ABSTRACT:Hyperbranched poly(triphenylamine)s with various end functional groups were prepared starting from 4,4 -diamino-4 -bromotriphenylamine through palladium catalyzed C-N coupling reaction. The self-polycondensation of the monomer afforded secondary amino groups predominantly. End-capped polymers were isolated by the chemical modification of unreacted amino groups by acid chlorides. The properties of the hyperbranched poly(triphenylamine)s, such as solubility, thermal stability and ionization potential, were dependent on the end functional groups. The hyperbranched poly(triphenylamine)s were examined as a hole transporting material for organic light emitting diodes. The multi-layered device composed of ITO/hyperbranched poly(triphenylamine)/Alq 3 /Mg-Ag showed yellow-green emission derived from Alq 3 . The device performance was improved when the polymer end-capped with alkyl chlorides were used as a hole transporting material. Since the ionization potentials of the hyperbranched polymer with alkyl amide end groups were higher than that with aromatic amide end groups, efficient hole injection from ITO/hyperbranched poly(triphenylamine)/Alq 3 might be achieved to improve the device performance.KEY WORDS Hyperbranched Polymer / Triphenylamine / C-N Coupling / Palladium Catalyst / EL Device / Dendritic macromolecules, such as dendrimers and hyperbranched polymers deserve much attention from both synthetic and application viewpoints, and are characterized by low viscosity, good solubility and amorphous nature in solid state. [1][2][3][4][5][6][7][8][9][10][11] It is also well-known that the properties of the dendritic macromolecules are dependent on terminal functional groups in addition to backbone structure. 12, 13 Therefore, the properties of dendritic macromolecules can be tuned in some extent by the chemical modification of end functional groups. Although multi-step procedures required for the preparation of dendrimers allow the precise control of molecular architecture, one-step process to prepare hyperbranched polymers seems to be attractive for mass production and industrial applications.Palladium catalyzed condensations are one of the useful propagation reactions for polycondensation. We have previously reported the palladium catalyzed polycondensations to form linear polyamides, 14 polycinnamamides, 15, 16 and hyperbranched polyesters. 17 Recently, Buchard and Hartwig have been independently reported palladium catalyzed C-N coupling reactions. [18][19][20][21][22] The reaction conditions required for the palladium catalyzed C-N coupling are apparently much milder in comparison with conventional Ullmann type coupling reactions.Polycondensa- † To whom correspondence should be addressed.tions through the amination were also reported by Kanbara, [23][24][25][26][27] Hartwig, 28, 29 and Meyer. 30 Among them, Meyer reported linear and hyperbranched mpolyanilines through the amination in the presence of BINAP ligand and sodium t-butoxide. According to the model reaction for the polymerization, triphenylamine...

EXPERIMENTAL MaterialsCotton fabric used was 0.021 cm thick and weighed 108 g/m'. Counts of warp and weft for the fabric were 19 and 18 tex, respectively. Threads per cm for the fabric were 32 in ends and 27 in picks, respectively. The fabric was purified with aqueous solution of 0.2% nonionic surfactant at 40°C before cellulase treatment.Congo Red (C.I. Direct Red 28) used was of specific reagent grade. Chrysophenine (C.I. Direct Yellow 11) and

Cotton fibers mercerized under the relaxed state were hydrolyzed with crude cellulase. The mercerization treatment examined included ammonia treatment, sodium hydroxide treatment, and two combined treatments using ammonia and sodium hydroxide. Crystalline regions of the mercerized fibers were hydrolyzed in the first step of hydrolysis. In this step, ammonia treatment decreased the crystallite size to a great extent due to the hydrolysis of the cellulose III crystalline phase. Cellulase treatment rendered the crystallite surface highly accessible to water molecules. The crystalline phase was closely related to water sorption of cellulase‐treated fibers. The sequence of treatment had an influence on the fiber structure in the case of the combined mercerization treatment with ammonia and sodium hydroxide. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 364–370, 2000

Unprocessed and mercerized cotton fibers were treated with commercial crude cellulase. The changes in the dyeability and structural features of the fiber due to cellulase treatment were studied. The dyeability was examined in terms of uptake of three reactive dyes and the apparent affinity of Congo Red to cotton fiber. The dyeability of the unprocessed fiber was assumed to be influenced by some impurities present in it. This fiber probably resembled polynosic fiber in molecular aggregate at a certain stage of hydrolysis. Mercerized cotton showed a similar pattern in dyeability as weight loss increased, regardless of dye species. Enzyme more easily penetrated the mercerized fiber than the unprocessed fiber. Cellulase treatment influenced the X-ray crystalline reflection pattern for the mercerized fiber but nominally influenced that for unprocessed fiber. Scanning electron micrographs revealed that cellulase treatment caused swelling of the fibrils. They also revealed that the disordered regions between the fibrils in the secondary walls were removed at low weight loss for the unprocessed fiber. The mercerized fiber at high weight loss had large cracks oblique to the fiber axis and showed no individual fibrils in the secondary wall. The primary wall was removed in the initial stage of hydrolysis for both the unprocessed and mercerized fibers.

Unprocessed and mercerized cotton fibers were treated with commercial crude cellulase. The changes in the dyeability and structural features of the fiber due to cellulase treatment were studied. The dyeability was examined in terms of uptake of three reactive dyes and the apparent affinity of Congo Red to cotton fiber. The dyeability of the unprocessed fiber was assumed to be influenced by some impurities present in it. This fiber probably resembled polynosic fiber in molecular aggregate at a certain stage of hydrolysis. Mercerized cotton showed a similar pattern in dyeability as weight loss increased, regardless of dye species. Enzyme more easily penetrated the mercerized fiber than the unprocessed fiber. Cellulase treatment influenced the X‐ray crystalline reflection pattern for the mercerized fiber but nominally influenced that for unprocessed fiber. Scanning electron micrographs revealed that cellulase treatment caused swelling of the fibrils. They also revealed that the disordered regions between the fibrils in the secondary walls were removed at low weight loss for the unprocessed fiber. The mercerized fiber at high weight loss had large cracks oblique to the fiber axis and showed no individual fibrils in the secondary wall. The primary wall was removed in the initial stage of hydrolysis for both the unprocessed and mercerized fibers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 155–164, 1997