Semi‐fluorinated polyarylenes: Microwave‐assisted synthesis and structure–property relationships

Abstract

A series of three fluorine containing and three non-fluorinated Diels-Alder step-growth polyarylene polymers and copolymers was synthesized via conventional oil bath heating (days/weeks). A drastic time reduction was realized with a microwave-assisted polymerization (hours). The polymers were characterized by multinuclear (1 H, 13 C, and 19 F) NMR and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, thermal analysis (thermogravimetric analysis [TGA], differential scanning calorimetry [DSC], and dynamic mechanical analysis [DMA]), gel permeation chromatography, X-ray diffraction (XRD), water contact analysis, and refractive index (RI) measurements. The NMR spectra indicated a mixture of para and meta conformations through the polymer backbone increasing to more para with greater fluorine content. TGA revealed the fluorine-containing polyarylenes possessed the highest char yields at almost 80% at 1000 C under nitrogen, and all the polyarylenes possessed onset of degradation temperatures above 550 C under nitrogen and air atmospheres. XRD analysis indicated more ordering for the fluorine-containing polyarylenes which afforded the high char yields. DMA gave storage moduli values in the range of 1-10 GPa for the polyarylenes. Molecular weights for all samples were above 100 kg/mol. Water contact angles did not change with fluorine content due to the shielding effect of the pendant phenyl groups. However, the RI decreased to 1.6497 at 632.8 nm for the polyarylene with the highest fluorine content.

Synthesis and characterization of phenylated phenylenediamine and bisphenol a diglycidyl ether epoxy networks

“…The mixture of the para and meta isomer configurations could lead toward further tailoring of chemical and thermomechanical properties if the isomer ratio can be controlled during the synthesis. 9 Curing and glass transition temperature curves were studied with DSC. ATR-FTIR was used to characterize the cured networks' structures.…”

“…Microwaveassisted polymerization has also been demonstrated with this system, resulting in a decrease in reaction time. 9,10 Depending on the approach of the reactants, the possible Diels-Alder products exist as a mixture of the para and meta conformations, with the isomer ratio changing slightly when the reaction temperature is changed. 11,12 No further confirmation has been shown or reported in the literature specifically for the polyarylene system.…”

Synthesis, characterization and nanoparticle formation of polyarylene poly(amic acid)s and polyimides containing fluorescent dye moieties

“…The DSC results indicated the typical high T g characteristic of other polyarylenes. 50 The T g values for the naphthalene and perylene polyimides were 381 and 396°C, respectively. Perylene is a more aromatic dye as compared to naphthalene and even though the perylene-containing polyimide is of lower molecular weight, the higher T g is likely due to the greater rigidity.…”

On the evolution of sulfonated polyphenylenes as proton exchange membranes for fuel cells

“…71 Similar findings have been reported using non-sulfonated Diels-Alder polyphenylenes, where the molecular weight of a phenylated polyphenylene obtained from a 35 h MW-assisted polymerization was higher than that of the same polymer obtained from a 480 h conventional (thermal) polymerization. 214 Water transport through sulfo-phenylated polyphenylenes. The water transport within prefunctionalized sPPPs was investigated by Y. Wu et.…”