Synthesis And Characterization Of Poly(Aryl Ether Ketone) And Poly(Aromatic Esters) Containing Alkyl Side Chains

There are some ways to improve the processibility of rigid polymers in practical application. Adopted the method of the grafted flexible side chain in this paper, a serious of comb-like rigid polymers with alkyl side-chains were synthesized by after grafting method and before grafting method respectively. The structures of the monomers, intermediates and polymers were confirmed by Fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance(NMR), matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS) and X-ray diffraction(XRD). Furthermore, the thermal property was confirmed by differential scanning calorimetry(DSC).Poly(aryl ether ketone) as main chains, a series of rigid polymers with alkyl side-chain containing different lengths and contents were synthesized via the after grafting method which grafted alkyl groups to the main chains. The common layered crystal structure formed in many comb-like rigid copolymers with alkyl side chains was not observed in this case due to the hydrogen bonding interaction between carboxyl groups limiting the mobility of the alkyl side chains. From the DSC data, the glass transition temperatures of these grafted polymers decrease. The content of side chain is the main factor affecting the glass transition temperatures of the grafted polymers, while the hydrogen bonding interaction between carboxyl groups and the length of the side chain are the secondary factors.From the view of molecular structure, the diacid monomers 5,5'-methylenedisalicylic acid with different lengths of alkyl chain were designed and synthesized via the before grafting method, which were further used to synthesize the grafted polyesters with alkyl side-chain. The structure and thermal properties of the monomers and the polyesters were characterized in detail. The results show that crystal structures do not exist in the polyesters, which is due to the short alkyl side-chain. With the increase of the length and the content of side chain,the glass transition temperatures of the polyesters decrease.