Hyperbranched polyester copolymers for thermal printing papers: The effects of alkyl chain units in the polymer backbone on developing capability

Palladium-Catalyzed Functionalization of Kraft Lignin: Ether Linkages through the Telomerization Reaction

Kraft lignin was efficiently functionalized with octadienyl ether linkages through the palladium-catalyzed telomerization of 1,3-butadiene. Comparison with molecular model substrates assessed the grafting of phenols and alcohols and an optimization study led to up to 69 % conversion of the total number of hydroxyl groups present in lignin. This catalytic study evidenced the partial oxidation of triphenylphosphine into triphenylphosphine oxide and triphenylphosphine sulfide by contaminants present in the industrial grade kraft lignin. The telomerised lignin is a malleable material and a preliminary study of the thermal properties showed a decrease in the glass transition in comparison with the starting material.

Development of novel electrically conductive scaffold based on hyperbranched polyester and polythiophene for tissue engineering applications

A novel electrically conductive scaffold containing hyperbranched aliphatic polyester (HAP), polythiophene (PTh), and poly(ε-caprolactone) (PCL) for regenerative medicine application was succesfully fabricated via electrospinning technique. For this purpose, the HAP (G4; fourth generation) was synthesized via melt polycondensation reaction from tris(methylol)propane and 2,2-bis(methylol)propionic acid (bis-MPA). Afterward, the synthesized HAP was functionalized with 2-thiopheneacetic acid in the presence of N,N-dicyclohexyl carbodiimide, and N-hydroxysuccinimide as coupling agent and catalyst, respectively, to afford a thiophene-functionalized G4 macromonomer. This macromonomer was subsequently used in chemical oxidation copolymerization with thiophene monomer to produce a star-shaped PTh with G4 core (G4-PTh). The solution of the G4-PTh, and PCL was electrospun to produce uniform, conductive, and biocompatible nanofibers. The conductivity, hydrophilicity, and mechanical properties of these nanofibers were investigated. The biocompatibility of the electrospun nanofibers were evaluated by assessing the adhesion and proliferation of mouse osteoblast MC3T3-E1 cell line and in vitro degradability to demonstrate their potential uses as a tissue engineering scaffold. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2673-2684, 2016.