1 research outputs found
Dealkylation of Poly(methyl methacrylate) by TiCl<sub>4</sub> Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material
This study examines the chemical reaction pathways for
vapor phase
infiltration (VPI) of TiCl4 into poly(methyl methacrylate)
(PMMA). VPI is a processing method that transforms organic polymers
into organic–inorganic hybrid materials with new properties
of interest for microelectronic patterning, technical textiles, and
chemical separations. Understanding the fundamental chemical mechanisms
of the VPI process is essential for establishing approaches to design
the chemical structure and properties of these hybrid materials. While
prior work has suggested that TiCl4 infiltration into PMMA
does not disrupt the polymer’s carbonyl bond, a clear reaction
mechanism has yet to be proposed. Here, we present a detailed X-ray
photoelectron spectroscopy study that presents evidence for a concerted
reaction mechanism that involves TiCl4 coordinating with
the PMMA’s ester group to dealkylate the methyl side group,
creating a chloromethane byproduct and primary chemical bonds between
the organic and inorganic components of the hybrid material. Additional
spectroscopy, quartz crystal microbalance gravimetry, and thermophysical
and chemical property measurements of this material, including solubility
studies and thermal expansion measurements, provide further evidence
for this chemical reaction pathway and the subsequent creation of
inorganic cross-links that network these TiOx–PMMA hybrid materials