A New Approach Utilizing Aza-Michael Addition for Hydrolysis-Resistance Non-Ionic Waterborne Polyester

Abstract

This work first synthesized a series of linear polyesters by step-growth polycondensation, then an amino-terminated hydrophilic polyether was grafted to the polyester as side-chains through aza-Michael addition to prepare a self-dispersible, non-ionic waterborne comb-like polyester (NWCPE). In contrast to traditional functionalization methods that usually require harsh reaction conditions and complex catalysts, the aza-Michael addition proceeds efficiently at room temperature without a catalyst. In this facile and mild way, the NWCPE samples with number-average molecular weight (Mn) of about 8000 g mol−1 were obtained. All dispersions showed excellent storage stability, reflected by no delamination observed after 6 months of storage. The NWCPE dispersion displayed better hydrolysis resistance than an ionic waterborne polyester, as was indicated by a more slight change in pH value and Mn after a period of storage. In addition, the film obtained after the NWCPE dispersion was cross-linked with the curing agent, it exhibited good water resistance, adhesion, and mechanical properties.

Aza‐Michael Reaction: A Decade Later – Is the Research Over?

“…Finally, last years the aza‐Michael reaction is widely used in the polymer chemistry for modifying of monomer molecules or post‐polymerization modification of reactive polymeric substrates during the preparation of various functional materials. Several aspects of the researches are presented in recent publications regarding the use of the aza‐Michael reaction applied to the general polymer chemistry (see, for example: [204] to silicon‐based polymers, [205] to post‐synthetic functionalization of polymer scaffolds [206–208] and to modification of multifunctional molecules into new biobased monomers for polymerization reactions) [209] . Moreover, covalent modification of proteins through the aza‐Michael reaction has been reported [210] .…”

Copper Fluorapatite-Catalyzed Aza-Michael Reaction and Kinetic Studies

“…If the adsorbents are not degradable and recyclable, CO 2responsive cellulose fibers prepared by simple esterification and AM reaction 16 can resolve the issue of solid waste by reverse adsorption−desorption. Fu et al 17 synthesized self-dispersible and nonionic waterborne comblike polyesters from polycondensation by step-growth and then polyether to polyester from grafting of an amino-terminated hydrophilic using AM addition.…”