Lamellar and interlamellar structure in melt‐crystallized polyethylene. I. Degree of crystallinity, atomic positions, particle size, and lattice disorder of the first and second kinds

Kavesh, S.; Schultz, J. M.

doi:10.1002/pol.1970.160080205

Cited by 178 publications

(117 citation statements)

References 36 publications

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“…These results are in compliance with the contemporary notions of polymer structure changes during the annealing process [19,36,37]. For PE at annealing temperatures higher than 110 ~ (this is the temperature of the solid-plastic crystal transition [38]), as a result of reorganisational processes, the following changes occur: the crystallite polydispersity as to size and perfection decrease, the crystal structure becomes more perfect and the crystallite dimensions and the long period increase [37,39]. This in its turn narrows the melting interval.…”

Section: Resultssupporting

confidence: 92%

Melting of nascent and thermally treated super-high molecular weight polyethylene

Kresteva

Nedkov

Radilova

1985

Colloid & Polymer Sci

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Abstract:The melting of nascent and thermally treated super-high molecular weight polyethylene (SHMWPE) is investigated by means of differential scanning calorimetry (DSC). Higher melting temperatures and enthalpies of the nascent and annealed samples are observed. The melting temperatures and enthalpies of melt crystallized SHMWPE is lower and depends on the temperature of thermal treatment. All melting properties are explained by presuming that the lamellar structure contains a high concentration of entangled tie macromolecules in amorphous regions formed during polymerization. It was supposed that the concentration of the entanglements and the stressed tie molecules are changed with the temperature of the thermal pretreatment.

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Section: Resultssupporting

confidence: 92%

Melting of nascent and thermally treated super-high molecular weight polyethylene

Kresteva

Nedkov

Radilova

1985

Colloid & Polymer Sci

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“…Before doing so, we recall here the structure of the orthorhombic PE crystal [12]. The unit cell contains two chains, each consisting of 2 CH 2 groups, giving a total of 12 atoms per unit cell.…”

Section: Constant Pressure Simulation Methodsmentioning

confidence: 99%

Orthorhombic phase of crystalline polyethylene: A Monte Carlo study

Martoňák

Paul

Binder

1997

The Journal of Chemical Physics

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In this paper we present a classical Monte Carlo simulation of the orthorhombic phase of crystalline polyethylene, using an explicit atom force field with unconstrained bond lengths and angles and periodic boundary conditions. We used a recently developed algorithm which apart from standard Metropolis local moves employs also global moves consisting of displacements of the center of mass of the whole chains in all three spatial directions as well as rotations of the chains around an axis parallel to the crystallographic c-direction. Our simulations are performed in the N pT ensemble, at zero pressure, and extend over the whole range of temperatures in which the orthorhombic phase is experimentally known to be stable (10 -450 K). In order to investigate the finite-size effects in this extremely anisotropic crystal, we used different system sizes and different chain lengths, ranging from C 12 to C 96 chains, the total number of atoms in the super-cell being between 432 and 3456. We show here the results for structural parameters, such as the orthorhombic cell parameters a, b, c, and the setting angle of the chains, as well as internal parameters of the chains, such as the bond lengths and angles. Among ther-1 modynamic quantities, we present results for thermal expansion coefficients, elastic constants and specific heat. We discuss the temperature dependence of the measured quantities as well as the related finite-size effects. In case of lattice parameters and thermal expansion coefficients, we compare our results to those obtained from other theoretical approaches as well as to some available experimental data. We also suggest some possible ways of extending this study.

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“…Surface. The model surface was constructed of a creates a dynamic model of a set of molecules by solving 2-D array of n-hexane molecules with the methylene groups the equations of motion that simulate the responses of the placed in the crystal structure of PE (20). The terminal individual atoms to external forces.…”

Section: Simulation Proceduresmentioning

confidence: 99%