Synthesis and characterization of poly(butylene terephthalate) copolyesters derived from threitol

The synthesis, characterization, and thermal properties of partially renewable poly(butylene terephthalate) copolyesters containing alditol units are described. These copolyesters were obtained by polycondensation in solution from mixtures of 1,4-butanediol and 2,3-di- O-benzyl-L-threitol with terephthaloyl chloride. Copolyesters with weight-average molecular weights oscillating between 4 000 and 12 000 g·mol−1 and dispersities around 1.5 were obtained. All them had a random microstructure and were thermally stable well above 300°C. Copolyesters containing up to 30% of dibenzyl threitol units were found to be crystalline and to adopt the same crystal structure as the parent homopolyester poly(butylene terephthalate). The melting temperature and crystallinity were observed to decrease, and the glass transition temperature to increase, with increasing amounts of alditol units incorporated in the copolyester. Furthermore, the crystallizability was depressed by copolymerization.

Methods for the synthesis of dichloroanhydrides of phthalic acids

Dichloroanhydrides of isophthalic (isophthaloyl chloride) and terephthalic (terephthaloyl chloride) acids are, undoubtedly, strategically important compounds. Among their main application areas is synthesis of Aramid fibers to be used for manufacturing dual use materials including synthesis of Terlon®, Phenylon®, Armos®, Tegelen®, SVM®, and Rusar® fibers. Specific requirements for quality of the target anhydrides and feedstock determine the choice of the synthetic methods. In the review paper, various methods, including catalytic methods, for the synthesis of iso- and terephthaloyl chlorides based on the use of different types of feedstock are discussed. Main methods for analysis of these compounds are described in detail.

The introduction of benzimidazole and ether moieties into poly(p-phenylene terephthalamide): effects on its microstructure, interactions and properties

Co-poly(p-phenylene terephthalamide) fibers containing 4,4′-oxidianiline and 2-(4-aminophenyl)-5-aminobenzimidazole in terephthaloyl chloride and p-phenylene diamine were prepared via a wet spinning method, followed by water washing and drawing at high temperature.

Macrocycle crosslinked mesoporous polymers for ultrafast separation of organic dyes

Mesoporous polymers were synthesized by interfacial polymerization of macrocycles (sulfonatocalix[4]arenes and pillar[5]arenes) and terephthaloyl chloride.

Novel organosoluble polyarylates based on diphenylamine-fluorene units

Two kinds of polyarylates with diphenylamine-fluorene units were synthesized from the bisphenol monomer “ N, N-di(4-hydroxyphenyl)-2-amino-9,9-dimethylfluorene” with two different benzenedicarbonyl chlorides. These polyarylates were highly soluble in N, N-dimethylacetamide, tetrahydrofuran, and chloroform and could be easily solution-cast into transparent films. Both of the polyarylates exhibited a couple of reversible redox with half-wave potentials in the range of 0.87–0.90 V. During the electrochromic process, the color of the film changed from colorless (neutral state) to grey green (oxidation state) with a high coloration efficiency of 242 cm2 C−1. Compared with the polyarylates prepared from terephthaloyl chloride, the polyarylates prepared from isophthaloyl chloride exhibited enhanced fluorescence because of the reduced charge-transfer effect. Furthermore, its fluorescence could be reversibly switched under the applied potentials.

Preparation and Co (II) Removal of ZnO/Poly-Piperazineamide Nanofiltration Membranes

A series of nanofiltration membranes were prepared by interfacial polymerization of piperazine and terephthaloyl chloride on the surface of polyacrylonitrile (PAN) ultrafiltration membranes. ZnO nanoparticles were incorporated in the active separation layer to modify the performances of the membranes. The preparation conditions as the monomer concentration, dosage of nano-ZnO particles and the reaction time on removal of a simulated radioactive nuclide Co (II) were investigated. Fourier transform infrared in attenuated total reflection mode verified the formation of polyamide on the PAN ultrafiltration membrane. The scanning electron microscope images showed that the nano-ZnO particles can homogeneously fixed on the membrane surface. The retention of Co (II) increased with increasing the dosage of nano-ZnO in the range of 0∼0.03 g. Further adding more nano-ZnO, the rejection rate of Co (II) first decreased and then increased. The concentration of piperazine and terephthaloyl chloride showed similar effect on removal of Co (II) ion. 5 minutes polymerization time was sufficient to form an active separation layer on the substrate membrane which changed the separation mechanism from ultrafiltration to nanofiltration. The separation performance of NF3 prepared by the following conditions was optimum: 0.03g nano-ZnO, 0.6 wt% piperazine, 0.5 wt% terephthaloyl chloride, and the reaction time was 15 min. The rejection rates of 1000 mg/L Na2SO4 and Co2+ in CoCl2 solution were 90% and 75% respectively. The Co (II) removal rate can be increased to nearly 90% by using ethylenediaminetetraacetic acid disodium salt. Increasing the operation pressure or the feeding concentration of Co (II) can also improve the performances of the membranes in this experiment.

Tightening polybenzimidazole (PBI) nanostructure via chemical cross-linking for membrane H2/CO2separation

Polybenzimidazole in solid state is facilely cross-linked with terephthaloyl chloride, decreasing free volume and significantly increasing membrane H2/CO2separation properties.