiber composites are increasingly being used in many industries, including the defense in... more Polymer fiber composites are increasingly being used in many industries, including the defense industry. However, for protective applications, in addition to high specific strength and stiffness, polymer composites are also required to have a high energy absorption capacity. To improve the performance of fiber-reinforced composites, many researchers have modified them using multiple methods, such as the introduction of nanofillers into the polymer matrix, the modification of fibers with nanofillers, the impregnation of fabrics using a shear thickening fluid (STF) or a shear thickening gel (STG), or a combination of these techniques. In addition, the physical structures of composites have been modified through reinforcement hybridization; the appropriate design of roving, weave, and cross-orientation of fabric layers; and the development of 3D structures. This review focuses on the effects of modifying composites on their impact energy absorption capacity and other mechanical propert...

Research paper thumbnail of Polymer Composites Based on Polycarbonate (PC) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing (MEM) Technology

Polymers

As part of the present work, polymer composites used in 3D printing technology, especially in Mel... more As part of the present work, polymer composites used in 3D printing technology, especially in Melted and Extruded Manufacturing (MEM) technology, were obtained. The influence of modified fillers such as alumina modified silica, quaternary ammonium bentonite, lignin/silicon dioxide hybrid filler and unmodified multiwalled carbon nanotubes on the properties of polycarbonate (PC) composites was investigated. In the first part of the work, the polymer and its composites containing 0.5–3 wt.% filler were used to obtain a filament using the proprietary technological line. The moldings for testing functional properties were obtained with the use of 3D printing and injection molding techniques. In the next part of the work, the rheological properties—mass flow rate (MFR) and mechanical properties—Rockwell hardness, Charpy impact strength and static tensile strength with Young’s modulus were examined. The structure of the obtained composites was also described and determined using scanning e...

Research paper thumbnail of Compositions of unsaturated polyester resins used for facing layers of laminates

Polimery

Hybrid composites of unsaturated polyester resin with the addition of glass microspheres and bent... more Hybrid composites of unsaturated polyester resin with the addition of glass microspheres and bentonite modified with a quaternary ammonium salt were obtained. The content of bentonite in composites was 3 wt %, while glass microspheres varied in the range of 5-15 wt %. The effect of the addition of glass microspheres on the rheological and mechanical properties of unsaturated polyester resin composites containing modified bentonite was investigated. On the basis of the obtained results, it was found that the optimum content of glass microspheres in polyester composites at which a clear increase in the value of most mechanical parameters was achieved, is 15 wt %. The Young's modulus, flexural modulus, tensile strength, and Charpy impact strength increased by 14.7, 38.7, 17.7 and 25%, respectively, compared to the unmodified resin. On the other hand, with relation to the sample containing 3 wt % of bentonite, a significant improvement was achieved only in the case of the flexural modulus and impact strength, amounting to 16.5 and 36.0%, respectively. In addition, composite with 15 wt % of glass microspheres was characterized by a smaller, by about 25%, flexural strength in relation to the unfilled resin and resin with 3 wt % of bentonite. In turn, rheological studies have shown that as the content of glass microspheres increased, there was an increase in viscosity and a decrease in gelation time in relation to the reference sample and the sample with 3 wt % of bentonite.

Research paper thumbnail of Epoxy resin compositions containing liquid phosphorus flame retardants used in infusion technology

Polimery

This study investigates the impact of the type and amount of liquid phosphorus flame retardant ad... more This study investigates the impact of the type and amount of liquid phosphorus flame retardant additive on the flammability and mechanical properties of epoxy compositions dedicated to the infusion process. To this purpose, epoxy resin (EP) compositions containing 10 and 20 wt % of liquid ammonium polyphosphate (APPL) and dimethyl methylphosphonate (DMMP) were obtained. Mechanical properties and flame resistance of obtained epoxy compositions were determined in terms of their use as a matrix in laminate infusion technology. Based on the results obtained, it was found, that the flame resistance increases, while the mechanical properties decreases with flame retardant loading. The best flame resistance results were obtained for a composite containing 20 wt % APPL: limiting oxygen index LOI = 23.9% instead of 19.8%-EP, peak of heat release rate pHRR = 427.3 kW/m 2 instead of 1046.3 kW/m 2-EP.

Research paper thumbnail of The Mechanical Properties of Kevlar Fabric/Epoxy Composites Containing Aluminosilicates Modified with Quaternary Ammonium and Phosphonium Salts

Materials

We investigated the effect of modified aluminosilicates, including bentonite from Armenia (BA) mo... more We investigated the effect of modified aluminosilicates, including bentonite from Armenia (BA) modified with quaternary ammonium salts (BAQAS) and phosphonium salts (BAQPS), on the mechanical properties and morphology of Kevlar/epoxy composites. The Kevlar/epoxy composites containing 1.0 or 3.0 wt.% modified bentonites were fabricated using the hand lay-up technique. The mechanical properties, including the tensile, flexural, and in-plane shear strength, were tested. Based on the obtained results, we found that the mechanical properties increased with modified bentonite loading. The best results were obtained for composites containing 3 wt.% BAQAS, as most of the mechanical properties were significantly improved (tensile strength 302.9 MPa (+30%), Young’s modulus 16.3 GPa (+17%), flexural modulus 23.4 GPa (+12.5%), in-plane shear strength 22.8 MPa (+24.5%), and in-plane shear modulus 677.2 MPa (+42%)). The obtained improvements in the mechanical properties are attributed to the unif...