Molecule-Design, Preparation, Characterization And Functionalization Of Hyperbranced Poly(Aryl Ether Ketone)s

In the past decade, hyperbranched polymers have attracted more and more attention and large amounts of hyperbranched polymers have been prepared. Because of their unique architecture, these polymers show attractive properties such as low viscosity and excellent solubility in organic solvents. Hyperbranched polymers are typically prepared by self-condensation reaction of AB2-type monomers. Here, A and B represent two kinds of functional groups which can react with each other but cannot undergo self-reaction. However, the direct synthesis of a hyperbranched polymer from a monomer containing one hydroxybenzene and two flourbenzophenon (or one flourbenzophenon and two hydroxybenzene groups) is much restricted by the AB2-type monomers, which are not always commercially available, and access to the monomers sometimes involves in tedious multistep organic synthesis, especially, is cumbersome to synthesize and purify a new functional AB2 monomer. Recently, the synthesis of hyperbranched polymer by A2 + B3 polymerization approach has been reported. The hyperbranched polymer obtained by A2 + B3 approach have a loose-packing, low branching density topology with a high solution viscosity compared with that prepared by AB2 approach. Therefore the polymers prepared by nonideal A2 + B3 polymerization have strong chain entanglement and intermolecular interaction. Moreover, the A2 + B3 polymerization approach shows many advantages, such as facile preparation and scaling up, easy to tailor structure, etc. In this work, a nideal A2+B3 polymerization strategy was employed for the preparation of hyperbranched poly(aryl ether ketone)s (HPAEK). The terminal units and the thermal stability, crystallizability and functionality of the polymer were controlled by using different A2 /B3 ratio and varying tailor structure and chain length of A2, respectively. The controllable aggregate structure, molecular weight and functionization laid the groundwork for the molecule-design, preparation, characterization and functionalization of PAEKs. Firstly, a new trifluoro-end groups containing an aryl ether ketone structure, 1,3, 5-tris [4-(4-flourobenzoyl) phenoxy] benzene (B3 type monomer) was synthesized. Nine insoluble hyperbranched PAEKs were obtained by changing the structure and the length of A2 monomer. The glass transition temperature (Tg) of polymer increases with increasing chain length between branching points, rigidity of the backbone and polarity of the chain-end functional groups. By contraries, thermal stability of polymer decreases with increasing chain length between branching points, rigidity of the backbone and polarity of die chain-end functional groups. Then typical hyperbranched PAEK was selected to blend with the linear PAEK for the preparation of composites. The rheological results show that both the G' and G" of the composites are lower than that of pure PEEK, the same with the shear viscosities within the shear scope, which indicates that the hyperbranched PEEK act as lubricant in the molecular chain of linear PEEK. Secondly, flourine-contained optical waveguide materials have been synthesized by table approach using B3 and functionalized A2 as monomers. If the polymers have the same terminal units, the more the functional groups, the lower the refractive indexes. If the amounts of functional group are similar, the refractive indexes of the polymers with functional group bonded to aryl group are lower than that of...