Evaluation of the curing process of polyurethane end‐capped with trialkoxysilanes by a boron trifluoride/amine complex and organotin compound

Polyurethanes end‐capped with some trialkoxysilanes, such as trimethoxysilane, triethoxysilane, tripropoxysilane, and tributoxysilane (silylated polyurethanes), were synthesized. Boron trifluoride/monoethylamine (BF3–MEA) complex and dibutyltin dimethoxide (DBTDM) were examined as curing catalysts for the obtained silylated polyurethanes to compare their curing speeds. It was found that BF3–MEA worked as a more efficient catalyst for the condensation reaction of the alkoxysilyl groups in the silylated polyurethanes to form the corresponding networked polyurethanes. BF3–MEA had a great advantage as one of the curing catalysts because it gave a fast curing speed for the silylated polyurethanes having long alkoxysilyl groups (ethoxy, propoxy, and butoxy) in comparison with DBTDM.