Novel tin‐coupled star‐shaped medium vinyl butadiene rubber. I. Arm number and its effect on properties

Abstract

To achieve low rolling resistance, high wet grip, and favorable overall performance, star-shaped medium vinyl butadiene rubber (S-MVBR) was designed and prepared by ''core-first'' method, where novel multifunctional organolithium containing Sn atom as initiator, THF as structure regulator, and carbon-hydrogen compound as solvent. The results showed that coupling reaction between SnCl 4 and dilithium is stoichiometrical, and this method has much higher efficiency than the ''arm-first'' method. When dilithium is composed of 4-10 repeating units, the average arm number of S-MVBR is conveniently controlled between 3 and 5 by initiator functionality, which can be easily regulated by the mole ratio of active lithium of dilithium short chain to Cl À in SnCl 4 . As Sn coupling decreases numbers of noncrosslinking free ends, S-MVBR has lower rolling resistance, dynamic heating and higher wet grip than linear MVBR. Meanwhile, mechanical properties and processing properties are improved. And the formation of multiarm structure has little effect on viscosity. S-MVBR with arm number of 3.8 has optimal overall performance.

Preparation, structure, and properties of end‐functionalized miktoarms star‐shaped polybutadiene–sn–poly(styrene–butadiene) rubber

“…It is reported that in the tire industry tan δ value of the tread rubber at 0°C represents its wet‐skid resistance and tan δ value of tread rubber at 60°C represents its rolling resistance. Therefore, the high performance tire tread material should have higher tan δ at 0°C and lower tan δ at 60°C . The temperature ( T ) dependence of the storage modulus ( E ′) and tan δ of four composites at a constant frequency are shown in Figure and Table .…”

Tin‐coupled star‐shaped block copolymer of styrene and butadiene (II) properties and application

“…7,8 The coupled structure of the tin-coupled rubber also benefits to the reduction of the rolling resistance, because it contains less amount of free chain terminals. 9,10 In our previous work, a novel multifunctional organo-lithium was used to synthesize a new kind of tin-coupled star-shaped block copolymer: tin-coupled polybutadiene-b-ploy(styrene-butadiene) ((SB-B) 4 Sn). This star-shaped block copolymer contained two different types, namely S-PB-PSB and S-PB-PSB-PS, depending on the styrene content in loading solution (St%).…”

“…Effect of the SnC bond transfer in the blending process could benefit the dispersion of carbon black so as to reduce the rolling resistance 7, 8. The coupled structure of the tin‐coupled rubber also benefits to the reduction of the rolling resistance, because it contains less amount of free chain terminals 9, 10…”

Synthesis of a novel star polymer consisting of a dendritic polyamidoamine core and polystyrene arms and its self‐assembly to form large multimolecular micelles

“…One is the so‐called arm‐first method, in which reactive linear polymers are coupled with a multifunctional reagent 4–10. The other is the so‐called core‐first method, in which a multifunctional initiator is used to initiate the polymerization of a monomer to form a multiarm star polymer 11–13. Dendrimers and hyperbranched polymers, with numerous functional groups, have been used as core moieties for the preparation of star polymers 14–19…”