Fully bio-based furyl-functionalized bisphenols and bio-based cross-linking poly(aryl ether ketone)s with high biomass content, thermo-reversibility, excellent processing and mechanical properties

Poly(aryl ether ketone)s (PAEKs) exhibit excellent thermal and mechanical properties, but their poor processability limit further application. In this regard, a bio-based cross-linking high-performance PAEK was prepared through the Diels-Alder (DA) reaction between furyl-functionalized PAEK and N,N'-4,4′-diphenylmethylene-bismaleimide (BMI). First, two novel fully bio-based furyl-functionalized bisphenols, BPF-M and BPF-AM, were prepared by simple one-step aromatic substitution of two bio-based o‑methoxy-phenols and furfural. Orbital interaction of the DA reactions between the two bisphenols and BMI was investigated with B3LYP density functional method, and the quantitative study was performed with DSC and 1 H NMR. Next, a series of PAEKs (LINKERs) with high biomass content of 58.7–72.8% were prepared with BPF-M, 2,5-bis(4-flurobenzoly)furan (BFBF) and 6-(4hydroxy-3-methoxyphenyl)pyridazin-3(2H)-one (GSPZ). LINKERs had excellent thermal properties (T g  = 182–212 °C, T d10%  = 415–452 °C), processing properties (lowest rheology viscosities = 178–3217 Pa·s) and solution processability. Finally, PAEK themo-reversible gel and cross-linking film were prepared through the DA reaction between LINKER-73 and BMI. The film had solvent resistance and high tensile strength, which increased from 75 MPa to 101 MPa compared to the uncrosslinked one. Besides, LINKERs gained the ability of reprocessing and recycled via DA and r-DA reactions. We expect to provide important theoretical and practical references on bio-based furyl-functionalized bisphenols and high-performance PAEKs.