Novel hyperbranched polysiloxanes containing acetoacetyl groups synthesized through transesterification reaction

Development of an innovative strategy to prepare hyperbranched polysiloxanes (HBPS) is highly desirable due to the significant shortcomings of conventional fabrication approaches: the precursors need pre-synthesis, the hydrosilylation reaction is conducted using costly catalysts, and hydrolysis of organosiloxanes easily results in gelation. Here, novel HBPS containing acetoacetyl groups (HBPS-Ac) are synthesized through a cost-efficient and easily controllable transesterification reaction. It is shown by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), ¹H NMR, and gas chromatography (GC) measurements that the polymerization process is a straightforward technique to prepare new HBPS. The polymers are capable to remove formaldehyde due to the highly efficient reaction of the active methylene in the acetoacetyl group with formaldehyde at room temperature. Notably, coatings incorporating 4 wt% of the polymers allow for formaldehyde absorption, while integrated performances are kept almost unaffected. Therefore, HBPS-Ac are promising as scavengers for formaldehyde. Novel hyperbranched polysiloxanes containing acetoacetyl groups are successfully fabricated from tetraethyl orthosilicate and polyols through a transesterification reaction using a two-step procedure. The polymers can capture formaldehyde due to the highly efficient reaction of the active methylene in the acetoacetyl group with formaldehyde at room temperature. Therefore, they are promising as effective formaldehyde scavengers.