Preparation Of Low-temperature Resistant Elastomers And Their Application In The Field Of Winter Tire

With the advancement of winter tire technology and the need for green development,tread rubber requires materials with excellent low-temperature resistance,ice skid resistance performance,fuel saving,and wear resistance,and hopes to gradually improve the proportion of sustainable tread material.Therefore,in this work,we designed and synthesized bio-based elastomers with different structures based on isoprene andβ-myrcene monomers using coordination polymerization.The application of the biobased low-temperature resistant elastomer in the field of winter tire materials was also carried out.The main work of this thesis is as follows.In the first part（Chapter 2 of the thesis）,poly（isoprene）（PI）,poly（myrcene）（PMy）,and poly（isoprene-myrcene）（PIMy）were prepared by choosing the coordination polymerization method and using rare-earth Nd-based catalyst to initiate the polymerization of isoprene（IP）andβ-myrcene（My）.The effects of catalyst system,polymerization temperature,and monomer feeding ratio on the polymerization of PIMy were investigated.The results showed that the number average molecular weight（M_n）of PIMy synthesized by the Nd（vers）₃/Al（i-Bu）₃/EASC catalytic system reached 1.6×10⁵g/mol.The catalytic system was able to control the microstructure of the polymers well,and the cis-1,4 structure content of PIMy exceeded 95%,which makes its T_g below-64°C and no crystallization at low temperature,and can meet the performance requirements of elastomer at low temperature.In the second part（Chapter 3 of the thesis）,silica and carbon black were used as fillers to reinforce PI and PIMy,and the properties were compared with commercially available butadiene rubber（BR）,natural rubber（NR）,and emulsion styrene-butadiene rubber（ESBR）.The dispersion of silica was improved after the addition of myrcene into isoprene-based elastomers,and the tensile strength of silica/PIMy composites decreased and the wet skid resistance was improved with the increase of myrcene content,and PIMy with My content of 5～20 mol%had better overall performance.PI and PIMy have better low-temperature resilience and wet skid resistance than BR and ESBR.Therefore,PIMy has the potential to be applied in the field of high performance winter tires.In the third part（Chapter 4 of the thesis）,PI and PIMy were incorporated into solution polymerized styrene-butadiene rubber（SSBR）to improve the low-temperature resistance of SSBR.The incorporation of PI and PIMy could improve the mechanical properties and low-temperature resilience of SSBR composites.The addition of PI and PIMy improve the loss factor of SSBR at-20°C and improves the ice skid resistance performance of SSBR.The friction coefficient test results showed that the addition of PI and PIMy significantly improved the friction coefficient of SSBR on ice surface with the maximum improvement of 161.1%.The two synthetic low-temperature resistant elastomer materials are expected to be used in the field of winter tires.