Synthesis And Propelrties Of Novel Aromatic Polyamides And Polyimides Bearing Anthrone Moieties

Polyamide?PA?and polyimide?PI?are widely used in high-tech fields such as aerospace,microelectronics and optoelectronic materials.However,the rapid development of society has made the performance requirements of polymer materials in the high-tech field more demanding.The properties of traditional polyamids and polyimides have not fully met the needs of scientific and technological development,so it is particularly urgent to research and develop new monomers and polymers with better performance.In this work,two novel diamines?BATPPA and BAYPA?containing an anthrone structure were designed and synthesized based on bulk anthrone structural unit with a rigid planar structure,a series of novel polyamids and polyimides containing an anthrone structure are then prepared by polymerization with various aryl diacid chlorides and aryl dianhydrides respectively.The specific research contents are as follows:1.10,10-bis?4-hydroxyphenyl?-9?10H?-anthrone?BHPA?was prepared from anthrone,sulfoxide chloride and phenol by "one-pot,two-step" reaction,followed by nucleophilic substitution reaction with 5-chloro-2-nitrobenzotrifluoride?CNTB? gives10,10-bis[4-?4-nitro-2-trifluoromethylphenoxy?phenyl]-9?10H?-anthrone?BNTPPA?.Then,10,10-bis[4-?4-amino-2-trifluoromethoxyphenyl?phenyl]-9?10H?-anthrone,a new aromatic diamine monomer,?BATPPA??mp=195.9–196.7 ??,was obtained by reduction of Pd/C and hydrazine hydrate.Last,it is subjected to low-temperature polymerization with terephthaloyl chloride and other aryl dichlorides to obtain a series of novel PAs having a trifluoromethyl side group and an anthrone structure in the main chain.This series of polymers has a logarithmic viscosity of 0.46–0.79 dL/g,a high glass transition temperature?Tg=226.6–309.0??,and excellent heat resistance?the 10% weight loss temperature is 377.8–441.5 ??,800 ? residual carbon rate>53.4%),excellent solubility,soluble in common NMP,DMAc,DMSO,THF and other organic solvents at room temperature.The films has excellent optical transmittance?optical transmittance at 500 nm is above 89.0%?and good mechanical properties?the tensile strength is 52.8–101.7 MPa,the elastic modulus is 0.55–3.02GPa,and the elongation at break is 3.7–13.6%?.The results indicate that the introduction of a large volume of anthrone structure and a trifluoromethyl side group in the PA backbone resulted in excellent solubility and thermal properties of the polymer.2.The aromatic diamine monomer BATPPA prepared above is separately polycondensed with pyromellitic dianhydride and other aryl dianhydrides to form a corresponding prepolymer PAA.Then,through cast film formation and thermal imidization,six novel PI films containing trifluoromethyl and anthrone structures were obtained.The results show that PIs have good solubility in organic solvents such as NMP,DMAc,DMSO,CHCl₃ and THF,and their logarithmic viscosity is 0.60-1.15dL/g.The prepared PI films has outstanding thermal properties?Tg=259.0–329.4?,the 10% weight loss temperature>538.8 ?,the maximum weight loss rate>536.6?? and mechanical properties?the tensile strength is 50.2–84.3 MPa,the modulus of elasticity is 0.63–1.34 GPa,the elongation at break is 9.5–18.1%?.In addition,this series of PI films exhibit good optical properties?optical transmittance at 600 nm is above 80.2%?.At the same time,the low dielectric constant and low moisture absorption rate?0.71–2.70%? of them helps to expand their application range.3.From the perspective of molecular design,the aryl diphenol BHPA prepared above and 2-chloro-5-nitro pyridine?CRPD?for nucleophilic substitution reaction to get 10,10–bis[4-?5–nitropyridin–2-yloxy?phenyl]-9?10H?-anthrone?BNYPA?,and then,via reduction with Pd/C and hydrated hydrazine to give a novel aromatic diamine monomer,10,10–bis[4-?4–aminopyridin-2-yloxy? phenyl]-9?10H?-anthrone?BAYPA??mp=255.5-256.8??.Finally,a series of novel PAs containing pyridine ring and anthrone structure in the main chain were obtained by polymerization with aromatic diacid chlorides such as terephthaloyl chloride at low temperature.The series of polymers have a logarithmic viscosity of 0.47–0.94 dL/g and are soluble in strong polar organic solvents and even weakly polar tetrahydrofuran and pyridine solvents.The PA films has outstanding heat resistance?Tg=262.6–354.8 ?,the 5%weight loss temperature>415??,excellent mechanical properties?the tensile strength is 84.2–96.7 MPa,the modulus of elasticity is 1.96–3.15 GPa,the elongation at break is 3.8-13.1%?.In addition,the series of films have a cut-off wavelength of342–362 nm,and the light transmittance at 600 nm has exceeded 84%,that showing good optical transmission.The results exhibit that the introduction of a large volume of anthrone structure and a rigid pyridine ring in the PA backbone enables the polymer to have excellent solubility while maintaining excellent heat resistance and mechanical properties.4.The novel aromatic diamine monomer BAYPA prepared above is subjected to low temperature polycondensation reaction with pyromellitic dianhydride and other series of dianhydrides,and six novel PI membranes containing a pyridine ring and an anthracene structure were prepared by a physical imine method.The results show that the obtained PI films has both outstanding thermal properties?Tg=290.4–387.8 ?,the 5% thermal weight loss temperature is higher than 482.1?? and excellent mechanical properties?the tensile strength up to 116 MPa?.It can be dissolved in strong polar solvents such as NMP,DMF,DMAc,DMSO at room temperature,and the wavelength of 80%transmittance is higher than 594 nm,the XRD curves all show a broad dispersion peak indicating that the series of polymers have low crystallinity and are amorphous structures.