Inverse
vulcanization provides a facile route to transform industrial
byproduct sulfur into attractive polymeric materials with a variety
of applications. Herein, an inverse vulcanized copolymer (PSM) was
synthesized by copolymerization of biomass magnolol and sulfur. PSM
presents outstanding intrinsic flame retardancy by the formation of
a highly pyrolysis-resistant carbonaceous material during combustion.
Especially, it can serve as a multifunctional ingredient when utilized
in rubber composites. The presence of polysulfide segments and biphenol
moieties enables PSM to cross-link rubber effectively and react with
the oxygenic groups on the surface of carbon black (CB), thus resulting
in the improvement of CB dispersion and stronger interfacial interaction
between a rubber matrix and nanofillers than the conventional sulfur-cross-linked
rubber composite. Incorporation of PSM also significantly retards
the thermo-oxidation aging of the composites due to its radical scavenging
capability. Moreover, the dynamic covalent polysulfide segments in
the system confer the PSM-cross-linked rubber material reprocessability
and recyclability