Mechanical Anisotropy of Semicrystalline Polymer in Relation to Molecular Orientation

A brief review on the mechanical anisotropy of crystalline polymers in bulk in relation to the molecular orientations, is presented. First, a mathematical representation of orientation distribution of structural units within the bulk polymer, is given in terms of an expansion of the distribution function in a series of spherical harmonics. Each coefficient of the expanded series is discussed in relation to several kinds of orientation factors, average degrees of the orientation distribution, defined by different authors independently. Second, several optical techniques to evaluate the orientation factors, the second and fourth moments of the orientation distribution of crystalline and noncrystalline structural units from the optical dichroic quantities, are discussed. Some experimental results on the orientation behavior of crystalline polymers during uniaxially or biaxially stretching are demonstrated. Finally, the mechanical anisotropies of oriented crystalline polymers, including uniaxial- and orthogonally biaxial-symmetric systems, are interpreted in terms of the average degrees of orientation distributions of the two kinds of structural units, crystallites and noncrystalline chain segments, and the mechanical anisotropies of the structural units for the glassy state of the polymers ; i.e., in terms of the aggregate model of biphase structure on the basis of either the homogeneous stress or strain hypothesis. Furthermore, a modification of the Krigbaum's treatment for the elasticity of the crystalline polymers, which based on the kinetic theory of entropy elasticity, to the anisotropic body, is proposed for the rubbery (or leathery) state of the polymers

Quantitative Analyses of Small-Angle X-ray Scattering Profiles with a Linear Position Sensitive Detector

Quantitative data analyses of small-angle scattering (SAXS) profiles measured with a linear position sensitive detector (PSD) are discussed. We shall describe corrections of the measured SAXS profiles for (i) non-uniformity of the detector sensitivity along its length, (ii) collimation errors, and (iii) reduction of the position resolution due to the oblique incidence of photons to the detector. The correction of the profile for the collimation errors (i.e., desmearing) involves measurement of the slit weighting functions which depend on properties related to the PSD and its electronics (e.g., channel number or conversion gains of ADC and TAG, position resolution, and the uniformity of detector sensitivity) as well as the optical set-up of the SAXS apparatus. It is shown that properly corrected SAXS profiles obtained with the PSD quantitatively agree with those obtained with a conventional step-scan SAXS apparatus such as the Kratky U-slit system and the Beeman four slit system

Dynamic X-Ray Diffraction Technique for Measuring the Crystal Lattice Response in Semicrystalline Polymers against Mechanical Excitations

Dynamic mechanical and crystallographic features which are associated with mechanical excitations on the bulk specimen of the semicrystalline polymers are generalized on the basis of factors such as mechanical dispersions of orientation of crystallites and deformation of the crystal superstructure. The latter factor may further be divided into inter-lamellae and intra-lamella responses within the superstructure such as spherulite. The present paper describes the theory and techniques set up to observe the intralamella response in the semicrystalline polymers against mechanical excitations by means of a dynamic x-ray diffraction technique. This observation is required to measure the inphase and out-of-phase components of the angular vibration of the diffraction maximum raised by the forced sinusoidal strain of the test specimen. For this purpose, it was shown that a twin detector technique could successfnlly be applicable where the diffraction peak shift was amplified by simultaneous measurements of the shoulder intensities of the diffraction perk at the higher and the lower diffraction angles to the peak maximum

Chironomid fauna Piptera: Chironomidae) in the Hosomidani valley, western Chugoku Mountains, Japan

The Hosomidani riparian fbrest, located around the origin of the Ohta River basin, is one of the most nature-rich districts in Japan. We investigated chironomid fauna in the Hosomidani valley as　anindicator taxon to evaluate the species diversity of　&eshwater benthic macroinvertebrates. On 23 August and 2 November, 2005, ironomid lalvae were collected in the main stream of the Hosomidani River, small streamletsflowing Into the main stream and the floodplain marsh along the Hosomidani River,and were reared to adults in the laboratory to identify species. A total of 52 species was collected and of which 17 Were newly recorded in the Ohta River basin Thirty-five species were collected in the main stream and of which 14 were also fblmd in the streamiets. On the other hand, 12 out of 16 species collected inthefloodplain marshes were not found in the main streamand streamiets, Polypedilum (Trliodura) caudocula was only found in the noodplain and this is the second record next tothe descnptlOn Of this species in 1991 ･ These results indicate thaHhe high species diversity of cbironomids in tile Hosomidani valley is supported by the presence of the noodplain,Article信州大学山地水環境教育研究センター研究報告 6: 103-108(2010)departmental bulletin pape

Microphase Separation of Block Polymers

Block polymers composed of incompatible block chains of A and B undergo a microphase separation due to the repulsive interaction between A and B in solutions at concentrations above the critical concentration, or in bulk at temperatures below the critical temperature, Tc, (for the A-B system having an upper critical solution temperature) or above Tc (for the system having a lower critical temperature). The microphase separation results in a microdomain structure in solid state, the morphology of which controls the unique physical properties of the block polymer systems. This article reviews recent developments in the area of (i) microphase separation and phase-separated structure in solution and in bulk (ii) microdomain structure in solid state and (iii) polymer-polymer interphase in block polymers for amorphous and linear block polymer systems having simple architectures (e.g., polystyrene and polyisoprene or polystyrene and polybutadiene diblock or triblock polymers)

Dynamic X-ray Diffraction Technique for Measuring Rheo-optical Properties of Crystalline Polymeric Materials

A dynamic X-ray diffraction technique, which can follow the responses of polymer crystals (crystallization, orientation, and lattice deformation) to a mechanical excitation of sinusoidal strain induced to a bulk specimen, was described. The descriptions for such responses are qualitatively made by using a narrow sector technique, which can measure the X-ray diffraction intensity distribution at a particular phase angle of the sinusoidal strain as a function of static and dynamic strains, temperature, and angular frequency. A typical result is demonstrated in terms of the investigation of orientationcrystallization phenomena of natural rubber vulcanizates. More quantitative descriptions can be made by using a half-circle sector technique, which can measure the in-phase and out-of phase components of the dynamic X-ray diffraction intensity distribution. From these, one can obtain the dynamic strain-induced crystallization and orientation coefficients and the dynamic response of lattice deformation of a specific crystal plane both as functions of temperature and frequency. After a brief survey of the principle of the half-circle sector technique, frequency dependence of the dynamic strain-induced crystallization coefficients of the (002) and (200) crystal planes of natural rubber vulcanizates is demonstrated in terms of the two frequency dispersion regions around 10⁻² and 10¹ Hz at a room temperature. The former and latter dispersions must be correlated with the crystallization processes of the so-called α- and γ-filaments, respectively. In addition, frequency and temperature dispersions of the dynamic strain-induced orientation coefficient and the dynamic response of lattice deformation of the (110) crystal plane of polyethylene are demonstrated in relation to the so-called a₁ and a₂ dispersions of dynamic mechanical modulus function of this material

Time-resolved light scattering studies on kinetics of phase separation and phase dissolution of polymer blends. 1. Kinetics of phase separation of a binary mixture of polystyrene and poly(vinyl methyl ether

ABSTRACT The dynamics of liquid-liquid phase separation of a polymer blend of polystyrene and poly(viny1 methyl ether) was studied by time-resolved elastic light scattering techniques in both the nucleation-growth (NG) and spinodal-decomposition (SD) regimes. It was found that in the early stage of SD the scattered intensity a t a given momentum transfer q = (4r/X) sin (8/2) increases exponentially with time after the initiation of the isothermal phase separation involved by a temperature jump from the temperature well below the binodal point. The relaxation rate 2R(q) of the intensity increase is a function of q such that R(q)/q2 linearly decreases with q2, in accord with the linear theories of SD originally proposed by Cahn for small molecules and extended by de Gennes for polymers. The spinodal temperature was obtained from the dynamics measured as a function of temperature in the linear SD regime. In the later stage of SD, the intensity increase with time starts to deviate from exponential behavior and the scattering maximum shifts to smaller q, corresponding to the onset of the coarsening process. The higher the superheating, the earlier the stage where the coarsening starts. In the NG regime the intensity increases nonexponentially with time

日野川水系に分布するイワナ属魚類の亜種，頭部斑紋型，遺伝子型の組成について

鳥取県日野川水系におけるイワナ属魚類について，ゴギとニッコウイワナ，頭部斑紋型，遺伝子型の組成を調べた。計19の支流から38個体のサンプルが採集され，支流はその発する山塊ごとにグループ化された。ニッコウイワナは水系東部の大山・二子・花見山塊から発する支流に分布したが西部5山塊からの支流には分布せず，対照的にゴギは水系西部の鬼林・道後・三国・船通・鷹入山塊に分布したが東部3山塊には分布しなかった。斑紋型では東部3山塊ではＣ・Ｅ・Ｆ・Ｇ・Ｈは記録されたがＡ・Ｂ・Ｄ型は記録されなかった。一方，西部5山塊ではすべての型が記録された。遺伝子型では6および9つのハプロタイプがそれぞれニッコウイワナおよびゴギ特異的であり，1タイプのみ共通であった。デンドログラムではニッコウイワナおよびゴギそれぞれ5および6つのハプロタイプで構成される亜種特異的なクレードが見られたが，もう一つのクレードは両亜種で形成された。これらの結果は，日野川における両亜種の混棲，ゴギの複数起源性，地形変動等による分布拡大，さらに斑紋の易変異性を示唆する。Composition of 2 subspecies of white-spotted charr, Salvelinus leucomaenis imbrius (“Gogi”) and S. l. pluvius (“Nikko-iwana”), head spot types and genetic types were investigated for the Hino River, Tottori Prefecture, Japan. A total of 38 charr samples was collected from the 19 branches. All the branches were categorized into 8 groups based on the mountain mass from which the branch originates. Nikko-iwana was distributed in the Daisen, Futago and Hanami mountain masses in the eastern part of the basin and was not distributed in the other 5 mountain masses in the western part. In contrast, Gogi was distributed in the western Onibayashi, Dogo, Mikuni, Senzu and Takairi mountain masses and was not distributed in the 3 eastern mountain masses. For head spot types, C, E, F, G and H were distributed in the 3 eastern masses whereas A, B and D were not recorded from these masses. On the other hand, all the types were distributed in the 5 western masses. For genetic types, 6 and 9 haplotypes were Nikko-iwana- and Gogi-specific, respectively. Only a haplotype comprised both subspecies. In the dendrogram, 5 haplotypes constructed an exclusive clade of Nikko-iwana whereas 6 haplotypes constructed an exclusive clade of Gogi. However, the remaining clade was constructed by both subspecies. These results suggest the co-existence of both subspecies in the Hino River, multiple origins of Gogi, movements of charr by topographic events and plasticity of the head spots

海産ユスリカ種の形態学的系統樹と遺伝学的系統樹の関係

海産4属，Clunio，Semiocladius，TelmatogetonおよびThalassosmittiaと陸生のSmittia，淡水性のCricotopus属のエリユスリカ亜科と近縁亜科の形態学的系統樹と遺伝学的系統樹の関係を調べた。遺伝学的系統樹では3系統，すなわちSmittia，SemiocladiusとClunioを含む他の4属に分かれた。さらに，TelmatogetonとThalassosmittiaは別亜科にも拘わらず小さなクラスターを形成した。形態学的系統樹ではSemiocladiusとClunioは小さなクラスターを形成したが，TelmatogetonとThlassosmittiaはこれらだけではクラスターを形成しなかった。Cricotopusは最後に大きなクラスターに加わった。これらの結果は，Clunio，TelmatogetonとThalassosmittiaは淡水種の祖先から派生したこと，そして形態学的形質の中にいくらかの平行進化が存在することを示唆する。Relationships between morphological and genetic trees of 4 marine orthoclad and related genera, Clunio, Semiocladius, Telmatogeton and Thalassosmittia, of the dipteran family Chironomidae as well as a terrestrial genus Smittia and a freshwater genus Cricotopus were examined. In the genetic tree, there were 3 lineages; Smittia, Semiocladius and other 4 genera, comprising Cricotopus. Telmatogeton and Thalassosmittia formed an intimate clade in spite of their different affiliations to the subfamily. Semiocladius and Clunio made a small clade in the morphological tree, whereas Telmatogeton and Thlassosmittia did not form a clade by themselves. Cricotopus participated in the largest cluster. These results suggest that Clunio, Telmatogeton and Thalassosmittia have derived from a freshwater ancestor and there be some morphological parallelisms