UV radiation induced graft copolymerization of allyl acetate onto poly(ethylene terephthalate) (PET) films for fuel cell membranes

Ultraviolet（UV）-induced graft copolymerization of allyl acetate（AA） monomer onto polyethylene terephthalate) （PET） films and the subsequent sulfonation on the monomer units in the grafting chain using chlorosulfonic acid（ClSO₃H） were carried out to prepare proton exchange membranes（PEMs） for fuel cells.A maximum grafting value of 12.8%was found for 35 vol%allyl acetate after 3 h radiation time.Optimum concentration of C1SO₃H was selected for the sulfonation reaction to be 0.05 mol/L based on the degree of sulfonation and the tensile strength studies of the membrane.The degree of sulfonation increased as the sulfonation reaction temperature and sulfonation time were increasing.The radiation grafting and the sulfonation have been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy.The maximum ion exchange capacity（IEC） of 0.04125 mmol g^-1 was found at 12.1%degree of sulfonation and the maximum proton conductivity was found to be 0.035 S cm^-1 at 30℃and a relative humidity of 60%.The various physical and chemical properties of the PEMs such as water uptake,mechanical strength,thermal durability and oxidative stability were also studied.To investigate the suitability of the prepared membrane for fuel cell applications,its properties were compared with those of Nafion 117.     

The energy gap law for triplet states in Pt-containing conjugated polymers and monomers

The energy gap law established for aromatic hydrocarbons and rare earth ions relates the nonradiative decay rate to the energy gap of a transition through a multiphonon emission process. We show that this energy gap law can be applied to the phosphoresce of a series of conjugated polymers and monomers for which the radiative decay rate has been enhanced through incorporation of a heavy metal. We find that the nonradiative decay rate from the triplet state T(1) increases exponentially with decreasing T(1)-S(0) gap for the polymers and monomers at 300 and 20 K. Comparison of the nonradiative decay of polymers with that of their corresponding monomers highlights the role of electron-lattice coupling.     

A new series of luminescent phosphine stabilised platinum ethynyl complexes

A series of cis-platinum ethynyl complexes with the general formula cis-[Pt(dppe)(C[triple bond]CR)2](dppe = 1,2-bis(diphenylphosphino)ethane; R = C6H4-p-NO2 1, C6H4-p-CH3 2, C6H4-p-C[triple bond]CH 3 and C6H4-p-C6H4-p-C[triple bond]CH 4) have been prepared by the coupling reaction of cis-[Pt(dppe)Cl2] with two equivalents of the appropriate alkyne. The new complexes have been fully characterized by spectroscopic techniques, and the cis square planar arrangement at the platinum centre has been confirmed by single-crystal X-ray diffraction studies of complexes 1, 2 and 4. The absorption spectra of the complexes 1-4 are dominated by a pi-->pi* band that contains some platinum (n + 1) p orbital character. The position of the band is dependent on the electron donating or withdrawing properties of the ethynyl substituents, R. Complex 1 displays a triplet emission in the green, at room temperature, while complexes 2-4, display singlet emissions in the blue. Again, the difference can be attributed to the nature of the R substituents.     

Synthesis, characterisation and optical spectroscopy of platinum(II) di-ynes and poly-ynes incorporating condensed aromatic spacers in the backbone

A series of protected and terminal dialkynes with extended pi-conjugation through a condensed aromatic linker unit in the backbone, 1,4-bis(trimethylsilylethynyl)naphthalene, 1,4-bis(ethynyl)naphthalene, 9,10-bis(trimethylsilylethynyl)anthracene, 9,10-bis(ethynyl)anthracene, have been synthesized and characterized spectroscopically. The solid-state structures of and have been confirmed by single crystal X-ray diffraction studies. Reaction of two equivalents of the complex trans-[Ph(Et(3)P)(2)PtCl] with an equivalent of the terminal dialkynes 1,4-bis(ethynyl)benzene and, in (i)Pr(2)NH-CH(2)Cl(2), in the presence of CuI, at room temperature, afforded the platinum(II) di-ynes trans-[Ph(Et(3)P)(2)Pt-C[triple bond, length as m-dash]C-R-C[triple bond, length as m-dash]C-Pt(PEt(3))(2)Ph](R = benzene-1,4-diyl; naphthalene-1,4-diyl and anthracene-9,10-diyl ) while reactions between equimolar quantities of trans-[((n)Bu(3)P)(2)PtCl(2)] and under similar conditions readily afforded the platinum(II) poly-ynes trans-[-((n)Bu(3)P)(2)Pt-C[triple bond]C-R-C[triple bond]C-](n)(R = naphthalene-1,4-diyl and anthracene-9,10-diyl ). The Pt(II) diynes and poly-ynes have been characterized by analytical and spectroscopic methods, and the single crystal X-ray structures of and have been determined. These structures confirm the trans-square planar geometry at the platinum centres and the linear nature of the molecules. The di-ynes and poly-ynes are soluble in organic solvents and readily cast into thin films. Optical spectroscopic measurements reveal that the electron-rich naphthalene and anthracene spacers create strong donor-acceptor interactions between the Pt(II) centres and conjugated ligands along the rigid backbone of the organometallic polymers. Thermogravimetry shows that the di-ynes possess a somewhat higher thermal stability than the corresponding poly-ynes. Both the Pt(II) di-ynes and the poly-ynes exhibit increasing thermal stability along the series of spacers from phenylene through naphthalene to anthracene.     

Molecular characterisation of Bacillus chitinase for bioconversion of chitin waste

In this work chitin was extracted chemically from shrimp shells. Seventeen Bacillus isolates were screened for chitinolytic activity. The chitinolytic strains of Bt. were screened at different temperatures and pHs for their hydrolytic potentials. By using a pair of specific primers, endochitinase gene was amplified from SBS Bt-5 strain through PCR, and then cloned into pTZ57 TA cloning vector and transferred in Escherichia coli DH5α strain. The sequenced gene (GenBank Accession No: HE995800) consists of 2031 nucleotides capable of encoding 676 residues. The protein consisted of three functional domains with a calculated molecular mass of 74.53 kDa and a pI value of 5.83. The amino acid sequence of chi gene showed 99% similarity to the genes of Bt MR11 endochitinase, Bt serovar kurstaki chitinase (kchi), Bt strain MR21 endochitinase and Bacillus cereus B4264.     

On Jordan Triple Higher Derivable Mappings on Rings

Let R be a ring and \({\mathbb{N}}\) be the set of all non-negative integers. A family of maps \({D=\{d_n\}_{n \in\mathbb{N}}}\) is said to be Jordan triple higher derivable if \({d_n(aba)=\sum \nolimits_{p+q+r=n} d_p(a)d_q(b)d_r(a)}\) holds for all \({a,b \in R}\), where d ₀ = I _R , (the identity map on R). In this paper, we determine Jordan triple higher derivable map on a ring R, which contains a nontrivial idempotent which is automatically additive. An immediate application of our main result shows that every Jordan triple higher derivable map becomes higher derivation on R.     

Synthesis of pectin-N,N-dimethyl acrylamide hydrogel by gamma radiation and application in drug delivery (in vitro)

The objective of the work is to synthesize pectin-N, N-Dimethylacrylamide (DMAA) hydrogel by gamma radiation without using any initiators and cross-linking agents. Effect of radiation doses on gel fraction and equilibrium swelling as a function of pH were studied, and 5 kGy radiation dose was found to be the optimum dose for hydrogel synthesis. The grafting /crosslinking was investigated by Fourier transform infrared spectroscopy. Thermal properties and surface morphology were studied by differential scanning calorimetry and scanning electron microscopy. To study the drug release kinetics, 5-fluorouracil was loaded into the hydrogel and in vitro release was carried out in simulated gastric and intestinal fluid. The release profile of drug showed that more than 90% of the loaded drugs were released after 4 hours at both gastric fluid and intestinal fluid pH. Drug release data was fitted into zero order, Higuchi and Korsmeyer-Peppas kinetic models. Higuchi model was found to be the best fitted and release exponent ‘n’ value of Korsmeyer-Peppas model indicated the non-Fickian transport.     

Elemental fingerprint profile of beer samples constructed using 14 elements determined by inductively coupled plasma–mass spectrometry (ICP-MS): multivariation analysis and potential application to forensic sample comparison

Determination of elemental fingerprint profile of 40 commercial beer samples was performed using inductively coupled plasma–mass spectrometry combined with principal component analysis and receiver operating characteristic (ROC) analysis. Fourteen trace elements, ⁵¹V, ⁵²Cr, ⁵⁹Co, ⁶⁰Ni, ⁷⁵As, ⁸²Se, ⁹⁵Mo, ¹¹¹Cd, ¹¹⁵In, ¹²¹Sb, ¹³³Cs, ²⁰⁸Pb, ²⁰⁹Bi, and ²³⁸U, were monitored. All 40 beer samples are distinguishable by using the proposed method. ROC analysis showed that individual beer samples can be correctly identified via the magnitude of its correlation coefficient with respect to the other beers with low false positive rate. The obtained results suggested that the elemental fingerprint technique is feasible for sample differentiation and comparison.