Strain polymers

Lodge AS (1964) Elastic liquids an introductory vector treatment of finite-strain polymer rheology. Academic, London... 

On the other hand, strong SAXS reflections of uniaxial material are, in general, found on the meridian8. So be sure that a SAXS detector covers the meridian whenever fiber material or strained polymers are studied. 

AA Popov. NYa Rapoport, GE Zaikov. Oxidation of Oriented and Strained Polymers. Moscow Khimiya, 1987, p 25 [in Russian]. 

Einaga.Y., Osaki.K., Kurata,M., Kimura,S.,Tamura,M. Stress relaxation of polymers of polymers under large strain. Polymer J. (Japan) 2,550-552 (1971). See also Polymer J. (Japan) 5,91-96 (1973). 

Kahar, P., Tsuge, T., Taguchi, K., and Doi, Y. 2004. High yield production of polyhy-droxyalkanoates from soybean oil by Ralstonia eutropha and its recombinant strain. Polym. Degrad. Stab.,55,79-86. 

The 4th and 5th sessions of the Conference were held on October 5 at the Emanuel Institute of Biochemical Physics. The 4th session included seven reports. Dr. G.E. Zaikov presented the information about the latest achievements on reduction of inflammability of polymer materials and the use of nanocomposites as antipyrenes (substances that reduce the inflammability of polymer materials) Dr. A.A. Popov reported on the kinetics of destruction of strained polymers (strained molecules reactivity). The structural and dynamic parameters of interfacial layers in filled polymers were the subject of the report by A.L. Kovarskii and... 

Al-Saidi LF, Mortensen K, Almdal K (2003) Environmental stress cracking resistance behaviour of polycarbonate in different chemicals by determination of the time-dependence of stress at constant strains. Polym Degradat Stabil 82(3) 451—461... 

Y.Einaga, K.Osaki, M.Kurata, Stress relaxation of pol3nmer solutions under large strain, Polym. J. 2 (1971), 550-552. 

Relaxation and spin-diffiision parameter imaging of strained polymers... 

The disposition of phenyl groups in the solid amorphous polymer is of relevance to the photophysical properties. Following refractive index measurements Prest has proposed (1 5) that the phenyl units are oriented in the plane of the film and indeed a thin layer of highly strained polymer can be produced by solvent casting. Since the bulk of excitation radiation is absorbed in the surface of a sample the major component of the emission can occur from a birefringent surface layer, so that the observed polarisation/depolarisation can be dominated by this influence rather than by e.e.m., and therefore by sample preparation. 

Zhurkov and his collaborators (77) presented a mechanism, by which of a micro-crack is initiated by a pair of mechano-radicals and is formed in a solid polymer under large stress. They assumed a pair formation of the mechano-radicals in a highly strained polymer, as shown as b in Fig. 11. The radicals primarily produced by a chain scission are end radicals having an unpaired electron at the chain end. Each of these end radicals subtracts a hydrogen from neighbouring polymers to leave two chain radicals, in which an unpaired electron exists in the middle of a chain (c in Fig. 11). By this hydrogen subtraction the borken ends are stabilized, while the two chain radicals convert into the two stable ends and the two end radicals, according to the Zhurkov s mechanism (d in Fig. 11). Then, the two end radicals are reproduced... 

At small strains, polymers (both amorphous and crystalline) show essentially linear elastic behavior. The strain observed in this phase arises from bond angle deformation and bond stretching it is recoverable on removing the applied stress. The slope of this initial portion of the stress-strain curve is the elastic modulus. With further increase in strain, strain-induced softening occurs, resulting in a reduction of the instantaneous modulus (i.e., slope decreases). Strain-softening phenomenon is attributed to uncoiling... 

Internal disk cracking (blistering) in resins was first reported by Steel [42] in 1967, and attributed to swelling, followed by rupture due to hydrolytic attack on the strained polymer chain. Ashbee et aL [43] found that fully cured polyester resins developed disk -shaped internal cracks when exposed to hot water and proposed an osmosis hypothesis for blister formation. 

Hara, S., T. Zama, W. Takashima, and K. Kaneto. 2004. Gel-like polypyrrole based artificial muscles with extremely large strain. Polymer J 36 933. 

The energetic and entropic contributions to the force in the intramolecular process of stretching the chains can be obtained in experiments where there is no other energetic contribution resulting from changes in (intermolecular) van der Waals forces. Therefore, these experiments must be performed at constant volume. A basic postulate of the elasticity of amorphous pol5uner networks is that the stress exhibited by a strained polymer network is assumed to be entirely intramolecular in origin. That is, intermolecular interactions play no role in deformations at constant volume and composition. 

Fig. 9. Schematic of the energy landscape for a strained polymer for Esring s model of viscous flow.

K. Osaki, Y. Einaga, M. Kurata, N. Yamada, and M. Tamura, Stress Relaxation of Polymer Solutions under Large Strain Application of Double-Step Strain Polym. J. 5, 283-287 (1973). 

The melting temperatures and thermal stabilities of several polybenzimidazoles are shown in TABLE I. For all aromatic polybenzimidazoies, melting points are over 600 C. Generally, the presence of other structural elements will reduce melting points and thermal stabilities. For example, TABLE I includes polybenzimidazoles condensed from either a tetraamine ether or a diacid ether. Strained polymer structures also reduce polybenzimidazole stability as evidenced by the low melting point of a polymer formed with a biphenyl-2,2 -dicarboxylate. Not surprisingly, the aliphatic, adipic acid forms a much less stable polybenzimidazole than the aromatic examples above it in the table. 

At small strains, polymers are linear viscoelastic An increase in stress causes a proportional increase in strain. At larger strains, this is not true anymore. 

Kahar P, Tsuge T, Taguchi K, Doi Y (2004) High yield production of polyhydroxyalkanoates from soybean oil by Rahtonia eutropha and its recombinant strain. Polym Degrad Stabil 83 79-86 Kasuya K, Inoue Y, Doi Y (1996) Adsorption kinetics of bacterial PHB depolymerase on the surface of polyhydroxyalkanoate films. Int J Biol Macromol 19 35 0 Kim JS, Lee BH, Kim BS (2005) Production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by Rahtonia eutropha. Biochem Eng J 23 169-174... 

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