Versatile Cascade Esterification Route to MQ Resins

Abstract

We describe a versatile cascade route for manufacturing MQ resins using alkoxysilanes (e.g., tetraethoxysilane (TEOS)) or equivalent oligomers (e.g., ethyl polysilicate (polyTEOS)), a carboxylic acid (typically acetic acid), and hexamethyldisiloxane (MM) as starting materials; a strong acid catalyst is also employed in the one-pot reaction. The siloxane resin synthesis is accompanied by esterification of the carboxylic acid to give ethyl acetate, which acts as an important solvent, making the process more controllable. Contrary to traditional sol–gel methods, no water is introduced in the experiments, but is generated in situ. The strategy offers several advantages, including reproducibility, high yields of siloxane resins with excellent batch-to-batch consistency and without gel formation, narrow dispersity, low Si-hydroxyl residues in the final products, and the ability of increasing the molecular weight by thermal treatment. The process utilizes the green chemistry concepts of lower pollutant formation and higher atom efficiency.

Silicone Nanocomposites with Enhanced Thermal Resistance: A Review

“…The relationships discussed above can also be clearly observed when analysing the properties of highly branched MQ silicone resins consisting of a monofunctional siloxane (R3SiO1/2, the M units) and a tetrafunctional siloxane (SiO4/2, the Q units) [13,14]. These polymers have favourable thermal stability due to the formation of new regular macromolecular structures and the introduction of phenyl groups [15].…”

A Simple Preparation Route for Bio-Phenol MQ Silicone Resin via the Hydrosilylation Method and its Autonomic Antibacterial Property

“…MQ silicone resin is an organic–inorganic hybrid material with a three-dimensional structure consisting of tetra-functional siloxane (SiO 4/2 , Q units) and mono-functional siloxane (R 3 SiO 1/2 , M units). The core of MQ silicone resin is a cage-type SiO 2 (Q units) with high density, while the shell is M units with low density, and organic/inorganic groups such as methyl, aryl, vinyl, or silicon hydrogen bonds exist in M units [1,2,3]. This organic–inorganic distinctive structure gives the MQ silicone resin excellent thermal stability [4], high weather resistance [5], high chemical resistance [6], etc.…”

Hyperbranched Silicone MDTQ Tack Promoters

“…MQ resins are an important class of commercial silicone resins. They can be prepared in a sol-gel process by acidification of sodium silicate followed by capping [4], or hydrolysis and condensation [5]; recently, a transesterification approach to their synthesis using Si(OEt 4 ) was described (Figure 1A–C) [6].…”