Reactive and Functional Polymers (v.68, #4)
Editors and Editorial Board (IFC).
Itaconic acid – grafted – LDPE as compatibilizer for LDPE – plasticized Tapioca starch blends by R.R.N. Sailaja; S. Seetharamu (831-841).
LDPE has been blended with plasticized Tapioca starch with starch loadings varying from 20% to 50%. As the starch loading increases, the mechanical properties reduce and drop down to nearly 30% of that of neat LDPE. In order to enhance the adhesion between starch and LDPE, itaconic acid (naturally obtained during fermentation of sugars) was grafted onto LDPE to obtain LDPE-g-itaconic acid and used as compatibilizer. Addition of this compatibilizer substantially improved the mechanical properties, especially the tensile strength and tensile modulus. Scanning electron micrographs of the blend specimens also supported the above observations. Thermogravimetric analysis was carried out to assess the degradation of blends. Thermal ageing for a short span was also carried out to probe the trend of degradation and its effect on mechanical properties.
Keywords: LDPE; TS; Compatibilizer; Mechanical properties; Degradation; Blends;
Selective mercury uptake by polymer supported hydroxyethyl sulfonamides by Ceren Oktar; Levent Yılmaz; H. Onder Ozbelge; Niyazi Bicak (842-850).
Hydroxyethyl sulfonamide function supported on styrene-divinyl benzene (9% mol/mol) bead resin is presented as mercury selective reagent. The resin product with 3.49 mmol g−1 of 2-hydroxyethyl sulfonamide content removes reasonable quantities of mercuric ions (0.83–1.64 mmol g−1) from aqueous solutions of HgCl2, Hg (CH3COO)2 and Hg (NO3)2, in non-buffered conditions. Experiments showed that, the resin is able to extract mercury selectively, in the presence of foreign ions such as Zn(II), Cd(II), Fe(III), and Pb(II). Only negligible amount of sorption was detected for the case of Fe(III) (0.31 mmol g−1).The loaded resin can be regenerated by HCl solution (2 M) and mercuric ions can be recovered (99% in the first contact) without any hydrolysis. Having advantage of hydrolytic stability of the sulfonamide linkage, the resin presented shows no loss in the capacity after 20 sorption–desorption cycle.
Keywords: Functional resin; Selective extraction; Selective mercury removal; Traces mercury;
About the mode of incorporation of silanol-terminated polysiloxanes into butylene terephthalate-b-dimethylsiloxane copolymers by Vesna V. Antić; Marija V. Vučković; Biljana P. Dojčinović; Mališa P. Antić; Miroljub B. Barać; Milutin N. Govedarica (851-860).
The modality of the incorporation of silanol-terminated siloxanes into copolymers with butylene terephthalate were investigated and determined. Besides siloxanes, the other participants in this well-known copolymerization, called the catalyzed two-step transesterification/polycondensation reaction, are dimethyl terephthalate and 1,4-butanediol. The employed approach to this problem was to exactly examine all the possibilities of the reactions between particular pairs of reactants, as well as of single reactants. The final results were, firstly, that reactions between siloxanes and dimethyl terephthalate did not occur and, secondly, that the only possibility for silanol-terminated siloxanes to be incorporated into the copolymers was by means of their condensation with 1,4-butanediol. This means that siloxanes are incorporated into the copolymer by ether and not by ester linkages.
Keywords: Thermoplastic elastomers; Silanol-terminated siloxanes; Two-step transesterification–polycondensation reaction;
Electrochemical polymerization and spectroscopic investigation of 2-methylindole by Yasemin Arslan Udum; Meltem Düdükcü; Fatih Köleli (861-867).
Synthesis of poly (2-methylindole) (P2MI) was achieved by direct anodic oxidation of 2-methylindole in LiClO4/acetonitrile solution. The P2MI film was generated potentiodynamically between 0.00 V and +1.80 V (vs. Ag/AgCl, saturated KCl). The oxidation of 2-methylindole in this medium was initiated at +0.65 V. The electroactive P2MI film exhibited a good air stability and electrochromic properties. The P2MI film presented an electrical conductivity close to 10−3–10−4 S cm−1. Electrochemical polymerization mechanism of 2-methylindole was proposed as 3–6 linkage sites of the monomer. P2MI film was characterized by cyclic voltammetry, dry conductivity measurements, scanning electron microscopy (SEM) pictures, electron spin resonance (ESR), Fourier transfer infrared (FT-IR) and electrochemical impedance spectroscopies (EIS).
Keywords: Indole; Conducting polymer; Electropolymerization; ESR; EIS;
A carbene insertion approach to functionalised poly(ethylene oxide)-based gels by Anton Blencowe; Chris Blencowe; Kevin Cosstick; Wayne Hayes (868-875).
Carbenes photogenerated from the novel bisdiazirine, 1,3-bis(3-(trifluoromethyl)diazirin-3-yl)benzene 1, have been applied successfully to cross-linking of mono-methyl poly(ethylene oxide) (MePEO5000) in the presence of dichloromethane, leading to the simultaneous incorporation of alkylhalide functionalities. The PEO-based gels swell in a wide range of solvents with polarity index values varying from 3.1 to 9.0. Reaction of the alkylhalide functionalities present in the gels with 4-phenylazophenol provided loading capacities of up to 0.20 mmol g−1 and demonstrated the potential of these materials for gel-phase synthesis applications.
Keywords: Carbene; Diazirine; Poly(ethylene oxide); Gel;
Synthesis, characterization, reactivity and antibacterial activity of new peroxovanadium(V) complexes anchored to soluble polymers by Diganta Kalita; Swapnalee Sarmah; Siva Prasad Das; Diganta Baishya; Ashok Patowary; Sashi Baruah; Nashreen S. Islam (876-890).
New peroxovanadate (pV) complexes anchored to soluble polymers of the type, Na3[V2O2(O2)4(carboxylate)]–PA [PA = poly(acrylate)] (PAV) and Na2[VO(O2)2(carboxylate)]–PMA [PMA = Poly(methacrylate)] (PMAV) have been synthesized from the reaction of V2O5 with H2O2 and the sodium salts of the respective macromolecular ligands at pH ca. 6. The compounds were characterized by elemental analysis, SEM, EDX, TGA and spectral studies. In PMAV, the pV moieties are anchored in monomeric form to the polymer chain through unidentately co-ordinated O (carboxylate) atoms. Carboxylate groups of PA chain co-ordinate to V(V) centres, in a bridging bidentate fashion leading to the formation of dimeric pV structures in PAV. The PAV complex efficiently mediated bromination of organic substrates in aqueous-organic media at ambient temperature. Complex PMAV, was inactive in bromination under analogous conditions. The compounds are relatively resistant to degradation by the enzyme catalase compared to its natural substrate, H2O2. The polymeric complexes along with the free polymer and neat DPV were screened for their antibacterial activity against Staphylococcus aureus and Escherichia coli.
Keywords: Polymer bound peroxovanadate; Dinuclear peroxovanadate; Bromide oxidant; Peroxidative bromination; Antibacterial activity;
Preparation and characterization of an ion exchanger based on semi-carbonized polyacrylonitrile fiber by Sujuan Zhang; Shuixia Chen; Qikun Zhang; Peiyuan Li; Chane Yuan (891-898).
A novel type of weakly acidic cation exchange fiber (SC-IEF) was prepared by oxidizing the semi-carbonized polyacrylonitrile fiber (SC-PAN) with nitric acid solution. The physicochemical properties and adsorption performance of SC-IEF were characterized. Effects of the temperature, reaction time, concentration and dosage of nitric acid on the oxidation process of SC-PAN were studied. The experimental results indicate that the SC-IEF prepared shows higher thermal stability than conventional ion exchange fiber based on the hydrolysis of polyacrylonitrile. The content of the surface oxygen-containing groups on SC-IEF is up to 3.78 mmol/g. The static adsorption capacities of SC-IEF for Pb2+, Cu2+ and Mg2+ ions are 25.4, 8.2 and 4.5 mg/g, respectively, which reveals an excellent adsorption property of this novel ion exchange fiber. SC-IEF also shows an excellent selectivity for the adsorption of Pb2+ ions with the coexistence of Cu2+ and Mg2+ ions in the solution.
Keywords: Cation exchange fibers; Semi-carbonized polyacrylonitrile fiber; Adsorption; Metal ions;
Synthesis of high selectivity polymeric adsorbent and its application on the separation of ginkgo flavonol glycosides and terpene lactones by Ping Ren; Xiaolin Zhao; Jing Zhang; Rongfu Shi; Zhi Yuan; Chunhong Wang (899-909).
A kind of weak hydrophobic adsorbent with functional group was synthesized. The relationship between the structure of the adsorbents and their adsorption properties was investigated in detail. With decrease of the content of non-polarity moiety in the adsorbent, i.e. divinylbenzene (DVB), the hydrophobic affinity of the adsorbent decreased. And then the adsorbent with appropriate DVB moiety content and functional group, i.e. amide group, can selectively adsorb flavonol glycosides based mainly on the synergistic mechanism of hydrogen bonding and weak hydrophobic interaction, while showing a fairly low adsorption capacity for terpene lactones by very weak hydrophobic affinity alone. In this study it was found that the adsorbent with amide group containing 8% DVB moiety would be favorable to separate the flavonol glycosides and terpene lactones in the extract of ginkgo leaves. After the adsorption and desorption process, the ratio of the weight of flavonal glycosides and terpene lactones in desorption solution was improved from 3.94:1 to 99.3:1, and the ratio of the weight of flavonal glycosides and terpene lactones in effluent solution was reduced from 3.94:1 to 0.114:1. The FTIR spectrum also verified the existence of the hydrogen bonding interaction between the adsorbent and the flavonol glycosides, just as expected. The adsorption mechanism was indicated to be the synergistic effect of the hydrogen bonding and the hydrophobic interaction.
Keywords: Hydrophobic interaction; Hydrogen bonding; Synergistic effect; Terpene lactones; Flavonol glycosides;
Photorefractivity of Poly[methyl(3-phenothiazine-10-ylpropyl) siloxane] doped with chromophore and C60 by In Kyu Moon; Chil-Sung Choi; Nakjoong Kim (910-914).
A novel hole-transporting poly[methyl(3-phenothiazine-10-ylpropyl)siloxane] (PSX-PTZ) was synthesized by a post hydrosililation and it showed low glass transition temperature (T g). The 50 μm thick PR material containing 30 wt.% nonlinear optical chromophore (PSX-PTZ composite) has several attractive feature when compared to the poly(N-vinylcarbaz)-based composite, including no need for additional plasticizers. PSX-PTZ composite showed a diffraction efficiency 67% at 30 V/μm, which corresponded to a speed of 4.2 s.
Keywords: Phenothiazine; Polysiloxane; Photogeneration efficiency; Photoconductivity; Photorefractive;