Study on the structure and properties of SSBR with large-volume functional groups at the end of chains

• Published in: Polymer (Guilford) 2010-04, Vol.51 (9), p.2084-2090
• Main Authors: Wang, Lei, Zhao, Suhe, Li, An, Zhang, Xingying
• Format: Article
• Language: English
• Subjects: Applied sciences; Copolymerization; Dispersions; End-capping modification; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; Solution polymerized styrene-butadiene rubber (SSBR)
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2010.03.006

Solution polymerized styrene-butadiene rubber (SSBR) and SSBR with tert-Butylchlorodiphenylsilane (TBCSi, large-volume functional groups) at the two ends of macromolecular chains (T-SSBR) were prepared by anionic polymerization. The molecular structure parameters of T-SSBR and SSBR were characterized and the ratio of the amount of macromolecular chain ends connected with TBCSi to total macromolecular chain ends (i.e., end-capping efficiency) was calculated. The comprehensive properties of T-SSBR and SSBR composites filled with carbon black (CB) were investigated. The results showed that T-SSBR composites presented lower Payne effect (namely better CB dispersion) than those of SSBR composites, which led to decrease in hardness, internal friction, dynamic compression heat built-up and permanent set of T-SSBR composites, significant increase in tensile strength, elongation at break, tear strength and resilience of T-SSBR composites, and excellent balance between wet-skid resistance and rolling resistance. However, compared with SSBR composites, T-SSBR composites presented longer stress-relaxation time, bigger die-swell and higher apparent viscosity, as well as slightly inferior dynamic-cutting resistance. All the above, owing to the end-capping of TBCSi, which could immobilize the free chain ends of T-SSBR (i.e., to reduce the friction loss of molecular chains and create a greater degree of orientation in the force field), and adsorb CB, the comprehensive performances of T-SSBR were better than those of SSBR and T-SSBR terminated with styrene-TBCSi (TS-SSBR) were far superior to those of T-SSBR terminated with butadiene-TBCSi (TB-SSBR). Accordingly, the former was suitable for the tread of green tires. [Display omitted]