The invention relates to a polydialkene composite rubber of trans-1,4- structure and preparation methods thereof. The composite rubber consists of 10 to 80
mass percent of trans-1,4-polyisoprene and 20 to 90
mass percent of trans-1,4-butadiene-
isoprene copolymer, wherein over 90 percent of structural units of all dialkenes in the composite rubber have trans-1,4-structures. The first preparation method comprises the following steps of: homopolymerizing
isoprene to obtain trans-1,4-polyisoprene by adopting a Ziegler-
Natta catalysis system consisting of MgCl2 supported
titanium and organic aluminum compound, and then adding butadiene to synthesize the trans-butadiene-
isoprene copolymer. The second preparation method comprises the following steps of: adding mixed monomers of butadiene and isoprene into a
polymerization device at the same time, performing copolymerization to obtain the butadiene-isoprene
copolymer of the trans-1,4-structure, and continuously polymerizing the isoprene to obtain the trans-1,4-polyisoprene after the butadiene with high
polymerization speed is completely consumed. The used
polymerization device is a stirring reaction kettle or a screw extruder. The composite rubber has excellent performance such as low
rolling resistance, low generated heat, abrasion resistance, particularly fatigue break increment resistance and the like, and is suitable for dynamically used rubber products such as tyres,
vibration absorption materials and the like.