Research articles

Polypropylene (PP)-knitted fabrics were finished with β-cyclodextrin (β-CD) through their crosslinking with citric acid (CTR). The polyCTR–β-CD polymer-coated fibers were wash resistant. We report that the rate of immobilized CD was controlled by temperature and curing time. The weight increase of the fabrics on their modification with native β-CD and CTR could reach 30 %wt. The treated PP supports were dyed by applying classical dyeing processes involving disperse, acid and reactive dyes. Standard tests of wash fastness (shade change and staining) were conducted and showed that all dyes were fixed, because of inclusion complexation with the immobilized cavities on one hand and sorbed hydrogen or ionic bonds that also occurred between the polyCTR–β-CD coating and the tested dyestuffs on the other.

Isotactic (it-) and syndiotactic (st-) uniform poly(methyl methacrylate)s (PMMAs) with hydroxyl end group, isolated by supercritical fluid chromatography (SFC), were reacted with benzene-1,3,5-tricarbonyl trichloride, and two types of uniform three-arm star-PMMAs with different stereoregular arms, [it/it/st]- and [it/st/st]-3-star-PMMAs, were isolated by SFC from the product mixture. The stereocomplex formation of these stereostar PMMAs was examined in acetone. Although both stereostar PMMAs formed intramolecular stereocomplexes, the [it/st/st]-3-star-PMMA, in particular, was found to form two types of intramolecular stereocomplexes with different hydrodynamic volumes because of different compositions of it- and st-PMMA arms involved in the stereocomplexes.

Hyperbranched polycarbonates (HBPCs) were synthesized by A₂+B₃ polymerization, particularly using di-tert-butyl tricarbonate (DBTC) as A₂ monomer and 1,1,1-tris(4-hydroxyphenyl)ethane (THPE) as B₃ monomer. The terminal functionalized HBPCs with Boc and phenol were obtained by using 1-pot or 2-pot synthesis.

Arm-replaceable star-like nanogels consisting of poly(methyl methacrylate) arms and poly(divinylbenzene) cores with alkoxyamine units at their branching points were synthesized by a combination of atom transfer radical polymerization and nitroxide-mediated radical polymerization. The arms of the star-like nanogels were replaced by means of dynamic covalent exchange processes, and arm detachment and arm exchange reactions were successfully accomplished. The structural changes were confirmed by gel permeation chromatography–multiangle light scattering measurements, small-angle X-ray scattering measurements and scanning force microscopic observation.

Distinct skin-core structured PET X(a) proved notch sensitive as shown in Y(a) when 5–60 μm-deep hairline cracks were introduced. PET was annealed in hot edible oil to alter its morphology and remove internal stresses [PET X(b)] in order to improve toughness. Results showed significant reduction in its notch sensitivity, as shown in Y(b). Therefore, annealing in hot oil proved to be effective in achieving more dispersed skin-core morphology, thus improving the toughness of PET.

Poly(arylene sulfone)s (PASs) containing 9,9′-spirobifluorene (SBF) skeleton in the main chain were synthesized in high yields by the oxidations of the corresponding poly(arylene thioether)s. The PASs exhibited good thermal stability (T_g 257–370 °C, T_d5>400 °C under nitrogen), and showed high solubility in ordinary organic solvents, such as CHCl₃, N-methylpyrrolidone (NMP) and N,N-dimethyl formamide (DMF). All films of PASs showed higher refractive indices in the range 1.65–1.67 at 587.6 nm than those of commercially available polysulfone, whereas it hardly showed birefringence. These excellent optical and thermal properties are derived from the C₂ symmetry and high aromatic component of SBF moiety. Polymer: (i) High refractive index, (ii) Low birefringence, (iii) High thermal stability, (iv) High transparency, (v) High solubility and (vi) Less coloration.

Hydroxyl-group-alkoxylated lignophenols (LPs) with various types of alkyl halides were prepared by Williamson ether synthesis to reutilize lignin, an industrial waste material, and make it processable. As compared with raw LP, alkoxylated LPs exhibited good organosolubility and thermal stability (temperatures at 5% loss in weight were estimated to be more than 330 °C by thermogravimetric analyses). Alkoxylated LPs could also form transparent thin films; in particular, films of hexyloxyl LPs exhibited high refractive indices (≈1.55) similar to that of bisphenol A-based poly(carbonate) (PC). Furthermore, these films had lower birefringence (<0.001) than that of PC; therefore, alkoxylated LPs can be utilized as natural-polymer-based optical materials.

Permeation of model drugs with different molecular weights through a bioconjugated membrane having antigen–antibody complexes as reversible crosslinks was investigated in the absence and presence of a target antigen. The bioconjugated membrane regulated the drug permeation in response to the concentration of a target antigen. This paper focuses on the effect of the molecular size of the drugs on controlled permeability of the antigen-responsive membrane.

For the purpose of an electric paper application, alginate hydrogel particles were prepared. To increase their zeta potential for well response by electric fields, their surface were modified chemically. Electro-response behaviors were observed between comb-shaped electrodes. It was found that surface-modified alginate hydrogel particles were well responded by applied low voltage 4–9 V.

X-ray scattering from an organogel made from discotic triazine triamide was measured at SPring-8 at a quite wide q range of 0.050 nm⁻¹ <q <20 nm⁻¹. Analyses revealed (1) an amorphous nature of the molecular stacking at a distance of 0.32 nm, (2) the presence of a semiflexible rod-like scattering object with a radius of 1.3 nm and a Kuhn length of 55 nm and (3) branching of the cylinder formed at the gel state.

The reaction in the presence of poly(γ-glutamic acid) (γPGA) proceeded faster than that without γPGA and the larger molecular weight γPGA was slightly more efficient to catalyze the reaction.

The molecular chaperone function of polysaccharide nanogel was demonstrated for the folding of newly synthesized green fluorescent protein (GFP) in a cell-free protein synthesis system. Nanogel comprising cholesteryl group-bearing pullulan (CHP) trapped unfolded or partially folded GFP expressed in the cell-free system. The structure of the CHP nanogel was disrupted by the addition of cyclodextrins, and the protein complexed with the nanogel was released and folded into the mature form.

PPMC with a high M_n of up to 6.0 × 10⁴ g mol⁻¹ can be readily afforded under the catalysis of an immobilized lipase from Candida antarctica (Novozym-435). The result sounds attractive, as presently the low catalytic efficiency is known as the main restriction for the industrialization of enzyme catalysis.

Liquefied bamboos were multihydroxy compounds and could react with bisphenol-A and epichlorohydrin to prepare a novel epoxy resin. Curing behavior of copolymer epoxy resins prepared with phenol- and polyhydric alcohol-liquefied bamboo could be analyzed by differential scanning calorimetry and dynamic mechanical analysis to obtain more advanced information.

Allyl benzoate (ABz) was polymerized using dicumyl peroxide (DCPO) at 130 °C; almost no direct contribution of cumyloxy radical to initiation reaction was observed. This was extended to other organic peroxide initiators; it was confirmed that the initiation by methyl radical generated by β-scission of alkoxy radicals occurred predominantly in allyl polymerization at elevated temperatures.

New oligomeric electrolytes with a number of different anions were obtained in high yields by anion exchange reactions. Although the starting material with chloride as a counter anion was not soluble in any organic solvent, the excellent miscibility and gelation ability of the oligomeric electrolytes were consequently observed with dipolar protophilic and aprotic solvents. Furthermore, the ionogels based on aliphatic ionic liquids were readily formed using the oligomer with bis(trifluoromethanesulfonyl)amide anion at a 40 g l⁻¹ concentration.

Novel combined liquid crystalline (LC) polymers based on ethyl cellulose (EC) were synthesized by N,N′-dicylcohexylcarbodiimide coupling, and the effect of flexible spacer length on the mesophase structure was investigated. The results showed that the mesophase structures of polymers consisted of a large-scale ordered lamellar structure constructed by EC backbone and a relatively small-scale ordered structure formed by azobenzene side chains. All the polymers form the similar lamellar structure at large scale; however, the small-scale ordered structure becomes disordered relatively, that is, from crystal (m=2) to smectic B (m=4) to smectic A (m=6) at lower temperature.

Maleic anhydride grafted polypropylene (PP-g-MA) with different grafting contents and approximately the same molecular weight was prepared. The grafting content of PP-g-MA in the range of 0.2–1.4 wt% shows no appreciable influence on the dispersion of organoclay, whereas the loading of PP-g-MA can effectively influence the intercalation and delamination of clay. The intercalation and exfoliation mechanism of prepared PP-g-MA is discussed and compared with that of PP-g-MA oligomer.

Poly(fluorene) composed of alternating structures are considered to assume an ordered macrostructure involving lamellar and π–π stacking in the film state. The ordered structure gives rise to perfect interpolymer excimeric luminescence, which can be used as a luminescence layer in an electroluminescent device.