Nanotechnology in Urology: History of Development and Applications in Urology

Investigation of thermal and mechanical properties of new nitrogen-rich organic based heat stabilizers for poly (vinyl chloride)

“…For this purpose the enthalpy changes (ΔH°), the Gibbs free energy changes (ΔG°) of the process were performed with the Becke–Lee–Yang–Parr functional (B3LYP) DFT method 28 and the 6-311++G(d, p) basis set. 42…”

“…For this purpose the enthalpy changes (ΔH°), the Gibbs free energy changes (ΔG°) of the process were performed with the Becke-Lee-Yang-Parr functional (B3LYP) DFT method 28 and the 6-311++G(d, p) basis set. 42 ΔH°value for UCA structure showed a lower energy about -438.78 Kcal/mol compared to the À235.10.40 Kcal/mol for the urea and the À564.15 Kcal/mol for cyanoric acid.…”

“…24,25 The thermal stability mechanism of urea derivatives includes inhabitation of the autocatalytic effect of HCl by absorbing released HCl during the degradation of PVC and, after that reacting with PVC chains to avoid the formation of conjugated double bonds. [26][27][28] Urea cyanurate (UCA) is a nitrogen-containing compound that is mostly used as a preservative in the storage of agricultural crops and in the production of cyanuric acid and also could be used as a thermal stabilizer in PVC. 29,30 The important point in choosing of these nitrogen-containing organic compound is to consider the good compatibility of these thermal stabilizers with PVC along with no negatively effect on the transparency and other expected properties of the final product.…”

“…24,25 The thermal stability mechanism of urea derivatives includes inhabitation of the autocatalytic effect of HCl by absorbing released HCl during the degradation of PVC and, after that reacting with PVC chains to avoid the formation of conjugated double bonds. 26–28…”