Functional-Polymer Library through Post-Polymerization Modification of Copolymers Having Oleate and Pentafluorophenyl Pendants.

Poly[2-(methacryloyloxy)ethyl oleate-co-pentafluorophenyl methacrylate] [P(MAEO-co-PFPMA)] random copolymers with oleate and pentafluorophenyl side-chain pendants were synthesized. These copolymers were utilized as dual-reactive polymeric scaffolds in a range of post-polymerization modification strategies involving thiol-ene and para-fluoro-thiol substitution, amidation, trans-esterification, and epoxidation followed by amidation. The 2-(methacryloyloxy)ethyl oleate (MAEO) functional handle in the copolymer is open to functionalization at its internal double bond through thermally initiated thiol-ene reaction, whereas the pentafluorophenyl moiety of the pentafluorophenyl methacrylate (PFPMA) unit undergoes para-fluoro-thiol substitution under basic conditions at room temperature. By means of these modification approaches, the P(MAEO-co-PFPMA) copolymer was orthogonally ligated with thiol compounds having, for example, alkyl, hydroxyl, and protected amine functional groups. Furthermore, different functional groups such as benzyl, allyl, methacrylate, pyrene, and water-soluble poly(ethylene glycol) were easily introduced into the side chain of the P(MAEO-co-PFPMA) copolymer by amidation, trans-esterification, and epoxidation followed by amidation. Functionalization of both the reactive pendants with the various organic substituents was confirmed by 1 H and 19 F NMR spectroscopy, gel permeation chromatography, and fluorescence spectroscopy.

Polyisobutylene-based glycopolymers as potent inhibitors for in vitro insulin aggregation.

A family of amphiphilic diblock copolymers containing a hydrophobic polyisobutylene (PIB, Mn = 1000 g mol-1) segment and a hydrophilic block with sugar pendants has been synthesized by combining living cationic and reversible addition-fragmentation chain transfer (RAFT) polymerization techniques; to explore their potential in insulin fibrillation inhibition. The glucose content in the hydrophilic segment has been tailor-made from 20 to 57 units to prepare block copolymers. The removal of the acetates from the pendent glucose units resulted in amphiphilic block copolymers that generated micellar aggregates in aqueous media. The treatment of insulin with these block copolymers affected the fibril formation process which was demonstrated using an array of biophysical techniques, namely, thioflavin T (ThT) fluorescence, tyrosine (Tyr) fluorescence, Nile red (NR) fluorescence, isothermal titration calorimetry (ITC), etc. The Tyr fluorescence assay and NR fluorescence study revealed the crucial role of hydrophobic interaction in the inhibition process, whereas ITC measurements confirmed the importance of polar interaction. Thus, the block copolymers exhibit potent inhibition of insulin fibrillation owing to hydrophobic (from PIB segment) and glycosidic cluster effect (from sugar pendant block).

Recent advances in catalytic chain transfer polymerization of isobutylene: a review.

This review presents the development of highly reactive polyisobutylene (HRPIB), a major commercial intermediate toward fuel and lubricant additives. Recent years have witnessed very substantial advances in the catalytic chain transfer polymerization (CCTP) of isobutylene/industrial Raffinate-1 (C4 Raffinate) to produce HRPIB, particularly in nonpolar solvents at elevated temperatures. The main subjects of this review are cationic polymerization of isobutylene, progress in HRPIB research and existing challenges, and recent advances of CCTP. New initiating/catalyst systems based on ionic liquids with Lewis acids are detailed, and this approach may open new views in the synthesis of HRPIB. Some current developments in CCTP of industrial Raffinate-1 and mechanistic studies are also described. This review strongly supports that the hydrocarbon soluble Lewis acid·ether (LA·ether) complex catalyzed CCTP will become the most popular technique for preparing HRPIB and could replace the traditional BF3 catalyzed industrial method.