Preparation of epoxy-ended hyperbranched polymers with precisely controllable degree of branching by thiol-ene Michael addition
ABSTRACT
Epoxy-ended hyperbranched polymers (EHPs) have a wide range of applications due to their outstanding performances. Because their microstructures are not positively identified, it is very difficult to ascertain the reinforcing and toughening mechanisms of EHPs and their interface interaction with other matrixes. Controllable synthesis of EHPs with precise degree of branching (DB) remains to be a major challenge. Here, a method for preparing novel nitrogen-phosphor skeleton epoxy-ended hyperbranched polymers (NPEHP) with controllable DB by a thiol-ene Michael addition between thiol-ended hyperbranched polymers (NPHSH) and glycidyl methacrylate have been firstly reported. NPHSH is synthesized by an esterification between hydroxyl-ended hyperbranched polymers (NPHOH) and 3-mercaptopropionic acid. NPHOH is prepared by a thiol-ene Michael addition between methacrylate group of a monomer and thiol group of linear monomer (AB) and/or branched monomer (AB2). The molar ratio between the AB and AB2 monomers controls the DB of the products. The 1H NMR spectra analysis of NPHOH shows that their experimentally determined DBs are very close to their theoretical values, indicating good controllability of their DBs. The narrow molecular weight distributions of NPHOH, NPHSH, and NPEHP suggest high efficiency of the thiol-ene Michael addition. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44277.
