Parametric investigation of polymethacrylate monolith synthesis and stability via thermogravimetric characterisation

Abstract

Polymethacrylate monoliths are synthetic adsorbents with macroporous and mesoporous interconnected channels that can be engineered to target the hydrodynamic features of a wide range of molecular species. However, rigorous study into the effect of synthesis conditions on their thermal stability is limited. This work attempts to characterise the influence of key synthesis process variables on the stability of polymethacrylate monoliths using thermogravimetric analysis at a heating rate of 10°C/min. Experimental results showed that the thermal stability of polymethacrylate monoliths increased with decreasing polymerisation temperature from 85 to 65°C. Increasing the total porogen (P) to monomer (M) ratio increased the thermal stability of the monolith by >62% and >50% for P40/M60-P60/M40 and P60/M40-P80/M20, respectively. The impact of the initiator concentration, monomer variation, biporogen ratio, washing and activation of the monoliths was investigated. Nuclear magnetic resonance analyses conducted confirmed the hydrolysis of epoxy moieties on the monolith.

Synthesis and Characterization of Polymeric Microspheres Template for a Homogeneous and Porous Monolith

“…This is due to their intriguing properties of high surface area, chemical stability, and high pore volumes. Higher permeability and reduced flow resistance as a result of the interconnected pores enable high-speed separation providing high throughput, resolution, and separation in short run times [5,6]. It is important that the porosity of the monolith is well structured to enable mass transport and diffusion.…”

Preparation of Polystyrene Microsphere-Templated Porous Monolith for Wastewater Filtration

“…A previous study reported monolith degradation at a lower temperature of around 200 °C. That monolith was made of similar monomer chemicals, but was templated using porogen as prepared by Acquah, Danquah, Moy, Anwar and Ongkudon [ 22 ]. Yusuf, et al [ 34 ] also reported initial monolith degradation at 210 °C in their study.…”

“…The first deterioration of the monolith prepared using a 60:40 template/monolith ratio occurred at 243 • C, with the second degradation beginning at 332 • C. At 700 • C, the monolith samples had been completely degraded and converted into ashes. A previous study reported monolith degradation at a lower temperature of around 200 • C. That monolith was made of similar monomer chemicals, but was templated using porogen as prepared by Acquah, Danquah, Moy, Anwar and Ongkudon [22]. Yusuf, et al [34] also reported initial monolith degradation at 210 • C in their study.…”

“…The solution was sonicated at 20 °C for 20 min. Subsequently, the solution was inserted into a casting mold and heated at 60 °C for 3 h inside a water bath to allow the polymerization to occur [ 22 ]. The resulting solid monolith was removed and kept at room temperature until further use.…”

“…The thermal stability of the resulting solvent-treated microsphere-templated monoliths was further analyzed. Thermogravimetric analysis (TGA) determines the thermal stability of the material, indicating its stability against elevated temperature [22], as presented in Figure 7. The first deterioration of the monolith prepared using a 60:40 template/monolith ratio occurred at 243 • C, with the second degradation beginning at 332 • C. At 700 • C, the monolith samples had been completely degraded and converted into ashes.…”