Bottlebrush Cell- <i>g</i> -PBA- <i>b</i> -PMMA Copolymer Elastomers with Disentangled Short Side Chains To Possess Applicable Mechanical Properties

The traditional thermoplastic elastomers are usually linear block polymers, and there is little research on bottlebrush copolymers as thermoplastic elastomers. The lengths of the grafted side chains are usually much shorter than those of the backbone of bottlebrush copolymers, so the mechanical properties are generally not strong enough for applications. Herein, we choose rigid cellulose as the backbone and the poly(n-butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) diblock as the side chains to obtain bottlebrush Cell-g-PBA-b-PMMA copolymer elastomers with disentangled short side chains, which still show applicable mechanical properties. It is found that the self-assembly of PBA-b-PMMA diblocks and orientation of rigid cellulose backbones play important roles on the resistance of the bottlebrush copolymers to tensile deformation due to the physical cross-linking points formed by PMMA hard microdomains and the reinforcing effect of orientated cellulose backbones. The self-assembled microphase morphology and the evolution of the microstructures for the bottlebrush Cell-g-PBA-b-PMMA copolymer elastomers prior to and after tensile deformation have been investigated and reveal the relationships between the internal microstructures and mechanical properties. This study provides an important theoretical basis for the bottlebrush copolymers as a new candidate of thermoplastic elastomers.