Synthesis Of Hyperbranched Poly(Aryl Ether Ketone)s Via A₂+B₃ Approeach Improved By Monomer With Functional Groups Of Different Reactivity

In recent years ,hyperbranched polymers have become the focus of the field of polymer because of its unique architectures,properties and potential practical value.One of the hyperbranched polymer - poly(aryl ether ketone)s(PAEK) have better prospects because that it can improve the linear PAEK from several aspects.However,when it comes to the synthesis of Hyperbranched PAEK,both the ABn approach and the A2+B3 approach have its disadvantages respectively which limit the development of the hyperbranched PAEK.In this work,the nuclear idea of the latest approach which is used to synthesize hperbranched polymers is put to use. First of all,a new monomer(B3 type monomer)which has three phenolic hydroxys of different reactivity was synthesized.And then,4 hyperbraned PAEK were synthesized in traditional gelation area by changed the feed ratio of the A2 monomer and B3 monomer.From the results of the experiments,the new gelation area which is narrower than the traditional one of the new approach was confirmed.Meantime,the reactivity order of the phenolic hydroxys of the monomer was worked out by the theoretical and experimental methods.And the degree of branch(DB) of the synthesized hyperbranched PAEK were estimated by the synthesis of the model compounds.Hyperbranched PAEK with different chain structure were synthesized by the B3 monomer and different A2 monomers.With the study of the hyperbranched PAEK which we synthesized,we find that the more the feed ratio of A2 and B3 is closed to 1,the corresponding polymer have higher molecular weight and glass transition temperature(Tg).The viscosity of the polymers were also increase,but are still in a low range.And the hyperbranched PAEK have excellent solubility in general organic solvent. However,the synthesized hpyerbranched PAEK have low crystallizability. With the increased of chain length of the polymer,the solubility of the polymers were decrease.When the ratio of the ketone bonds increasing,the glass transition temperature(Tg) and crystallizability of the hyperbranched PAEK increase,and when ratio of the ether bonds increasing,the glass transition temperature(Tg) and crystallizability of the hyperbranched PAEK decrease.