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Although cellulose is the oldest macromolecule we have known, its intrinsic properties are still not well understood because of the lack of suitable solvents. The recent development of ionic liquids enables preparation of cellulose solutions in which cellulose molecules are supposed to be dispersed molecularly. Conventionally a semi-flexible-chain model or a worm-like chain model has been applied to describe the dilute solution properties of cellulose. A semi-flexible chain model is specified in terms of a persistent length to determine the chain stiffness of a solute molecule, completely neglecting details of the solvent–solute interaction, and the discussion is mainly focusing on the conformation of a solute molecule. In this paper we adapt a cylinder model which at least specifies the local shape of a solute molecule. Since the ionic liquids are now available as a new solvent of cellulose, we have prepared cellulose/ionic liquid solutions for small-angle X-ray scattering (SAXS) measurements which provide information on the local structure of cellulose molecules in the restricted range. The SAXS measurements were performed on the cellulose/ionic liquid solutions at two independent synchrotron facilities and confirmed the consistency of the observed scattering profile. Standard methods were applied to analyze the scattered data first, and afforded a model for representing a cellulose molecule in ionic liquid solutions. Two types of ionic liquids were used, and it was ascertained that cellulose was not degraded under the conditions used. The solution characteristic was found to change by heating during the preparation of each solution. The heating effect on the conformational change of cellulose was discussed in terms of the solute–solvent interaction from the simulation with a coaxial double layer cylinder model. The state of solvent packing was considered as well from the thickness and relative electron density of the sheath in the simulated coaxial double layer cylinder model.

This article compares color assessments of automotive exteriors at four locations in China, Thailand and Japan. This study employed painted panels of twelve colors, thirty sensory words and fifteen pairs of emotion variables. It also used reference figures of nine cars that included four styling categories, namely sedans, compacts, sport utility vehicles and sports cars. The results of like–dislike tests revealed that basic automotive exterior colors, such as black, white and red, were highly preferred across locations. However, geographical differences are apparent in the preference for some non-basic colors. To elucidate these geographical differences, a Chi-square test and principal component analysis were performed on the data on emotion variables. The results revealed both similarities and differences in color preferences among the four locations. Color preferences were similar in Hong Kong and Shanghai when simply evaluated by color samples. However, similar preferences for automotive exterior colors were observed in Hong Kong, Kyoto and Bangkok, but not in Shanghai. These results suggest that there is fluctuation in the emotion evoked by a color when the color is considered in the context of automotive exteriors. Therefore, this study indicates that automotive sales can be secured in the global marketplace by creating a single palette of exterior colors based on similar color preferences across countries. However, these results also indicate that preparing market-specific automotive-color line-ups can be an effective marketing strategy.

This is a preprint of an article published in Journal of Polymer Science: Part B: Polymer Physics. 46(19): 2126-2142 (2008)., The initial stage of fiber structure development in the continuous neckdrawing of amorphous poly(ethylene terephthalate) fibers was analyzed by in situ wide-angle X-ray diffraction, small-angle X-ray scattering, and fiber temperature measurements. The time error of the measurements (\600 ls) was obtained by synchrotron X-ray source and laser irradiation heating. A highly ordered fibrillar-shaped two-dimensional (smectic-like) structure was found to be formed less than 1 ms after necking. By analyzing its (0010) and (0020) diffractions, the length of the structure 60–70 nm were obtained. A three-dimensionally ordered triclinic crystal began to form with the vanishing of the structure around 1 ms after necking. The amount and size of the crystal were almost saturated within several milliseconds of necking, during which time a mainly exothermic heat of crystallization was also observed., Article, Journal of Polymer Science: Part B: Polymer Physics. 46(19): 2126-2142 (2008)

General principles of electromagnetic wave scattering are sum-marized, with emphasis laid on small-angle X-ray scattering. Theconventional analysis of scattering data is based on the various waysof plotting the data according to the simple model approximation. Inorder to avoid the artifact due to the simple model approximation,the analysis of the scattering data is performed by either adaptinga triaxial model of homogeneous density distribution, a molecularmodel, or a density distribution function.

The chemical crosslinking of funoran, a sulfated galactan, was attempted by using polyethylene glycol diglycidyl ethers in order to prepare a gel for using as a water-absorbing network polymer contained in disposable napkins. The funoran gel was not obtained under a series of crosslinking conditions. Other sulfated polysaccharides, such as Kappa-and Lambda-carrageenan, were not also crosslinked by the diglycidyl ethers, while agarose was chemically crosslinked to give its gel. Agarose has the same chemical main chain as funoran but has no sulfuric acid groups. The bulky sulfuric acid groups may intercept sterically the reaction between the hydroxyl groups and the glycidyl groups of the crosslinker.

This is a preprint of an article published in JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS. Vol 43(9): 1090-1099 (2005)., Article, JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS. 43(9): 1090-1099 (2005)

Effect of counter-anion on the properties and morphology of aliphatic poly(oxytetramethylene) ionenes was investigated, and the relationship between the properties and morphology was elucidated. The ionenes possess elastic properties at low elongations whereas they predominantly exhibit a plastic deformation at high elongations. The morphology of the ionenes was analysed in the nanometer scale by fitting a cascade model for randomly branched f -functional polycondensates incorporated in Debye–Bueche random-two-phase model and the interference term by the interdomain interaction on their small-angle X-ray scattering profiles. The size of ionic domains and distance between the domains were smaller and shorter in the ionene with bromide counter-anion than those in the ionene with chloride counter-anion, respectively. The formation of crystallite of poly(oxytetramethylene) (POTM) segments was detected in the ionene with chloride counter-anion at room temperature. These characteristics of aliphatic POTM ionenes gave the difference in their mechanical and thermal properties.

We have studied the strip biaxial tensile behavior of natural rubber vulcanizates filled with silica by the conventional milling method and by the in-situ silica filling method. The rapid increase of both stresses along the stretching and the fixed axes after the initial stretching was observed on samples filled with a conventional silica by the milling method. Low strain dependence of stresses in the successive strain regions was followed by the rapid increase of the stresses at the higher deformation region. On the other hand, we did not observe such behavior for the samples filled with silica generated in-situ in the rubber matrix before curing. The transmission electron microscopic measurements showed that a highly developed aggregated structure of silica particles was suggested in the conventional silica filled samples and just a simple aggregation was suggested in the case of the in-situ silica filled samples. The differences between samples reinforced with two different filling methods in low tensile region are mainly attributed to the aggregate structure of the silica particles dispersed in the rubbery matrix. We estimated the functional form of the strain energy density function for the samples filled with silica in intermediate and large deformation regions: =C10(I1−3)+C01(I2−3)+C20(I1−3)2 The estimated W was found to reproduce the experimental stress-strain curves in intermediate and large deformation region. The relative contributions of three terms in the estimated W for the samples prepared by the in-situ method show the different dependence on the silica content from those of the samples containing silica mixed by the conventional method.

The characteristics of the running of color (“nijimi”) were quantitatively analyzed in order to elucidate the difference of natural indigo dyeing and conventional synthetic indigo dyeing. The luminance distribution curves and half-widths of the running of color were evaluated for the clothes tie-dyed with traditional natural indigo and conventional synthetic indigo. A single Gaussian function fits to the profile of the running of color produced by natural indigo reduced by fermentation, while the running of color produced by synthetic indigo prepared with sodium hydrosulfite was approximately represented by a linear sum of two Gaussian functions. The half-width profile of the running of color is in the following order : synthetic indigo ⁄ reduction method (sodium hydrosulfite) > synthetic indigo ⁄ reduction method (zinc powder) > natural indigo ⁄ reduction method (fermentation). The running of color is thus concluded to be due to the mode of indigo penetration into fiber, which depends on dyebath preparation. A critical difference in dyeing process is the speed of reduction of indigo, and could not be attributed to a small amount of impurity contained in natural indigo.

The structure, mechanical properties, and thermomechanical properties of poly(ethylene terephthalate) (PET) fibers obtained by laser-heated drawing were investigated in terms of their dependence on the draw ratio and feed speed and the differences between neck-drawn fibers and flow-drawn fibers. The long period at a draw ratio of 6.0 reached 19.0 nm, notably larger than at lower ratios, whereas the tilting angle of the laminar structure was constant at about 60°, regardless of the draw ratio. A maximum value of 15.0 GPa was attained for the initial modulus, and 1.07 GPa was attained for the tensile strength. A higher tensile strength orientation-induced crystallized fiber at the same initial modulus was obtained from higher molecular weight PET. The relationship between the compliance and molecular orientation of the amorphous phase was studied with a series model of crystalline and amorphous phases. The results revealed that, in the high-draw-ratio fibers, the compliance of the amorphous phase decreased with the draw ratio at a higher rate than indicated by extrapolation to intrinsic values. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 79–90, 2004

The effects of copper plate surface-treatment with 3-aminopropyltriethoxysilane (APS) on the adhesion between the copper plate and polyethylene plate through polyethylene gel have been investigated by tensile shear test, DSC measurement, and FT-IR measurement. The copper plate was treated with an ethanol–water mixed solvent containing water content of 30 vol% as a solvent of the APS, the polysiloxane structure favorable for the adhesion between polyethylene and copper plate is formed rapidly. The interfacial shear strength goes up to over 8 MPa when treated with the APS solution in concentration of about 5.0 × 10-2 moll-1. The flexible polysiloxane networks formed from the APS solution on copper plate were found to act effectively for the adhesion. Experiments for model substances corresponding to the interphase in the present adhesion on the basis of DSC measurement and FT-IR measurement have revealed that the flexible polysiloxane networks formed from the APS solution and polyethylene chains as an adhes...

The method for the formation of adhesive phase onto polyethylene (PE) fiber surface by passage of the PE fiber through hot PE solutions has been investigated for making composite materials reinforced by the PE fibers. When the PE fiber is treated by the low density PE (LDPE) solution in o-xylene in the range of 120 to 135°C, the tensile strength of the PE fiber is maintained at that of the original PE fiber. Adhesive strength between the PE fiber surface and LDPE phase formed on the PE fiber through the hot PE solution is found to be so high that the PE fiber itself is torn off. The application of the present method to PE fiber-reinforced PE composites will be expected.

膨潤時に応力を印加して伸長する, いわゆるプレ延伸を付加した膨潤-延伸法に重量平均分子量330万のポリエチレンを適用して, 超延伸が可能になる条件を探索した. その結果, シート成形時の融解温度に保持する時間 (融解時間) および冷却速度がプレ延伸性および延伸性に大きな影響を及ぼすことがわかった. 融解時間については8時間, 冷却側速度については4℃/minのとき延伸率は極大を示すことがわかった. この条件で成形したシートを104℃のトルエン-シクロヘキサン (体積比, 95: 5) の混合溶媒中で2.2×102kg/m2の応力を印加して26倍までプレ延伸した後115℃で延伸すると, 得られる最大強度および弾性率は, それぞれ5.3GPaおよび215GPaに達することを明らかにした.

Poly(ethylene terephthalate) fibers were continuously drawn to high draw ratios under heating by CO2 laser irradiation. The structure of the drawn fiber was analyzed based on measurements of refractive index, wide-angle x-ray diffraction, and small-angle x-ray scattering. The average refractive index, birefringence, crystallite size, crystal orientation and the long period of the fiber structure were found to increase with the draw ratio. However, for fibers drawn to a final ratio of 6:1, neither the diameter of the laser beam, the feed speed, nor the laser power affected the fiber structure appreciably. The crystallite size and long period of a fiber drawn to a ratio of 4:1 were both altered more after annealing at fixed fiber length than for the 6:1 fiber. The lamellae structure inclination angle of samples drawn to both 6:1 and 4:1 was about 60°, decreasing after annealing to 50° for the 6:1-drawn samples and 30° for the 4:1-drawn samples.

The cascade model for randomly branched f-functional polycondensates incorporated in Debye–Bueche random-two-phase model and the interference term by the interdomain interaction was found to good fit the small-angle X-ray scattering profiles of physically cross-linked amphiphilic elastomers. The samples were poly(oxyethylene)-grafted butyl rubber, butyl rubber with D-maltose derivative as pendant groups, and microcrystalline ionene elastomer composed of poly(oxytetramethylene) and 4, 4′-bipyridinium unit. The hydrophilic segments of these amphiphilic elastomers aggregated in the flexible polymer matrix to form the domains that function as cross-linking sites and fillers. Good fitting for all samples by using the proposed model gave the size of the physically aggregated domains, the average distance between the centers of neighboring aggregated domains and the their interdomain interaction distance. All samples were found to be in the vicinity of the gel point from the viewpoint of the cascade model. The r...

Thermally stable hydrogels have been prepared starting from aqueous gellan physical gels by partial self-cross-linking of the polysaccharide chains (formation of essentially interchain ester bonds, with no added bridging moieties) with the aid of the water-soluble 1-ethyl-3-[3-(dimethylammino)propyl]carbodiimide (EDC). The structure of the hydrated networksphysicochemical gelswas analyzed on the basis of the results of small-angle X-ray scattering experiments. Here a molecular model, which is composed of a bundle of 48 gellan double helices aligned in parallel, was proposed to represent the ordered domains in the hydrogels. The rigid bundles formed by associated gellan double helices constitute the junction zones which sustain the overall gel structure displaying solidlike properties. Relatively large cavities supported by rigid bundles inside the gels absorb water quickly as indicated by kinetic water uptake data. A network structure formed by rigid microfibrils of associated gellan double helices connec...

Three viologen-type poly(tetramethylene oxide) (PTMO) ionenes with chloride anions (PTVs) were synthesized by living cationic polymerization, whose molecular masses of PTMO segments between the viologen units were 6100, 9800 and 12000 g/mol. The PTV films were elastomers and possessed the microphase-separated structure consisting of three phases, i.e., PTMO amorphous phase, PTMO crystalline phase and ionic aggregated phase. The effect of ionic content, i.e., the effect of molecular mass between the ionic segments on the higher-order structure and properties of the PTV films were investigated by differential scanning calorimetry, dynamic mechanical analysis, wide-angle X-ray diffraction and small-angle X-ray scattering (SAXS) measurements. The lower the ionic content was, the smaller the amorphous PTMO phase became and the more the long range-ordered structure of PTMO crystals of lamellae was regularly formed. This crystalline part significantly influenced the dynamic mechanical properties. The distance between the ionic domains became larger with the increase of the PTMO segments. The scattering peaks attributed to the crystalline phases and ionic domains were detected by SAXS for the PTV films whose molecular masses of PTMO segments were 9800 and 12000 g/mol. The distance between the ionic domains was changed little before and after the melting of PTMO crystals of PTV films.

Tamarind seed polysaccharide (TSP) xyloglucan consists of a (1→4)-β-D-glucan spine (cellulose spine) with (1→6)-α-branched xylose, which is partially substituted by (1→2) -β-galacto-xylose. Thus TSP xyloglucan yields three types of monomer units (heptasaccharide DP7, octasaccharide DP8 and nonasaccharide DP9 where DPdenotes the number of residues), which differs in the number of galactose side chains. Three types of monomers were prepared and their conformation in water was elucidated in detail by means of small-angle X-ray scattering and molecular dynamics. Dimers, trimers and tetramers (constituted of a mixture of arbitrary combinations of three types of monomers) were also prepared and their conformation was analyzed from the results of small-angle X-ray scattering. The results confirm the thin ribbon-like structure of xyloglucan oligomers. The conformation of xylose and galacto-xylose branches was also discussed.

A novel ionene elastomer (DPI) consisting of 2,2‘-bipyridinium units and poly(oxytetramethylene) (POTM) segments was synthesized by cationic polymerization of tetrahydrofuran followed by termination using 2,2‘-bipyridine. The molecular mass between the ionic sites was ca. 10 000 g/mol. The DPI film displayed a high tensile strength up to 34 MPa and 540% elongation at break at 25 °C. The higher-order structure of the DPI film was investigated by thermal and dynamic mechanical analyses and by wide-angle X-ray diffraction and small-angle X-ray scattering (SAXS) measurements. The DPI film had a microphase-separated structure consisting of three phases of the POTM amorphous matrix, the POTM crystalline domain and the ionic domain at room temperature. The POTM crystalline domain was lamellar, and its spacing was ca. 270 A. A new model was proposed to successfully account for the upturn of the scattering intensity toward zero angle in the SAXS profile of DPI at 65 °C, where two phases of the POTM amorphous matri...

The inhomogeneous structure of crosslinked polyurethanes based on poly(butadiene)diol (PBD), 4,4′-diphenylmethane diisocyanate (MDI) and poly(oxypropylene) triol (POPT) prepared with various PBD contents were studied by dynamic mechanical analysis (DMA) and synchrotron small-angle X-ray scattering (SAXS). An inhomogeneous two-phase structure of networks containing PBD was revealed by SAXS. One phase consists of PBD chains while the other of densely crosslinked POPT/MDI network with much higher glass transition temperature. The range of inhomogeneity depends on PBD content, and is estimated as about 70–120 A from the Bragg spacing. The scattering data are fitted using the Percus-Yevick hard sphere model. © 1997 Elsevier Science Ltd.

The process of the microphase separation leading to an inhomogenous structure of the polyurethanes prepared from poly(butadiene)diol (PBD), 4,4′-diphenylmethane diisocyanate (MDI) and poly(oxypropylene)triol (POPT) has been investigated by synchrotron small-angle X-ray scattering (SAXS). The development of the two-phase structure of the polyurethanes, consisting of microdomains of higher electron density dispersed in the matrix of PBD chains, was revealed. When POPT is not used in the preparation, the interdomain distance does not increase with time and it corresponds to the root-mean-square end-to-end distance of the PBD chains. In the presence of POPT a distinct growth in the microdomain size and interdomain distance is observed. The scattering data are discussed in terms of the modified Percus-Yevick hard sphere model. © 1997 Elsevier Science Ltd.

Monodisperse hydrogel microspheres (microgels) were prepared by precipitation polymerization from acrylamide (AAm), methylenebisacrylamide (MBAAm), and methacrylic acid (MAc) in isopropanol. MAc was found to be essential for the preparation of fine spherical particles. The structural analysis of microgels at each step of conversion suggests that the precipitation polymerization proceeds in two steps of (1) the formation of star-shaped nuclei mainly by crosslinking agents and the coupling of the nuclei to constitute a network structure, and (2) the incorporation of remaining acrylamide onto the microgel surface and the further crosslinking with free double bonds in microgels. The particle size was found to depend on various polymerization conditions, including the monomer composition, the amount of initiator and the total monomer concentration. The internal structure of microgels was observed by small-angle X-ray scattering (SAXS). The scattering profile was analyzed by Fourier-transformation to yield the distance distribution function p(r), and by fitting an assumed scattering function to evaluate the correlation length ξ and the fractal dimension D.

Two series of inorganic/organic hybrid gels were prepared by the sol-gel reaction of triethoxysilyl-terminated poly(tetramethylene oxide) and tetraethoxysilane. The structure of hybrid gels was observed by small-angle X-ray scattering, and the scattered profiles were analysed by assuming a priori the density correlation functions. The results suggest that the hybrid gel is composed of organic-rich, inorganic-rich and organic/inorganic mixed regions. The size and structure of respective regions were discussed in terms of the correlation lengths evaluated from the scattering profiles.

Poly(ethylene oxide)-grafted butyl rubbers (IIR-g-PEOs), which were synthesized from potassium salt of polyethylene glycol monomethyl ether (PEGM) and chlorinated butyl rubber, were found to behave like thermoplastic elastomers. The poly(ethylene oxide) (PEO) content of these amphiphilic polymers was ca. 10 wt %, and their PEO lengths were 750, 2000, and 5000, respectively. The grafted segments of PEO in butyl rubber (IIR) aggregated to form the PEO domains in IIR matrix. At constant PEO content, the longer the PEO segment length, the larger the size and the crystallinity of PEO domains became. This PEO domain worked as a cross-linking site and a reinforcing filler. The degree of swelling in water of IIR-g-PEO film that was prepared from PEGM-5000 was largest, but its emulsification ability was smallest among them. © 1995 John Wiley & Sons, Inc.

Mullite crystallization behavior was studied using two kinds of gels obtained from the same compositional solutions from which mullite precursor fiber is spinnable. The gels were obtained by the following two different procedures: (1) Al(OPri)3 and TEOS were simultaneously added to Al(NO3)3 containing aqueous solution, and (2) Al(OPri)3 was added to Al(NO3)3 containing aqueous solution, then TEOS was added to these solutions. XRD experiments for both gels after heating at 1000°C showed that Al and Si mixing is away from the ideal homogeneity. The gel prepared by the latter procedure had less complete molecular-scale homogeneity of Al and Si mixing than that by the former procedure. Mullite crystal was detected after heating at 600°C in the former and at 800°C in the latter. These mullite particles were presumed to act as nuclei and to increase the crystallization rate at isothermal treatment. The difference of mullite crystallization temperature were interpreted from the differences of changes in radii of gyration for the concentration process of these solutions. The differences of mullite nucleation and growth from the gel specimen obtained by the different processes were attributed to these different solution structures, even though the raw materials had the same compositions.

The mesophase (lyotropic liquid crystal) of the inorganic rod-like polymer, imogolite, displays a typical fingerprint texture under a polarized optical microscope (POM), although the mesophase reveals no circular dichroism. The scanning electron microscope revealed a honeycomb structure of thin sheets having pleats in the freeze-dried sample prepared from the mesophase solution, and POM shows also a fingerprint texture from the same sample. A novel polarized optical microscopic observation procedure was introduced to eliminate the contrast variation and extinction due to the zero amplitude effect which depends on the orientational variation of anisotropic bodies with respect to a polarizer direction under the crossed Nicols. Various textures of lyotropic imogolite liquid crystals were observed with the procedure, and the results were accounted for by a honey-comb structure of curled thin sheats having pleats. The honey-comb model is consistent with the observation by scanning electron microscopy on the freeze-dried sample.

Time-resolved small-angle X-ray scattering was observed on systems undergoing gelation. A polysiloxane network was used as a model system, where the polysiloxane network was formed by hydrosylation of VT-M with F4-C. The Flory-Stockmayer model for gelation was found to be satisfactory to describe the polysiloxane network formation. No inhomogeneous distribution of densely crosslinked region exists, and in this respect the gel formed by the polysiloxane network is homogeneous. The invariance of the correlation length ξ evaluated from the Lorenzian term suggests that the local network architecture would not change by gelation.

Gellan gum undergoes gelation by forming domains composed of associated double helices. Gellan gum aqueous solutions were prepared with or without adding various metal salts, and their gel-sol transitions were observed by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). The SAXS results are analyzed in terms of the molecular models of associated double helices, and the DSC endo-thermic peaks are attributed to the possible dissociation processes of the domains formed upon gelation. The mechanism of the gel-sol transition is discussed from the view point of the role of metal cations.

Publisher Summary Small-angle X-ray scattering is characterized by its small scattering angle. A scattering process is described in terms of a reciprocal law. The molecular mass determination by small-angle X-ray scattering is less practical than other methods, such as light scattering, osmotic pressure, and sedimentation. The small-angle X-ray scattering equipment for solutions (SAXES) is designed for scattering experiments on non-crystalline materials including polymer solutions, metals and alloys, and was constructed to fit to BL-10C. Small-angle X-ray scattering is suitable for observing particles of dimensions 10–500 A, which covers most colloidal particles including biological or synthetic polymers. The time-resolved small-angle X-ray scattering is observed from poly (ethyleneterephthalate) film during isothermal crystallization using a double focusing camera for synchrotron radiation at the storage ring DORIS. The advantage of small-angle X-ray scattering (SAXS) over spectroscopic methods may be that the SAXS reflects directly the structure of a macromolecule itself.

The characterization of the gel structure by means of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) is described by taking the examples of monovalent and bivalent cation κ-carrageenates in aqueous solution, polyvinyl alcohol)-borate gels and the inorganic/organic hybrid gels from tetraethoxysilane and poly(oxytetra-methylene). The SAXS and SANS results were analysed and discussed in terms of the classic gelation thoery as well as the scaling concepts.

Critically branched polyurethanes of varying molecular weight were prepared from poly(oxypropylene)triol and methylenedi-p-phenylene diisocyanate with and without solvent. The static/dynamic light scattering from DMF solutions of these samples was measured. The results were discussed in terms of the classical (Flory-Stockmayer, FS) and percolation theory of gelation; the bulk-polymerized sample obeyed the FS process, whereas the solution-polymerized samples were better described by the percolation process.

Imogolite, though achiral, forms cholesteric spherulites in the anisotropic phase as shown by the regular striations arranged in a swirl-like or fingerprint pattern observed through a polarizing microscope. Electron microscopy revealed the raft-like imogolite sheet floating in the anisotropic phase. The structure of the imogolite sheet was deduced from periodicities observed by an electron microscope using various imaging conditions. The origin of the twisting force to maintain the cholesteric ordering is also discussed.

The static structure factor and the first cumulant of the time correlation function in dynamic light scattering have been calculated for a regularly branched molecule with n shells of branching generations which are connected by chains of m repeating units per chain. Ideal flexibility for the chains is assumed. The dynamic scattering functions of these soft spheres show behavior significantly different from that of a hard sphere. The theory describes very satisfactorily the static and dynamic light scattering results obtained experimentally with polyvinyl acetate microgels. The possibility of determining the glass transition temperature of latex particles is briefly discussed.

The path-weighting generating function (pwgf) method is applied to calculate the hydrodynamic radii of the randomly crosslinked system as well as its monodisperse faction. Exactly the same relation is found for the z-average reciprocal effective hydrodynamic radius of the linear and the randomly crosslinked system as a function of the weight-average degree of polymerization DPw′, where b〈R h −1 〉 z = C(DP w ) − 1 2 with a constant C depending on the primary chain distribution. The weight-average reciprocal effective hydrodynamic radius, however, depends on the number average degree of polymerization and only moderately changes with crosslinking. The effective hydrodynamic radius of the monodisperse fraction is proportional to the quadratic root of the number of crosslinks. The technique is also applied to the dynamic scattering where formulae for the preaveraged and the non-preaveraged first cumulants are given.

Augmentation brutale des periodes longues a une certaine temperature au-dela de laquelle le degre de cristallinite re-augmente proportionnellement a la vitesse de chauffage. Presence de plusieurs endothermes dans la courbe de DSC, endotherme dont le 1 er intervient a la temperature mentionnee plus haut. Il est conclu que les cristaux originels fondent a chaque pic du thermogramme et que de nouveaux cristaux sont produits par recristallisation

A rapid temperature‐jump (T‐J) device was designed for the kinetic measurements of small‐angle x‐ray scattering from solutions of biological macromolecular systems. The dead time of the apparatus is reduced to a few hundred milliseconds. The structural change of biological macromolecules in solutions can be monitored in the time scale of a few hundred milliseconds by the synchrotron small‐angle x‐ray scattering with a combination of a CAMAC data‐acquisition system and the present T‐J apparatus.

Normal stresses and the shear stress in steady shear flow as well as the dynamic complex modulus are measured for dilute solutions of poly-n-butyl methacrylate in chlorinated diphenyl, in the range of concentration, 0.2∼1.0 wt.% and of molecular weight, 5.21×105∼2.30×106. The secondary normal stress was negligibly small compared to the principal one when the rate of shear was low. The steady shear compliance was proportional to the number of polymer molecules in the solution and its magnitude was of the order predicted from the spring-beads model theories. A relatively strong tendency to non-Newtonian effect was observed for the solutions with relatively high concentrations, and the reduced plot which was successfully performed for polystyrene solutions failed in this case at high rate of shear.