Two biocomposites based on cellulose (UFC) and starch modified urea formaldehyde (UFS) resin (F/U ratio of 0.8) were synthesized using the same procedure. The hydrolitical, thermal, and radiation stability of biocomposites are determined. Also, released formaldehyde during the acid hydrolysis is determined. Biocomposites based on modified UF resin have been irradiated with (50 kGy). Cellulose modified UF resin after γ‐radiation has 1.38% released formaldehyde; unmodified UF resin has 2.21% released formaldehyde. Thermal stability of biocomposites is determined using nonisothermal thermogravimetric analysis, differential thermal gravimetry (DTG), and differential thermal analysis with IR spectroscopy. Moving the DTG peak to higher temperatures indicates an increased thermal stability of cellulose modified UF resin, which is confirmed by the FTIR analysis. Gamma radiation most often causes a decrease in the intensity of the peaks in the FTIR spectrum. POLYM. COMPOS., 40:1287–1294, 2019. © 2018 Society of Plastics Engineers

Boron-doped diamond electrodea prestigious unmodified carbon electrode for simple and fast determination of bentazone in river water samples

A novel efficient differential pulse voltammetric (DPV) method for determination gallic acid (GA) was developed by using an electrochemical sensor based on [Cu2tpmc](ClO4)4 immobilized in PVC matrix and coated on graphite (CGE) or classy carbon rod (CGCE). The proposed method is based on the gallic acid oxidation process at formed [Cu2tpmcGA](3+) complex at the electrode surface. The complexation was explored by molecular modeling and DFT calculations. Voltammograms for both sensors, recorded in a HNO3 as a supporting electrolyte at pH 2 and measured in 2.5×10(-7) to 1.0×10(-4) M of GA, resulted with two linear calibration curves (for higher and lower GA concentration range). The detection limit at CGE was 1.48×10(-7) M, while at CGCE was 4.6×10(-6) M. CGE was successfully applied for the determination of the antioxidant capacity based on GA equivalents for white, rosé and red wine samples.

Differential pulse voltammetric determination of antipsychotic drug trifluoperazine on boron-doped diamond electrode.

The simple PVC-based membrane containing N,N',N'',N'''-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) as an ionophore and dibutyl phthalate as a plasticizer, directly coated on a glassy carbon electrode was examined as a new sensor for Cu 2þ ions. The potential response was linear within the concentration range of 1.0 Â 10 À1 -1.0 Â 10 À6 M with a Nernstian slope of 28.8 mV/decade and detection limit of 7.0 Â 10 À7 M. The electrode was used in aqueous solutions over a wide pH range (1.3 -6). The sensor exhibited excellent selectivity for Cu 2þ ion over a number of cations and was successfully used in its determination in real samples.