Elastomers with optimal mechanical performance and

healability are indispensable for applications such as wearable

electronics, automotive, and future robotics. Herein, an infrequent

strategy was developed to build graft copolymer elastomers with

polar polyacrylonitrile (PAN) as semicrystalline side chains and

poly(methyl acrylate) (PMA) as amorphous backbones, in which the

fraction of PAN segments and junction points was designed.

Miniemulsion polymerization was utilized to increase the incorpo-

ration of semicrystalline macromonomers into amorphous back-

bones. The resultant graft copolymer elastomers (PMA-g-PAN)

presented that the maximum toughness could reach 19.3 MJ/m3. For PMA-g-PAN with a PAN content of 10.6 wt % and appropriate

graft density (junction points of 10.1), the minimum residual strain was approximately 20% after the tenth stretch to 200% strain.

The maximum residual strain runs up to approximately 70% after the tenth stretch to 400% strain. Results indicated that high

toughness and excellent elasticity after cyclic stretching were assigned to the high molecular weight, optimized polar interaction

between cyano groups, and crystallinity of side chains (PAN, 10.6 wt %) as well as the numerous junction points (10.1) of the graft

copolymer. Additionally, elastomers in this work possessed excellent healability, and the healing efficiency was 82% under 50 °C only

by interaction between cyano groups in side chains. In this work, we report a superior and convenient strategy for improving

mechanical properties and prolonging the lifetime of polymeric elastomers only by importing polar and semicrystalline segments into

the graft copolymer elastomer.