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Lubura J, Kočková O, Strachota B, Bera O, Pavlova E, Pavličević J, Ikonić B, Kojić P, Strachota A. Natural Rubber Composites Using Hydrothermally Carbonized Hardwood Waste Biomass as a Partial Reinforcing Filler-Part II: Mechanical, Thermal and Ageing (Chemical) Properties. Polymers (Basel) 2023; 15:polym15102397. [PMID: 37242972 DOI: 10.3390/polym15102397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/12/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Natural rubber composites were reinforced by the co-fillers 'hydrochar' (HC), obtained by hydrothermal carbonization of hardwood sawdust and commercial carbon black (CB). The content of the combined fillers was kept constant while their ratio was varied. The aim was to test the suitability of HC as a partial filler in natural rubber. Due to its larger particle size and hence smaller specific surface area, large amounts of HC reduced the crosslinking density in the composites. On the other hand, due to its unsaturated organic character, HC was found to display interesting chemical effects: if it was used as the exclusive filler component, it displayed a very strong anti-oxidizing effect, which greatly stabilized the rubber composite against oxidative crosslinking (and hence embrittlement). HC also affected the vulcanization kinetics in different ways, depending on the HC/CB ratio. Composites with HC/CB ratios 20/30 and 10/40 displayed interesting chemical stabilization in combination with fairly good mechanical properties. The performed analyses included vulcanization kinetics, tensile properties, determination of density of permanent and reversible crosslinking in dry and swollen states, chemical stability tests including TGA, thermo-oxidative aging tests in air at 180 °C, simulated weathering in real use conditions ('Florida test'), and thermo-mechanical analyses of degraded samples. Generally, the results indicate that HC could be a promising filler material due to its specific reactivity.
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Affiliation(s)
- Jelena Lubura
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Olga Kočková
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Beata Strachota
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Oskar Bera
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Ewa Pavlova
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Jelena Pavličević
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Bojana Ikonić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Predrag Kojić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Adam Strachota
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
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Lubura J, Kojić P, Pavličević J, Ikonić B, Balaban D, Bera O. A Novel Approach for Simulation and Optimization of Rubber Vulcanization. Polymers (Basel) 2023; 15:polym15071750. [PMID: 37050369 PMCID: PMC10097246 DOI: 10.3390/polym15071750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023] Open
Abstract
The kinetic model, encompassing the curing and reversion phenomena of the NR/SBR rubber vulcanization process, was developed by means of the finite element method simultaneously with heat transfer equations, including heat generation due to curing reactions. The vulcanization simulation was conducted for three spheres of different diameters (1, 5 and 10 cm) and two rubber wheels, one of which was a commercial product of the rubber industry. The proposed advanced simulation model, based on products’ two-dimensional axisymmetry, includes cooling after vulcanization, during which the crosslinking reactions continue to take place as a result of the products’ heated interiors. As a criterion for removing the product from the mold, an average vulcanization degree of 0.9 was set, whereby, during cooling, the vulcanization degree increases, due to crosslinking reactions. Based on the minimal difference between the maximal and minimal vulcanization degrees, which did not exceed a value of 0.0142, the optimal process parameters for each product were determined, achieving homogeneity and obtaining high-quality rubber products, while simultaneously ensuring a more efficient vulcanization process and enhanced cost effectiveness for the rubber industry.
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Cvetanović Kljakić A, Radosavljević M, Zengin G, Yan L, Gašić U, Kojić P, Torbica A, Belović M, Zeković Z. New Biological and Chemical Insights into Optimization of Chamomile Extracts by Using Artificial Neural Network (ANN) Model. Plants (Basel) 2023; 12:1211. [PMID: 36986900 PMCID: PMC10058048 DOI: 10.3390/plants12061211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/09/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Chamomile is one of the most consumed medicinal plants worldwide. Various chamomile preparations are widely used in various branches of both traditional and modern pharmacy. However, in order to obtain an extract with a high content of the desired components, it is necessary to optimize key extraction parameters. In the present study, optimization of process parameters was performed using the artificial neural networks (ANN) model using a solid-to-solvent ratio, microwave power and time as inputs, while the outputs were the yield of the total phenolic compounds (TPC). Optimized extraction conditions were as follows: a solid-to-solvent ratio of 1:80, microwave power of 400 W, extraction time of 30 min. ANN predicted the content of the total phenolic compounds, which was later experimentally confirmed. The extract obtained under optimal conditions was characterized by rich composition and high biological activity. Additionally, chamomile extract showed promising properties as growth media for probiotics. The study could make a valuable scientific contribution to the application of modern statistical designs and modelling to improve extraction techniques.
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Affiliation(s)
| | - Miloš Radosavljević
- Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Gokhan Zengin
- Department of Biology, Science Faculty, Selcuk University, Konya 42130, Turkey
| | - Linlin Yan
- Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry, Nanjing 210042, China
| | - Uroš Gašić
- Institute for Biological Research “Siniša Stanković”, National Institute of Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Predrag Kojić
- Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Aleksandra Torbica
- Institute of Food Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Miona Belović
- Institute of Food Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
| | - Zoran Zeković
- Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia
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Lubura J, Kobera L, Abbrent S, Pavlova E, Strachota B, Bera O, Pavličević J, Ikonić B, Kojić P, Strachota A. Natural Rubber Composites Using Hydrothermally Carbonized Hardwood Waste Biomass as a Partial Reinforcing Filler- Part I: Structure, Morphology, and Rheological Effects during Vulcanization. Polymers (Basel) 2023; 15:polym15051176. [PMID: 36904417 PMCID: PMC10007617 DOI: 10.3390/polym15051176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
A new generation biomass-based filler for natural rubber, 'hydrochar' (HC), was obtained by hydrothermal carbonization of hardwood waste (sawdust). It was intended as a potential partial replacement for the traditional carbon black (CB) filler. The HC particles were found (TEM) to be much larger (and less regular) than CB: 0.5-3 µm vs. 30-60 nm, but the specific surface areas were relatively close to each other (HC: 21.4 m2/g vs. CB: 77.8 m2/g), indicating a considerable porosity of HC. The carbon content of HC was 71%, up from 46% in sawdust feed. FTIR and 13C-NMR analyses indicated that HC preserved its organic character, but it strongly differs from both lignin and cellulose. Experimental rubber nanocomposites were prepared, in which the content of the combined fillers was set at 50 phr (31 wt.%), while the HC/CB ratios were varied between 40/10 and 0/50. Morphology investigations proved a fairly even distribution of HC and CB, as well as the disappearance of bubbles after vulcanization. Vulcanization rheology tests demonstrated that the HC filler does not hinder the process, but it significantly influences vulcanization chemistry, canceling scorch time on one hand and slowing down the reaction on the other. Generally, the results suggest that rubber composites in which 10-20 phr of CB are replaced by HC might be promising materials. The use of HC in the rubber industry would represent a high-tonnage application for hardwood waste.
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Affiliation(s)
- Jelena Lubura
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
- Correspondence: (J.L.); (A.S.)
| | - Libor Kobera
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Sabina Abbrent
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Ewa Pavlova
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Beata Strachota
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
| | - Oskar Bera
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Jelena Pavličević
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Bojana Ikonić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Predrag Kojić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Adam Strachota
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 00 Praha, Czech Republic
- Correspondence: (J.L.); (A.S.)
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Lubura J, Kojić P, Ikonić B, Pavličević J, Govedarica D, Bera O. Influence of biochar and carbon black on natural rubber mixture properties. POLYM INT 2022. [DOI: 10.1002/pi.6439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jelena Lubura
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
| | - Predrag Kojić
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
| | - Bojana Ikonić
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
| | - Jelena Pavličević
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
| | - Dragan Govedarica
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
| | - Oskar Bera
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 21000 Novi Sad Serbia
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Milićević N, Kojić P, Sakač M, Mišan A, Kojić J, Perussello C, Banjac V, Pojić M, Tiwari B. Kinetic modelling of ultrasound-assisted extraction of phenolics from cereal brans. Ultrason Sonochem 2021; 79:105761. [PMID: 34601448 PMCID: PMC8531846 DOI: 10.1016/j.ultsonch.2021.105761] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/11/2021] [Accepted: 09/14/2021] [Indexed: 05/16/2023]
Abstract
Cereal brans are by-products of the milling of cereal grains, which are mainly used as low value ingredients in animal feed. Wheat and oat bran is a rich source of bioactives and phytochemicals, especially phenolic compounds. Within this study, the application of ultrasound (US) technology to assist the extraction of phenolics from oat and wheat bran was investigated (20-45 kHz). Peleg's mathematical model was used to study the kinetics of ultrasound-assisted extraction (UAE) and subsequent stirring of total phenolic compounds (TPC). The surface morphology of cereal brans after extraction was studied using SEM analysis. The excellent agreement was determined between the values of TPC calculated from Peleg's mathematical model and actual experimental results. The constant that represents a time required for the initial phenolic concentration to be extracted to one-half of its initial value has been introduced (K1/2). It was shown that the TPC extraction kinetics was dependent only on K1/2 enabling fast kinetics fitting and comparison between extraction rates. Moreover, different values of K1/2 constant could indicate the differences in brans composition and consequently different influence of US pretreatment on these samples.
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Affiliation(s)
- Nataša Milićević
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Predrag Kojić
- University of Novi Sad, Faculty of Technology, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Marijana Sakač
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Aleksandra Mišan
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Jovana Kojić
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Camila Perussello
- Food Chemistry and Technology, Teagasc Food Research Centre, Dublin, Ireland
| | - Vojislav Banjac
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia
| | - Milica Pojić
- University of Novi Sad, Institute of Food Technology in Novi Sad, Bulevar cara Lazara 1, Novi Sad, Serbia.
| | - Brijesh Tiwari
- Food Chemistry and Technology, Teagasc Food Research Centre, Dublin, Ireland
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Bera O, Pavličević J, Ikonić B, Lubura J, Govedarica D, Kojić P. A new approach for kinetic modeling and optimization of rubber molding. POLYM ENG SCI 2021. [DOI: 10.1002/pen.25636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Oskar Bera
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
| | - Jelena Pavličević
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
| | - Bojana Ikonić
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
| | - Jelena Lubura
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
| | - Dragan Govedarica
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
| | - Predrag Kojić
- University of Novi Sad Faculty of Technology Novi Sad, Bulevar cara Lazara 1 Novi Sad Serbia
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Pezo L, Pezo M, Banjac V, Jovanović AP, Krulj J, Kojić J, Kojić P. Blending performance of the coupled Ross static mixer and vertical feed mixer - Discrete element model approach. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2020.07.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ikonić B, Bera O, Pavličević J, Kojić P, Jokić A, Ikonić P, Pojić M, Šaranović Ž. Artificial neural network modeling and optimization of wheat starch suspension microfiltration using twisted tape as a turbulence promoter. J FOOD PROCESS PRES 2019. [DOI: 10.1111/jfpp.14219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bojana Ikonić
- Faculty of Technology Novi Sad University of Novi Sad Novi Sad Serbia
| | - Oskar Bera
- Faculty of Technology Novi Sad University of Novi Sad Novi Sad Serbia
| | - Jelena Pavličević
- Faculty of Technology Novi Sad University of Novi Sad Novi Sad Serbia
| | - Predrag Kojić
- Faculty of Technology Novi Sad University of Novi Sad Novi Sad Serbia
| | - Aleksandar Jokić
- Faculty of Technology Novi Sad University of Novi Sad Novi Sad Serbia
| | - Predrag Ikonić
- Institute of Food Technology University of Novi Sad Novi Sad Serbia
| | - Milica Pojić
- Institute of Food Technology University of Novi Sad Novi Sad Serbia
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Kojić P, Omorjan R. Predicting hydrodynamic parameters and volumetric gas–liquid mass transfer coefficient in an external-loop airlift reactor by support vector regression. Chem Eng Res Des 2017. [DOI: 10.1016/j.cherd.2017.07.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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