25189-84-8Relevant articles and documents
The reaction of perfluoro-2,5-diazahexane 2,5-dioxyl with alkenes
Green, Michael J.,Tipping, Anthony E.
, p. 115 - 126 (1993)
The liquid-phase reaction at room temperature of the title dioxyl (1) with an excess of the alkenes CH2=CHR (R = H, F, COCl), CF2=CHF, CHCl=CCl2 and cis-CHCl=CHCl gives 1:1 copolymers 3 in high yield, although with the alkenes CH2=CH2, CH2=CHF and CF2=CHF cyclic 1:1 adducts 2 are also formed in low yield.The reactions with the alkenes CH2=CMe2, CH2=CHEt, CH2=CHCO2H, and cis-HO2CCH=CHCO2H produce copolymers which are not 1:1 copolymers.The 1:1 copolymer 3f from acryloyl chloride is hydrolysed readily by water to the acrylic acid/dioxyl 1 1:1 copolymer 3j.Gas-phase reaction at room temperature of 1 with an excess of the alkenes CH2=CHR (R=Cl, Br, COCl, COF), CH2=CXCH3 (X = Cl, Br), CHCl=CCl2, cis- and trans-CHCl=CHCl, CH2=CCl2, CF2=CCl2, CF2=CFCl and CF2=CFBr affords cyclic 1:1 adducts 2 (11.5-78percent) and copolymers 3 (18.5-76.5percent): hydrolysis of the acryloyl fluoride 1:1 adduct 2j gives the acrylic acid 1:1 adduct 2s in high yield.
Modified chitosan for the collection of reactive blue 4, arsenic and mercury from aqueous media
Dhanapal,Subramanian
, p. 123 - 132 (2015)
In the present investigation a series of modified chitosan as adsorbents were synthesized free radically at 70°C using acryloylated chitosan (AC-chitosan) as macromer, 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS), 2-(diethylamino) ethylmethacrylate (DAEMA) as co-monomers and N,N'-methylenebisacrylamide (N-MBA) as a crosslinker for using as adsorbents in effluent remediation. Their structures(1H and13C NMR), thermal stability (TG/DTG), surface morphology (SEM), reactive blue 4 (RB4), toxicmetals such as arsenic (AsO2-) and mercury (Hg2+) uptake, swellability and reusability were evaluated.The adsorption of RB4 (701 mg/g), and the uptake of AsO2- (551 mg/g) and Hg2+ (455 mg/g) showed Lang-muir isotherm behavior with pseudo-first-order kinetics. The diffusion of water, RB4, AsO2- and Hg2+ into the matrix followed non-Fickian mechanism. The evaluated changes in Gibbs free energy (δG°), entropy(δS°) and enthalpy (δH°) for adsorption indicated that the process was exothermic..
The molecular design of photo-curable and high-strength benzoxazine for 3D printing
Lu, Yong,Ng, Kok Wei Joseph,Chen, Hui,Chen, Xuelong,Lim, Song Kiat Jacob,Yan, Weili,Hu, Xiao
, p. 3375 - 3378 (2021)
Low viscosity photo-curable benzoxazines (BZs) are designed and synthesized for use in stereolithography 3D printing. An initial investigation shows that the thermally polymerized polybenzoxazines (PBZs) have remarkably highTg(264 °C) and flexural modulus (4.91 GPa) values. Subsequently, the formulated photoprintable resins are employed for use in high-resolution projection micro-stereolithography (PμSL) printing. Complex PBZ 3D structures can be achieved from the as-printed objects after they are thermally treated. These findings advance the design of BZ monomers for photopolymerization-based 3D printing and offer a method for the efficient fabrication of high-performance thermosets for various demanding engineering applications.
Fluorescence probe studies on the complexation between poly(methacrylic acid) and poly(N, N-diethylacrylamide)
Liu, Shouxin,Fang, Yu,Gao, Gailing,Liu, Mingzhu,Hu, Daodao
, p. 887 - 892 (2005)
The complexation between poly(methacrylic acid) (PMAA) and poly(N, N-diethylacrylamide) (PDEAM) in aqueous phase was studied by UV-vis and fluorescence probe techniques. It was demonstrated that the complexation of PMAA with PDEAM occurs within a pH range of 1-6.5 and along with the complexation, the conformation of PMAA changed from a hypercoiled to a loose coiled form. The complex ratio between the two polymers is 1:1 (PMAA:PDEAM, in monomer unit). Salt effect studies showed that the complexation occurred due to formation of hydrogen bonds between the two polymers. Based upon these conclusions and the "compact micelle-like structure" for PMAA at low pH, a "ladder" model was proposed for the structure of PMAA-PDEAM complex formed at low pH.
Synthesis of sulfonated cholesterol derivatives - Electrical, thermal, and optical properties
Hoque, Samiul,Dass, Narendra Nath,Bhattacharyya, Krishna Gopal,Sarma, Neelotpal Sen
, p. 149 - 162 (2014)
Poly(cholesterylacrylatesulfone) (PCHAS) and poly(cholesterylacrylatesulfone-co-1-hexene)s (PCHASHs) at different ratios are synthesized from the monomer cholesteryl acrylate. The liquid crystalline phases are observed under a hot stage fitted with a polarizing optical microscope. The polysulfone and copolysulfones are characterized by FT-IR, 1H-NMR, DSC, and TGA techniques. From SEM (EDX) the qualitative amounts of elemental sulfur found in PCHAS and PCHASH11 are 2.90 weights (%) and 4.39 weights (%), respectively. The GPC data using THF as the solvent shows that the number average molecular weight of the PCHAS is 5268 g/mol and the molecular weights of the PCHASHs are higher than the PCHAS. Copyright Taylor & Francis Group, LLC.
Synthesis, characterization and ionic conductivity of supramolecular structure of uracil-functionalized PEG/LiClO4 blend system
Rajendran,Jaisankar
, p. 646 - 648 (2015)
In this paper, the synthesis and ionic conductivity behaviour of supramolecular structure based end group functionalized poly(ethylene glycol) with uracil are reported. The uracil (U) functionalized poly(ethylene glycol) (PEG), (U-PEG-U) was synthesised through Michael addition. The synthesized polymer electrolyte was characterized by Fourier-transform infrared and nuclear magnetic resonance spectral methods. Further, we described the interaction behaviour of synthesized polymer electrolyte with Li+ ions. Differential scanning calometry and FTIR studies demonstrates that the significant ability of functionalized poly(ethylene glycol) to donate its electron to coordinate with lithium ion. It is further observed that the ionic conductivity of polymer electrolyte is not only dependent on the electron donation strength of carbonyl group, but also on the molecular structure of polyester.
Role of hydrophobicity on structure of polymer-metal complexes
Varghese, Shyni,Lele, Ashish K.,Srinivas,Mashelkar, Raghunath A.
, p. 5368 - 5373 (2001)
Metal complexation of a series of polymeric gels, with different degrees of ionization, prepared from acrylic acid and acryloyl amino acid monomers (CH2=CHCONH(CH2)nCOOH, where n = 4, 6 and 8), were investigated. The binding of Cu(II) ions to the gels was studied by means of swelling, quantitative determination of the amount of "bound" or complexed Cu(II), and EPR spectroscopy of Cu(II) complexes. Both the amount of Cu(II) and the structure of polymer-Cu(II) complex were influenced by the length of the pendent chain, i.e., "hydrophobicity" of the polymer gels. The metal uptake by the gels increases with increasing "hydrophobicity". Two types of polymer-Cu(II) complexes (monomer and dimer, respectively) were identified by EPR spectroscopy, their concentrations were found to be a function of hydrophilic-hydrophobic balance of the polymer gels.
Fabrication of poly[zinc aerylate-co-acrylic poly(ethylene glycol) ester] Nanoflbers
Zhao, Qingchun,Xu, Ling
, p. 378 - 379 (2009)
In this paper, we report a facile chemical route to fabricate polymer nanofibers under ambient conditions using aqueous/organic polymerization. The chemical structures of obtained polymers were investigated by infrared spectra and 1H NMR. Scanning electron microscopy (SEM) observation shows poly[zinc acrylate-co-acrylic poly(ethylene glycol) ester] nanofibers with average diameter 100-140 nm and several micrometers length. A possible mechanism for the formation of polymer nanofibers was investigated. Copyright
Molecular tailoring of thermoreversible copolymer gels: Some new mechanistic insights
Badiger,Lele,Bhalerao,Varghese,Mashelkar
, p. 1175 - 1184 (1998)
We earlier reported the role of hydrophobic and hydrogen bonding interactions on the transition temperatures of thermoreversible copolymer gels. We show here that the chemical structure of the hydrophobe and its concentration determine the transition temperatures [lower critical solution temperature (LCST)] and the heat of transition of new hydrophobically modified poly(N-isopropyl acrylamide) [PNIPAm] copolymer gels. The gels, prepared by copolymerizing NIPAm monomer with hydrophobic comonomers containing increasing lengths of alkyl side groups and a terminal carboxyl acid group, showed lower LCST and lower heat of transition when compared to pure PNIPAm gel. The experimental results were also compared with theoretical calculations based on a lattice-fluid-hydrogen-bond [LFHB] model. We show experimentally and theoretically that a linear correlation exists between the transition temperature and length of the hydrophobic alkyl side group. Also, in apparent contradiction to previous work, we found a reduction in the heat of transition with increasing hydrophobicity. We propose that the presence of the terminal carboxyl acid group on the hydrophobic side chain of the comonomer prevents the association of water molecules around the hydrophobe, thereby causing a reduction in the heat of transition. The LFHB model supports this argument.
Asymmetric Allylation Catalyzed by Chiral Phosphoric Acids: Stereoselective Synthesis of Tertiary Alcohols and a Reagent-Based Switch in Stereopreference
Lazzarotto, Mattia,Hartmann, Peter,Pletz, Jakob,Belaj, Ferdinand,Kroutil, Wolfgang,Payer, Stefan E.,Fuchs, Michael
supporting information, p. 3138 - 3143 (2021/04/28)
The substrate scope of the asymmetric allylation with zinc organyls catalyzed by 3,3-bis(2,4,6-triisopropylphenyl)-1,1-binaphthyl-2,2-diyl hydrogenphosphate (TRIP) has been extended to non-cyclic ester organozinc reagents and ketones. Tertiary chiral alcohols are obtained with ee's up to 94% and two stereogenic centers can be created. Compared to the previous lactone reagent the stereopreference switches almost completely, proving the fact that the nature of the organometallic compound is of immense importance for the asymmetry of the product. (Figure presented.).
