Synthesis of cross-linked poly(methyl methacrylate) via dispersion polymerization in supercritical carbon dioxide

• Published in: Colloid and polymer science 2010-02, Vol.288 (3), p.271-282
• Main Authors: Shin, Jungin, Bae, Won, Kim, Hwayong
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon dioxide; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Crosslinking; Density; Dispersions; Exact sciences and technology; Field emission; Food Science; Nanotechnology and Microengineering; Organic polymers; Original Contribution; Physical Chemistry; Physicochemistry of polymers; Polymer Sciences; Polymerization; Polymethyl methacrylates; Preparation, kinetics, thermodynamics, mechanism and catalysts; Soft and Granular Matter; Thermal stability
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-009-2157-2

Cross-linked poly(methyl methacrylate) particles were prepared via dispersion polymerization in supercritical carbon dioxide (scCO₂) using poly(heptadecafluorodecyl methacrylate) (PHDFDMA) and 2,2′-azobisisobutyronitrile as the dispersant and the initiator, respectively. The following chemicals were used as cross-linking agents: ethylene glycol dimethacrylate (EGDMA), 1,4-buthanediol di(meth)acrylate (1,4-BD(M)A), and trimethylolpropane trimethacrylate. PHDFDMA was synthesized by solution polymerization in scCO₂. We investigated the effect of the chemical structure, concentration of the cross-linking agents, reaction pressure, and CO₂ density on the morphology, the polydispersity, and the cross-linking density of polymer particles. The resulting polymer particle was characterized by field emission SEM, differential scanning calorimetry, and thermal gravimetric analysis. The cross-linked PMMA particles is more agglomerate as the cross-linking agent concentration increased and as pressure decreased at constant temperature. Glass-transition temperature (T g) of the resulting polymer increased as the cross-linking agent increased with temperature and pressure increasing at the same CO₂ density. Decomposition temperature is slightly increased as 1,4-BDA concentration increased. From these results, we can confirm that the thermal stability of the polymer increased as the cross-linking agent and EGDMA is the best cross-linking agent in term of the thermal stability.