Block copolymers and telechelic oligomers by end group reaction of polymethacrylates

Block copolymers and telechelic oligomers bearing methacrylate moities were obtained by means of a new highly selective end group reaction. Starting from polymethacrylates that were prepared by radical polymerization in the presence of mercaptanes as chain transfer agents, the resulting ester end group linked to the terminal tertiary carbon atom of the polymer backbone can be either transesterified or saponified selectively. The selectivity of the end group reactions was determined by MALDI-TOF-mass spectrometry. Polymethacrylate-b-poly(ethylene oxide)-, polymethacrylate-b-poly(methacrylic acid)- and polymethacrylate-b-polysiloxane-b-polymethacrylate-copolymers as well as α,ω-dihydroxy- and α,ω-dicarboxy-telechelic polymethacrylates were prepared by applying end group transesterification or end group saponification.     

Telechelic Polyisobutenes with Asymmetrical Reactivity

3-Chlorocyclopentene-(1) has been used as initiator in the quasiliving cationic polymerization of isobutene. Polyisobutenes in the molecular weight range Mw = 300 - 60000 Dalton with a molecular weight distribution MWD between 1.17 and 1.34 have been synthesized. The linear polymer was selectively hydrosilated on one or both ends. With a furan coupling agent, the PIB (polyisobutene) was dimerized, yielding polymers with a cyclopentene head- and tail group.     

ChemInform Abstract: The Extended Stability Range of Phosphorus Allotropes.

A complete stability range of known and new crystalline allotropes of phosphorus including recently discovered tubular modifications and not‐yet‐known crystal structures of [P₁₂] nanorods, and not‐yet‐isolated [P₁₄] nanorods is given using quantum chemical DFT calculations.