关键词: 生物质呋喃衍生物, 受阻路易斯酸碱对, 线性聚硅醚, 随机共聚, 玻璃化转变温度

Poly(silyl ether)s (PSEs) are a class of polymers with Si-C-O linkages in the main chain. They feature high thermal stability, low glass transition temperature, flame retardancy and degradability, and thus hold broad application prospects in elastomers, gas-permeable films, and biocompatible coatings. The degradation behavior and functional properties of poly(silyl ether)s can be tailored by adjusting the sequence of structural units and molecular packing of the main chain. Therefore, the development of efficient catalytic systems for the mild synthesis of bio-based PSEs is highly desirable. In this work, a frustrated Lewis pair (FLP) catalytic system composed of an oxygen-bridged constrained planar arylborane (DOBA) as a weak Lewis acid and tri-n-butylphosphine oxide (TBPO) as a weak Lewis base was employed for the synthesis of bio-based PSEs under mild conditions. A series of biomass-derived furan monomers, including 2,5-diformylfuran (DFF), 2,5-bis(hydroxymethyl)furan (BHMF), and bis(5-formylfurfuryl) ether (OBMF), together with terephthalaldehyde (TPAL), were copolymerized with 1,4-bis(dimethylsilyl)benzene (1,4-BDSB) through stepwise method and one-pot method under mild conditions to efficiently synthesize furan-based poly(silyl ether) copolymers. The obtained polymers exhibited number-average molecular weights (Mn) ranging from 5.95 to 18.99 kDa, with dispersities (Đ) of 1.33-2.41. Thermal analysis revealed low glass-transition temperatures (T_g = -29.8 to -21.1 °C) and good thermal stability, with 5% weight-loss temperatures (T_d, 5%) ranging from 275.3 to 310.1 °C. Comparative analysis further indicated that the molecular structures of the monomers strongly influenced the thermal and thermomechanical properties of the resulting polymers: the incorporation of rigid aromatic units enhanced thermal stability, whereas flexible furan-derived ether segments favored lower T_g values. These results demonstrate that the structural diversity of biomass-derived monomers can be exploited to regulate the properties of PSEs. This work establishes an efficient metal-free FLP-catalyzed strategy for the synthesis of bio-based linear poly(silyl ether)s under mild conditions and provides a viable approach for integrating renewable furan-derived building blocks into sustainable silicon-containing polymeric materials.

Key words: Biomass furan derivatives, Frustrated Lewis pairs, Linear poly(silyl ether)s, Random copolymerization, Glass transition temperature