Synthesis and properties of methyl acrylate-co-MSiA copolymers

Abstract

A novel silane coupling agent, 3,3-dimethoxy-8-oxo-2,9-dioxa-7-aza-3-silaundecan-11-yl acrylate (MSiA), is synthesized via reaction of 2-hydroxyethyl acrylate and 3-isocyanate propyl trimethoxy silane. Methyl acrylate-co-MSiA copolymers with low molecular weights and viscosities are synthesized via conventional free radical polymerization, using dodecyl mercaptan as the chain transfer agent to adjust the molecular weights and viscosities of copolymers. The performances of methyl acrylate-co-MSiA copolymer films cross-linked under ambient conditions are investigated. The results show the molecular weights and viscosities of methyl acrylate-co-MSiA copolymers decrease with the increase amount of dodecyl mercaptan in the radical polymerization. The methyl acrylate-co-MSiA copolymer with molecular weight of 1.07 × 10⁴ and the viscosity of 3100 mPa·s can be obtained when the amount of chain transfer agent is 5 wt %. With MSiA being copolymerized into main chain, methyl acrylate-co-MSiA copolymers can be cross-linked under moisture and room temperature conditions. With the increment of MSiA, the tensile strength of the moisture-cured film increases, while the elongation at break decreases. When the amounts of dodecyl mercaptan and MSiA are 3 and 10 wt % of monomers, respectively, the methyl acrylate-co-MSiA copolymer with viscosity of 8500 mPa·s and the cross-linked methyl acrylate-co-MSiA copolymer film with the tensile strength of 1.12 MPa and the elongation at break of 161.2% can be obtained. These show that synthesis of methyl acrylate-co-MSiA copolymers with low viscosities via conventional free radical polymerization using dodecyl mercaptan to adjust the viscosity is a facile method to synthesize moisture-curable polyacrylates, which may find applications in adhesive and coatings.

Keywords:

• Methyl acrylate copolymers
• chain transfer agent
• moisture curable
• conventional free radical polymerization
• polyacrylates

Compliance with ethical standards

This work complies with ethical standard.

Disclosure statement

The authors declare that they have no conflict of interest.