Poly thermoreversible

Yamauchi K, Lizotte JR, Long TE. Thermoreversible poly(alkyl acrylates) consisting of self-complementary multiple hydrogen bonding. Macromolecules 2003 36 1083-1088. 

Inoue K, Yamashiro M, Iji M (2009) Recyclable shape-memory polymer poly(lactic acid) crosslinked by a thermoreversible Diels-Alder reaction. J Appl Polym Sci 112 876-885... 

Modification of macromolecular material properties by hydrogen bond formation has been demonstrated at the example of thermoreversible networks Stadler modified poly(butadiene) elastomers with urazole groups to introduce hydrogen-bonded cross-links into the system. In fact, thermoreversible cross-linking appeared due to the urazol-urazole molecular recognition, causing intermolecular cross-links [408,467]. The group of Meijer expanded the approach by the synthesis of two... 

Recently, alkyl chain substituted main chain poly(hydrazides) were synthesized, exhibiting a hexagonally ordered eolumnar mesophase. In this polymer always two hydrazide-monomers are jointed together via hydrogen bonds and eonsequently the compound has to be considered as a thermoreversible highly eross-linked network [411]. 

Used to render surfaces biocompatible and resistant to protein adhesion copolymers with poly(propylene oxide) form thermoreversible gels for drug delivery... 

Takeda M, Norisuye T, Shibayama M (2000) Critical dynamics of cross-linked polymer chains near the gelation threshold. Macromolecules 33 2909-2915 Te Nijenhuis K (1997a) Thermoreversible networks. Introduction. Adv Polym Sci 130 1-12 Te Nijenhuis K (1997b) Thermoreversible networks. Gelatin. Adv Polym Sci 130 160-193 Theiss D, Schmidt T, Dorschner H, Reichelt R, Arndt K-F (2005) Filled temperature-sensitive poly(vinyl methyl ether) hydrogels. J Appl Polym Sci 98 2253-2265 Toomey R, Freidank D, Riihe J (2004) Swelling behavior of thin, surface-attached polymer networks. Macromolecules 37 882-887... 

M.B. Huglin, Y. Liu and J.L. Velada, Thermoreversible swelling behavior of hydrogels based on /V-isopropylacrylamide with acidic comonomers, Polymer, 1997, 38, 5785 M.K. Yoo, Y.K. Sung, C.S. Cho and Y.M. Lee, Effect of polymer complex formation on the cloud-point of poly(JV-isopropylacrylamide) (PNIPAAm) in the poly(NIPAAm-co-acrylic acid) polyelectrolyte complex between poly(acrylic acid) and poly(ally-lamine), Polym., 1997, 38, 2759. 

Jeong B, Lee DS, Shon J-i, Bae YH, Kim SW. Thermoreversible gelation of poly(ethylene oxide) biodegradable polyester block copolymers. J Polym Sci A 1999 37 751-760. 

You Y, Chen Y, Hua C, Dong C (2010) Synthesis and thermoreversible gelatirai of dendron-like polypeptide/linear poly(8-caprolactraie)/dendron-like polypeptide triblock copolymers. J Polym Sci A Polym Chem 48 709-718... 

Lin, H. H. Cheng, Y. L. (2001) In-situ thermoreversible gelation of block and star copolymers of poly(ethylene glycol) and poly(N-isopropylaciylamide) of varying architectures. Macromolecules, 34, 3710-3715. 

Shim, M.S. et al, 2002. Poly(D,L-lactic acid-co-glycoUc acid)-b-poly(ethylene glycol)-b-poly (D,L-lactic acid-co-glycolic acid) triblock copolymer and thermoreversible phase transition in water. Journal of Biomedical Materials Research, 61, 188-196. 

Lee, JW Hua, FJ Lee, DS. Thermoreversible gelation of biodegradable poly(e-caprolaetone) and poly(ethylene glycol) multiblock copolymers in aqueous solutions. J Control Rel, 2001, 73, 315-327. 

No.17, 24th Aug.1999, p.5552-60 RAMAN SPECTROSCOPIC CHARACTERISATION OF ASSOCIATION AND THERMOREVERSIBLE GELATION IN AQUEOUS SYSTEMS OF POLY(N-ACETAMIDOACRYLAMIDE)... 

A study was made of self-association and thermoreversible gelation in aqueous solutions of poly(N-acetamidoacrylamide) using Raman spectroscopy. The presence of polymer-polymer coordination was observed even at low concentrations, indicating polymer cluster formation. The influence of sodium thiocyanate, as denaturant, on intermolecular and intramolecular interactions was also examined and the effects of polymer concentration, level of denaturant addition and type of solvent, on gel formation evaluated. 41 refs. 

Thermoreversible gelation of rigid rod-like and semirigid polymers 13.2 POLY(AMINO ACID)S... 

Hot (100 C) 97% sulfuric acid is a good solvent for poly(p-phenylenebenzobisthiazole) (PBT) (Figure 13.5). A drastical drop in the solvent power is achieved by a decrease in temperature which causes thermoreversible gelation of the system [47]. The formation of a porous structure from a uniform, homogeneous, isotropic solution has been observed. Indications were found that the gel melting temperature increases with concentration and molecular weight of PBT. 

Winnik [49] used fluorescence measurements of transfer of the electronic excitation between donor-naphthalene and acceptor-pyrene chromophores attached to the same polymer chain for studies of thermoreversible phase separation of aqueous solutions of poly(N-isopropylacrylamide) (PNIPAM). Dilute solutions of the doubly labelled polymer PNIPAM were heated from 277 K to 313 K, and the fluorescence emission intensity of pyrene (integrated spectrum) was measured when the system was excited with 290 nm, donor excitation, and when excited with 328 nm, acceptor excitation. Non radiative energy transfer between excited naphthalene and pyrene occurred in aqueous solution of the polymer. The increase in intensity of pyrene fluorescence when the solution was excited at 290 nm, shown in Figure 4.13, is due to a phase separation process at lower critical solution temperature (LCST). When the LCST was reached, the phase separation into polymer-rich and polymer-lean phases occurred. It was concluded that the collapse of the polymer chain leading to densification of polymer phase is followed by domination of intramolecular contributions to the energy transfer process. 

NAK Nakano, S., Ogiso, T., Kita, R., Shinyashiki, N., Yagihara, S., Yoneyama, M., and Katsumoto, Y., Thermoreversible gelation of isotactic-rich poly(iV-isopropylacrylamide) in water, J. Chem. Phys., 135, 114903, 2011. 

It is well-known that many polymers, synthetic and natural, form physical, thermoreversible aggregates in dilute solutions, whereas in moderately concentrated solutions gels can be formed. Examples are poly(vinyl chloride), polyacrylonitrile, poly(vinyl alcohol), atactic polystyrene, mixtures of syndiotactic and isotactic poly(methyl methacrylates), liquid crystalline polymers, gelatin, agarose, carrageenans etc. 

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