Highly cis‐1,4 Selective Living Polymerization of Unmasked Polar 2‐(2‐Methylidenebut‐3‐enyl)Furan and Diels–Alder Addition

The polymerization of a new polar diene‐based monomer 2‐(2‐methylidenebut‐3‐enyl)furan (MBEF) without masking is achieved by using the bis(phosphino)carbazoleide‐ligated yttrium (Y) alkyl complex upon the activation of [Ph₃C][B(C₆F₅)₄]. Under mild conditions, the polymerizations under the monomer‐to‐Y ratios ranging from 100:1 to 500:1 perform fluently in high yields. The afforded polydienes bearing pendant terminal furan groups have high cis‐1,4‐regularity up to 98.6% and molecular weights close to the theoretic values and narrow polymer dispersity index(PDI) (1.13–1.17) suggesting a livingness polymerization mode. In addition, this novel polydiene is an excellent building block for preparing functional rubber materials. For example, via Diels–Alder addition of furan groups under mild conditions, hydroxyl groups are successfully introduced on the side chains efficiently in a 75% conversion. Furthermore, the copolymerization of polar MBEF and nonpolar isoprene is also successfully realized by the bis(phosphino) carbazoleide‐ligated scandium analog to access furan‐modified cis‐1,4 (>97%) polyisoprene with different MBEF contents (5.3%, 8.7%).     

Filler networks in elastomers

Elastomers are soft materials that can be reinforced by dispersing into them nanosized solid particles. Common examples of the latter are silica or carbon black aggregates. However, the mechanism of reinforcement is still not yet fully understood. Our work consists in investigating by small-angle X-ray scattering (SAXS) the structure of the aggregate network spreading throughout the matrix in the initial sample and its modification during and after straining (elongation). The goal is to relate the macroscopic mechanical behaviour with the structure of the aggregate network. The present paper is a qualitative overview of recent results obtained on well defined composites.