Cyclodextrin-based hyperbranched polymers by acyclic diene metathesis polymerization of an ABn monomer: molecule design, synthesis, and characterization

Abstract

A novel cyclodextrin-based hyperbranched polymer (HBP) was synthetized via acyclic diene metathesis (ADMET) polymerization in homogeneous water/organic mixtures. A modified α-cyclodextrin (α-CD) molecule with one electron-rich terminal alkene and many electron-poor acrylates was first prepared through the esterification reaction, and then utilized as an AB n -type monomer for subsequent ADMET polymerization between alkene and acrylate using the second generation Hoveyda-Grubbs catalyst, yielding HBP with the reaction time prolonged. The chemical structures of monomer and HBP were characterized by elemental analysis, IR, gel permeation chromatography with multiangle laser light scattering, and NMR measurements. The degree of branching was determined by using 1 H NMR spectroscopy and the values ranged from 0.51 to 0.42. Influence of the molecular weight on the properties (thermal stability and solubility) was also investigated. The resulting HBPs showed the good thermal stability, and higher molecular weight resulted in higher decomposition temperature from 361°C to 383°C. These thermally stable HBPs also displayed the excellent solubility in aprotic polar solvents.

Subnanoporous Highly Oxygen Permselective Membranes from Poly(conjugated hyperbranched macromonomer)s Synthesized by One-Pot Simultaneous Two-Mode Homopolymerization of 1,3-Bis(silyl)phenylacetylene Using a Single Rh Catalytic System: Control of Their Structures and Permselectivities

“…On the other hand, hyperbranched polymers ( HBP ) − are synthesized easily by polymerization, and the syntheses are much easier than those of dendrimers, although the regularity of the molecular structure is lower. Therefore, we planned synthesis of poly­(hyperbranched macromonomer)­s (poly­( HBM )) instead of poly­(dendron macromonomer)­s.…”