Synthesis and characterization of new aromatic polyesters containing biphenyl side groups

Abstract

Aromatic polyesters containing biphenyl side groups were synthesized by phase-transfer catalyzed interfacial polycondensation of 1-(4-biphenylyl)-1,1-bis(4-hydroxyphenyl) ethane (BBHPE) with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and a mixture of TPC/IPC (50 : 50 mol ratio). Copolyesters were synthesized by utilizing different molar proportions of BBHPE and 4,4 0 -isopropylidenediphenol (BPA) with IPC and TPC. The inherent viscosities of polyesters were in the range 0.44-1.26 dL/g. All the polyesters were soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, meta-cresol, pyridine, N,Ndimethylformamide, N,N-dimethylacetamide, and 1-methyl-2-pyrrolidinone. Tough, transparent, and flexible films could be cast from chloroform solutions of these polyesters. WAXD measurements indicated that all the polyesters and copolyesters were amorphous in nature. Glass transition temperature of polyesters were in the range 198-2568C, while the initial degradation temperature of polyesters were in the range 444-4818C. Copolyesters derived from BBHPE exhibited improved solubility and higher glass transition temperatures compared to the corresponding polyesters based on BPA.

Synthesis and characterization of new aromatic polyesters containing pendent naphthyl units

“…Dimethyl substitutions on bisphenols results into an asymmetric segment, which could have resulted in less efficient packing than unsubstituted bisphenols. The T g values of polyesters obtained in the present study were comparable with T g values (232–256°C) of corresponding polyesters containing biphenyl pendent groups 5…”

“…It was observed that the T g values for NABP‐IPC and NABP‐TPC were higher than those of the corresponding polyesters based on BPA. The T g values for polyesters based on BPA‐IPC and BPA‐TPC are 181°C and 210°C, respectively 5. It was observed that the T g values for NABP‐based polyesters with IPC, TPC and IPC/TPC were higher than those of the corresponding polyesters based on o ‐NABP.…”

“…A lot of efforts have been expended to improve the processing characteristics of aromatic polyesters. One of the approaches to obtain high T g and yet soluble polyesters is the introduction of bulky pendent groups along the polymer backbone 5–26…”

“…In our earlier work, we demonstrated that polyesters containing biphenyl as pendent groups exhibited high glass transition temperatures (232–256°C) and improved solubility 5. In this work, we wish to report synthesis of two bisphenols, viz., 4,4′‐[1‐(2‐naphthalenyl) ethylidene]bisphenol (NABP) and 4,4′‐[1‐(2‐naphthalenyl)ethylidene]bis,3‐methylphenol ( o ‐NABP).…”

Assessment of parameters influencing fiber characteristics of chitosan nanofiber membrane to optimize fiber mat production

“…For this purpose, what is known as Taguchi's method was used [27–29]. The main advantage of this methodology is the possibility to handle with a larger numbers of control parameters with relatively small amount of trials [30–32].…”