28537-73-7Relevant academic research and scientific papers
Reversible polymer composition
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Page/Page column 10, (2015/02/25)
A composition includes a reversible polymer material, which can reversibly transition between a liquid state and a solid state by reversible cycloaddition reactions, wherein upon cooling, the reversible polymer material transitions from a liquid state to a solid state by reversible cycloaddition reactions within a time period of less than about 10 seconds.
Investigation of the thermal self-healing mechanism in a cross-linked epoxy system
Bai, Nan,Simon, George P.,Saito, Kei
, p. 20699 - 20707 (2013/11/06)
The mechanism of self-healing of a cross-linked epoxy system based on the diglycidyl ether of bisphenol A (DGEBA) and a new diamine cross-linker with two Diels-Alder (DA) adducts has been investigated. The location of the DA adducts on the diamine means that the cross-linker is the structural element that can be thermally cleaved and reformed, thereby allowing the cross-linked polymer to flow and fill or heal cracks and scratches. Since the stimulus for opening up the cross-linked network to allow flow and heal is heat, the temperature of the original network cure also becomes an important variable, and in this work different curing conditions have been explored to find suitable curing conditions which can cause the epoxy-amine to react, whilst avoiding initial scission of the DA adducts. The thermal self-healing mechanism of cured samples was studied by following the effect of scission on a range of properties such as the chemistry of the adducts, the glass transition of the polymer network, the size of units into which the network fragments upon scission and the ability of the network to swell. The appropriate conditions required to heal surface scratches of a micrometre size-scale were also studied. The Royal Society of Chemistry 2013.
Effect of spacer chemistry on the formation and properties of linear reversible polymers
Mayo, James D.,Adronov, Alex
, p. 5056 - 5066 (2013/11/06)
A series of four pairs of bismaleimide and bisfuran monomers were combined to make thermally reversible linear polymers. The monomers were prepared using diamines having different spacer chemistries, n-octyl, cyclohexyl, phenyl, and ethylenedioxy, such that a relatively constant spacer dimension among the four monomers was achieved. Heating of the bismaleimide/bisfuran couples resulted in low-viscosity, easily processable liquids. Subsequent cooling to room temperature resulted in the formation of hard films, with the rate of hardening varying significantly within the series of compounds. The rate and degree of polymerization were determined using 1H NMR spectroscopy and were both found to be dependent on the chemistry of the spacer group, as was the film rheology, which was measured using nanoindentation. Adhesion of the polymers was quantified by measurement of their tensile adhesive strength, and this was also found to be spacer dependent. Polymerization reversibility was verified using 1H NMR spectroscopy. Copyright
An efficient reverse Diels-Alder approach for the synthesis of N-alkyl bismaleimides
Rao, Venkataramanarao,Navath, Suryakiran,Kottur, Mohankumar,McElhanon, James R.,McGrath, Dominic V.
, p. 5011 - 5013 (2013/09/02)
Bismaleimides are useful precursors for Diels-Alder reactions, Michael additions, and thiol-maleimide based conjugation for the synthesis of materials and polymers. Use of bismaleimide cross linkers for generating polymers, bioconjugate molecules, and useful imaging molecules is an active area of research. An efficient and practical synthetic protocol for N-alkyl bis-maleimide cross linkers starting from furan protected maleimide employing a reverse Diels-Alder reaction is reported.
A New Class of Bradykinin Antagonists: Synthesis and in Vitro Activity of Bissuccinimidoalkane Peptide Dimers
Cheronis, John C.,Whalley, Eric T.,Nguyen, Khe T.,Eubanks, Shad R.,Allen, Lisa G.,et al.
, p. 1563 - 1572 (2007/10/02)
A systematic study on the dimerization of the bradykinin (BK) antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe7-Leu8-Arg9 has been performed.The first part of this study involved compounds wherein dimerization was carried out by sequentially replacing each amino acid with cysteine and cross-linking with bismaleimidohexane.The second part of this study utilized a series of bissuccinimidoalkane dimers wherein the intervening methylene chain was varied systematically from n = 2 to n = 12 while the point of dimerization was held constant at position 6.The biological activities of these dimers were then evaluated on BK-induced smooth muscle contraction in two different isolated tissue preparations: guinea pig ileum (GPI) and rat uterus (RU).Several of the dimeric BK antagonists displayed remarkable activites and long durations of action.In addition, dimerization at position 4, 7, 8, or 9 produced dimeric analogues with markedly reduced potency.Rank order of antagonist potency as a function of dimerization position is as follows: rat uterus, 6 > 5 > 0 > 2 > 1 >3 >> 4, 7, 8, 9; guinea pig ileum, 6 > 5 > 3 > 2 > 1 > 0 >> 4, 7, 8, 9.Evaluation of the linker length as represented by the number of methylene units indicated an optimal distance between the two monomeric peptides of six to eight methylene moieties.These studies also revealed that the carbon-chain length significantly affected the duration of action in vitro and resulted in partial agonism effects when n > 8.The optimum activity in vitro was achieved with dimerization at position 6 and n = 6 (designated herein as compound 25; alternatively, CP-0127).Similar effects in potency were also seen when the monomeric antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe7-Phe8-Arg9 (NPC-567) was dimerized using similar chemistry.These results suggest that the development of BK antagonists of significant therapeutic potential may be possible using a dimerization strategy that can overcome the heretofore limiting problems of potency and in vivo duration of action found with many of the BK antagonists in the literature.
