Terephthaloyl Chloride Research Articles

Non-destructive modification of aramid fiber by building nanoscale-coating solution to enhance the interfacial adhesion properties of the fiber-reinforced composites

The poor interfacial adhesion between the aramid fiber (AF) and the matrix limits the application of the final composites. In this study, a novel coating method was adopted to modify AF Through metallization/grafting reaction, the copolymer synthesized by the low-temperature poly-condensation of p-phenylenediamine (PPDA), 4,4′-diaminodiphenyl ether (ODA) and terephthaloyl dichloride (TPC), was added into the dimethyl sulfoxide/sodium hydride (DMSO/NaH) solution, and a nano AF solution was obtained. Then epoxy groups were introduced to the amide bond by grafting Epichlorohydrin (ECH). By further grafting on Poly (propylene glycol) bis (2-aminopropyl ether) (PEA), more functional groups were introduced, which could increase the polarity of the fiber and the interfacial adhesion of the composites. The results show that not only the interfacial shear strength (IFSS) and the flexural strength of the aramid-reinforced composites has a significant increase compared with the untreated fibers, but the modification still maintains the mechanical properties of the fiber, indicating that building nanoscale coating solution is a very effective method to achieve non-destructive modification to ehance its interfacial adhesion with epoxy resin.

Finely tailored pore structure of polyamide nanofiltration membranes for highly-efficient application in water treatment

• PIP has been applied as a structure regulator to enlarge pores of PA NF membranes. • The addition of PIP enhances the permeance by 97.3% with rejection of MO above 98%. • TPC has been deployed for narrowing pore size distribution of the PA NF membranes. • The incorporation of TPC enhances rejection to positive multi-valent ions greatly. • The finely tailored membranes show strong promise in waste water treatment. With fine pore structures and abundant surface charge, polyamide nanofiltration membranes have been widely deployed for separating small active organic molecules and multi-valent ions. However, lack of highly permeable membranes with excellent rejection towards target molecules hampers the widespread application of the polyamide (PA) nanofiltration membranes on a large scale. In current study, we conceive a facile strategy to regulate the molecular structure of polyamide selective layer through introducing piperazine (PIP) or terephthaloyl chloride (TPC) as a structural regulator during the interfacial polymerization between polyethyleneimine (PEI) and trimesoyl chloride (TMC). On the one hand, adding PIP to aqueous solution enlarges the length between the crosslinked networks, thereby enhancing the pure water permeance by 97.3% (to 23.70 L m −2 h −1 bar −1 ). Interestingly, the membranes exhibit excellent performance for dyes separation (rejection greater than 98%) and molecular weight cut-off (MWCO) about 554.34 Da under the optimum separation conditions. On the other hand, the introduction of TPC could assist the formation of crosslinked structures, thereby narrowing the pore size distribution of the membranes. The well-designed membranes reject above 98% PbCl 2 with permeance about 6.36 L m −2 h −1 bar −1 and MWCO below 150 Da under the optimum operation conditions, which is preferable to the state-of-art PA membranes. Excitingly, all of the well-designed membranes demonstrate excellent anti-fouling performances. In summary, with finely tailored pore structure, high permeance and high rejection, and excellent anti-fouling performance, the obtained membranes show strong promise in treating effluence from printing and dyeing industry, and metallurgy and mining industry, respectively.

Partially Bio-based Colorless and Transparent Poly(amide-imide)s Derived from 2,5-Furandicarboxylic Acid

Two series of partially bio-based colorless and transparent poly(amide-imide)s (CPAIs) derived from bio-based 2,5-furandicarboxylic acid (FDCA) were synthesized by a two-step condensation reaction. 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride, 2,2′-bis(trifluoromethyl)benzidine, and terephthaloyl chloride were used as basic monomers for the CPAIs. The highest bio-based content of the CPAIs was 11.32%. With increasing contents of FDCA units in the CPAIs, their glass transition temperatures and mechanical properties decreased gradually due to the decreased intermolecular interactions, whereas their transparency and yellowness indices were not significantly affected. The overall properties of the CPAIs are believed to be suitable for applications in optoelectronic device industries.

Synthesis and characterization of new thermally stable, antimicrobial and red-light-emitting poly(azomethine-ester)s

Two new diphenol Schiff base monomers were prepared through condensation reaction between 4-hydroxybenzaldehyde and 4,4′-diaminodiphenyl sulfone (dapsone) or 1,2-cyclohexanediamine. The resulting Schiff bases were reacted with terephthaloyl dichloride through polycondensation and formed two novel poly(azomethine-ester)s. The molecular masses of diphenol Schiff bases were determined through E.I mass spectroscopy. The elemental composition of poly(azomethine-ester)s was evaluated through CHN analysis. The structures of diphenol Schiff bases and poly(azomethine-ester)s were confirmed though FT-IR, 1HNMR, UV–Vis spectroscopy, fluorescence, SEM and thermal analysis (TG/DTA). All the synthesized compounds were fluorescent and indicated 2–4 emission bands with maximum emission intensities within 342–682 nm at different excitation wavelengths. The diphenol Schiff bases showed violet-light emission, while their derived polyesters showed red-light emission. The poly(azomethine-ester)s indicated good thermal stability (347 °C and 561 °C) which was estimated through $$T_{ \hbox{max} }$$ (temperature at which rate of weight loss is maximum) value obtained from DTG (derivative thermogravimetry) graph. The synthesized compounds were also tested for their antimicrobial activities against different species of bacteria and fungi. The Schiff base having dapsone moiety showed 55% inhibition, while its derived poly(azomethine-ester) showed 40% inhibition against bacterial species Shigella flexneri.

Irreversible Amide‐Linked Covalent Organic Framework for Selective and Ultrafast Gold Recovery

AbstractDesign of stable adsorbents for selective gold recovery with large capacity and fast adsorption kinetics is of great challenge, but significant for the economy and the environment. Herein, we show the design and preparation of an irreversible amide‐linked covalent organic framework (COF) JNU‐1 via a building block exchange strategy for efficient recovery of gold. JNU‐1 was synthesized through the exchange of 4,4′‐biphenyldicarboxaldehyde (BA) in mother COF TzBA consisting of 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline (Tz) and BA with terephthaloyl chloride. The irreversible amide linked JNU‐1 gave good stability, unprecedented fast kinetics, excellent selectivity and outstanding adsorption capacity for gold recovery. X‐ray photoelectron spectroscopy along with thermodynamic study and quantum mechanics calculation reveals that the excellent performance of JNU‐1 for gold recovery results from the formation of hydrogen bonds C(N)−H⋅⋅⋅Cl and coordinate interaction of O and Au. The rational design of irreversible bonds as both inherent linkage and functional groups in COFs is a promising way to prepare stable COFs for diverse applications.

Irreversible Amide-Linked Covalent Organic Framework for Selective and Ultrafast Gold Recovery.

Design of stable adsorbents for selective gold recovery with large capacity and fast adsorption kinetics is of great challenge, but significant for the economy and the environment. Herein, we show the design and preparation of an irreversible amide-linked covalent organic framework (COF) JNU-1 via a building block exchange strategy for efficient recovery of gold. JNU-1 was synthesized through the exchange of 4,4'-biphenyldicarboxaldehyde (BA) in mother COF TzBA consisting of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (Tz) and BA with terephthaloyl chloride. The irreversible amide linked JNU-1 gave good stability, unprecedented fast kinetics, excellent selectivity and outstanding adsorption capacity for gold recovery. X-ray photoelectron spectroscopy along with thermodynamic study and quantum mechanics calculation reveals that the excellent performance of JNU-1 for gold recovery results from the formation of hydrogen bonds C(N)-H⋅⋅⋅Cl and coordinate interaction of O and Au. The rational design of irreversible bonds as both inherent linkage and functional groups in COFs is a promising way to prepare stable COFs for diverse applications.

From cyclohexanone to photosensitive polyesters: Synthetic pathway, basic characterization, and photo-/halochromic properties

A bifunctional photosensitive monomer, 2,6-bis-(4-hydroxybenzylidene)cyclohexanone (DHCH) was successfully synthesized by the condensation reaction of cyclohexanone with p-hydroxybenzaldehyde in the presence of hydrochloric acid, as a catalyst. Based on DHCH, a series of new photosensitive polyesters were prepared by a polycondensation reaction, in solution, using two phosphonic dichlorides, namely, phenylphosphonic dichloride and phenyl dichlorophosphate, or two aromatic dichlorides, namely, terephthaloyl chloride and terephthaloyl-bis-(4-oxybenzoylchloride). The synthesis of monomer and polymers was structurally confirmed by FT-IR and NMR spectroscopies. The thermal behavior of polyesters was investigated by DSC measurements and polarized optical microscopy observations, which evidenced thermotropic liquid crystalline properties for some of the studied polymers. The photoresponsive properties of the prepared polyesters were extensively investigated in CHCl3 and DMSO solutions, under irradiation with UV light (254 and 365 nm) at different time intervals and after successive titrations with acid/base solutions. Under UV light irradiation, these compounds undergo photocrosslinking reactions and their photoluminescence properties were strongly enhanced. Deprotonation (under the basic conditions) of the polymers led to the emergence of a new absorption band (with maximum at 508 nm), accompanied by a photochromic behavior. This color change, from colorless to orange, observed upon titration with dilute NaOH solution, was completely recovered to its original colorless after the addition of an equivalent amount of dilute HCl solution. The reversible color changes (halochromic properties) observed upon protonation/deprotonation prove that these polymers have potential applications in chemical sensors.

Zinc oxide doped arylidene based polyketones hybrid nanocomposites for enhanced biological activity

The application of Friedel-Craft reactions has been extended to the biological systems. Recently, these reactions have led to the generation of a new set of polyketones (PKa-c) along with the related zinc oxide doped nanocomposites (ZnOPKd-f). Prior to the process of polymerization, these newly synthesized monomers were subjected to spectral analysis to reveal their chemical structures. Three arylidene monomers based on three different moieties including benzylidene, thiophenylidene and furfurylidene were synthesized through a direct condensation reaction. These monomers interacted with terephthaloyl chloride in the presence of anhydrous AlCl3 in organic methanol solvent via Friedel–Crafts reaction, to produce the desired PKa-c. Further, a series of ZnOPKd-f nanocomposites were fabricated using a 10% loading of ZnO nanoparticles throughout the same experimental procedure as required to develop PKa-c. A common characterization tool was employed to prove the structures for PKa-c and its related ZnOPKd-f TGA results established enhancement in the thermal behavior of PK a-c with the different structures. PDTmax values showed that all the polymers had a similar identity which appeared in the range from 578° to 630°. Additionally, the morphological properties were assessed by using scanning electron microscopy which revealed the formation of ZnOPKd-f and ZnO nanoparticles. The latter are spherical particles, ranging in of 29 to 223 nm loaded on the polymer surface. The TEM images illustrated the uniform distribution of the ZnO nanoparticles in the polymer matrix. The ZnOPKd-f nanocomposites were examined for their antimicrobial activity against variable kinds of bacteria and fungi. Based on the biological screening, it was observed that the ZnOPKd-f nanocomposite materials can be used as moderate antibacterial and antifungal agents.

Synthesis and characterization of new poly(diketone imide)s derived from 1,4-bis(3,4-dicarboxybenzoyl)benzene dianhydride and various diamines

1,4-Bis(3,4-dicarboxybenzoyl)benzene dianhydride, an aromatic bis(ketone anhydride) monomer, was synthesized by the Friedel–Crafts reaction of terephthaloyl dichloride and o-xylene, followed by the oxidation of the intermediate tetramethylated compound and cyclodehydration of the resulting tetraacid. A series of new poly(diketone imide)s (PDKIs) were prepared from this dianhydride with various aromatic diamines via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization. Most of the PDKIs through chemical imidization were soluble in aprotic amide solvents, such as N, N-dimethylacetamide, N-methyl-2-pyrrolidone, m-cresol, and so on. The resulting PDKIs had good thermal property with the glass transition temperature of 203–275°C, the temperature at 5% weight loss of 500–539°C, and the residue of 51–60% at 800°C in nitrogen. Additionally, strong and flexible PDKI films obtained by thermal imidization exhibited outstanding mechanical property with the tensile strength of 88.8–158.5 MPa, tensile modulus of 1.9–3.5 GPa, and elongation at breakage of 7–21%.

Thermal and optical properties of aromatic polyamide–hydrazides modified with multiwalled carbon nanotubes

Three wholly aromatic polyamide–hydrazides I–III containing various amounts of meta-/para-phenylene rings and their multiwalled carbon nanotube (MWCNT) composites have successfully been synthesized. These polymers were synthesized via a low-temperature solution polycondensation reaction of either meta-aminobenzhydrazide or para-aminobenzhydrazide (PABH) with an equimolar amount of isophthaloyl chloride (ICl) producing polymer I (100% meta-phenylene rings) and II (50% para-phenylene rings/50% meta-phenylene rings), respectively. The polymer III (75% para-phenylene rings/25% meta-phenylene rings) was synthesized by reacting PABH with mixture of equimolar ratios of terephthaloyl chloride and ICl. MWCNTs (0.1 wt%) have been incorporated into these three polymer matrices via a solution sonication technique. The structures of the polymers were confirmed by elemental analyses, Fourier-transform infrared, and proton nuclear magnetic resonance spectroscopy. The homogeneous distribution of the MWCNTs within the polymer matrices was proved by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy observations. Thermal and optical properties of the as-prepared polymers were being enhanced to some extent upon inclusion of MWCNTs as illustrated from the results of thermogravimetric analysis and ultraviolet–visible spectroscopy.

Acetaldehyde gas removal by a nylon film–TiO2 composite sheet prepared on a paper surface using interfacial polymerization and electrostatic interactions

In this study, preparation of a nylon film–TiO2 composite sheet with both physical durability under UV irradiation and TiO2 photocatalysis functionality was investigated. First, a nylon film was directly prepared on paper by interfacial polymerization using ethylenediamine and terephthaloyl chloride in a cyclohexane–chloroform mixture (3:1, v/v). Next, the nylon-coated paper was treated with tetraethyl orthosilicate and 3-aminopropyltrimethoxysilane to prepare polysiloxane on its surface. This was followed by fixation of TiO2 powder via electrostatic interactions with the polysiloxane. Although nylon films on paper usually decompose under TiO2 photocatalysis, the nylon film–TiO2 composite sheets prepared using 0.5%–1.0% (w/v) TiO2 did not decompose under photocatalysis. The residual rate of strength of the sheet remained at almost 100% after 240 h, which could be attributed to protection of the sheet by the polysiloxane layer. The nylon film was fibrous and could effectively adsorb acetaldehyde gas. All of the nylon film–TiO2 composite sheets prepared using 0.5%–5.0% TiO2 photocatalytically removed acetaldehyde under UV irradiation and no acetaldehyde gas was detected after 240–300 min. These results show the nylon film–TiO2 composite sheet can effectively remove acetaldehyde gas by photocatalysis and adsorption and could be applied to removal of volatile organic compounds in indoor air.

(Invited) Electrochemical Functionalizations of [60]Fulleroindolines

In this talk, we will present our recent progress in the electrochemical functionalizations of [60]fulleroindolines. The electrochemically generated dianions of [60]fulleroindolines react with electrophiles such as 1,2-bis(bromomethyl)benzene and phthaloyl chloride to 1,2,4,17-functionalized [60]fullerene derivatives with an unprecedented addition pattern, where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is fused to an adjacent [6,6]-junction. Furthermore, the obtained tetra-functionalized compounds can be successively manipulated to 1,2,3,4,9,10-functionalized [60]fullerene derivatives with an intriguing “S”-shaped configuration via a novel electrochemical protonation.

Synthesis and properties of colorless polyamide films with high thermal resistance and dimensional stability

Polyamides (PAs) based on terephthaloyl chloride and a series of aromatic diamines were synthesized; PA films were prepared by solution casting without mechanical stretching to produce high-performance films with good optical transparency and dimensional stability. The PA films displayed high heat resistance with glass transition temperatures ( Tg) of 342–399°C. Good mechanical properties were obtained with tensile modulus and strength up to 5.38 GPa and 195.4 MPa, respectively. Coefficient of thermal expansion of the as-cast PA films achieved to an ultralow value of 8.3 ppm °C−1 and could be tailored in a wide range as a function of the macromolecular composition. The series of PA films showed a transparent and colorless feature, with the cutoff wavelength in the range of 355–365 nm. The data were discussed from the perspective of structure–property relationship, may give helpful knowledge for the topic of PA chemistry, and this method could provide an alternative for the production of high-performance colorless polymer films.

High-solubility aromatic polyesters with fluorene and phthalein groups: Synthesis and property

A series of aromatic polyesters bearing fluorene and phthalein groups were synthesized from commercially available 9,9-bis(4-hydroxyphenyl)fluorene (BPF), phenolphthalein, and terephthaloyl chloride through an interfacial polymerization method. The microstructure, molecular weight, morphology, thermal properties, and thermal decomposition mechanism of these aromatic polyesters were investigated. Their mechanical properties were also evaluated. The results suggested that the copolymer compositions were approximately equal to the feed compositions. Moreover, the increase in the BPF unit content increased the glass transition and weight loss temperatures of the aromatic polyesters, owing to the strong rigidity of the bulky fluorene group. All the polymers were amorphous and exhibited good solubility in common organic solvents. Hence, the synthesized polymers could be easily cast into flexible films. The copolymer film samples exhibited better mechanical properties than those of the homopolymers. The tensile strength, Young’s modulus, and elongation at break of the polymers first increased gradually, and then decreased with increasing BPF content. Notably, the copolymers exhibited the best mechanical properties at the BPF content range 30–50%. Owing to their characteristics, these synthesized polymers show great potential for application as high performance membrane materials.

Synthesis and characterization of processable aromatic poly(ether ether ketone amide)s modified by phenoxy and 1,3 ketone moiety linkages

New series of aromatic poly(ether ether ketone amide)s were synthesized by low-temperature solution polymerization of novel aromatic diamine, namely 1,3-bis-4′-(4″-aminophenoxy benzoyl)benzene (XIV), and aromatic diacid chlorides, viz. isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). Co-poly(ether ether ketone amide)s were also synthesized by employing various mole proportions of IPC and TPC with diamine (XIV). These poly(ether ether ketone amide)s were characterized by FTIR, solubility, inherent viscosity, TGA, DSC, and XRD. Inherent viscosities of these poly(ether ether ketone amide)s were in the range of 0.41–0.52 dL/g in DMAc, indicating the formation of moderate to high molecular weight of polymers. Poly(ether ether ketone amide)s showed good solubility in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N-methyl 2-pyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide. These poly(ether ether ketone amide)s had glass transition temperatures, as determined by DSC, in the range of 252–302 °C. These polymers showed similar decomposition patterns and had no weight loss below 335 °C, and temperatures for 10% weight loss (T10) were in the range of 397–406 °C, indicating that these polymers showed good thermal stability.

Methods for the Synthesis of Phthalic Acid Dichlorides

Isophthalic and terephthalic acid chlorides (also known as isophthaloyl and terephthaloyl chlorides) are without doubt strategically important compounds. One area in which they are used is the synthesis of aramid fibers employed in the production of dual-purpose functional and construction materials. These include Terlon®, SVM®, Armos®, Fenilon®, Togilen®, and Rusar®. Special requirements for the quality of target acid dichlorides and raw materials used in their synthesis often determine how these compounds are obtained. Different methods for the synthesis of iso- and terephthaloyl chlorides (including catalytic syntheses), in which different initial materials are used, are considered below. The main methods for the analysis of the above compounds are described in detail.

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives.

With the recent advance in chemical modification of fullerenes, electrosynthesis has demonstrated increasing importance in regioselective synthesis of novel fullerene derivatives. Herein, we report successively regioselective synthesis of stable tetra- and hexafunctionalized [60]fullerene derivatives. The cycloaddition reaction of the electrochemically generated dianions from [60]fulleroindolines with phthaloyl chloride regioselectively affords 1,2,4,17-functionalized [60]fullerene derivatives with two attached ketone groups and a unique addition pattern, where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is fused to an adjacent [6,6]-junction. This addition pattern is in sharp contrast with that of the previously reported biscycloadducts, where both cycles are appended to [6,6]-junctions. The obtained tetrafunctionalized compounds can be successively manipulated to 1,2,3,4,9,10-functionalized [60]fullerene derivatives with an intriguing “S”-shaped configuration via a novel electrochemical protonation. Importantly, the stability of tetrafunctionalized [60]fullerene products allows them to be applied in planar perovskite solar cells as efficient electron transport layers.

Molecular structure of 1,4-bis(substituted-carbonyl)benzene: A combined experimental and theoretical approach

The reaction of pyrazole derivatives (pyrazole (Pz), 3-methylpyrazole (MPz) and 3,5-dimethylpyrazole (DMPz)) with terephthaloyl dichloride (TD) in the presence of Et3N afforded the desired products, 1,4-bis(pyrazolylcarbonyl)benzene (1), 1,4-bis(3-methylpyrazolylcarbonyl)benzene (2) and 1,4-bis(3,5-dimethylpyrazolylcarbonyl)benzene (3).Good quality crystals were isolated and diffraction data for single crystal were collected which revealed that compounds 1–3 are monoclinic with space group P21/n, C2/c and P21/c, respectively. These compounds were obtained as a result of C–N coupling reaction between the acid chloride and pyrazol derivatives with the intent to explore their structure in solution as well as solid state. Density function theory (DFT) calculations using B3LYP and CAM-B3LYP functionals with 6-311G(d,p) basis set were performed to explore geometric and electronic properties of compounds. The Root Mean Square Error (RMSE) has also been calculated for the values of geometric parameters, indicating a good agreement with experimental findings. Moreover, frontier molecular orbitals (FMOs) and natural bond orbitals (NBOs) analyses were carried out through B3LYP/6-311G(d,p) level of theory. The linear polarizability (α) values of nonlinear optical (NLO) analysis were calculated with the same level of theory and basis set as FMO but under different solvent conditions. Time Dependent Density Functional Theory (TD-DFT) study of these pyrazole substituted derivatives was performed aiming to investigate UV–Visible behavior. The stability of molecule has been additionally analyzed by Hirshfeld surface analysis in addition to NBO analysis. The calculated HOMO and LUMO energies from FMO assisted in calculating global reactivity parameters (Chemical hardness, chemical softness, electronegativity, EA, IP and electrophilicity). Natural population analysis (NPA) and Molecular electrostatic potential (MEP) were also performed to obtain insights about the reactivity of compounds 1–3. Theoretical calculations indicate that these compounds have considerable low reactivity and can be used for development of coordination chemistry under optimum conditions.

Synthesis of high transparency polyarylates containing cyclohexane group

A new kind of polyarylates containing different proportion of cyclohexane units in the main chain were synthesized by using 2,2-bis (4-hydroxyphenyl) propane (BPA), 4, 4′-cyclohexane-1, 1′-diyldiphenol (BPZ), terephthaloyl dichloride (TPC) and isophthaloyl dichloride (IPC) through interfacial copolymerization at 25 °C. The intrinsic viscosity of resultant PZAs was 0.49–0.97 dL/g. The FT-IR, 1H NMR and XRD was used to characterize the chemical structure of polymer. The optical properties of PZAs were performed on UV–vis spectrophotometer. With the cyclohexane unit proportion in the polymer backbones increased to 40%, the transmittance at 400 nm and 450 nm can reach up to 87.41% and 88.07% respectively and the cutoff wavelength is 294 nm. These resultant copolymers were also found to have good thermal, mechanical performance and melt flowability (glass transition temperature of 194.8–197.1 °C, 5% mass loss temperature about 461 °C, tensile strength of 60–71 MPa, Young's modulus:1.47–1.61 GPa, melt complex viscosity of 47–790 Pa s at 310 °C during the testing time (30 min)). The comprehensive properties of the resultant copolymers were similar or even much better than that of the commercial polyarylate U-100, they can be facile processed with solution or melt method and can be potential used in optical thin films and optical microlens.

Preparation and Characterization of Thermally Stable Polybenzoxazole Copolymer Films Fabricated from Their Precursors

The polyhydroxyamide copolymers (F-PHAs) were synthesized by low-temperature solution polycondensation of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (BAHHFP) and/or 3,3′-dihydroxybenzidine (DHB) with terephthaloyl chloride (TPC) in N,N-dimethylacetamide (DMAc) with the aid of lithium chloride (LiCl). A series of polybenzoxazole copolymer (F-PBO) films were fabricated via an efficient solution-casting and thermal-treatment technique, using their precursors (F-PHA films) with different BAHHFP fractions (25-100 mol%). The solubility results show that F-PHAs with higher BAHHFP content (≥75 mol%) are readily soluble in anhydrous DMAc and N-methyl-2-pyrrolidinone (NMP) without LiCl at room temperature. Differential scanning calorimetry (DSC) indicates that the thermal cyclization temperature of the F-PHA films decreases with increasing BAHHFP content. Thermogravimetric analysis (TGA) reveals that the F-PHA and F-PBO films are well prepared and completely converted. The UV-visible spectra indicate that the F-75-PBO film (BAHHFP content: 75 mol%) has reasonable transparency, with 84.9 % transmittance at 600 nm and 397-nm UV cut-off wavelength. It also has lower coefficient of thermal expansion (CTE) (48 ppm/°C) and water absorption (WA) values (0.14%). The BAHHFP as diamine component provides the final F-PBO film with desirable properties, e.g., flexibility, thermal stability, transparency, and WA values.