Recyclable polyvinylidene fluoride/silicone rubber (PVDF/SR) thermoplastic vulcanizates (TPVs) containing a high mass ratio of SR (50%) with excellent mechanical performances and shape memory behavior were fabricated. The inert PVDF was first dehydrofluorinated via β-H elimination reaction to introduce reactive double bonds. Then, the functional groups were initiated by dicumyl peroxide (DCP) during dynamic vulcanization to realize interfacial grafting (SR-g-PVDF) simultaneously. In situ grafted PVDF chains tightly bridge the immiscible phases, leading to the excellent interfacial adhesion. Consequently, the tensile strength, elongation at break, and tensile toughness were significantly increased to 14.5 MPa, 174.6%, and 12.3 kJ/m3, respectively, which were almost 2.0, 13.6, and 10.3 times than that without interfacial grafting reaction (7.2 MPa, 12.8%, and 1.2 kJ/m3). Also, their excellent mechanical properties were almost perfectly maintained after multiple repetitive processing. Furthermore, the chemical anchoring structure of SR-g-PVDF across the interface could effectively and quickly transfer the force, contributing to the shape memory performances. The obtained TPVs (m60 and m80) showed an impressive shape recovery ratio (>80%) even after two fixing-recovery cycles.
Despite great progress on the heterogeneous catalytic methoxycarbonylation of alkenes, the research on long-chain substrates is yet undeveloped. In this study, an efficient protocol was built by introducing 1-butyl-3-methylimidazole chloride (BmimCl) additive to the catalytic system of ceria-supported Ru clusters (Ru-CeO 2 ), providing the aliphatic esters with yields over 80 %. Experimental results combined mechanism studies demonstrated that the adsorption of chloride ion at oxygen vacancy (Vö) of CeO 2 during the catalysis delivered surfaces with reduced local concentration of Vö and electron-richer Ru sites. The synergistic effect between Vö and chloride ion boosted methanol (CH 3 OH) dissociation, providing higher coverage of dissociated CH 3 O species with lower adsorption energy and thereby accelerating the rate-limiting step of methoxycarbonylation. Importantly, the β-H elimination for competitive isomerization process was greatly inhibited on the electron-richer Ru sites. Meanwhile, the side hydrogenation was further suppressed by the restrained freedom of adsorbed H at such surfaces. These positive effects jointly offer a heterogeneous catalytic system of both efficient and selective on the challenging long-chain alkene substrates, taking methyl-4-pentenoate and chain alkenes with 6, 8, 10 and 12 carbon atoms as examples.
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