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