With excellent comprehensive properties,
polylactic acid/poly(butylene
adipate-co-butylene terephthalate) (PLA/PBAT) blends
have found wide applications as degradable materials. During the processing
procedure, a third component compatibilizer is introduced to improve
the compatibility and mechanical properties of PLA/PBAT blends. In
this work, environmentally friendly epoxidized soybean oil (ESO) is
used for the compatibilization of PLA/PBAT blends through the chemical
reaction of ESO with terminated hydroxyl groups of the two phases.
Through the adjustment of the amounts of ESO, the compatibilization
effect on the properties of PLA/PBAT blends is studied. The compatibilization
mechanism of ESO was analyzed by Fourier transform infrared spectroscopy
and differential scanning calorimetry testing, and the results prove
that ESO could react with PLA and PBAT to form a chemical bonding
interface. The PLA/PBAT blends compatibilized with ESO demonstrated
a significant increase in tensile strength, elongation at break, and
notched impact strength.
Sulfur-cured butyl rubber was devulcanized completely in supercritical CO 2 by using diphenyl disulfide (DD) as a devulcanizing reagent. The optimum devulcanizing conditions were studied and the sol fraction of the reclaimed rubber obtained was up to 98.5%. The possible devulcanizing mechanism was investigated. Then, the sol component of reclaimed rubber was characterized by gel permeation chromatography, 1 H-NMR, and differential scanning calorimetry, and the reclaimed rubber was characterized by TGA. Because of the substitution of a large portion of allylic hydrogen by sulfurated functional groups during vulcanization, the signal of the olefinic proton shift. As a result of the numerous decreases in the active crosslinking sites and the remaining DD, reclaimed rubber could not be cured by sulfur. At last, the blends of virgin butyl rubber and different contents of reclaimed rubber were revulcanized and their mechanical properties investigated.
A visible-light-mediated radical
tandem cyclization of ortho-isocyano-α-bromo
cinnamates to 2-substituted
indole-3-glyoxylates is achieved by formation of both C–C/C–S
and C–O bonds. The reaction proceeds through a hitherto unprecedented
bromine- or methoxy-group-promoted umpolung back electron transfer
from an α-carbonyl radical to the photocatalyst. This method
allows preparation of diverse 2-arylated or 2-thioarylated indole-3-glyoxylates.
The glyoxylate group installed in the products can be utilized for
several biologically relevant manipulations.
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