Synthesis Of Bio-Based Heterocyclic Poly(aryl Ether Ketone)s And Their Performances

In recent years,with the massive loss of non-renewable resources,the efficient utilization of renewable biomass resources has become an importing solution for alleviating resource and environmental problems.Bio-based PAEKs have become an important research and development direction for sustainable,high-performance thermoplastic resins in the future.However,there are few kinds of monomers with aromatic ring and aromatic heterocyclic that can be used to prepare bio-based PAEKs.This study aims to prepare bio-based PAEKs with good thermal performances,processability and excellent mechanical properties.From the perspective of molecular structure design,a series of bio-based monomers containing aromatic heterocyclic structure with polymerization activity were prepared and then were employed to synthesize bio-based PAEKs.The main work of this study is as follows:（1）In order to prepare bio-based PAEKs with good heat resistance,mechanical properties and processability,two kinds of aromatic heterocyclic bio-based monomers,BFBF and GSPZ,have been selected to prepare a bio-based PAEK（PGFEKK）by a nucleophilic substitution route.The optimal polymerization conditions for nucleophilic substitution were explored by orthogonal experiments to synthesize PGFEKK with high molecular weight,which proved that the two bio-based monomers had sufficient nucleophilic polymerization reactivity.The biomass content of the resin reached 58.7%,improving the utilization rate of renewable energy.T_g of PGFEKK resin was 212℃and T_d10%was 452℃,showing excellent heat resistance and thermal stability.E’at 25℃was 2207 MPa,and theσ_t and E_t were 84 MPa and1.81 GPa,respectively,showing excellent mechanical properties.Besides,the resin had excellent thermoforming and solution processing capabilities.In this experiment,the petroleum-based monomers DHPZ and BFBB were used to replace the two bio-based monomers to prepare other three kinds of PAEKs,in order to study the effect of monomers on polymer properties.（2）In order to prepare thermos-reversible cross-linking bio-based PAEKs to improve mechanical properties,solvent resistance and processability,two novel bisphenols,BPF-M and BPF-AM,containing aromatic ring monomers with polymerization activity and Diels-Alder reaction activity were synthesized in this study.FT-IR and ¹H NMR tests demonstrated that both monomers were successfully prepared.BMI was used to carry out DA model reaction with two bisphenols,which proved that the DA reaction was successfully carried out.The nucleophilic copolymerization of two bisphenols and BFBF was successfully carried out to prepare PAEKs,proving that both monomers had sufficient polymerization activity.Gels of the two resins were prepared by DA reaction of BMI with linear polymers.By comparing the DA reactivity,nucleophilic polymerization activity,polymer properties and polymer DA reactivity,BPF-M was selected to prepare bio-based cross-linkable PAEK copolymers.（3）In order to prepare bio-based PAEK with good thermal resistance,processability,excellent mechanical properties and reusable ability,BPF-M,BFBF and GSPZ were used as comonomers to prepare a series of polymer LINKERs.The DA reaction between macromolecules improved the mechanical properties and solvent resistance.The biomass content of LINEKRs was 58.7-72.8%,which was the highest in the current literature.The three monomers had sufficient nucleophilic copolymerization activity.LINKERs had high molecular weights,good thermal properties(T_g was 182-212℃,T_d10%was 415-452℃),thermoforming and solution processability.Bio-based thermally reversible PAEK gels and cross-linked films were prepared through DA reaction of LINKER-73 and BMI.Gel testing demonstrated the material had ability to be reprocessed and recycled.The cross-linking film had excellent solvent resistance and the tensile strength was upgraded（from 75 MPa to 101MPa）.