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Trees and Natural Fibers
Published in Antonio Paesano, Handbook of Sustainable Polymers for Additive Manufacturing, 2022
Horst et al. (2016) developed filaments for FFF made of sustainable semi-crystalline TP resins extracted from three trees: (a) Stirax benzoin or benzoin, from India, South-East Asia, Malaysia, and Indonesia; (b) Commiphora myrrha or myrrh, native to the Arabian peninsula and Africa; (c) Boswellia papyrifera or frankincense, growing in Ethiopia, Nigeria, Sudan, and other African countries. The purchased resins, without undergoing any treatment such as purification and distillation, were converted through a Filastruder extruder from powder into a 1.75 mm diameter filament that was processed on a FFF desktop printer at 80−100°C to print tensile and compressive coupons. Table 10.27 lists selected properties and processing settings. The tensile and compressive strength were two orders of magnitude lower than same properties of PLA and ABS, which are the most popular sustainable and non-sustainable filaments for home printing, respectively. Another major drawback was that the filaments were too brittle to be wound on a reel, and were manufactured as 1 m × 1.75 mm sticks. These two shortcomings make these filaments inadequate for load-bearing applications.
Role of Nanobiotechnology in Hydrogels and Their Medicinal Advancements
Published in Anujit Ghosal, Ajeet Kaushik, Intelligent Hydrogels in Diagnostics and Therapeutics, 2020
Shumaila Shaukat, Yinmao Wei, Muhammad Arsalan
Among the different synthetic hydrogels, largely homopolymer hydrogel (Figure 2.2) consisting of:Monomer: (i) poly(2-hydroxyethyl methacrylate) (PHEMA), (ii) 2-hydroxyethyl methacrylate (HEMA), or (iii) polyethylene glycol (PEG).Cross-linker: polyethylene glycol dimethacrylate or triethylene glycol dimethacrylate (TEGDMA).Initiator: benzoin isobutyl ether. They have been largely used in drug delivery systems, scaffolds for protein recombination in tissue engineering, and contact lenses [10, 11.
P
Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
Degassing agents are surface-open agents used in powder coating formulations (use levels 0.2–1.0% by weight).31 The most common degassing agent is benzoin. Benzoin allows films to degas during cure, decreasing porosity and brittleness of the films. The mechanism of this phenomenon is not fully understood.
Spectroscopic evidence of chirality in tetranuclear Cu(II)-Schiff base complexes, catalytic potential for oxidative kinetic resolution of racemic benzoin
Published in Inorganic and Nano-Metal Chemistry, 2021
Dipali Sadhukhan, Prithwi Ghosh, Susanta Ghanta
Enantiopure benzoin is usually synthesized by (i) enzymatic hydrolysis such as benzaldehyde lyase (BAL) or benzoylformate decarboxylase (BFD) enzyme,[32] (ii) multistep enantioselective benzoin condensations by using polycyclic triazolium salt or its analogues as catalysts.[33] Our effort is to synthesize enantioenriched benzoin by a single step and non-enzymatic process. In this article, we report our initial findings regarding chiral Schiff base-Cu(II) complex catalyzed oxidative kinetic resolution of racemic benzoin. (±) Benzoin was reacted with 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and the enantiopure chiral complexes C1 and C2 in the presence of molecular oxygen. The oxidized product benzil is obtained and the unreacted benzoin was recovered in enantiomerically enriched form (Scheme 1). To optimize the reaction conditions we have varied the percentage of TEMPO and the catalysts, solvent, temperature and reaction time as listed in Table S7.
Molecular dynamics simulations of the chiral recognition mechanism for a polysaccharide chiral stationary phase in enantiomeric chromatographic separations
Published in Molecular Physics, 2019
Xiaoyu Wang, David W. House, Priyanka A. Oroskar, Anil Oroskar, Asha Oroskar, Cynthia J. Jameson, Sohail Murad
The paucity of the canonical attractive structures of the type eclipsed face-to-face, parallel-displaced, etc. that we have seen in Figure 7 is likewise found here. The angle distributions are more sharply different between S and R benzoin for those snapshots in which there is at least one hydrogen bond between the drug and the ADMPC, compared to the corresponding plots in Figure 7, which plots are from a uniform sampling of snapshots over the entire trajectory. This indicates that formation of a hydrogen bond between the enantiomer and the ADMPC is often accompanied by preferential distribution of ring-ring angles, signifying that persistent hydrogen bonds are often assisted by ring-ring interactions, and that the hydrogen-bonding and ring-ring orientations are coordinated, despite the encounters being highly dynamic. For the hydrogen-bonded benzoin there is an observed preference for average angles in the vicinity of γ = 10°, θ = 30° for both rings in benzoin and the ADMPC rings. The maps generated for Rcen < 5.0 Å for comparison to Figure 8 have more points, but the highly probable angles shown by the bright regions are unchanged, and no population at all corresponding to the canonical structures, except for occasional observations close to γ = 90°, θ = 90° for ring#1.
P(2-VP) supported Ru(II) material as catalyst for H2 production from the methanolysis of NaBH4
Published in Inorganic and Nano-Metal Chemistry, 2020
Melek Tercan, Elif Karacan Yeldir, Osman Dayan, Ayhan Oral
Benzoin was used as a type I photoinitiator and tetrahydrofuran (THF) was used as solvent in the polymerization of 2-VP. Initiator an amount of 1% of by mass of the monomer was placed into quartz tube and degassed with nitrogen. Than, THF and the monomer, 2-VP, were added into tube under N2 atmosphere. Photopolymerization occured at 310 nm for benzoin. The contains of tube was dissolved in methanol after specified time (1.5, 3, 6, 9, 12 and 24 h). The polymer was precipitated with diethyl ether, than filtered and washed with diethyl ether for three times.