Polymer Bulletin

It was found that the drift mobility of carriers in tetracene and p-quaterphenyl polycrystalline layers is dependent on electric field. A simple model to explain the dependence is presented in this paper.

We present the results of a calculation of the spin-lattice and spin-spin relaxation for dipolar solid when it is irradiated by the WAHUHA and MREV-8 pulse sequences. The spin-spin relaxation rate which is determined by the second-order dipolar interaction term of the average Hamiltonian depends on thermal motion of four atoms. It has been shown that from the temperature dependence of this relaxation rate the degree of correlated atomic motion can be estimated.

This paper describes the theoretical comparison of the reactivity as comonomers of some nitrogen-containing monomers. Theoretical calculations of monomers commonly used as comonomer in preparation of micro- or nano-gels were carried out by using CAM-B3LYP/6-31+G and B3LYP/6-311G+ (d,p) basis sets of density functional theory. The vibrational frequencies and chemical shifts were calculated by both methods and compared with each other. VEDA 4 program was used for detailed frequency analysis. HOMO and LUMO analysis, electronic properties and NBO analysis are also determined using the same methods and compared. NBO analysis confirms the delocalization of electron density within the monomers. In addition, molecular electrostatic potential maps were generated for each monomer to identify reactive regions. Finally, thermodynamic functions and Mulliken atomic charges were calculated, and the results calculated by both methods matched well.

The synthesis and thermal as well as proton conducting properties of complex polymer electrolytes based on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) PAMPS and poly(1-vinyl-1,2,4-triazole) PVTri were investigated. The materials were produced by complexation of PAMPS with PVTri at various compositions to get PVTriP(AMPS) x where x is the molar ratio of the polymer repeating units and varied from 0.25 to 4. The structure of the materials was confirmed by FT-IR spectroscopy. The TGA results verified that the polymer electrolytes are thermally stable up to approximately 200 °C. The DSC and SEM results demonstrated the homogeneity of the materials. The electrochemical stability of the materials was studied by cyclic voltammeter (CV). Proton conductivity, activation energy, and water/methanol uptake of these membranes were also measured. After humidification (RH = 50%), PVTriP(AMPS)2 and PVTriP(AMPS)4 showed proton conductivities of 0.30 and 0.06 S/cm at 100 °C, respectively.

A series of new polymers have been synthesized by condensation of the dianions of acyclic bis(Reissert compounds) (A-A dinucleophile) with dihaloalkanes (B-B dielectrophile). These thermoplastic polyamides (10) are soluble in a wide range of solvents including THF, CHCl3, DMF, NMP, etc. Intrinsic viscosities vary between 0.07 and 0.48dL/g. The Tg's vary from 72°C to 116°C, depending upon the spacer derived from the electrophile. These polymers are stable up to 225°C (in air) and exhibit a 10% weight loss (in air) above 300°C.

Chitosan is a biodegradable natural polymer which is safe and non-toxic and used in different applications. Grafting of chitosan with aniline derivatives is an important route to improve its properties. Chitosan has different active groups that can be blocked in the grafting process, which could be confirmed by calculation studies. The author thinks that the confirmation of chitosan active group included in the grafting by calculations is not given before. So authors give evidence to the direction of grafting and mechanism. Poly(2-methylaniline) (P2-MA), poly(2-hydroxyaniline) (P2-HA) and their copolymers are used in the present study. Quantum mechanics calculations using density functional theory were applied to study the grafting process. The obtained data reveal that grafting occurs at NH2 groups, which is less energetic (2.04). This conclusion confirms the experimental studies. Computational calculations show that the interaction between chitosan and both P2-MA and P2-HA takes place at the NH2 group of chitosan with high stabilization energy (− 1346.7746). A complete next-to-leading order (NLO) values show that the graft could be a better candidate for NLO application (42.25 kcal mol−1) global properties (hardness). Also, the grafting process gives high reactive products due to a decrease in band gap energy.

Polyguaiacol was successfully synthesized by enzyme-catalyzed polymerization in an aqueous micelle system with horseradish peroxidase (HRP) as the catalyst. As-synthesized polyguaiacol was characterized by infrared spectrometry and gel permeation chromatography, and its thermal stability was evaluated by thermogravimetric analysis. Besides, the thermal antioxidant behavior of the as-synthesized phenolic polymer as an antioxidant in polypropylene was evaluated by differential scanning calorimetry and accelerated aging test, and the apparent activation energies of thermal decomposition of polypropylene (PP) were calculated by Friedman method. Results show that the as-synthesized polyguaiacol as an antioxidant is able to significantly increase the oxidation induction time of virgin PP, and it exhibits better antioxidative performance than corresponding monomer. Moreover, polyguaiacol, the as-synthesized phenolic polymer, exhibits good resistance against aging of polypropylene.

The initial step in molecular biology and genetic engineering fields are the finding of optimal methods for the extraction of the genomic DNA from microorganisms and cells. There are several methods for the extraction of bacterial DNA and the use of magnetic nanoparticles is a novel method for the isolation of nucleic acid. In the present study, the synthesized magnetic nanoparticles were used to extract the genomic DNA of Escherichia coli. In this study, the naked (Fe3O4) and coated (Fe3O4/SiO2; Fe3O4/SiO2/TiO2) magnetic nanoparticles were synthesized by precipitation methods. The purity of the product was assessed using energy-dispersive x-ray spectroscopy (EDS) and x-ray crystallography. The morphology and size of specimens were observed via field emission scanning electron microscopy (FESEM). The efficacy of the synthesized nanoparticles in genomic DNA extraction from Escherichia coli strain ATCC25922 was compared. The quality of the resulting DNA was analyzed by NanoDrop spectrophotometer, agarose gel electrophoresis, and PCR assays. According to the findings of SEM, the size of Fe3O4/SiO2/TiO2 magnetic nanoparticles was about 43.25 nm (Fe3O4/SiO2/TiO2). XRD analysis showed that the product nanoparticles were synthesized without impurities. The extraction results also showed that the purity and concentration of extracted genomic DNA by coated magnetic nanoparticles in comparison with naked magnetic nanoparticles were higher. In addition, the use of 0.4 mg of nanoparticles and 80% polyethylene glycol were optimal conditions for achieving a higher quality of DNA. According to the obtained results, the coated magnetic nanoparticles Fe3O4/SiO2/TiO2 can be used to extract genomic DNA of high quality from gram-negative bacteria.