33 results on '"Pakuła, Daria"'
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2. Trimming flow, plasticity, and mechanical properties by cubic silsesquioxane chemistry
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Sztorch, Bogna, Brząkalski, Dariusz, Głowacka, Julia, Pakuła, Daria, Frydrych, Miłosz, and Przekop, Robert E.
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- 2023
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3. Modification of gelcoat based unsaturated polyester resin with functionalized octaspherosilicates to reduce the ice adhesion strength
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Kozera, Rafał, Ziętkowska, Katarzyna, Krawczyk, Zuzanna, Przybyszewski, Bartłomiej, Boczkowska, Anna, Sztorch, Bogna, Pakuła, Daria, Brząkalski, Dariusz, Przekop, Robert Edward, and Trzciński, Jakub
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- 2024
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4. Metal and metal oxide particles as modifiers for effective layer melting and Z-axis strength in 3D printing
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Sztorch, Bogna, Romańczuk-Ruszuk, Eliza, Gabriel, Ewa, Pakuła, Daria, Kozera, Rafał, and Przekop, Robert E.
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- 2024
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5. Spherosilicate-modified epoxy coatings with enhanced icephobic properties for wind turbines applications
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Kozera, Rafał, Ziętkowska, Katarzyna, Przybyszewski, Bartłomiej, Boczkowska, Anna, Sztorch, Bogna, Pakuła, Daria, Przekop, Robert E., Trzciński, Jakub, and Borras, Ana
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- 2023
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6. Characterisation of carbonate lake sediments as a potential filler for polymer composites
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Borkowski Grzegorz, Martyła Agnieszka, Dobrosielska Marta, Marciniak Piotr, Głowacka Julia, Pakuła Daria, Gabriel Ewa, and Przekop Robert E.
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sediments ,mineral fillers ,natural fillers ,caco3 ,calcite ,Chemistry ,QD1-999 - Abstract
The purpose of the study was to determine whether lake sediments could be a potential raw material for the plastics industry. The examined samples were obtained in a complex process of sediment collection from Lake Swarzędzkie located in the region of Wielkopolska, Poland, followed by granulometric analysis by sieving and quartz grain shape analysis, with preparation of geotechnical sheets. The works involved the examination of physico-chemical characteristics of carbonate lake sediments and the analysis of impact of the sediments’ depth extraction on their chemical composition and physico-chemical properties. The lake sediment consists mainly of calcium carbonate (CaCO3) and can be a potential filler for plastics. Tests were carried out to determine chemical composition of the sediments and their thermal stability. The thermogravimetric analysis showed the three stages of the thermal decomposition. Sediments in deeper layers of the lake are characterised by the presence of not only CaCO3 and silica, but also other chemical compounds, including aluminosilicates. In addition, as the depth increases, the average size of sediment particles changes, with the main fraction particle size being the smallest for the material from the 6–12 m depth. Additionally, carbon content systematically decreases with increasing depth.
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- 2023
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7. Recent advances and prospects in high purity H2 production from sorption enhanced reforming of bio-ethanol and bio-glycerol as carbon negative processes: A review
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Xu, Yongqing, Wu, Mengna, Yang, Xiaoxiao, Sun, Shuzhuang, Li, Qinghai, Zhang, Yanguo, Wu, Chunfei, Przekop, Robert E., Romańczuk-Ruszuk, Eliza, Pakuła, Daria, and Zhou, Hui
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- 2023
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8. Enhancing the Thermal Resistance of UV-Curable Resin Using (3-Thiopropyl)polysilsesquioxane.
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Pakuła, Daria, Sztorch, Bogna, Topa-Skwarczyńska, Monika, Gałuszka, Karolina, Ortyl, Joanna, Marciniec, Bogdan, and Przekop, Robert E.
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DIFFERENTIAL scanning calorimetry , *THERMAL properties , *COMPOSITE coating , *CONTACT angle , *ORGANOSILICON compounds , *ACRYLIC coatings , *THERMAL resistance - Abstract
This study delineates a methodology for the preparation of new composites based on a photocurable urethane-acrylate resin, which has been modified with (3-thiopropyl)polysilsesquioxane (SSQ-SH). The organosilicon compound combines fully enclosed cage structures and incompletely condensed silanols (a mixture of random structures) obtained through the hydrolytic condensation of (3-mercaptopropyl)trimethoxysilane. This process involves a thiol-ene "click" reaction between SSQ-SH and a commercially available resin (Ebecryl 1271®) in the presence of the photoinitiator DMPA, resulting in composites with significantly changed thermal properties. Various tests were conducted, including thermogravimetric analysis (TGA), Fourier transmittance infrared spectroscopy (FT-IR), differential scanning calorimetry (Photo-DSC), and photoreological measurement mechanical property, and water contact angle (WCA) tests. The modification of resin with SSQ-SH increased the temperature of 1% and 5% mass loss compared to the reference (for 50 wt% SSQ-SH, T5% was 310.8 °C, an increase of 20.4 °C). A composition containing 50 wt% of SSQ-SH crosslinked faster than the reference resin, a phenomenon confirmed by photorheological tests. This research highlights the potential of new composite materials in coating applications across diverse industries. The modification of resin with SSQ-SH not only enhances thermal properties but also introduces a host of functional improvements, thereby elevating the performance of the resulting coatings. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Micro- and Nano-Pollutants from Tires and Car Brakes Generated in the Winter Season in the Poznan City Urban Environment.
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Przekop, Robert E., Sztorch, Bogna, Pakuła, Daria, Romańczuk-Ruszuk, Eliza, Konieczna, Roksana, and Frydrych, Miłosz
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AUTOMOBILE tires ,AUTOMOBILE brakes ,NANOSATELLITES ,TIRES ,NUCLEAR magnetic resonance ,SCANNING electron microscopy ,ARTIFICIAL rubber - Abstract
This research, focusing on the environmental impact of tire and brake disc pad wear, constitutes a significant area of transport-related studies. These two key vehicle components are not only the most frequently worn but also generate micro- and nano-pollutants (i.e., rubber, metal oxides) that potentially harm the environment. Over half of the globally produced natural and synthetic rubbers, which amounted to about 30 million tons in 2022, are used for tire production. This work focuses on the study of roadside snow, sand, and standing water deposits from various locations in the urban agglomeration (Poznań, Poland) during the winter season, determining their qualitative composition and the quantitative content of pollutants originating from tire abrasion. In addition, the method of washing nano- and micro-rubber particles and their full characteristics was also presented. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic studies, optical and scanning electron microscopy (SEM-EDS), particle size studies using a dynamic light scattering (DLS) particle analyzer, and thermogravimetric analysis (TGA) were conducted for a detailed characterization of the pollutants in the environment. The conducted particle separation methods allowed for the extraction of a fraction mainly containing gum residues with particle sizes less than 2 µm. The results of these tests make it possible to estimate the level of contamination with rubber and metal residues during the abrasion of tires, pads, and brake discs while driving, which is crucial for understanding the impact of vehicle part exploitation on the environment. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Preparation and Characterization of Composites Based on ABS Modified with Polysiloxane Derivatives.
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Sztorch, Bogna, Konieczna, Roksana, Pakuła, Daria, Frydrych, Miłosz, Marciniec, Bogdan, and Przekop, Robert E.
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ACRYLONITRILE butadiene styrene resins ,THREE-dimensional printing ,CONTACT angle ,HYDROPHOBIC surfaces ,CONSTRUCTION materials ,ORGANOSILICON compounds - Abstract
In this study, organosilicon compounds were used as modifiers of filaments constituting building materials for 3D printing technology. Polymethylhydrosiloxane underwent a hydrosilylation reaction with styrene, octadecene, and vinyltrimethoxysilane to produce new di- or tri-functional derivatives with varying ratios of olefins. These compounds were then mixed with silica and incorporated into the ABS matrix using standard processing methods. The resulting systems exhibited changes in their physicochemical and mechanical characteristics. Several of the obtained composites (e.g., modified with VT:6STYR) had an increase in the contact angle of over 20° resulting in a hydrophobic surface. The addition of modifiers also prevented a decrease in rheological parameters regardless of the amount of filler added. In addition, comprehensive tests of the thermal decomposition of the obtained composites were performed and an attempt was made to precisely characterize the decomposition of ABS using FT-IR and optical microscopy, which allowed us to determine the impact of individual groups on the thermal stability of the system. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Click Addition Reaction of Urethane–Acrylate Resin Using Octa(3-thiopropyl)silsesquioxane Derivatives as Cross-Linking Agents.
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Pakuła, Daria, Sztorch, Bogna, Przekop, Robert E., and Marciniec, Bogdan
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ADDITION reactions ,ALKYL group ,OCTENE ,HEXENE ,CONTACT angle - Abstract
In this work, new partially substituted derivatives of octa(3-thiopropyl)silsesquioxane (SSQ-8SH) were synthesized. The article compares the thiol-ene reaction using two methods: radical mechanism, thermally initiated (AIBN), and in the presence of a photoinitiator (DMPA). Both the crystalline and the oil forms of SSQ-8SH were functionalized. Olefins with nonpolar alkyl groups (hexene, octene, and octadecene) and vinyltrimethoxysilane, allyl glycidyl ether, allyl 2,2,3,3,4,4,5,5-octafluoropentylether, allyl methacrylate, and styrene were used in the reactions, allowing to obtain seven new derivatives. All compounds were characterized using spectroscopic (
1 H NMR and29 Si NMR) and spectrometric (MALDI-TOF-MS) methods. The influence of functional groups on the water contact angle value was determined. The functionalization of the compound led to a contact angle value above 95° (SSQ-4SH-4OD). Density measurements and thermogravimetric analysis (TGA) were carried out for all compounds. The highest onset temperature (357.4 °C) and temperature at the maximum mass loss rate (377.3 °C) were observed for SSQ-SH-4OD. The addition of alkyl groups significantly decreased the density of compounds with increasing chain length (1.198 g/cm3 ; 1.162 g/cm3 ; 1.095 g/cm3 for hexene, octene, and octadecene, respectively). Silsesquioxanes have potential applications in various materials, such as UV-curable resins, allowing to modify, for example, their surface properties. Modification of a commercial photocurable resin with selected derivatives was carried out to determine the impact on physicochemical properties (TGA, WCA). [ABSTRACT FROM AUTHOR]- Published
- 2023
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12. Comparison of the Bioactive and Bacteriostatic Performance of Different Alginate-Based Dental Prosthetic Impression Materials with and without Zirconium Phosphate-Based Ion Exchange Resin Containing Silver: An In Vitro Study.
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Raszewski, Zbigniew, Mikulewicz, Marcin, Brząkalski, Dariusz, Pakuła, Daria, and Przekop, Robert E.
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DENTAL impression materials ,ION exchange resins ,GYPSUM ,ZIRCONIUM ,DENTAL impressions ,STREPTOCOCCUS mutans ,SILVER ,ALGINIC acid - Abstract
Featured Application: An alginate-based impression material with bacteriostatic properties for application in the production of dental prosthetics, requiring a less labour-intensive process of disinfection. Disinfection of alginate impressions used in dental prosthetics is a very problematic procedure, during which the dimensions of the obtained model can change, and it can be easily mechanically damaged. Therefore, it would be beneficial to create a material with bacteriostatic properties for this application. In this work, we investigated alginate materials with the addition of 0.25–1.0 wt% of zirconium phosphate-based ion exchange resin containing silver and compared them with commercial alginate impression products. The obtained materials passed the normative requirements of ISO 21563:2021 (setting time, elastic recovery, strain in compression, compatibility with gypsum, detail reproduction, tearing strength, and linear dimensional change) as well as bacteriostatic properties in relation to Streptococcus mutans. The newly developed alginate materials met all the properties required by the standards. Their setting time was comparable to the commercial materials, and their 24 h contraction did not exceed 1.3%. Furthermore, the tearing strength was 0.42–0.48 MPa, less than that of the comparative commercial materials (0.52–0.56 MPa). From the point of view of clinical practice, it will be possible to create an alginate material with bacteriostatic properties that will prevent the transmission of cross-infections. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Liquid to Fused Deposition Modeling (L-FDM)—A Revolution in Application Chemicals to 3D Printing Technology—Mechanical and Functional Properties.
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Przekop, Robert E., Gabriel, Ewa, Pakuła, Daria, and Sztorch, Bogna
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FUSED deposition modeling ,THREE-dimensional printing ,CHEMICAL testing ,MANUFACTURING processes ,RADIOACTIVE substances ,PLASTIC extrusion ,PHOSPHATE fertilizers ,POLYMERS - Abstract
Featured Application: The L-FDM technique enables the direct introduction of chemicals, dyes, radioactive substances, pesticides, antibiotics, nanoparticles, trace elements, fertilizers, phosphors, monomers for polymerization, proteins, peptides, and active ingredients in the direct printing process from a polymer material with a typical FDM printer. With the proposed technology, it is now possible to introduce chemical substances into polymer filaments that were previously impossible to apply due to undergoing physical or chemical transformations during previous processing processes. This article discusses methods that eliminate the need for costly and energy-consuming processing equipment. These methods can be utilized in any laboratory by users without access to specialized devices. A novel L-FDM technique that builds upon the fundamentals of the FDM additive manufacturing process has been developed. It includes a mechanism that directly incorporates a chemical substance and alters polymer fibers throughout the fine process. This method eliminates the need for additional extrusion operations and compounding equipment to introduce chemical additives and solvents. This advancement opens up new opportunities for printers to be used in chemical labs to test new or known chemical substances. The paper outlines the technological assumptions, potential applications, and practical examples of direct filament modification using the L-FDM technique. The modifications made to the mechanical properties of the printed objects were confirmed through thermal analysis techniques (DSC), water contact angle measurements, electron microscopy (SEM-EDS), and mechanical analysis. [ABSTRACT FROM AUTHOR]
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- 2023
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14. Transparent Silicone–Epoxy Coatings with Enhanced Icephobic Properties for Photovoltaic Applications.
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Ziętkowska, Katarzyna, Przybyszewski, Bartłomiej, Grzęda, Dominik, Kozera, Rafał, Boczkowska, Anna, Liszewska, Malwina, Pakuła, Daria, Przekop, Robert Edward, and Sztorch, Bogna
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CONTACT angle ,SURFACE coatings ,DUST ,SILICONES ,SNOW accumulation ,OPTICAL coatings ,SURFACE roughness - Abstract
Recently, the photovoltaic technology has become very popular as a means to produce renewable energy. One of the problems that are still unsolved in this area of the industry is that photovoltaic panels are subject to a significant loss of efficiency due to the accumulation of dust and dirt. In addition, during the winter season, the accumulation of snow and ice also reduces or stops the energy production. The current methods of dealing with this problem are inefficient and pollute the environment. One way with high potential to prevent the build-up of dirt and ice is to use transparent coatings with self-cleaning and icephobic properties. In this work, the chemical modification of an epoxy–silicone hybrid resin using dually functionalized polysiloxanes was carried out. The icephobic properties (ice adhesion and freezing delay time of water droplets), hydrophobic properties (water contact angle, contact angle hysteresis, and roll-off angle), average surface roughness, and optical properties were characterized. It can be concluded that the performed chemical modification resulted in a significant improvement of the icephobic properties of the investigated coatings: ice adhesion decreased by 69%, and the freezing delay time increased by 17 times compared to those of the unmodified sample. The polysiloxanes also caused a significant reduction in the contact angle hysteresis and roll-off angle. The chemical modifications did not negatively affect the optical properties of the coatings, which is a key requirement for photovoltaic applications. [ABSTRACT FROM AUTHOR]
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- 2023
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15. Liquid for Fused Deposition Modeling Technique (L-FDM)—A Revolution in Application Chemicals to 3D Printing Technology: Color and Elements.
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Przekop, Robert E., Gabriel, Ewa, Pakuła, Daria, and Sztorch, Bogna
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FUSED deposition modeling ,THREE-dimensional printing ,COLOR printing ,CHEMICAL testing ,RADIOACTIVE substances ,PLASTIC extrusion ,POLYMERS ,PHOSPHATE fertilizers - Abstract
Featured Application: The L-FDM technique enables the direct introduction of chemicals, dyes, radioactive substances, pesticides, antibiotics, nanoparticles, trace elements, fertilizers, phosphors, monomers for polymerization, proteins, peptides, and active ingredients in the direct printing process from a polymer material with a typical FDM printer. With the proposed technology, it is now possible to introduce chemical substances into polymer filaments that were previously impossible to apply due to undergoing physical or chemical transformations during previous processing processes. This article discusses methods that eliminate the need for costly and energy-consuming processing equipment. These methods can be utilized in any laboratory by users without access to specialized devices. This article presents a novel 3D printing technique called L-FDM (liquid for fused deposition modeling), which is based on the deposition of molten thermoplastic material. The new method allows for the direct introduction of chemicals and polymer filament modifications during the printing process. In contrast to traditional incremental methods, L-FDM eliminates the need for extra granulating, extrusion, and processing equipment, making it possible to introduce chemical additives to the polymer matrix directly. This opens up exciting possibilities for chemical laboratories to test and experiment with new and known chemicals through 3D printing. The article discusses the technical aspects of L-FDM and its potential applications and provides practical examples of direct filament modifications using the technique. The results of these modifications were verified using a colorimeter, electron microscopy (SEM/EDS), and optical microscopy. [ABSTRACT FROM AUTHOR]
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- 2023
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16. The 3D-Printed (FDM/FFF) Biocomposites Based on Polylactide and Carbonate Lake Sediments—Towards a Circular Economy.
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Przekop, Robert E., Gabriel, Ewa, Dobrosielska, Marta, Martyła, Agnieszka, Jakubowska, Paulina, Głowacka, Julia, Marciniak, Piotr, Pakuła, Daria, Jałbrzykowski, Marek, and Borkowski, Grzegorz
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LAKE sediments ,CIRCULAR economy ,POLYLACTIC acid ,INJECTION molding ,POLYESTER fibers ,THREE-dimensional printing ,FLEXURAL strength ,WEATHERING ,CHARCOAL - Abstract
In this study, composites containing polylactide and carbonate lake sediment in concentrations of 2.5, 5, 10, and 15% by weight were prepared by a 3D printing method. The material for 3D printing was obtained by directly diluting the masterbatch on an injection moulder to the desired concentrations, and after granulation, it was extruded into a filament. The material prepared thusly was used to print standardised samples for mechanical testing. To compare the mechanical properties of the composites obtained by 3D printing and injection moulding, two sets of tests were performed, i.e., mechanical tests (tensile strength, flexural strength, and impact strength) and hydrophobic–hydrophilic surface character testing. The degree of composite waste in the 3D printing was also calculated. Mechanical and surface tests were performed for both systems conditioned at room temperature and after accelerated ageing in a weathering chamber. The study showed differences in the properties of composites obtained by 3D printing. Sedimentary fillers improved the hydrophobicity of the systems compared with pure PLA, but it was not a linear relationship. The PLA/CLS sedB composite had higher strength parameters, especially after ageing in a weathering chamber. This is due to its composition, in which, in addition to calcite and silica, there are also aluminosilicates, causing a strengthening of the PLA matrix. [ABSTRACT FROM AUTHOR]
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- 2023
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17. Molybdenum Disulphide Modified Polylactide for 3D Printed (FDM/FFF) Filaments.
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Kujawa, Maciej, Głowacka, Julia, Pawlak, Wojciech, Sztorch, Bogna, Pakuła, Daria, Frydrych, Miłosz, Sokolska, Justyna, and Przekop, Robert E.
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MOLYBDENUM disulfide ,POLYLACTIC acid ,FIBERS ,BENDING strength ,MICROSCOPY ,TENSILE strength ,PLASTIC additives - Abstract
MoS
2 is an additive used to improve the tribological properties of plastics. In this work, it was decided to verify the use of MoS2 as a modifier of the properties of PLA filaments used in the additive FDM/FFF technique. For this purpose, MoS2 was introduced into the PLA matrix at concentrations of 0.025–1.0% by weight. Through extrusion, a fibre with a diameter of 1.75 mm was obtained. 3D printed samples with three different filling patterns were subjected to comprehensive thermal (TG, DSC and HDT), mechanical (impact, bending and strength tests), tribological and physicochemical characteristics. The mechanical properties were determined for two different types of fillings, and samples with the third type of filling were used for tribological tests. Tensile strength has been significantly increased for all samples with longitudinal filling with improvement up to 49%. In terms of tribological properties, higher values of the addition (0.5%) caused a significant increase of up to 457% of the wear indicator. A significant improvement in processing properties in terms of rheology was obtained (416% compared to pure PLA with the addition of 1.0%), which translated into more efficient processing, increased interlayer adhesion and mechanical strength. As a result, the quality of printed objects has been improved. Microscopic analysis was also carried out, which confirmed the good dispersion of the modifier in the polymer matrix (SEM-EDS). Microscopic techniques (MO, SEM) allowed for the characterization of the effect of the additive on changes in the printing process (improvement of interlayer remelting) and to assess impact fractures. In the tribological area, the introduced modification did not bring spectacular effects. [ABSTRACT FROM AUTHOR]- Published
- 2023
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18. Feldspar-Modified Methacrylic Composite for Fabrication of Prosthetic Teeth.
- Author
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Raszewski, Zbigniew, Kulbacka, Julita, Pakuła, Daria, Brząkalski, Dariusz, and Przekop, Robert E.
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TEETH ,DENTAL materials ,COMPRESSIVE strength ,AMELOBLASTS ,FELDSPAR ,DENTIN ,METHYL methacrylate - Abstract
This study was aimed at investigating poly(methyl methacrylate) (PMMA), modified with a silanized feldspar filler at 10 wt.% and 30 wt.%, as a dental material system for the production of prosthetic teeth. Samples of this composite were subjected to a compressive strength test, three-layer methacrylic teeth were fabricated with the said materials, and their connection to a denture plate was examined. The biocompatibility of the materials was assessed via cytotoxicity tests on human gingival fibroblasts (HGFs) and Chinese hamster ovarian cells (CHO-K1). The addition of feldspar significantly improved the material's compressive strength, with neat PMMA reaching 107 MPa, and the addition of 30% feldspar raising it up to 159 MPa. As observed, composite teeth (cervical part made of neat PMMA, dentin with 10 wt.%, and enamel with 30 wt.% of feldspar) had good adhesion to the denture plate. Neither of the tested materials revealed any cytotoxic effects. In the case of hamster fibroblasts, increased cell viability was observed, with only morphological changes being noticed. Samples containing 10% or 30% of inorganic filler were determined to be safe for treated cells. The use of silanized feldspar to fabricate composite teeth increased their hardness, which is of significant clinical importance for the duration of use of non-retained dentures. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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19. 3D Printing Ceramics—Materials for Direct Extrusion Process.
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Romanczuk-Ruszuk, Eliza, Sztorch, Bogna, Pakuła, Daria, Gabriel, Ewa, Nowak, Krzysztof, and Przekop, Robert E.
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CERAMIC materials ,THREE-dimensional printing ,EXTRUSION process ,FUSED deposition modeling ,MATERIALS science - Abstract
Additive manufacturing and 3D printing methods based on the extrusion of material have become very popular in recent years. There are many methods of printing ceramics, but the direct extrusion method gives the largest range of sizes of printed objects and enables scaling of processes also in large-scale applications. Additionally, the application of this method to ceramic materials is of particular importance due to its low cost, ease of use, and high material utilization. The paper presents the most important literature reports on ceramics printed by direct extrusion. The review includes articles written in English and published between 2017 and 2022. The aim of this literature review was to present the main groups of ceramic materials produced by extrusion-based 3D printing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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20. Direct Synthesis of Silicon Compounds—From the Beginning to Green Chemistry Revolution.
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Pakuła, Daria, Marciniec, Bogdan, and Przekop, Robert E.
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SILICON compounds ,SUSTAINABLE chemistry ,ORGANOSILICON compounds ,SEMICONDUCTOR industry ,CATALYTIC activity ,CHLOROSILANES - Abstract
This paper discusses the historical beginnings and the current state of knowledge of the synthesis of organosilicon compounds and chlorine derivatives of silicon. The key importance of these compounds for modern industry, including the semiconductor industry (photovoltaic cells, microprocessors, memory chips and many other electronic elements) is highlighted. Significant environmental threats related to the production of these compounds and the research challenges aimed at their elimination are discussed. The complexity of the catalytic mechanism of direct reaction of silicon with CH
3 Cl and alcohols is presented in an accessible way. In the last part of the work, the directions of the development of direct synthesis technology in line with the principles of green chemistry are indicated. [ABSTRACT FROM AUTHOR]- Published
- 2023
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21. Hydro- and Icephobic Properties and Durability of Epoxy Gelcoat Modified with Double-Functionalized Polysiloxanes.
- Author
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Ziętkowska, Katarzyna, Kozera, Rafał, Przybyszewski, Bartłomiej, Boczkowska, Anna, Sztorch, Bogna, Pakuła, Daria, Marciniec, Bogdan, and Przekop, Robert Edward
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MEASUREMENT of shear strength ,SILICON compounds ,SILICONES ,EPOXY resins ,CONTACT angle ,ORGANOSILICON compounds - Abstract
Anti-icing coatings have provided a very good alternative to current, uneconomic, active deicing methods, and their use would bring a number of significant benefits to many industries, such as aviation and energy. Some of the most promising icephobic surfaces are those with hydrophobic properties. However, the relationship between hydrophobicity and low ice adhesion is not yet clearly defined. In this work, chemical modification of an epoxy gelcoat with chemical modifiers from the group of double organofunctionalized polysiloxanes (generally called multifunctionalized organosilicon compounds (MFSCs)) was applied. The anti-icing properties of manufactured coatings were determined by means of measurements of shear strength between the ice layer and the modified surface, conducted using a tensile machine. In the work, tests were also performed on the roughness, wettability, and durability of the properties in an aging chamber. It was found that the performed modifications of the coating's chemical composition by the addition of polysiloxanes enabled us to reduce ice adhesion by 51% and to increase the water contact angle by 14% in comparison to the neat gelcoat. A reduction in ice adhesion was also observed with the increasing water contact angle and with decreasing surface roughness. In addition, only one modification recorded an increase in ice adhesion after exposure in the aging chamber. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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22. Silane‐Bearing Borasilsesquioxanes: Synthetic Protocol and Unsuspected Redistribution Reactions.
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Frydrych, Miłosz, Sztorch, Bogna, Brząkalski, Dariusz, Pakuła, Daria, Przekop, Robert E., Srishailam, Kanugula, Reddy, Byru Venkatram, and Marciniec, Bogdan
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EXCHANGE reactions ,ALKOXY group ,PLATINUM catalysts ,HYDROSILYLATION ,SILANE compounds - Abstract
The presented work is a continuation of research on the reactivity of unsaturated borasilsesquioxanes under the conditions of common organometallic transformations. The catalytic hydrosilylation reaction with silanes, siloxanes and silsesquioxanes in presence of platinum catalyst was explored. The majority of the products were obtained in high yields (>90 %) and their structures were confirmed and characterized by spectroscopy and spectrometry, i. e. NMR and MALDI‐TOF‐MS. The most significant segment of the work is research on the spontaneous redistribution reaction of the alkoxy group from silane to borane moiety occurring in the obtained products, not being limited to the heterosilsesquioxane chemistry, however. The products were confirmed using GC‐MS, ESI‐MS methods and B3LYP exchange‐correlation, in order to ascertain formation of the silicon‐boron hybrid molecule. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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23. The Influence of Organofunctional Substituents of Spherosilicates on the Functional Properties of PLA/TiO 2 Composites Used in 3D Printing (FDM/FFF).
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Sztorch, Bogna, Pakuła, Daria, Kustosz, Magdalena, Romanczuk-Ruszuk, Eliza, Gabriel, Ewa, and Przekop, Robert E.
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THREE-dimensional printing , *TITANIUM dioxide , *FLEXURAL strength testing , *THERMOMECHANICAL properties of metals , *PIGMENTS , *SILICON compounds , *ORGANOSILICON compounds - Abstract
In this study, the influence of TiO2 pigment filler modified with spherosilicate derivatives on the processes and thermomechanical properties of composites based on PLA was investigated. Rheological tests (MFR) were carried out, on the basis of which it was found that the addition of organosilicon compounds has a plasticizing effect on the polymer-filler systems. TGA and DSC analysis were performed. The analysis of the contact angle showed that 1.5% of the additives had an influence on the superhydrophobic properties of TiO2 (above 135°), and a slight improvement of this parameter was also observed for composites containing the modified pigment. Microscopic analysis and mechanical tests (tensile strength, impact strength and flexural strength tests) were carried out as well. It has been observed that the addition of certain derivatives adversely affects the dispersion of the filler, thus a slight improvement in mechanical properties is observed. For modifiers that do not affect filler agglomeration, a plasticizing effect on the composite is observed. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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24. Natural and Synthetic Polymer Fillers for Applications in 3D Printing—FDM Technology Area.
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Sztorch, Bogna, Brząkalski, Dariusz, Pakuła, Daria, Frydrych, Miłosz, Špitalský, Zdeno, and Przekop, Robert E.
- Subjects
THREE-dimensional printing ,BIOPOLYMERS ,EXTRUSION process ,COMPOSITE materials ,THERMOPLASTICS - Abstract
This publication summarises the current state of knowledge and technology on the possibilities and limitations of using mineral and synthetic fillers in the field of 3D printing of thermoplastics. FDM technology can be perceived as a miniaturised variation of conventional extrusion processing (a microextrusion process). However, scaling the process down has an undoubtful drawback of significantly reducing the extrudate diameter (often by a factor of ≈20–30). Therefore, the results produced under conventional extrusion processing cannot be simply translated to processes run with the application of FDM technology. With that in mind, discussing the latest findings in composite materials preparation and application in FDM 3D printing was necessary. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
25. Carbonate Lake Sediments in the Plastics Processing-Preliminary Polylactide Composite Case Study: Mechanical and Structural Properties.
- Author
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Borkowski, Grzegorz, Martyła, Agnieszka, Dobrosielska, Marta, Marciniak, Piotr, Gabriel, Ewa, Głowacka, Julia, Jałbrzykowski, Marek, Pakuła, Daria, and Przekop, Robert E.
- Subjects
LAKE sediments ,POLYLACTIC acid ,CARBONATES ,PARTICLE size distribution ,WEATHERING ,PLASTICS ,BIODEGRADABLE plastics ,FLEXURAL strength - Abstract
In this study, the influence of carbonate lake sediments (Polylactide/Carbonate Lake Sediments–PLA/CLS) on the mechanical and structural properties of polylactide matrix composites was investigated. Two fractions of sediments originating from 3–8 and 8–12 m were analysed for differences in particle size by distribution (Dynamic Light Scattering–DLS), phase composition (X-ray Diffraction–XRD), the presence of surface functional groups (Fourier Transform-Infrared–FT-IR), and thermal stability (Thermogravimetric Analysis–TGA). Microscopic observations of the composite fractures were also performed. The effect of the precipitate fraction on the mechanical properties of the composites before and after conditioning in the weathering chamber was verified through peel strength, flexural strength, and impact strength tests. A melt flow rate study was performed to evaluate the effect of sediment on the processing properties of the PLA/CLS composite. Hydrophobic-hydrophilic properties were also investigated, and fracture analysis was performed by optical and electron microscopy. The addition of carbon lake sediments to PLA allows for the obtention of composites resistant to environmental factors such as elevated temperature or humidity. Moreover, PLA/CLS composites show a higher flow rate and higher surface hydrophobicity in comparison with unmodified PLA. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. Sulfur‐Containing Silsesquioxane Derivatives Obtained by the Thiol‐ene Reaction: Synthesis and Thermal Degradation.
- Author
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Pakuła, Daria, Przekop, Robert E., Brząkalski, Dariusz, Frydrych, Miłosz, Sztorch, Bogna, and Marciniec, Bogdan
- Subjects
- *
FLUOROALKYL group , *ALKYL group , *ARYL group , *THERMAL stability , *THERMAL analysis - Abstract
This article presents the synthesis of new derivatives of octa(3‐thiopropyl)silsesquioxane (SSQ‐8SH) via thiol‐ene reaction with simple olefins bearing alkyl groups as well as methoxysilyl, substituted aryl or fluoroalkyl groups. All products were characterized by 1H NMR, 13C NMR, 29Si NMR, FTIR, GPC, MALDI‐TOF‐MS, as well as thermal analysis (TGA) to confirm their structures, purity and thermal stability, and finally give some insight into their thermal degradation pathway. In some of the structures obtained, the T5% values take place at high temperatures and are close to 230 °C. The thiol‐ene reaction allowed to obtain 7 new compounds with high yield (>92 %), no by‐products and in a relatively short time (24 h). All products are characterized by high conversion >99 %. New derivatives can find potential use as modifiers of plastics to improve their certain properties for example hydrophobicity or thermo‐oxidative stability. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
27. Novel Multifunctional Spherosilicate-Based Coupling Agents for Improved Bond Strength and Quality in Restorative Dentistry.
- Author
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Raszewski, Zbigniew, Brząkalski, Dariusz, Jałbrzykowski, Marek, Pakuła, Daria, Frydrych, Miłosz, and Przekop, Robert E.
- Subjects
OPERATIVE dentistry ,BOND strengths ,NUCLEAR magnetic resonance ,HYDROLYSIS ,FRACTURE mechanics ,MICROSCOPY - Abstract
The aim of this study was to investigate the restorative connections of composite materials after fracture, under controlled conditions of treating the materials with novel, spherosilicate-based (SS) primers bearing both methacryl (MA) and trimethoxysilyl (TMOS) groups. The chemistry of methacrylate group insertion and reactive groups hydrolysis has been studied with the aid of
1 H NMR (Nuclear Magnetic Resonance) spectroscopy. The light-cured resin composites were repaired by activating the connection site with the obtained primers and, for comparison, a silane (methacryloxypropyltrimethoxysilane, MATMOS) as a conventional coupling agent bearing the same reactive groups. The resistance of such a joint was tested in a three-point bending test after 24 h and 28 days period of sample conditioning. The effect of bond application was also studied, showing that spherosilicate-based primers may be used more effectively than MATMOS for two-step (primer-composite) restorative process, while for silane, the three-step process with bond application is crucial for satisfactory joint quality. The joint failure mode was determined by microscopic analysis and it was found that SS-4MA-4TMOS and SS-2MA-6TMOS application resulted in mostly composite, and not joint, failure. After 28 days of conditioning, the flexural strength of the joint repaired with SS-4MA-4TMOS was at 94% of the neat, solid material under the same procedure. However, the strength of the neat composite was observed to decline during the conditioning process by ~30%. The joint behavior was explained on the basis of the gradual hydrolysis effect (the greatest decrease being observed for silane). [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
28. The Influence of Gravity on 3D Printing with the FFF/FDM Technique - Reverse FDM/FFF 3D Printing.
- Author
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Przekop, Robert E., Pakuła, Daria, Frydrych, Miłosz, and Jałbrzykowski, Marek
- Subjects
GRAVITY ,THREE-dimensional printing ,FIELD-flow fractionation ,TRIZ theory ,REDUCED gravity environments - Abstract
Often, simple questions do not have obvious answers and require an experiment that yields an unexpected answer. Have you ever wondered what will happen if you turn 180 degrees to the commonly accepted FDM printing convention? The paper presents the verification of the possibility of using the reverse orientation of the print head in traditionally used 3D printers of FFF/FDM systems. It has been shown that the mechanical parameters of the printed object can be even higher when reverse printing is used. The presented concept opens up new possibilities of designing printers in FFF/FDM systems, which use changed heat convection and the reverse effect of gravity on the printed object. This work was carried out using the TRIZ methodology. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
29. New Functionalized Borasilsesquioxanes Obtained via Metathetical Transformation of 4‐Vinylphenylborasilsesquioxanes.
- Author
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Frydrych, Miłosz, Sztorch, Bogna, Brząkalski, Dariusz, Pakuła, Daria, Frąckowiak, Dawid, Majchrzak, Mariusz, and Marciniec, Bogdan
- Subjects
FIRE resistant polymers ,ACID catalysts ,MOLECULAR probes ,METATHESIS reactions ,RUTHENIUM catalysts ,LEWIS acids ,LEWIS acidity - Abstract
We report here functionalizing borasilsesquioxanes in a cross‐metathesis reaction in the presence of a ruthenium catalyst. The procedure provides new, silsesquioxanes containing boron atoms in their structure, which may find potential application in the preparation of special materials, e.g. flame retardants for polymers, organoboron Lewis acids for catalysts and scavengers, or molecular probes. The most attractive aspect of this study was obtaining hybrid silsesquioxane systems in the metathesis reaction of styrylborasilsesquioxane with mono‐ and octavinylsilsesquioxanes as well as diborate systems with vinylborate derivatives. Most of the compounds were obtained in good yields (> 75 %) and were characterized by spectroscopic methods (NMR, MALDI‐TOF‐MS). [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. Where ppm Quantities of Silsesquioxanes Make a Difference—Silanes and Cage Siloxanes as TiO 2 Dispersants and Stabilizers for Pigmented Epoxy Resins.
- Author
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Brząkalski, Dariusz, Przekop, Robert E., Frydrych, Miłosz, Pakuła, Daria, Dobrosielska, Marta, Sztorch, Bogna, and Marciniec, Bogdan
- Subjects
SILANE compounds ,ORGANOSILICON compounds ,TITANIUM dioxide ,DISPERSING agents ,SILANE coupling agents ,SILOXANES ,EPOXY resins - Abstract
In this work, silsesquioxane and spherosilicate compounds were assessed as novel organosilicon coupling agents for surface modification of TiO
2 in a green process, and compared with their conventional silane counterparts. The surface-treated TiO2 particles were then applied in preparation of epoxy (EP) composites and the aspects of pigment dispersion, suspension stability, hiding power, as well as the composite mechanical and thermal properties were discussed. The studied compounds loading was between 0.005–0.015% (50–150 ppm) in respect to the bulk composite mass and resulted in increase of suspension stability and hiding power by over an order of magnitude. It was found that these compounds may be an effective alternative for silane coupling agents, yet due to their low cost and simplicity of production and manipulation, silanes and siloxanes are still the most straight-forward options available. Nonetheless, the obtained findings might encourage tuning of silsesquioxane compounds structure and probably process itself if implementation of these novel organosilicon compounds as surface treatment agents is sought for special applications, e.g., high performance coating systems. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
31. Novel Silsesquioxane-Derived Boronate Esters—Synthesis and Thermal Properties.
- Author
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Frydrych, Miłosz, Pakuła, Daria, Sztorch, Bogna, Brząkalski, Dariusz, Przekop, Robert E., and Marciniec, Bogdan
- Subjects
- *
BORONIC esters , *THERMAL properties , *THERMAL analysis , *HYDROSILYLATION , *ATOMS - Abstract
The functionalization of mono- and octahydrospherosilicate with vinylboranes and allylboranes via hydrosilylation reaction in the presence of a Karstedt's platinum (0) catalyst is presented. This is the catalytic route to obtain a new class of silsesquioxanes containing boron atoms in their structure in high yields (>90%) and with satisfactory selectivity. The obtained compounds were fully characterized by spectroscopic (1H, 13C, 29Si NMR) and spectrometric methods (MALDI-TOF-MS), as well as thermal analysis (TGA). The obtained compounds were subjected to thermal tests, characterizing the processes of melting, thermal evaporation, sublimation and thermal decomposition. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. Why POSS-Type Compounds Should Be Considered Nanomodifiers, Not Nanofillers—A Polypropylene Blends Case Study.
- Author
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Brząkalski, Dariusz, Przekop, Robert E., Sztorch, Bogna, Frydrych, Miłosz, Pakuła, Daria, Jałbrzykowski, Marek, Markiewicz, Grzegorz, and Marciniec, Bogdan
- Subjects
POLYPROPYLENE ,POLYMER blends ,DIFFERENTIAL scanning calorimetry ,PLASTIC additives ,CHONDROITIN sulfates ,SILICONES - Abstract
In this work, a series of silsesquioxanes (SSQ) and spherosilicates (SS), comprising a group of cage siloxane (CS) compounds, was tested as functional additives for preparation of isotactic polypropylene (iPP)-based nanocomposites and discussed in the aspect of their rationale of applicability as such additives. For this purpose, the compounds were prepared by condensation and olefin hydrosilylation reactions. The effect of these cage siloxane products on properties of obtained CS/iPP nanocomposites was analyzed by means of mechanical, microscopic (scanning electron microscopy-energy dispersive spectroscopy), thermal (differential scanning calorimetry, thermogravimetry), thermomechanical (Vicat softening point) analyses. The results were compared with the previous findings on CS/polyolefin composites. The role of CS compounds was discussed in terms of plastic processing additives. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
33. Limonene Derivative of Spherosilicate as a Polylactide Modifier for Applications in 3D Printing Technology.
- Author
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Brząkalski, Dariusz, Sztorch, Bogna, Frydrych, Miłosz, Pakuła, Daria, Dydek, Kamil, Kozera, Rafał, Boczkowska, Anna, Marciniec, Bogdan, Przekop, Robert E., Rubinsztajn, Sławomir, Cypryk, Marek, and Stanczyk, Wlodzimierz
- Subjects
THREE-dimensional printing ,POLYLACTIC acid ,LIMONENE ,INJECTION molding ,WASTE minimization - Abstract
The first report of using limonene derivative of a spherosilicate as a modifier of polylactide used for 3D printing and injection moulding is presented. The paper presents the use of limonene-functionalized spherosilicate derivative as a functional additive. The study compared the material characteristics of polylactide modified with SS-Limonene (0.25–5.0% w/w) processed with traditional injection moulding and 3D printing (FFF, FDM). A significant improvement in the processing properties concerning rheology, inter-layer adhesion, and mechanical properties was achieved, which translated into the quality of the print and reduction of waste production. Moreover, the paper describes the elementary stages of thermal transformations of the obtained hybrid systems. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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