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Using the confined thin film melt polymerization technique lamellar single crystals, of two morphologies, have been grown for poly(p-phenylene terephthalamide). Electron diffraction (e.d.) patterns from these crystals and from fibre-like samples polymerized from sheared monomer, are in best agreement with a modified phase I cell. The lattice parameters (a = 7.88, b = 5.22, c = 12.9 ; α, β, γ =...
The chain conformation and molecular packing of poly(p-oxybenzoate) (PpOBA) at room temperature have been determined using computer modelling and direct phasing based on electron diffraction data from lamellar and whisker single crystals. In the triclinic (metrically orthorhombic) phase I and orthorhombic phase II the unit cell parameters are a = 7.45, b = 5.64, c = 12.47 9, α = β = γ = 90° for...
The skin/core morphology of viscose fibres was analysed by X-ray microbeam diffraction applied to individual fibres and by electron diffraction on longitudinal fibre cross-sections. Both techniques yield position-resolved diffraction maps which reveal that (1) the cellulose molecules are far better aligned in the fibre skin than in their core and (2) there is no significant difference between skin...
Novel data about the crystal morphology and the electron diffraction of syndiotactic poly(p-methylstyrene) (s-PPMS) in form I and in the clathrate forms including o-dichlorobenzene and tetrahydrofuran are presented. Preparative routes of s-PPMS samples in the various polymorphs suitable for electron microscopy and diffraction have been devised. This investigation provides data, unavailable in the...
The structure of poly(diethylsilylenemethylene) (PDESM), poly(di-n-butylsilylenemethylene) (PDBSM), poly(di-n-pentylsilylenemethylene) (PDPeSM) and poly(di-n-hexylsilylenemethylene) (PDHSM) have been studied using X-ray and electron diffraction methods. The structure of poly(di-n-propylsilylenemethylene) (PDPrSM) has been studied and reported in a separate paper. PDBSM, PDPrSM, PDPeSM and PDHSM all...
Sodium 2,2'-methylene-bis-(4,6-di-t-butylphenylene)phosphate(NA-11) is widely used as a nucleating agent in the processing of isotactic polypropylene(iPP). To reveal its act as the nucleating agent on iPP, the crystallization behavior of NA-11 on isotactic polypropylene was investigated. NA-11 was crystallized on the oriented, thin iPP film from the solution in dimethyformamide at various temperatures...
Characterizing the nanostructures of spider major ampullate (dragline) silks is an important step in understanding the origin of their high mean strength and toughness, and for producing polymeric analogs that mimic these properties. Here we present transmission electron microscopy (TEM) diffraction patterns and an accompanying structure factor analysis for the dragline silk of Latrodectus hesperus...
The morphology and crystal structures of poly(2,6-naphthalene terephthalate) (PNT) and poly(2,6-naphthalene naphthalate) (PNN), prepared by confined thin film melt/solution polymerization (CTFMP/CTFSP), were characterized by transmission electron microscopy, electron diffraction and molecular modeling. The unit cells of PNT and PNN are both monoclinic (P12 1 /a1 space group) with parameters...
Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to examine the nanostructure of a natural polymer—a spider dragline silk—that has potential applications as an engineering material. The silk studied was collected from the cob-web weaving spider Latrodectus hesperus. Single crystal and polycrystalline electron diffraction patterns indicate the presence of crystals with a...
A-type single crystals were prepared in dilute water/acetone solutions by crystallizing narrow fractions of short amylose chains biosynthesized in vitro. The 5 μm-long spindle-shaped crystals were observed by scanning and transmission electron microscopy. Electron diffraction patterns were recorded from frozen-hydrated crystals at different tilt angles around selected crystallographic axes. In particular,...
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