Synthesis and properties investigation of hydroxyl functionalized polyisoprene prepared by cobalt catalyzed co-polymerization of isoprene and hydroxylmyrcene

• Published in: Polymer chemistry Vol. 11; no. 12; pp. 234 - 243
• Main Authors: Xu, Yuechao, Zhao, Junyi, Gan, Qiao, Ying, Weilun, Hu, Zhonghan, Tang, Fuming, Luo, Wanwei, Luo, Yunjie, Jian, Zhongbao, Gong, Dirong
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.03.2020
• Subjects: Bonding strength; Cobalt compounds; Copolymerization; Core loss; Crystallography; Fillers; Fourier transforms; Glass transition temperature; Hydrogen bonds; Hydrophobicity; Isoprene; NMR; Nuclear magnetic resonance; Phosphine oxide; Polymer chemistry; Rubber; Silicon dioxide; Stretchability; Tensile strength
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c9py01808e

The intrinsic hydrophobicity of rubber matrices renders compatibility with polar fillers rather difficult in most cases. In this manuscript, a cobalt complex supported by a 2-oxazoline-pyridine ligand armed with a labile 6-(di- tert -butyl-phosphine oxide) moiety is prepared and characterized. In combination with excess AlEt 2 Cl, the precursor actively copolymerizes isoprene with the bio-sourced myrcene derivative 2-methyl-6-methyleneoct-7-en-3-ol with adjustable comonomer incorporation from 4.4 mol% to 31.5 mol%. The presence of hydroxyl functionalized polyisoprene was characterized by using Fourier transform infrared spectroscopy, 1 H/ 13 C NMR, and validated by the improved hydrophilicity, elevated glass transition temperature and microphase separation observed by AFM. Up to 30 wt% SiO 2 loading can be individually dispersed in the 4.4 mol% hydroxyl functionalized polyisoprene copolymer with substantially reduced aggregation. The improved filler-polymer interfacial interactions via "hydrogen bonds" offer not only effective improvement of the tensile strength (9.6 ± 0.2 MPa), but an unusual stretchability of over 885.3 ± 2.0% and improved hysteresis loss with respect to pristine polyisoprene/SiO 2 vulcanizates. Controlled copolymerization of isoprene and hydroxylmyrcene afforded well-defined hydroxyl functionalized polyisoprene. Blends of functionalized polyisoprene/SiO 2 displayed enhanced miscibility, and remarkable vulcanization and mechanical properties.