Study on the performance of methyl methacrylate polymerization: Comparison of partially oxidized tri-n-butylborane and benzoyl peroxide with aromatic tertiary amines

• Published in: Dental Materials Journal Vol. 38; no. 3; pp. 430 - 436
• Main Authors: INAMI, Chidzuru, SHIMIZU, Hirohisa, SUZUKI, Shiro, HARAGUCHI, Naoki, ITSUNO, Shinichi
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Society for Dental Materials and Devices 01.06.2019; Japan Science and Technology Agency
• Subjects: Amines; Benzoyl peroxide; Bulk polymerization; Chemical industry; Conversion; Dental material; Dentistry; Electron paramagnetic resonance; Electron spin; Electron spin resonance; Methyl methacrylate; Molecular weight; Peroxide; Polymerization; Polymers; Polymethyl methacrylate; Polymethylmethacrylate; Spin resonance; Tri-n-butylborane; Polymerization; Tri-n-butylborane; Dental material; Methyl methacrylate
• ISSN: 0287-4547; 1881-1361
• DOI: 10.4012/dmj.2018-166

In this study, we examined the polymerization performance of methyl methacrylate (MMA) initiated with partially oxidized tri-nbutylborane (TBBO) compared to that initiated with benzoyl peroxide and aromatic tertiary amine (BPO/amine) system. In the bulk polymerization of MMA at 37°C, conversion initiated with TBBO after 3 h was nearly quantitative, whereas the conversion with the BPO/amine system was low (~20%). The number-averaged and weight-averaged molecular weight of the TBBO-initiated polymer was more than twice as high as that of the BPO/amine-initiated polymer. Electron spin resonance (ESR) analysis of MMA polymerization indicated that the TBBO-initiated system maintained its radical intensities for a longer period than the BPO/amine-initiated system. Furthermore, the radical fragments in the TBBO-initiated PMMA after 72 h were still active as a polymerization initiator for MMA. These findings suggest that the polymerization mechanism of MMA initiated by TBBO functions as a living-like polymerization initiator.