Poly-(3-ethyl-3-hydroxymethyl)oxetanes-Synthesis and Adhesive Interactions with Polar Substrates

Hyperbranched polyoxetanes are a relatively new class of polymers. These are branched polyethers that are synthesized from oxetanes-four-member cyclic ethers bearing hydroxymethyl groups-via ring-opening polymerization. Four series of polyoxetanes were synthesized from 3-ethyl-3-(hydroxymethyl)oxetane and 1,1,1-tris(hydroxymethyl)propane as a core molecule. Reagents ratios ranged from 1:5 to 1:50, theoretical molar mass ranged from 714 g/mol to 5942 g/mol, and dispersities ranged from 1.77 to 3.75. The morphology of the macromolecules was investigated by a matrix-assisted laser desorption/ionization time of flight technique. The polyoxetanes' adhesive interactions with polar materials were analyzed and provided results as follows: the work of adhesion was 101-105 mJ/m², the bond-line tensile shear strengths were 0.39-1.32 MPa, and there was a brittle fracture mode within the polymer. The findings confirmed a good adhesion to polar substrates, but further research on polyoxetane modifications toward a reduction of brittleness is necessary.