Incorporation of Alkoxysilanes into Model Latex Systems:  Vinyl Copolymerization of Vinyltriethoxysilane and n-Butyl Acrylate

Abstract

The increase in industrial interest in the incorporation of alkoxysilanes in organic polymer coatings arises from their ability to form self-cross-linkable films at room temperature. In the past few years, many patents were published, offering solutions for avoiding premature cross-linking of alkoxysilane-containing latexes and for obtaining good film-forming properties without using organic solvents. The present paper proposes a miniemulsion approach for the incorporation of alkoxysilanes into acrylate latex systems in order to protect the silane moieties from hydrolysis and premature cross-linking by reducing their contact with water. Vinyltriethoxysilane (VTES)/n-butyl acrylate (BA) copolymer latexes were synthesized by both conventional emulsion and miniemulsion procedures. The amount of coagulum and conversion were determined by gravimetry. Differences in coagulum levels were observed with respect to the copolymerization procedure (1.1−32.7 wt % based on monomers in conventional systems vs 1.2−5.5 wt % on monomers in miniemulsion systems for a VTES feed of 1−50 mol %) and acrylate/alkoxysilane molar ratio. Gas chromatography was used to determine the reactivity ratios of VTES/BA pairs by analyzing the evolution of unreacted comonomers during copolymerization. The reactivity ratios between the alkoxysilane and acrylate differed by 2 orders of magnitude for VTES (monomer 1) and BA (monomer 2), where r 1 = 0.044 and r 2 = 8.56. These results were confirmed by FT-IR analysis of the copolymer composition (r 1 = 0.086, r 2 = 8.51).

Melt rheology of nanocomposites based on acrylic copolymer and cellulose whiskers

“…Such systems induce postcross-linking properties at room temperature after hydrolysis of the trialkoxy moiety into silanol groups, followed by condensation leading to ASiAOASiA linkage connecting adjacent polymer chains [14][15][16]. Nonetheless, while this mechanism is approved, all the reported studies agree that the silane content should be higher than 5 wt.%, preferably in the range of 10-12%, in order to promote the probability of (coupling) contact among the hydrolysed silanol to ensure efficient cross-linking.…”

Preparation and surface properties of core‐shell polyacrylate latex containing fluorine and silicon in the shell

“…19 The silicated monomer with multifunctional groups can be used as a crosslinker to fix fluoroalkyl groups on the surface of the latex films. 20 The hydrolysis and condensation reactions of alkoxysilane groups are expected to lead to postcrosslinking after film formation.…”

Synthesis and properties of UV-curable polyurethane acrylates containing fluorinated acrylic monomer/vinyltrimethoxysilane

“…On the other hand, hydrophobic vinylalkoxysilanes are some of the functional groups that can introduce self-cross-linking structure during the film formation process [26,27]. Some studies have reported the synthesis and properties of selfcross-linkable fluorinated acrylate copolymer emulsions [21,28,29], but there has been little research on the optimum content of hydrophobic bulky alkoxysilanes for improving the water/oil repellency (low surface tension) and mechanical properties.…”