No abstract

A detailed X-ray photoelectron spectroscopy study of a plasma-modified polystyrene (PS) surface was carried out after N2 plasma treatment. PS surfaces were found to be highly hydrophilic and reactive as it readily picks up oxygen giving rise to oxyfunctionalities on the surface. The plasma treatment also led to a slow chain scission with carboxyl, forming carbonate linkage.

No abstract

Detailed X-ray photoelectron spectroscopy analysis of sulfonated high-density polyethylene (HDPE) prepared by using a gaseous mixture of SO3 + N2 was carried out. It was shown that the surface contains, apart from sulfonic acid groups, sulfate, keto, and polyene linkages. The evolution of the different surface groups depends upon the conditions of sulfonation.

Well-defined multiarmed star random and block copolymers of e-caprolactone with L-lactide with controlled molecular weights, low polydispersities, and precise numbers of arms were synthesized by the ring-opening polymerization of respective cyclic ester monomers. The polymers were characterized by 1 H-NMR and 13 C-NMR to determine their chemical composition, molecular structure, degree of randomness, and proof of block copolymer formation. Gel permeation chromatography was used to establish the degree of branching. Star-branched random copolymers exhibited lower glass-transition temperatures (T g 's) compared to a linear random copolymer. When the star random copolymers were melt-blended with poly(L-lactic acid) (PLA), we observed that the elongation of the blend increased with the number of arms of the copolymer. Six-armed block copolymers, which exhibited higher T g 's, caused the maximum improvement in elongation. In all cases, improvements in the elongation were achieved with no loss of stiffness in the PLA blends.