A visible-light photoredox synthesis of α-amino amide or α-amino thioamide from N,N-dimethylaniline derivatives and aryl isocyanate or aryl isothiocyanate was developed. Bis[2-(4,6-difluorophenyl)pyridinato-C(2),N](picolinato)iridium(III) (FIrpic) was found to be the effective catalyst among six catalysts screened. The reaction involves generation of α-aminoalkyl radicals from tertiary amines, followed by radical addition to the electron-deficient carbon of isocyanate and isothiocyanate.

Physical aging characteristics of poly(ethylene terephthalate) have been evaluated in relationship to volume fraction levels of crystallinity up to 25%. Changes in the enthalpies of relaxation, monitored at aging temperatures from 55 to 658C, are found to give good fits with the Cowie-Ferguson model. Overall equilibrium enthalpy of relaxation values decrease linearly with increased crystallinity. They increase with decreased aging temperature, providing extrapolated lower temperature results that are validated in terms of specific heat relationships. Activation energies for enthalpic relaxations are found to increase from 337 to 361 kJ/mole as crystallinity increases up to 25%. Overall relaxation endotherms are further resolved into contributions from interspherulitic and intraspherulitic amorphous regions. Interspherulitic, equilibrium enthalpies of relaxation decrease with increased levels of crystallinity, while intraspherulic values show corresponding increases. Characteristic relaxation times of the intraspherulic regions increase greatly, as levels of crystallinity increase; however, interspherulitic relaxation times decrease very slightly. Dynamic differential scanning calorimetry results show two glass transitions in the case of a 25% crystalline sample and a single transition for noncrystallized material.

Poly(ethylene terephthalate) samples with volume fraction levels of crystallinity up to 27% have been evaluated in terms of physical aging, tensile mechanical properties, and environmental stress cracking failures. Specific enthalpy recovery values were found to correspond with transitions from ductile to brittle modes of tensile mechanical failures, exhibited by samples with each level of crystallinity. For samples exposed to aging temperatures from 45 to 60 C, these critical enthalpies decrease linearly with increased crystallinity. The environmental stress cracking behavior of semicrystalline PET was found to depend on both crystallinity levels and physical aging. Samples with higher levels of crystallinity undergo stress cracking failures at lower critical stresses than their less crystalline counterparts. Physical aging, before environmental stress cracking exposure, further decreases these critical stress values and leads to much shorter critical times for failures. It has been shown that the interspherulitic amorphous portion of the material is primarily responsible for the differences in tensile mechanical and environmental stress cracking behaviors, observed as a result of aging and exposure. This amorphous region becomes progressively more restricted with increasing crystallinity as well as with increased aging. It, therefore, requires shorter exposure times to exhibit brittle tensile mechanical failure and environmental stress cracking rupture.

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A homogeneous visible light photoredox TEMPO-mediated selective oxidation of primary alcohols to the corresponding carbonyl compounds was developed using molecular oxygen from air as the terminal oxidant. Ru(bpy) 3 (PF 6 ) 2 (bpy: bipyridyl) and Ir(dtb-bpy)(ppy) 2 (PF 6 ) (dtb-bpy: 4,4'-di-tert-butyl-2,2'-bipyridyl; ppy: 2-phenylpyridine) were used as the sensitizers.

The fracture of pipelines caused by corrosion cracks and the resulting oil and gas leakage can lead to great environmental pollution and economic losses. These negative effects are due to serious corrosion of the plain carbon steels used for armor of flexible pipe in oil and gas transmission medium. However, corrosion resistance of carbon steel armors has yet to be improved. In this study, the relationship between corrosion resistance and pearlite fraction in the plain carbon steels has been investigated through the application of pulsed electric current. Based on immersion test and electrochemical measurement, pulsed electric current increases the corrosion resistance of the plain carbon steels by reducing the fraction of pearlite phase. Pitting corrosion, which tends to initiate by galvanic corrosion of ferrite and cementite, is therefore inhibited due to the decrease in pearlite fraction (mixture of ferrite and cementite) under electropulsing.