2023, Vol. 8, No. 3
Display Method:
2023, 8(3): 215-223.
doi: 10.1016/j.jobab.2023.04.001
Abstract:
Matter organic non-glycerol (MONG) is a considerable waste output (20%−25% of crude glycerol) typically landfilled by soy biodiesel plants. In this work, soy MONG was characterized for potential use as a copolymer to produce filaments for 3D printing with an intent to add value and redirect it from landfills. As a copolymer, MONG was evaluated to reduce the synthetic polymer content of the natural fiber composites (NFC). Even though the general thermal behavior of the MONG was compared to that of a thermoplastic polymer in composite applications, it is dependent on the composition of the MONG, which is a variable depending on plant discharge waste. In order to improve the thermal stability of MONG, we evaluated two pretreatments (acid and acid + peroxide). The acid + peroxide pretreatment resulted in a stabilized paste with decreased soap content, increased crystallinity, low molecular weight small chain fatty acids, and a stable blend as a copolymer with a thermoplastic polymer. This treatment increased formic acid (17.53%) in MONG, along with hydrogen peroxide, led to epoxidation exhibited by the increased concentration of oxirane (5.6%) evaluating treated MONG as a copolymer in polymer processing and 3D printing.
Matter organic non-glycerol (MONG) is a considerable waste output (20%−25% of crude glycerol) typically landfilled by soy biodiesel plants. In this work, soy MONG was characterized for potential use as a copolymer to produce filaments for 3D printing with an intent to add value and redirect it from landfills. As a copolymer, MONG was evaluated to reduce the synthetic polymer content of the natural fiber composites (NFC). Even though the general thermal behavior of the MONG was compared to that of a thermoplastic polymer in composite applications, it is dependent on the composition of the MONG, which is a variable depending on plant discharge waste. In order to improve the thermal stability of MONG, we evaluated two pretreatments (acid and acid + peroxide). The acid + peroxide pretreatment resulted in a stabilized paste with decreased soap content, increased crystallinity, low molecular weight small chain fatty acids, and a stable blend as a copolymer with a thermoplastic polymer. This treatment increased formic acid (17.53%) in MONG, along with hydrogen peroxide, led to epoxidation exhibited by the increased concentration of oxirane (5.6%) evaluating treated MONG as a copolymer in polymer processing and 3D printing.
2023, 8(3): 224-234.
doi: 10.1016/j.jobab.2023.03.004
Abstract:
This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method. The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly. Super-high encapsulation efficiency was achieved when a 40% volume fraction of ethanol was used for the microencapsulation procedure, where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3% and 94.3%, respectively. Additionally, considering the operation cost, including time and energy consumption, an economical preparation was validated so that it would be viable for large-scale production. Based on the results of morphological and X-ray diffraction analysis, the crystal structure appeared to differ before and after microencapsulation. The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules. Furthermore, the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object, and the hydrophilic property was proved by a water contact angle measurement.
This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method. The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly. Super-high encapsulation efficiency was achieved when a 40% volume fraction of ethanol was used for the microencapsulation procedure, where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3% and 94.3%, respectively. Additionally, considering the operation cost, including time and energy consumption, an economical preparation was validated so that it would be viable for large-scale production. Based on the results of morphological and X-ray diffraction analysis, the crystal structure appeared to differ before and after microencapsulation. The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules. Furthermore, the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object, and the hydrophilic property was proved by a water contact angle measurement.
2023, 8(3): 235-245.
doi: 10.1016/j.jobab.2023.01.004
Abstract:
In the present study, the hydrolysates generated via autohydrolysis of spruce wood chips were directly used as feedstock for producing coagulants. The in-situ polymerization of acrylamide (AM) and lignocellulose (LC) of hydrolysates was successfully conducted. The reaction was optimized to generate lignocellulose-acrylamide (LC-AM) with the highest molecular weight (41, 060 g/mol) and charge density (–0.25 meq/g) under the optimum conditions, which were 3 h, 60 ℃, 4% (w) initiator based on the dried mass of hydrolysate, and an AM/LC molar ratio of 5.63. A nuclear magnetic resonance (NMR) spectroscopy confirmed the grafting of acrylamide on LC. Other properties of LC-AM were characterized by the elemental analyzer, zeta potential analyzer, gel permeation chromatography (GPC), and particle charge detector (PCD). The LC-AM was applied as a coagulant for removing ethyl violet dye from a simulated dye solution. The results indicated that 47.2% dye was removed from the solution at a low dosage of 0.2 g/g. The dual flocculation of LC-AM with other polymers for dye removal is suggested to further improve its effectiveness.
In the present study, the hydrolysates generated via autohydrolysis of spruce wood chips were directly used as feedstock for producing coagulants. The in-situ polymerization of acrylamide (AM) and lignocellulose (LC) of hydrolysates was successfully conducted. The reaction was optimized to generate lignocellulose-acrylamide (LC-AM) with the highest molecular weight (41, 060 g/mol) and charge density (–0.25 meq/g) under the optimum conditions, which were 3 h, 60 ℃, 4% (w) initiator based on the dried mass of hydrolysate, and an AM/LC molar ratio of 5.63. A nuclear magnetic resonance (NMR) spectroscopy confirmed the grafting of acrylamide on LC. Other properties of LC-AM were characterized by the elemental analyzer, zeta potential analyzer, gel permeation chromatography (GPC), and particle charge detector (PCD). The LC-AM was applied as a coagulant for removing ethyl violet dye from a simulated dye solution. The results indicated that 47.2% dye was removed from the solution at a low dosage of 0.2 g/g. The dual flocculation of LC-AM with other polymers for dye removal is suggested to further improve its effectiveness.
2023, 8(3): 246-264.
doi: 10.1016/j.jobab.2023.04.002
Abstract:
Wood as a material is a natural composite with a complex hierarchically arranged structure. All scale levels of wood structure contribute to its macroscopic mechanical properties. The nature of such characteristics and deformation modes differs radically at different scale levels. Wood macroscopic properties are well studied, and the relevant information can be easily found in the literature. However, the knowledge of the deformation mechanisms at the mesoscopic level corresponding to the cellular structure of early and late wood layers of annual growth rings is insufficient. It hinders building the comprehensive multiscale model of how wood mechanical properties are formed. This paper described the results of scanning of mechanical properties of softwood and hardwood samples, such as common pine, small-leaf lime, and pedunculate oak, by means of nanoindentation (NI). The NI technique allows varying the size of deformed region within a wide range by altering maximal load (Pmax) applied to the indenter so that one can repeatedly and non-destructively test wood structural components at different scale levels on the same sample without changing the technique or equipment. It was discovered that the effective microhardness (Heff) and Young's modulus (Eeff) decreased manifold with Pmax growing from 0.2 to 2 000 mN. This drop in Heff was observed when the locally deformed region grew, and resulting from Pmax increase generally follows the rule similar to the Hall-Petch relation for yield stress, strength, and hardness initially established for metals and alloys, though obviously in those cases the underlying internal mechanisms are quite different. The nature and micromechanisms of such size effect (SE) in wood revealed using NI were discussed in this study. At Pmax < 0.2 mN, the deformed area under the pyramidal Berckovich indenter was much smaller than the cell wall width. Hence, in this case, NI measured the internal mechanical properties of the cell wall material as long as free boundaries impact could be neglected. At Pmax > 200 mN, the indentation encompassed several cells. The measured mechanical properties were significantly affected by bending deformation and buckling collapse of cell walls, reducing Heff and Eeff substantially. At Pmax ≈ 1–100 mN, an indenter interacted with different elements of the cell structure and capillary network, resulting in intermediate values of Heff and Eeff. Abrupt changes in Heff and Eeff at annual growth ring boundaries allow accurate measuring of rings width, while smoother and less pronounced changes within the rings allow identification of earlywood and latewood layers as well as any finer changes during vegetation season. The values of ring width measured using NI and standard optical method coincide with 2%−3% accuracy. The approaches and results presented in this study could improve the understanding of nature and mechanisms lying behind the micromechanical properties of wood, help to optimize the technologies of wood farming, subsequent reinforcement, and utilization, as well as to develop new highly informative techniques in dendrochronology and dendroclimatology.
Wood as a material is a natural composite with a complex hierarchically arranged structure. All scale levels of wood structure contribute to its macroscopic mechanical properties. The nature of such characteristics and deformation modes differs radically at different scale levels. Wood macroscopic properties are well studied, and the relevant information can be easily found in the literature. However, the knowledge of the deformation mechanisms at the mesoscopic level corresponding to the cellular structure of early and late wood layers of annual growth rings is insufficient. It hinders building the comprehensive multiscale model of how wood mechanical properties are formed. This paper described the results of scanning of mechanical properties of softwood and hardwood samples, such as common pine, small-leaf lime, and pedunculate oak, by means of nanoindentation (NI). The NI technique allows varying the size of deformed region within a wide range by altering maximal load (Pmax) applied to the indenter so that one can repeatedly and non-destructively test wood structural components at different scale levels on the same sample without changing the technique or equipment. It was discovered that the effective microhardness (Heff) and Young's modulus (Eeff) decreased manifold with Pmax growing from 0.2 to 2 000 mN. This drop in Heff was observed when the locally deformed region grew, and resulting from Pmax increase generally follows the rule similar to the Hall-Petch relation for yield stress, strength, and hardness initially established for metals and alloys, though obviously in those cases the underlying internal mechanisms are quite different. The nature and micromechanisms of such size effect (SE) in wood revealed using NI were discussed in this study. At Pmax < 0.2 mN, the deformed area under the pyramidal Berckovich indenter was much smaller than the cell wall width. Hence, in this case, NI measured the internal mechanical properties of the cell wall material as long as free boundaries impact could be neglected. At Pmax > 200 mN, the indentation encompassed several cells. The measured mechanical properties were significantly affected by bending deformation and buckling collapse of cell walls, reducing Heff and Eeff substantially. At Pmax ≈ 1–100 mN, an indenter interacted with different elements of the cell structure and capillary network, resulting in intermediate values of Heff and Eeff. Abrupt changes in Heff and Eeff at annual growth ring boundaries allow accurate measuring of rings width, while smoother and less pronounced changes within the rings allow identification of earlywood and latewood layers as well as any finer changes during vegetation season. The values of ring width measured using NI and standard optical method coincide with 2%−3% accuracy. The approaches and results presented in this study could improve the understanding of nature and mechanisms lying behind the micromechanical properties of wood, help to optimize the technologies of wood farming, subsequent reinforcement, and utilization, as well as to develop new highly informative techniques in dendrochronology and dendroclimatology.
2023, 8(3): 265-279.
doi: 10.1016/j.jobab.2023.06.001
Abstract:
It is crucial to adapt the processing of forest bio-resources into biochemicals and bio-based advanced materials in order to transform the current economic climate into a greener economy. Tall oil, as a by-product of the Kraft process of wood pulp manufacture, is a promising resource for the extraction of various value-added products. Tall oil fatty acids-based multifunctional Michael acceptor acrylates were developed. The suitability of developed acrylates for polymerization with tall oil fatty acids-based Michael donor acetoacetates to form a highly cross-linked polymer material via the Michael addition was investigated. With this novel strategy, valuable chemicals and innovative polymer materials can be produced from tall oil in an entirely new way, making a significant contribution to the development of a forest-based bioeconomy. Two different tall oil-based acrylates were successfully synthesized and characterized. Synthesized acrylates were successfully used in the synthesis of bio-based thermoset polymers. Obtained polymers had a wide variety of mechanical and thermal properties (glass transition temperature from –12.1 to 29.6 ℃ by dynamic mechanical analysis, Young's modulus from 15 to 1 760 MPa, and stress at break from 0.9 to 16.1 MPa). Gel permeation chromatography, Fourier-transform infrared (FT-IR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and nuclear magnetic resonance were used to analyse the chemical structure of synthesized acrylates. In addition, various titration methods and rheology tests were applied to characterize acrylates. The chemical composition and thermal and mechanical properties of the developed polymers were studied by using FT-IR, solid-state nuclear magnetic resonance, thermal gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and universal strength testing apparatus.
It is crucial to adapt the processing of forest bio-resources into biochemicals and bio-based advanced materials in order to transform the current economic climate into a greener economy. Tall oil, as a by-product of the Kraft process of wood pulp manufacture, is a promising resource for the extraction of various value-added products. Tall oil fatty acids-based multifunctional Michael acceptor acrylates were developed. The suitability of developed acrylates for polymerization with tall oil fatty acids-based Michael donor acetoacetates to form a highly cross-linked polymer material via the Michael addition was investigated. With this novel strategy, valuable chemicals and innovative polymer materials can be produced from tall oil in an entirely new way, making a significant contribution to the development of a forest-based bioeconomy. Two different tall oil-based acrylates were successfully synthesized and characterized. Synthesized acrylates were successfully used in the synthesis of bio-based thermoset polymers. Obtained polymers had a wide variety of mechanical and thermal properties (glass transition temperature from –12.1 to 29.6 ℃ by dynamic mechanical analysis, Young's modulus from 15 to 1 760 MPa, and stress at break from 0.9 to 16.1 MPa). Gel permeation chromatography, Fourier-transform infrared (FT-IR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and nuclear magnetic resonance were used to analyse the chemical structure of synthesized acrylates. In addition, various titration methods and rheology tests were applied to characterize acrylates. The chemical composition and thermal and mechanical properties of the developed polymers were studied by using FT-IR, solid-state nuclear magnetic resonance, thermal gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and universal strength testing apparatus.
2023, 8(3): 280-291.
doi: 10.1016/j.jobab.2023.04.003
Abstract:
Petroleum-based materials are often used in the packaging industry. However, the single use value of such products can be problematic with regard to proper waste disposal. As such, molded pulp packaging can be used as an alternative, given its ease of recycling, composting, and eventual biodegradation. In this work, we aims to study the pulp properties of sunn hemp and its usage as molded pulp products. For this purpose, unbleached beaten and unbeaten soda pulps derived from the whole stem of sunn hemp were examined for their fiber morphology, fibrillation, fiber classification, and physical properties. The sunn hemp pulp was subsequently molded using a batch molding machine. To determine the hydrophobicity of the molded pulp products, the molded samples were manufactured with and without additives. Finally, some properties of the molded pulp products were examined and compared with the commercially available bleached bagasse molded pulp products. It was observed that the molded products made from sunn hemp pulp with additives had a higher water contact angle than that of the commercial products. In terms of general usage, the molded products from sunn hemp pulp with additives were found to be capable of storing hot water, hot cooking oil, as well as microwaving water. We concluded that the sunn hemp pulp could be used as an alternative fibrous raw material in the production of molded pulp packaging.
Petroleum-based materials are often used in the packaging industry. However, the single use value of such products can be problematic with regard to proper waste disposal. As such, molded pulp packaging can be used as an alternative, given its ease of recycling, composting, and eventual biodegradation. In this work, we aims to study the pulp properties of sunn hemp and its usage as molded pulp products. For this purpose, unbleached beaten and unbeaten soda pulps derived from the whole stem of sunn hemp were examined for their fiber morphology, fibrillation, fiber classification, and physical properties. The sunn hemp pulp was subsequently molded using a batch molding machine. To determine the hydrophobicity of the molded pulp products, the molded samples were manufactured with and without additives. Finally, some properties of the molded pulp products were examined and compared with the commercially available bleached bagasse molded pulp products. It was observed that the molded products made from sunn hemp pulp with additives had a higher water contact angle than that of the commercial products. In terms of general usage, the molded products from sunn hemp pulp with additives were found to be capable of storing hot water, hot cooking oil, as well as microwaving water. We concluded that the sunn hemp pulp could be used as an alternative fibrous raw material in the production of molded pulp packaging.
2023, 8(3): 292-305.
doi: 10.1016/j.jobab.2023.05.002
Abstract:
Boron (B) and nitrogen (N) co-doped 3D hierarchical micro/meso porous carbon (BNPC) were successfully fabricated from cellulose nanofiber (CNF)/ boron nitride nanosheets (BNNS)/ zinc-methylimidazolate framework-8 (ZIF-8) nanocomposites prepared by 2D BNNS, ZIF-8 nanoparticles, and wheat straw based CNFs. Herein, CNF/ZIF-8 acts as versatile skeleton and imparts partial N dopant into porous carbon structure, while the introduced BNNS can help strengthen the hierarchical porous superstructure and endow abundant B/N co-dopants within BNPC matrix. The obtained BNPC electrode possesses a high specific surface area of 505.4 m2/g, high B/N co-doping content, and desirable hydrophilicity. Supercapacitors assembled with BNPC-2 (B/N co-doped porous carbon with a CNF/BNNS mass ratio of 1꞉2) electrodes exhibited exceptional electrochemical performance, demonstrating high capacitance stability even after 5 000 charge-discharge cycles. The devices exhibited outstanding energy density and power density, as well as the highest specific capacitance of 433.4 F/g at 1.0 A/g, when compared with other similar reports. This study proposes a facile and sustainable strategy for efficiently fabrication of rich B/N co-doped hierarchical micro/meso porous carbon electrodes from agricultural waste biomass for advanced supercapacitor performance.
Boron (B) and nitrogen (N) co-doped 3D hierarchical micro/meso porous carbon (BNPC) were successfully fabricated from cellulose nanofiber (CNF)/ boron nitride nanosheets (BNNS)/ zinc-methylimidazolate framework-8 (ZIF-8) nanocomposites prepared by 2D BNNS, ZIF-8 nanoparticles, and wheat straw based CNFs. Herein, CNF/ZIF-8 acts as versatile skeleton and imparts partial N dopant into porous carbon structure, while the introduced BNNS can help strengthen the hierarchical porous superstructure and endow abundant B/N co-dopants within BNPC matrix. The obtained BNPC electrode possesses a high specific surface area of 505.4 m2/g, high B/N co-doping content, and desirable hydrophilicity. Supercapacitors assembled with BNPC-2 (B/N co-doped porous carbon with a CNF/BNNS mass ratio of 1꞉2) electrodes exhibited exceptional electrochemical performance, demonstrating high capacitance stability even after 5 000 charge-discharge cycles. The devices exhibited outstanding energy density and power density, as well as the highest specific capacitance of 433.4 F/g at 1.0 A/g, when compared with other similar reports. This study proposes a facile and sustainable strategy for efficiently fabrication of rich B/N co-doped hierarchical micro/meso porous carbon electrodes from agricultural waste biomass for advanced supercapacitor performance.
2023, 8(3): 306-317.
doi: 10.1016/j.jobab.2023.05.001
Abstract:
Lignin, as a natural antioxidant, shows great potential in food engineering and medicine. However, the inherent macromolecular structure, high polydispersity, and few phenolic hydroxy seriously limit its antioxidant activity. In this work, a mild iodocyclohexane demethylation for highly improving the antioxidant activity of lignin was proposed. The results showed –OCH3 content exhibited an almost linear decrease as a function of treating time, and the demethylation and cleavage of β–aryl ether bonds prompt an obvious increase in phenolic hydroxyl content (4.01 mmol/g) and a significant decline in aliphatic hydroxyl (~0.03 mmol/g). Meanwhile, attributing to the fragmentation of β–O–4, β–β, and β–5 substructures, the polydispersity of lignin molecular weight decreases from 2.7 to 2.2. As a result, the formed catechol-typed lignin showed an outstanding antioxidant activity, with the radical (DPPH·) scavenging index (inverse of concentration for 50% of maximal effect (EC50) value) over 2 000 mL/mg, much superior to the commercial antioxidants (< 500 mL/mg). Further structure-activity relationship analysis implied that the Ph–OH/–OCH3 ratio might act as a key factor influencing the antioxidant activity of lignin. This mild demethylation demonstrates a facile and effective method for highly enhancing the antioxidant activity of lignin and makes the catechol-typed lignin a green and promising product for practical use in food, medicine, and pharmacy.
Lignin, as a natural antioxidant, shows great potential in food engineering and medicine. However, the inherent macromolecular structure, high polydispersity, and few phenolic hydroxy seriously limit its antioxidant activity. In this work, a mild iodocyclohexane demethylation for highly improving the antioxidant activity of lignin was proposed. The results showed –OCH3 content exhibited an almost linear decrease as a function of treating time, and the demethylation and cleavage of β–aryl ether bonds prompt an obvious increase in phenolic hydroxyl content (4.01 mmol/g) and a significant decline in aliphatic hydroxyl (~0.03 mmol/g). Meanwhile, attributing to the fragmentation of β–O–4, β–β, and β–5 substructures, the polydispersity of lignin molecular weight decreases from 2.7 to 2.2. As a result, the formed catechol-typed lignin showed an outstanding antioxidant activity, with the radical (DPPH·) scavenging index (inverse of concentration for 50% of maximal effect (EC50) value) over 2 000 mL/mg, much superior to the commercial antioxidants (< 500 mL/mg). Further structure-activity relationship analysis implied that the Ph–OH/–OCH3 ratio might act as a key factor influencing the antioxidant activity of lignin. This mild demethylation demonstrates a facile and effective method for highly enhancing the antioxidant activity of lignin and makes the catechol-typed lignin a green and promising product for practical use in food, medicine, and pharmacy.
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