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, Available online , 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.
, Available online , 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.
, Available online , doi: 10.1016/j.jobab.2023.03.004
Abstract:
This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized coprecipitated 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 coprecipitated 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.
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