2 edition of synthesis and crystal structure of isotactic poly (4-phenyl-1-butene) found in the catalog.
synthesis and crystal structure of isotactic poly (4-phenyl-1-butene)
Frank John Golemba
Written in English
|Contributions||Toronto, Ont. University. Theses (M.Sc.)|
|LC Classifications||LE3 T525 MSC 1967 G65|
|The Physical Object|
|Number of Pages||61|
Isotactic and syndiotactic polymers are referred to as stereoregular—that is, polymers having an ordered arrangement of pendant groups along the chain. A polymer with a random orientation of groups is said to be atactic. Stereoregular polymers are usually high-strength materials because the uniform structure leads Read More. adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A.
One of the decisive factors for the efficiency of crystal nucleation is the effective dispersion of nucleating agents, for which three main mechanisms have been described: Particle dispersion by compounding, dissolution followed by re-crystallization from the melt, and in-situ synthesis .Following the latter route, in-reactor polymeric nucleation of Ziegler-Natta isotactic polypropylene (iPP. Isotactic polychloral (3) prepared by the helix-sense-selective polymerization of chloral with optically active initiators showed a high optical activity in the film state ([α] D +°), and.
3. Coiro VM, De Santis P, Liquori AM, Mazzarella L. The molecular conformation of isotactic poly (methyl methacrylate). J Polym Sci Part C. ;– The crystal structue of a highly isotactic optically active alternating styrene−carbon monoxide copolymer, obtained with a chiral cationic Pd(II) bioxazoline complex, is determined and refined.
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Synthesis and Characterization of Isotactic 1,2-Poly(Emethyl-1,3-pentadiene). Some Remarks about the Influence of Monomer Structure on Polymerization Stereoselectivity. Macromolecules42 (8), Cited by: The synthesis and the crystal structure of isotactic poly((R,S)methylpentene) (iP(R,S)3MP) are presented.
The synthetic strategy based on hydrogenation of isotactic 1,2-poly(Emethyl-1,3-pentadiene) has allowed for the preparation of a purely random copolymer of the two enantiomeric (R)- and (S)methylpentene by: 5. The crystal structure of form II of isotactic poly(4-methylpentene) is presented.
Samples of isotactic poly(4-methylpentene) in the pure form II have been obtained by crystallization from tetramethyltin solutions. The crystal structure has been determined by using X-ray powder diffraction data and packing energy calculations.
Chains in 41 helical conformation are packed in a monoclinic Cited by: The crystal structure of form III of isotactic poly‐1‐butene, (poly(1‐ethylethylene)), has been determined by X‐ray powder diffraction techniques, owing to the impossibility of obtaining fiber spectra on this form.
The polymer crystallizes in the orthorhombic system, with lattice dimensions: a = 12,38±0,08 Å; b = 8,88±0,06 Å; c = 7,56±0,05 Å; (direction coinciding with the helix Cited by: To account for the observed diffraction pattern of a commercial specimen of oriented fibers of isotactic polypropylene in the a modification, the crystal structure is described as belonging to the space group P 2 1 /c but having a certain disorder in the distribution of “up” and “down” chain direction.
As a result of this disorder, reflections having the (h + k) sum odd are weaker than Cited by: The crystal structure of isotactic cis‐1,4‐poly(1,3‐hexadiene) has been determined through a combination of X‐ray diffraction analysis and molecular reasonable values for unit cell parameters were obtained from the fiber diffraction pattern of a well‐oriented sample.
isotactic polystyrene (iPS),2 polybutene (iPB),3 poly(o-fluorosty-rene),4 and 1,2-poly(1,3-butadiene).5 The crystal structure of form I of iPB, a prototype of this class of polymer crystals, is shown in Figure 1A.
Chains in 3/1 helical conformation are packed in a trigonal unit cell with axes a. Chain Structure of Isotactic Polyvinyl Cyclohexane Fractionation of Predominantly Isotactic Polypropylene (abstract) Chain Structure of Poly-m-Methylstyrene (abstract) On Crystalline Poly-Fluorostyrenes Stereospecific Polymerizations of Conjugated Diolefins.
Note V: Preparation and Properties of Isotactic 1,2. The crystal structure of syndiotactic PP forms a 2/1 helix based on an orthorhombic system. The melting point of PP varies in accordance with the tacticity.
In particular, the melting point and glass-transition point of isotactic PP are – °C and ~20 °C, respectively, which depend on the molar fraction of the meso ratio.
Homogeneous catalyst systems able to polymerize 1-alkenes to isotactic polymers were first described by Giannini et al. in 58 Isotactic polypropene and polymethylpentene were obtained with catalysts originating from benzyl derivatives of Ti and Zr (typically MBz 4, MBz 3 X with M = Ti or Zr; X = halogen), even in the absence of a.
Riley, in Packaging Technology, Tacticity. Tacticity of a non-uniform monomer such as propylene in a polymer chain affects the T g of the polymer. In the last section it was said that polypropylene had a T g of −15°C, but this depends on the tacticity.
For example, atactic polypropylene has a T g of −19°C, whereas isotactic polypropylene has a T g of −8°C and therefore. The synthesis of a poly(3,5-tricyclo[ 2,6]heptylene) [poly(norbornadiene) (PNBD)] mediated by the TiCl 4 /Et 2 AlCl catalytic system is reported. This polymer is characterized by a rigid nortricyclene repeating structure and unique 3,5-enchainment and is obtained through a transannular cationic polymerization of norbornadiene involving both double bonds.
1. Introduction. Isotactic poly(1-butene) (iPB) is a semi-crystalline polyolefin with unique properties such as a relatively high heat distortion temperature, environmental stress cracking resistance, stiffness, low tendency to creep, high flexibility and good impact resistance , which is suitable for a broad range of applications like pressurized tanks, pumps, food packing, and hot water pipes.
The crystallization behavior and the morphology of blends obtained by mixing a highly crystalline and isotactic poly(1-butene) (iPB) and a copolymer of isotactic polypropylene (iPP) with 26 mol% of 1-hexene (C3C6 copolymer) have been studied.
We report the synthesis and the crystal structure of isotactic poly((R,S)methylpentene) (iP(R,S)3MP). A purely random achiral copolymer of two enantiomeric (R) and (S) 3-methylpentene monomers cannot be obtained by polymerization of the racemic mixture of.
The crystal structure of isotactic polystyrene was reported by Giulio Natta. Inthe Koppers Company in Pittsburgh, Pennsylvania, developed expanded polystyrene (EPS) foam under the trade name Dylite.
InDart Container, the largest manufacturer of foam cups, shipped their first order. Structure. Synthesis, Structure and Properties of Poly(lactic acid) Maria Laura Di Lorenzo, René Androsch (eds.) The series Advances in Polymer Science presents critical reviews of the present and future trends in polymer and biopolymer science.
Macromolecules All Publications/Website. OR SEARCH CITATIONS. * Corresponding authors a Department of Environmental and Life Sciences, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, AichiJapan E-mail: [email protected] ) nearly independent of the molecular weight and synthesis route of the used materials.
Furthermore, the linear viscoelastic behavior of isotactic poly-propylenes in the melt is not inuenced by their tacticity, as it is evident from similar plateau moduli from samples with a different degree of tacticity. Abstract. Isotactic polypropylene (PP) nanocomposites containing, and wt % silver (Ag) nanoparticles were prepared via melt compounding in a twin-screw extruder followed by injection molding The effects of the Ag nanoparticle additions on the structure and mechanical behavior of PP were studied using DSC, WXRD, optical microscopy, tensile and Izod impact techniques.Tacticity (from Greek τακτικός taktikos "of or relating to arrangement or order") is the relative stereochemistry of adjacent chiral centers within a macromolecule.
The practical significance of tacticity rests on the effects on the physical properties of the regularity of the macromolecular structure influences the degree to which it has rigid, crystalline long range order. Abstract.
The crystal structures of poly(l-lactic acid) (PLLA), its stereocomplexes, and some features of its crystallization process are exists in different crystal modifications that are based on two different left-handed helix geometries having three units in one turn (3 1) or ten units in three turns (10 3).The stable α-phase with a 10 3 helix exists in two variants: an.