H NMR characterization of copolymerization reactions of various 2-oxazoline monomers at different molar ratios offers detailed insight into the build-up and composition of the polymer chains. Various 2-oxazolines were copolymerized in one single solvent, butyronitrile, with 2-dec-9'-enyl-2-oxazoline, where the double bond allows for post-polymerization modification and can function as a crosslinking unit to form polymer networks. The types of the monomers and their molar ratios in the feed have a strong effect on the microstructure of the forming copolymer chains. Copolymers comprising 2-dec-9'-enyl-2-oxazoline and either 2-ethyl-, 2-isopropyl-, 2-butyl-, 2-heptyl, 2-nonyl- or 2-phenyl-2-oxazoline, show significant differences in sequential structure of copolymers ranging from block to gradient and random ordering of the monomer units. H NMR was found to be a powerful tool to uncover detailed oxazoline copolymerization kinetics and evolution of chain composition.
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http://dx.doi.org/10.1039/d1ra01509e | DOI Listing |
J Dent (Shiraz)
December 2024
Dept. Conservative Dentistry and Endodontics, St.Joseph Dental College, Duggirala, Eluru, Andra Pradesh, India.
Statement Of The Problem: Dentin bonding with etch-and-rinse adhesives involves demineralizing the 5-8µm of the surface dentin to create micro space for resin infiltration. The presence of continuous fluid movement in dentin tubules and positive pulpal pressure prevents complete water replacement by resin monomers. This results in areas of demineralized dentin, which contain collagen fibers without resin infiltration.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Polymer Reaction Design Group, School of Chemistry, Monash University, 19 Rainforest Walk, Building 23, Clayton, VIC 3800, Australia.
A continuous flow setup comprising an inline dialysis unit for immediate monomer removal is used for the depolymerization of poly(methyl methacrylate) (pMMA), synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The approach used allows one to carry out solution depolymerizations at much higher polymer content compared to batch processes while maintaining high depolymerization conversions. pMMA is efficiently depolymerized in the flow reactor, yielding up to 68% monomer recovery under catalyst-free reaction conditions at 160 °C, starting from a 1 molar repeat unit concentration, which is a 20-fold improvement compared to previous batch studies.
View Article and Find Full Text PDFLangmuir
December 2024
International College of Arts and Science, Fukuoka Women's University, Kasumigaoka 1-1-1, Higashi-ku, Fukuoka 813-8529, Japan.
In this paper, we proposed a thermodynamic procedure to evaluate binary surfactant mixed adsorbed film and mixed micelle compositions above critical micelle concentrations. This theory first calculates the change in the molar ratio of two surfactants in monomer and micelle states based on the phase-separation model and then imposes the chemical equilibrium between the mixed adsorbed film and mixed micelle of known composition and concentration. We applied this theory to a cationic-nonionic surfactant mixed system, and the relationship between the calculated mixed adsorbed film composition and foam film stability was discussed using the DLVO theory.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Hajduk Veljka 3, 21000 Novi Sad, Serbia.
Bile acid salts are steroid biosurfactants that build relatively small micelles compared to surfactants with an alkyl chain due to the rigid conformation of the steroid skeleton. In order to increase the capacity of micellar solubilization of the hydrophobic molecular guest, certain C7 alkyl derivatives were synthesized. Namely, introducing an alkyl group in the C7 position of the steroid skeleton results in a more effective increase in the micelle's hydrophobic domain (core) than the introduction in the C3 position.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
National and Local Joint Engineering Research Center for Advanced Packaging Materials and Technology, Key Laboratory of Advanced Packaging Materials and Technology of Hunan Province, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, China.
The market demand for black polyimide (BPI) has grown hugely in the field of flexible copper-clad laminates (FCCLs) as a replacement for transparent yellow polyimide. The 3,6-bis(thiophen-2-yl)diketopyrrolopyrroles (TDPP) derivative is recognized for its high molar extinction coefficient. In this research, we have synthesized a diamine monomer named 3,6-bis[5-(4-amino-3-fluorophenyl)thiophen-2-yl]-2,5-bis(2-ethylhexyl)pyrrolo[4,3-c]pyrrole-1,4-dione (DPPTENFPDA), featuring a TDPP unit attached by fluorinated benzene rings.
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