Fluorene-rich high performance polyesters: Synthesis and characterization of 9,9-fluorenylidene and 2,7-fluorenylene-based polyesters with excellent optical property

Synthesis and hygrothermal aging of polycarbonates containing a bisphenol fluorene moiety

This study aims to synthesize a specific type of polycarbonate with high refractive index, low birefringence, and resistance to hygrothermal aging by copolymerizing 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthyl (BNE) with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF). Comparative analysis revealed that the copolymer synthesized from BNE and BPEF demonstrated superior hydrolytic stability relative to the bisphenol A-based polycarbonate. This augmented stability can be attributed to the monomers' higher pKa values, rendering acidic substances less capable of dissociating and thereby mitigating ester hydrolysis under hygrothermal conditions. Furthermore, the investigation probed into the phenomenon of physical aging in copolymerized polycarbonate when exposed to hygrothermal environments. It was discerned that the enthalpy loss, observable under both dry and hygrothermal conditions, could be linearly correlated with the difference between the aging temperature and the glass transition temperature (Tg), signifying a close correlation between the magnitude of physical aging and Tg. A lower Tg in the copolymerized polycarbonate led to more pronounced physical aging within the same timeframe, resulting in an augmentation of tensile strength and modulus, while higher Tg effectively mitigated the physical aging phenomenon.

Correlation of the Abbe Number, the Refractive Index, and Glass Transition Temperature to the Degree of Polymerization of Norbornane in Polycarbonate Polymers

The influences of the average degree of polymerization (D_p), which is derived from M_n and terminal end group, on optical and thermal properties of various refractive indexed transparent polymers were investigated. In this study, we selected the alicyclic compound, Dinorbornane dimethanol (DNDM) homo polymer, because it has been used as a representative monomer in low refractive index polymers for its unique properties. DNDM monomer has a stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxy end group and phenolic end group polymers, the refractive index (n_d) decreased with increasing D_p, and both converged to same value in the high D_p region. However, the Abbe number (ν_d) of a hydroxy end group polymer is not dependent on D_p, and the ν_d of a phenolic end group polymer is greatly dependent on D_p. As for glass transition temperatures (T_g), both end group series were increased as D_p increased, and both converged to the same value.

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.

Preparation and characterization of novel soluble polyarylates derived from 9,9-bis[4-(4-chloroformylphenoxy)phenyl]xanthene with various bisphenols

A series of new polyarylates bearing cardo xanthene groups were synthesized by phase-transfer-catalyzed interfacial polycondensation of 9,9-bis[4-(4-chloroformylphenoxy)phenyl]xanthene with various bisphenols containing the isopropylidene, hexafluoroisopropylidene, 1-phenylethylidene, diphenylmethane, cyclohexane, and xanthene structures. High-molecular-weight polyarylates with number-average molecular weight and polydispersity index in the range of 30,100–35,300 and 1.82–2.17, respectively, exhibited high glass transition temperatures ranged from 226°C to 261°C, and their 10% weight loss temperatures were in the range of 421–452°C with char yields above 45% at 700°C in nitrogen. All the polyarylates were amorphous and readily soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, meta-cresol, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, and 1-methyl-2-pyrrolidinone at room temperature and could be cast into tough, transparent, and flexible films with tensile strengths of 85.6–108.3 MPa, elongations at break of 2–3%, and tensile moduli of 7–9 GPa.

Preparation and characterization of new aromatic poly(ether ester)s bearing cardo xanthene groups

A series of new aromatic poly(ether ester)s containing cardo xanthene groups were synthesized by phase transfer–catalyzed interfacial polycondensation of three cardo bisphenols such as 9,9-bis(4-hydroxyphenyl)xanthene, 9,9-bis (4-hydroxy-3-methylphenyl)xanthene, and 9,9-bis(4-hydroxy-3,5-dimethylphenyl)xanthene with terephthaloyl chloride and isophthaloyl chloride. Inherent viscosities and number average molecular weights of the polymers were in the range 0.56–0.80 dL g−1 and 30,300–36,200, respectively. The resulting poly(ether ester)s exhibited high glass transition temperatures ranged from 208°C to 274°C, and their 10% weight loss temperatures were in the range of 440–458°C with char yields above 45% at 600°C under a nitrogen atmosphere. All the poly(ether ester)s were amorphous and readily soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, meta-cresol, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidinone at room temperature and could be cast into tough, transparent, and flexible films with tensile strengths of 68.2–86.8 MPa, elongations at break of 2–3%, and tensile moduli of 5.7–7.8 GPa.