Grafting of Butadiene–Acrylonitrile Copolymer onto High
Vinyl Polybutadiene by Copolymerization
Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of
Science & Technology, Qingdao, China
XIN WANG, JING HUA
Institute of polymer Engineering and Science, Qingdao University of Science & Technology, Qingdao, 266042 China
Correspondence to: X. Wang; e-mail: firstname.lastname@example.org. and J. Hua; e-mail: email@example.com.
Received: January 27, 2016
Accepted: July 7, 2016
High vinyl polybutadiene-graft-(hydroxyl-terminated butadiene–acrylonitrile copolymer) (HVPBR-g-HTBN) was
successfully synthesized through the copolymerization of butadiene and HTBN using a molybdenum (Mo)-based catalyst. The
results indicated that the grafting coefﬁcient of the product was <1 and the nitrogen content of the product was higher than that of
linear HVPBR, demonstrating the grafting during the copolymerization by the Mo-based catalyst. Upon grafting, the intrinsic vis-
cosity of the product’s solution was lower, while the molecular weight was higher than that of linear HVPBR. Moreover, the
apparent viscosities of concentrated solutions of grafted products were lower than the linear counterpart, despite their higher
molecular weight. © 2016 Wiley Periodicals, Inc. Adv Polym Technol 2018, 37, 21750; View this article online at wileyonlinelibrar-
y.com. DOI 10.1002/adv.21750
Butadiene, Coordination polymerization, Grafting, HTNB
ecently, the amorphous high vinyl polybutadiene rubber
(HVPBR, molar mass of 1,2-unit more than 70%) has
received increasing attention due to the promulgation of the
Tire Labeling Law, which requires good wet skid resistance
and low rolling resistance of the tires. HVPBR has been
widely used in green, safety tires in consideration of its vari-
ous advantages such as excellent wet skid resistance, low roll-
ing resistance and good age resistance performance.
Molybdenum (Mo)-based catalysts have been successfully
applied in synthesizing atactic HVPBR with the content of 1,2-
unit over 80% and a trace of gel.
However, because of its
high molecular weight and narrow molecular weight distribu-
tion, a common technical problem in the synthesis of HVPBR
is the extremely high viscosity of the polymerization mixture
which is a thick slurry at the commercially desirable polymer
concentration of 10–25% by weight. To tackle the problem,
recent efforts have been made on reducing the molecular
weight of the polymer by adjusting the polymerization condi-
tions, types of catalyst, the molar ratio of the main catalyst
and co-catalyst, or by adding molecular weight regulators.
Nevertheless, the results reveal that the reduction in molecular
weight cannot effectively decrease the high viscosity of the
polymerization mixture, although it played an important role
on the viscosity of the bulk polymers.
Over the past ten years, our group has been working on
decreasing the viscosity of HVPBR reaction solution by vari-
ous methods, among which the most reliable way was to con-
trol the topology construction of the synthesized polymer and
consequently adjusted its visco-elastic behaviors.
constructions of polymers have attracted intense interest of
researchers due to the versatility of the topological structures
and their remarkable effects on the visco-elasticity.
polymer, which has a minimum hydrodynamic volume and
solution viscosity in comparison with that of the linear poly-
mer at the same molecular weight, is an example of topology-
constructed polymers. Grafting of polymers is a common
method to modify the topology with the convenience of easy
preparation. In contrast with the method of adjusting molecu-
lar weight, grafting can change the viscosity of the polymer-
ization reaction solution and the visco-elastic effects of the
polymers and provide an extra promotion of the compatibility
It is accepted that one of the most
widely adopted ways of grafting of polymers is to
Advances in Polymer Technology, Vol. 37, No. 4, 2018, DOI 10.1002/adv.21750
© 2016 Wiley Periodicals, Inc.
21750 (1 of 6)