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We investigate simultaneous lamellar contraction and the stress-strain response in styrene-ethylene propylene (SEP) lamellar diblock copolymer melts under shear. Lamellar contraction was found in predominately parallel lamellae in three SEP copolymers during steady shear. The amount of contraction strongly depends on the molecular weight of the block copolymers as well as the rate of deformation. These molecular weight and shear rate dependences are discussed in terms of chain distortions and entanglements in the interpenetration zones of the block copolymer lamellae. For three molecular weights and three shear rates, we report a unifying correlation between lamellar contraction and applied shear stress, indicating a strong dependence of the molecular-scale chain distortion and the macroscopic strength of deformation (stress).

The sol−gel transition, or gelation, in a polymer network-forming system is defined as the critical point in the polymerization at which an infinite macromolecule is formed. There are many studies in the literature concerning the exact and accurate determination of the gel point and its interpretation in terms of the critical conversions of reactant functional groups. However, these have mainly involved step-growth polymerizations with few studies of chain-growth polymerizations such as that described in this study. Chemorheological studies on a cationically polymerized epoxy network-forming system are used to determine accurate gel times and critical conversions, which are interpreted in terms of classical branching and chemical bond percolation models for nonlinear polymerizations. Rheological studies during the polymerization of a trifunctional epoxide monomer, using BF3 as the Lewis acid initiator, yielded a gel conversion of 0.17 ± 0.02 and a power law dependence for the development of shear modulus,...

Nineteen oxybutylene/oxyethylene/oxybutylene triblock copolymers [Bn/2EmBn/2, E = oxyethylene, OCH2CH2; B = oxybutylene, OCH2CH(CH2CH3)] were prepared and characterized. Twelve of the copolymers microphase-separated in the melt. Investigation of this microphase-separation behavior using small-angle X-ray scattering (SAXS) yielded values of the domain spacing (d-spacings) in the ordered phases and of the temperature of the order−disorder transition (TODT). In several cases the ordered phase structure was deduced from a combination of 1D and 2D SAXS and rheology. Values of TODT for the triblock copolymers were ca. 100 °C lower than those for EmBn diblock copolymers of identical composition and chain length but 30 °C higher if compared with diblock copolymers of half the triblock length. Values of the d-spacings indicated that the triblock copolymers were 10% more stretched than corresponding diblock copolymers. Determination of the Flory−Huggins parameter (χ) for the diblock and triblock systems gave identi...

Infrared and N.M.R. spectroscopy were used to assign structures to 3,4,4-trimethyl-5-pyrazolone, 3,4-dimethyl-5-pyrazolone, 3-methyl-5-pyrazolone, and their 1-phenyl analogues, 1-(p-sulphophenyl)-3-methyl-5-pyrazolone and the corresponding 3-carbethoxy and carboxy derivatives, together with 1-phenyl-3-methyl-4-phenylazo-5-pyrazolone, the corresponding 3-carboxylic acid and its methyl ester, and 1-phenyl-3-carbethoxy-4-(p-acetoxyphenylazo)-5-pyrazolone. All the above compounds exist in a keto form and the arylazo derivatives are in the form IX stabilized by strong intramolecular hydrogen bonding.

The spectra of o-, m- and p-methyl orange, the 2′-, 3′- and 4′-sulphonated derivatives of 2-methyl-4-dimethylaminoazobenzene, the 4′-sulpho derivative of 2′- and 3′-methyl-, 2,2′-, 2,3′- and 2′,6′-dimethyl-, and 2,2′,6′-trimethyl-4′-sulpho-4-dimethylaminoazobenzene, together with 2,2′,6′-trimethyl-4-dimethylaminoazobenzene have been examined in neutral and acidic solution. The effects observed in both cases can be accounted for by the electron attracting inductive effect of the sulphonate group. The relative amounts of protonated tautomers in acidic solution have been calculated. The amount of azonium form (III) of the protonated dyes was found to be dependent upon the position of the sulphonate group, diminishing in the order 2′, 3′, 4′. The presence of methyl groups in the same ring as the sulphonate group tended to increase the amount of azonium tautomer in comparison to the unsulphonated dye.

The metabolism of 4-nitroaniline, 2,6-dichloro, 2,6-dibromo- and 2,6-dimethyl-4-nitroaniline has been studied in rats. 4-Nitroaniline is excreted partly unchanged and also as 4-phenylenediamine and 2-amino-5-nitrophenol. Both halogenated derivatives undergo replacement of the nitro group by hydroxyl to yield halogenated 4-aminophenols. The chloro compound gave some of the corresponding phenylenediamine. Metabolites from the methylated derivative were unidentified but no aminophenols or phenylenediamine derivatives were detected. The results have been quantitated using isotopically-labelled compounds, all of which were well absorbed and rapidly excreted. The mechanism of the metabolic replacement of the nitro group by hydroxyl is discussed.