Theoretical Estimation of Segmental Orientation in Deformed Polymeric Networks Using a Lattice Model and Application to Orientation of Amorphous Chain Segments of Poly(ethylene terephthalate) and Oriented Crystallization of Polyethylene

Matsuo, Masaru; Ooki, Junko; Harashina, Yuuko; Ogita, Tetsuya; Manley, R. St. John

doi:10.1021/ma00118a024

Cited by 11 publications

(22 citation statements)

References 15 publications

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“…10 Table I summarizes change in melting point and crystallinity as a function of draw ratio. Upon the initial draw ratio from 1 Â 1 (un-drawn) to 2 Â 2, crystallinity and melting point decreases indicating the crystal transformation process from a folded to a fibrous type.…”

Section: Characteristics Of Test Specimensmentioning

confidence: 99%

“…10 The network chains will be assumed to be mono-disperse, i.e. composed of the same number m of rods having an ideal axial ratio x.…”

Section: General Conceptmentioning

confidence: 99%

“…To avoid this contradiction, the preferred axis was chosen along the direction between the two cross-linked points in the previous paper. 10 The treatment is similar to that of freely jointed chains of finite length represented by the distribution of Langevin.…”

Section: General Conceptmentioning

confidence: 99%

“…In previous paper, 10 oriented crystallization under uniaxial stretching was studied by using the lattice model in terms of the effect of amorphous chain segments by induced crystallization. The general concept proposed by Ziabick et al [19][20][21] is due to the fact that the crystallization of amorphous chain segments depends on their orientation.…”

Section: Application To Oriented Crystallization Of Polyethylene Undementioning

confidence: 99%

“…k is the fractional range of the solid angle replaced by (1=4Þ sin É k dÉ k . Here, as discussed before, 10 it is evident that an equilibrium distribution of segments among different orientations is obtained by minimizing the free energy of the system with respect to n j;k to find the distribution of the probabilities of different configurations of segments in the network between the two cross-link points. The imposition of external constrains requires the use of Lagrange multipliers to minimize the free energy.…”

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Segmental Orientation under Simultaneous Biaxially Stretching Using a Lattice Model and the Application of Oriented Crystallization of Polyethylene Films

Bin

Koganemaru

Nakashima

et al. 2005

Polym J

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ABSTRACT:A lattice model proposed before for uniaxial stretching of polyethylene films was applied to estimate the oriented crystallization of ultra-high molecular weight polyethylene (UHMWPE) dry gel films under simultaneous biaxially stretching. In this model system, the preferred axis associated with the preferred orientation of amorphous chain segments was chosen along the direction between two successive cross-linked points and the preferred axis was assumed to deform in an affine fashion with respect to the stretching direction. As the application of the proposed model, the orientation distribution function of crystallites was calculated on the basis of the lattice model and oriented crystallization model. The oriented crystallization model is based on the concept that a kinetically determined distribution of crystal chain axes as the normalized distribution of clusters found at the saddle point corresponding to a non-uniform orientation under conditions of a steady-state nucleation rate. Of course, the crystallites are oriented randomly with respect to the film normal direction. The parameter fitting for the formulated orientation distribution function of crystallites was done for the film which was prepared by the gelation/crystallization from solution with 0.9 g/ 100 mL concentration, the solvent being decalin, since the concentration assured the highest drawability under simultaneous biaxially stretching. The calculated orientation distribution functions 2q j ðcos j Þ of the reciprocal lattice vector of the crystal planes were in good agreement with the observed ones. Thus the numerical calculations indicate that the orientation of the c-axes depends on that of amorphous chain segments and the orientation behavior of crystallites is strongly affected by their rotation around the c-axis. [DOI 10.1295/polymj.37.192] KEY WORDS A Lattice Model / Simultaneous Biaxially Stretching / Preferred Orientation / A Steady-State Nucleation Rate / Orientation Distribution Function of Crystallites / Segmental orientation in uniaxially deformed elastomatic networks has been treated in terms of gas-like theories and liquid-like theories.1-4 In the gas-like theories, the chain vector and segment vector distributions have been estimated theoretically by using idealized models in which the effect of mutual interference between chain segments are neglected. On the other hand, in a liquid-like theory, 3,4 the effect of intermolecular interferences relating to orientation-dependent packing entropy was taken into consideration based on a lattice model. Erman et al. 5,6 have attempted to improve the liquid-like theory by considering the effect of chain stiffness on segmental orientation. For this purpose, they adopted the lattice theory of Flory 7,8 for chains with freely jointed rod-like segments and applied it to a thermotropic system with anisotropic polarizabilities. Namely, Erman et al. pointed out that a segment of polyethylene chains with 1-22 bonds may be viewed as a rod-like object on the basis of the concept of Flor...

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Section: Characteristics Of Test Specimensmentioning

confidence: 99%

“…10 The network chains will be assumed to be mono-disperse, i.e. composed of the same number m of rods having an ideal axial ratio x.…”

Section: General Conceptmentioning

confidence: 99%

Section: General Conceptmentioning

confidence: 99%

Section: Application To Oriented Crystallization Of Polyethylene Undementioning

confidence: 99%

mentioning

confidence: 98%

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Segmental Orientation under Simultaneous Biaxially Stretching Using a Lattice Model and the Application of Oriented Crystallization of Polyethylene Films

Bin

Koganemaru

Nakashima

et al. 2005

Polym J

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Modeling the mechanical properties of highly oriented polymer films: A fiber/gel composite theory approach

Breese

Beaucage

2008

J Polym Sci B Polym Phys

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Controlling the extent of orientation is of great interest in polymer processing and is effected by the choice of polymer, the fabrication technique and the processing conditions. Understanding the crystalline transitions that form highly oriented fibrils is necessary for modeling the changes in physical properties, relative to degree of orientation. A model is proposed to describe the mechanical properties of drawn semicrystalline polymer films based on structural transitions. With a minimal amount of experimental data (requiring testing on only two drawn films samples), this model can be used to predict film properties. These properties include the critical and maximum draw ratios, the moduli at the maximum draw ratio, the moduli of the fiber, the modulus of the nonfibrous gel relative to draw ratio, the volume fraction of fibers, and the rate of fibrillation. Where high degrees of uniaxial orientation are required, the polymer is typically drawn in the solid state, meaning the polymer is stretched in a single direction at temperatures below the melting point. During this process, pre‐existing crystallites are transformed into fiber‐like structures with large aspect ratios. The presence of these rigid asymmetric structures significantly enhances the moduli and break strength of the polymer. This work presents a model that describes the formation of fiber‐like structures. The volume fraction of fibers is predicted to be linear in draw ratio. The derived relationship between volume fraction of fibers and draw ratio can then be used for the prediction of the various properties of the oriented film. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 607–618, 2008

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Structure Development in Uniaxial and Biaxial Film Stretching

Kikutani,

Takarada

2014

Film Processing Advances

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Theoretical Estimation of Segmental Orientation in Deformed Polymeric Networks Using a Lattice Model and Application to Orientation of Amorphous Chain Segments of Poly(ethylene terephthalate) and Oriented Crystallization of Polyethylene

Cited by 11 publications

References 15 publications

Segmental Orientation under Simultaneous Biaxially Stretching Using a Lattice Model and the Application of Oriented Crystallization of Polyethylene Films

Segmental Orientation under Simultaneous Biaxially Stretching Using a Lattice Model and the Application of Oriented Crystallization of Polyethylene Films

Modeling the mechanical properties of highly oriented polymer films: A fiber/gel composite theory approach

Structure Development in Uniaxial and Biaxial Film Stretching

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