A new α-CBC polymer with elevated heat-resistance prepared via catalytic hydrogenation of α-methylstyrene-butadiene-styrene terpolymer over Ni_xPd/NCNT@MFN monolithic catalyst

Elevating the heat resistance of the highly transparent cyclic block copolymer (CBC) is of great significance for the synthesis of high-performance polymers. In this study, a novel bimetallic Ni_xPd/NCNT@MFN catalyst was prepared and applied in the hydrogenation of α-methylstyrene-butadiene-styrene (α-SBS) ternary block copolymer. Ni₂Pd/NCNT@MFN exhibited excellent catalytic performance, and after 8 h of reaction, a new fully hydrogenated polymer, α-CBC, was obtained. The hydrogenation of the butadiene segment in α-SBS became more difficult as the length of the segment increased. The presence of α-methyl resulted in the highest adsorption-activation energy for the α-methylstyrene monomer unit, leading to a longer hydrogenation time with increasing length of this segment. Furthermore, the introduction of α-methylstyrene not only increased the glass transition temperature of the styrene and α-methylstyrene (S) segments in α-SBS, but also increased the glass transition temperature of α-CBC even more after hydrogenation. This conclusion provides valuable theoretical guidance for the synthesis of high-heat-resistant α-CBC polymers.