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Mechanism of Cyclocopolymerization
Published in George B. Butler, Cyclopolymerization and Cyclocopolymerization, 2020
A charge-transfer complex has been proposed to explain the rapid cyclization. The charge-transfer complex concept can be applied here with the help of HOMO-LUMO theory to predict the ring structure of the cyclization step. The Mulliken theory of overlapping and orientation principle predicts that stabilization in the molecular complex formation should be determined essentially by the overlap of the donor HOMO and the acceptor LUMO.1-109 By examination of IR and Raman spectra of DVE, the presence of two rotational isomers10 was proposed. The more stable isomer has C symmetry, in which the two vinyl groups, although coplanar, are non-equivalent. The microwave spectrum was examined and assigned to the C conformer.11 A small nonplanarity caused by H-H repulsion between the α hydrogen of the cis-vinyl group and the β hydrogen of the trans-vinyl group was found (Structure 11-18).
Polymers Containing Pendent Pesticide Substituents
Published in Agis F. Kydonieus, Controlled Release Technologies: Methods, Theory, and Applications, 2019
The simplest vinyl derivative of a carboxylic acid is a vinyl ester. These compounds are readily prepared in the laboratory by the mercuric acetate-sulfuric acid catalyzed reaction of the acid with vinyl acetate.1–8 In this reaction the vinyl group in the acetate is transferred to the pesticide replacing the acidic hydrogen.
Emergency Treatment of Marine Oil Spill
Published in Lin Mu, Lizhe Wang, Jining Yan, Information Engineering of Emergency Treatment for Marine Oil Spill Accidents, 2019
Lin Mu, Lizhe Wang, Jining Yan
The synthesis of high oil-absorbing resin is basically divided into three categories: (1) The polymer prepared by cross-linking suspension polymerization of alkyl methacrylate or alkyl styrene monomer. (2) The copolymers prepared by cross-linking copolymerization of monomer with a vinyl group, such as vinyl acetate-vinyl chloride copolymer and alkyl styrene-alkyl acrylate copolymer. (3) Graft copolymers prepared by graft copolymerization of the monomers such as alkyl methacrylate and styrene with natural cellulose. This kind of high oil-absorbing resin has the characteristics of natural polymer and synthetic polymer, and has a good development prospect [191].
Additive manufacturing and characterization of mathematically designed bone scaffolds based on triply periodic minimal surface lattices
Published in Mechanics of Advanced Materials and Structures, 2023
The representative FTIR spectrum of 3D-printed scaffolds composed of soybean resin recorded from 4000 cm−1 to 400 cm−1 is presented in Figure 5. A wide band with maxima at around 3445 cm−1 was attributed to -OH stretching. The typical bands at 2920 cm−1 and 2856 cm−1 were attributed to C-H stretching methyl groups (CH3) of the triglyceride chains and methylene moieties (CH2) in the fatty acid backbone, respectively [41]. The band at 1723 cm−1 was attributed to C = O stretching [42]. A peak for ester carbonyl groups was expected at around 1742 cm−1; however, due to the formation of acrylate esters, a strong peak appeared at 1723 cm−1 [43]. The spectrum showed absorption bands of C = C (acrylate group) at 1637 cm−1 and 810 cm−1 [44]. The small intensity band at 985 cm−1 indicates that the vinyl group (CH2=CH) also remained after UV polymerization [43]. The C–O–C stretching vibration bands were observed at 1236 cm−1 and 1110 cm−1 [45].
Zinc Oxide–Coated Poly(HIPE) Annular Liners to Advance Laser Indirect Drive Inertial Confinement Fusion
Published in Fusion Science and Technology, 2018
Paul Fitzsimmons, Fred Elsner, Reny Paguio, Abbas Nikroo, Cliff Thomas, Kevin Baker, Haibo Huang, Mike Schoff, David Kaczala, Hannah Reynolds, Sean Felker, Mike Farrell, Brian J. Watson
The molecular structure of each foam was verified to ensure correct composition without contamination (Fig. 3). The infrared spectrum of the TPX shows high saturation of aliphatic C-H bonding in the region of 2800 to 3050 cm−1 as expected for a hydrocarbon polymer. Peaks were also observed near 1465, 1384, and 1367 cm−1, which is consistent for 4-methyl-1-pentene.30,31 The spectrum of the poly(HIPE) foam showed the characteristic signature of polystyrene combined with poly(divinylbenzene) with aliphatic interactions of the C-H groups observed in two sets of peaks at 2700 to 2975 and 2975 to 3110 cm−1. Peaks indicating polystyrene were also observed near 1600, 1492, 1452, 757, and 700 cm−1, which were also used to validate the composition of the poly(HIPE).32 The poly(HIPE) spectrum also showed features of poly(divinylbenzene) with additional peaks near 1500 cm−1 and in the region of 650 to 1000 cm−1, which indicate the vinyl group.33,34 FTIR was also attempted on CRF foam but was unsuccessful due to its high opacity to light. The infrared spectra confirmed the correct chemical structure after fabrication.
Phenylboronic acid modified hydrogel materials and their potential for use in contact lens based drug delivery
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Lina Liu, Talena Rambarran, Heather Sheardown
To create an ophthalmic biomaterial containing PBA capable of binding wetting agents and/or releasing ophthalmic drugs, the first step was to functionalize PBA with an acryl group by reacting acryloyl chloride with 3-aminophenylboronic acid. The acryl group of APBA enables it to be copolymerized with other hydrogel monomers, including HEMA, DMA, and NVP, using UV-initiated free radical polymerization. After synthesis of APBA, NMR was used to confirm the attachment of the carbon-carbon double bond to APBA. The successful synthesis of APBA was demonstrated by appearance of the chemical shifts at 5.7, 6.3 and 6.45 ppm, attributed to the three hydrogens of the vinyl group from acryloyl functional group.