Bartlomiej Przybyszewski

Bio: Bartlomiej Przybyszewski is an academic researcher from Warsaw University of Technology. The author has contributed to research in topics: Materials science & Contact angle. The author has an hindex of 5, co-authored 13 publications receiving 112 citations. Previous affiliations of Bartlomiej Przybyszewski include Dresden University of Technology.

Modification of glass reinforced epoxy composites by ammonium polyphosphate (APP) and melamine polyphosphate (PNA) during the resin powder molding process

Abstract: The aim of the studies was to manufacture glass reinforced epoxy composites using technology based on hot pressing with improve flame resistance with good mechanical properties. Ammonium polyphosphate (APP) and melamine polyphosphate (PNA) were used as flame retardants with ranging from 5 to 20 wt %. The thermal and mechanical properties of the composites were determined in the course of TGA analysis, flammability UL-94 test, limiting oxygen index (LOI) technique, Fourier Transform Infrared Spectroscopy, ultrasonic test and static tensile test. The flame retardancy of modified composites was significantly improved with addition of ammonium polyphosphate and melamine polyphosphate. Moreover, in most cases addition of flame retardants increased strength of composites. This study confirmed that fast and highly efficient Resin Powder Molding manufacturing process allows to produce high quality composites.

Novel MRE/CFRP sandwich structures for adaptive vibration control

Abstract: The aim of this work was the development of sandwich structures formed by embedding magnetorheological elastomers (MRE) between constrained layers of carbon fibre–reinforced plastic (CFRP) laminates. The MREs were obtained by mechanical stirring of a reactive mixture of substrates with carbonyl-iron particles, followed by orienting the particles into chains under an external magnetic field. Samples with particle volume fractions of 11.5% and 33% were examined. The CFRP/MRE sandwich structures were obtained by compressing MREs samples between two CFRP laminates composed. The used A.S.SET resin was in powder form and the curing process was carried out during pressing with MRE. The microstructure of the manufactured sandwich beams was inspected using SEM. Moreover, the rheological and damping properties of the examined materials with and without a magnetic field were experimentally investigated. In addition, the free vibration responses of the adaptive three-layered MR beams were studied at different fixed magnetic field levels. The free vibration tests revealed that an applied non-homogeneous magnetic field causes a shift in natural frequency values and a reduction in the vibration amplitudes of the CFRP/MRE adaptive beams. The reduction in vibration amplitude was attributed mainly to the stiffening effect of the MRE core and only a minor contribution was made by the enhanced damping capacity, which was evidenced by the variation in damping ratio values.

Improved Thermal Conductivity of Poly(trimethylene terephthalate-block-poly(tetramethylene oxide) Based Nanocomposites Containing Hybrid Single-Walled Carbon Nanotubes/Graphene Nanoplatelets Fillers

Abstract: The thermal conductivity of poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO)–based nanocomposites filled with the hybrid system of nanofillers, including single-walled carbon nanotubes (SWCNT) and graphene nanoplatelets (GNP) is studied. At the same loading, SWCNT provided greater thermal conductivity enhancement when added to thermoplastic elastomer matrix when compared to GNP. Moreover, SEM images showed that SWCNT and GNP were well dispersed in PTT-PTMO, suggesting that in situ polymerization is a highly efficient method for preparing hybrid nanocomposites with low loading of carbon nanofillers. To further improve thermal conductivity of PTT-PTMO–based nanocomposites, a hybrid SWCNT/GNP was used. When the ratio of SWCNT to GNP was 5:1, i.e. 0.5 wt% of SWCNT and 0.1 wt% of GNP, the PTT-PTMO–based nanocomposites exhibited the highest thermal conductivity of 0.30 W/m·K, higher than that filled with SWCNT and GNP alone. This suggests that the combination of two types of nanofillers, which differ in shape, allows obtaining the synergistic effect for the thermal conductivity enhancement of PTT-PTMO.

Controlling the Porosity and Biocidal Properties of the Chitosan-Hyaluronate Matrix Hydrogel Nanocomposites by the Addition of 2D Ti3C2Tx MXene.

Abstract: A recent discovery of the unique biological properties of two-dimensional transition metal carbides (MXenes) resulted in intensive research on their application in various biotechnological areas, including polymeric nanocomposite systems. However, the true potential of MXene as an additive to bioactive natural porous composite structures has yet to be fully explored. Here, we report that the addition of 2D Ti3C2Tx MXene by reducing the porosity of the chitosan-hyaluronate matrix nanocomposite structures, stabilized by vitamin C, maintains their desired antibacterial properties. This was confirmed by micro computed tomography (micro-CT) visualization which enables insight into the porous structure of nanocomposites. It was also found that given large porosity of the nanocomposite a small amount of MXene (1–5 wt.%) was effective against gram-negative Escherichia coli, gram-positive Staphylococcus aureus, and Bacillus sp. bacteria in a hydrogel system. Such an approach unequivocally advances the future design approaches of modern wound healing dressing materials with the addition of MXenes.

Thermal conductivity of polymers and polymer nanocomposites

Abstract: Polymers are widely used in industry and in our daily life because of their diverse functionality, light weight, low cost and excellent chemical stability. However, on some applications such as heat exchangers and electronic packaging, the low thermal conductivity of polymers is one of the major technological barriers. Enhancing the thermal conductivity of polymers is important for these applications and has become a very active research topic over the past two decades. In this review article, we aim to: 1). systematically summarize the molecular level understanding on the thermal transport mechanisms in polymers in terms of polymer morphology, chain structure and inter-chain coupling; 2). highlight the rationales in the recent efforts in enhancing the thermal conductivity of nanostructured polymers and polymer nanocomposites. Finally, we outline the main advances, challenges and outlooks for highly thermal-conductive polymer and polymer nanocomposites.

Economical and facile synthesis of a highly efficient flame retardant for simultaneous improvement of fire retardancy, smoke suppression and moisture resistance of epoxy resins

Abstract: An economical flame retardant additive dimelamine pyrophosphate (DMPY) was synthesized from melamine and sodium pyrophosphate and its chemical structure was well characterized and confirmed. It was used to flame retardant epoxy resin (EP) thermosets and the fire retarded performance, mechanical properties, moisture resistance and flame retardant mechanism of EP thermosets were investigated in details. The samples achieved UL-94 V-0 grade during vertical burning tests and the limiting oxygen index value reached 28.7% when 9 wt% DMPY was incorporated. DMPY stimulated the degradation of EP matrix in advance and the formation of intumescent and compact char layer during combustion. Besides, the nonflammable gases generated from the decomposition of DMPY exerted flame retarded effect in gas phase. Thus, the rate and total amount of heat release and smoke production were significantly suppressed. The moisture resistance of EP/DMPY thermosets was improved comparing with that of pure EP. The samples remained superior flame retardant performance and mechanical properties after water resistance tests due to the excellent water resistance of DMPY. In summary, the EP/DMPY thermosets exhibited excellent flame retardancy, moisture resistance, mechanical properties and fire safety performance. The presented investigation provided a broad application prospect in the high-performance field of flame retardant EP thermosets because of the low cost and easy industrialization of DMPY.

Fabrication of zeolitic imidazolate frameworks on layered double hydroxide nanosheets to improve the fire safety of epoxy resin

Abstract: ZIF@MgAl-LDH hybrids were synthesized by zeolitic imidazolate frameworks (ZIF) and MgAl-layered double hydroxide (MgAl-LDH) via electrostatic interactions. Their structure and morphology were systematically characterized. Then, ZIF@MgAl-LDH hybrids were added to epoxy resin (EP) to study their effects on the thermal properties and fire resistance of the material. The results of TGA showed that ZIF@MgAl-LDH could improve the char yield of the EP composites. The cone calorimetry, smoke density tests, limiting oxygen index (LOI) and UL94 vertical burning test showed that ZIF@MgAl-LDH effectively improved the flame retardancy and smoke suppression of EP. Furthermore, the laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS) results of the char residue showed that ZIF@MgAl-LDH promoted the formation of a char layer with high graphitization and thermal oxidation resistance, which was conducive to the reduction of the fire hazards. This simple treatment of EP may expand its fire safety applications.

A novel strategy for simultaneously improving the fire safety, water resistance and compatibility of thermoplastic polyurethane composites through the construction of biomimetic hydrophobic structure of intumescent flame retardant synergistic system

Abstract: The water resistance, compatibility and anti-dripping performance of flame retardant thermoplastic polyurethane (TPU) composites have still been a challenge in the fire science. Inspired by the hydrophobic surface structure of biomaterials, the hydrophobic charring agent N-methyl triazine-piperazine copolymer (MTPC) and modified magnesium oxide (MgO) were assembled on ammonium polyphosphate (APP) surface to prepare the hydrophobic intumescent flame retardant (HIFR) system. The constructed HIFR system presented excellent hydrophobic performance with the water contact angle of 139°. The HIFR was incorporated into TPU matrix. The tensile strength and elongation at break of TPU/10 wt% HIFR composites increased by 48 and 106% compared with that of TPU/10 wt% APP. Meanwhile, the specimens of TPU/10 wt% HIFR composites before and after water resistance tests achieved UL-94 V-0 rating without drippings and the limiting oxygen index value was 27.5 and 27.3%. TPU/HIFR composites still maintained excellent flame retardancy and mechanical properties after water treatment. Cone calorimeter tests revealed that the peak of heat release and smoke production, and CO yield of TPU/10 wt% HIFR composites were significantly decreased with the reduction of 87.0, 63.2 and 28.6% compared with that of neat TPU. The incorporation of HIFR effectively enhanced the fire safety for TPU composites. The investigation of flame retardant mechanism for TPU/HIFR demonstrated that HIFR catalyzed the TPU matrix charring in advance and the generated compact, homogeneous and partial graphitized char layer exerted barrier effect in condensed phase, and the released inert gases evoked dilution effect in gas phase. This presented work provided a novel promising approach for preparing TPU materials with excellent comprehensive performance as well as water resistance and highly flame retardant efficiency.