The structure characterization of thermosensitive poly(N‐isopropylacrylamide‐co‐2‐hydroxypropyl methacrylate) hydrogel

The goal of this work was to investigate a possible way of crosslinking polymer chains and the potential formation of intramolecular hydrogen bonds in thermosensitive poly(N‐isopropylacrylamide‐co‐2‐hydroxypropyl methacrylate) (p(NIPAM‐HPMet)) hydrogels obtained by radical polymerization. The chemical structure of the synthesized hydrogels was investigated by Fourier transform infrared (FTIR) spectroscopy and XRD. The FTIR spectrum confirmed the presence of hydrogen bonds formed between the chains in the copolymer. XRD analysis confirmed the amorphous ? crystalline structure of the copolymer. A three‐glass transition and two melting temperatures were detected by DSC. It was found that the addition of HPMet increased the glass transition and melting temperatures of the p(NIPAM‐HPMet) copolymer. The swelling transport mechanism of p(NIPAM‐HPMet) changed from non‐Fickian at 20 °C to case III or zero‐order time‐independent kinetics characterized by a linear mass uptake with time with increasing temperature at 40 °C. © 2013 Society of Chemical Industry     

Recollections on Lotus 1-2-3: Benchmark for Spreadsheet Software

These recollections trace the founding of Lotus Development Corp. and the genesis of Lotus 1-2-3, the spreadsheet software for personal computers that took the market by storm in the early 1980s. The author examines the state of the personal computer industry at the time and forces that favored Lotus 1-2-3's success.     

Disbonding of underwater-cured epoxy coating caused by cathodic protection current

Cathodic disbonding of the underwater-applied, ultra-thick, solvent free epoxy coating subjected to various levels of cathodic protection was investigated during the period of the coating cure. The results indicate that the partially cured coating was of low resistivity, between 10³ and 10⁵ Ω cm² for the cathodic polarization of on-potentials between −0.98 and −1.4 V_Ag/AgCl/sw. The coating was shown to be capable of withstanding normal levels of cathodic protection between off-potentials of −0.8 and −1.1 V_Ag/AgCl/sw while the IR drop, introduced by the coating in the same potential range, increased from 0.06 to 0.1 V and has to be taken into account at the design stage of the cathodic protection system. Beneficial influence of calcareous deposit formation on the cathodic protection current was confirmed, particularly for the failed coating. The initial period (1 week) of coating cure was shown as the most critical for disbonding processes caused by the excessive cathodic polarization.     

Corrosion inhibition of carbon steel in chloride solutions by blends of calcium gluconate and sodium benzoate

Inhibition efficiency of calcium gluconate, alone and in blends with sodium benzoate, on the corrosion of carbon steel in chloride solutions has been assessed by potentiodynamic polarization measurements and mass loss detection in the temperature range from 25 to 70 °C. Sodium benzoate efficient in hindering the general corrosion in chloride solutions can induce pitting of carbon steel. Along with decreasing the general corrosion calcium gluconate, an ecologically acceptable compound, eliminated the susceptibility to pitting formation. The inhibition of the anodic reaction by gluconate and benzoate, and the slowing down the cathodic reaction in solutions of calcium gluconate was confirmed.