An ab initio study of the structural and physical properties of a novel rigid-rod polymer: PIPD

Hageman, J.C.L.; Horst, J.W. van der; Groot, R.A. de

doi:10.1016/s0032-3861(98)00344-9

Cited by 45 publications

(35 citation statements)

References 18 publications

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“…We have found a similar effect for the rigid-rod polymer PIPD. 30 The length of the primitive cell at equilibrium (L 0 /5) is found to be 2.56 Å, somewhat larger than the experimental value (2.53 Å) and our previous result (2.51 Å). Again, this is in agreement with expectations for GGA.…”

Section: The Energy Barriercontrasting

confidence: 64%

Bond Scission in a Perfect Polyethylene Chain and the Consequences for the Ultimate Strength

Hageman¹,

Wijs²,

Groot³

et al. 2000

Macromolecules

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We present ab initio calculations concerning the bond scission rate in a polyethylene chain. The energy barrier for scission is calculated both by using an effective potential scheme based on ab initio data and from the ab initio transition state itself. In the latter case the prefactor for scission is calculated. In both methods the relaxation of the polymer chain is taken into account, leading to a strong strain dependence of the energy barrier. The two schemes agree quantitatively. The barrier is reduced from 3.9 eV at zero strain to 1.7 eV at a strain of 5%. The calculated scission rate is used to estimate the strength of a polyethylene fiber consisting of perfectly aligned, independent chains in a constant strain rate experiment resulting in 18 GPa at a strain of 8%. This value of the ultimate strength is a factor 2 larger than found in experiments. This contrasts previously reported quantum chemical calculations, which reported values a factor 5-10 larger than the experimental values.

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Section: The Energy Barriercontrasting

confidence: 64%

Bond Scission in a Perfect Polyethylene Chain and the Consequences for the Ultimate Strength

Hageman¹,

Wijs²,

Groot³

et al. 2000

Macromolecules

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“…7,8 The predictions of these ͑highly involved, ''parameter-free''͒ calculations are quite reasonable when it comes to the Young's modulus along the chain direction, but fail for the bulk modulus with predictions that are several times larger than results known from experiment. 7 This is indicative of an incorrect description of interchain interactions.…”

Section: Introductionmentioning

confidence: 93%

“…We further note that the crystal density used, e.g., in Ref. 8, enters their calculations not self-consistently, but were put in by hand.…”

Section: Introductionmentioning

confidence: 99%

Density functional theory for the elastic moduli of a model polymeric solid

Sushko

Schoot

Michels

2003

The Journal of Chemical Physics

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We apply a recently developed density functional theory for freely hinged, hard polymeric chains to calculate the elastic moduli of an idealized polymeric solid lacking long-range bond order. We find that for such a model packing effects dominate the elastic behavior of the polymeric solid in a similar way as is the case in the hard-sphere crystal, which we reexamine. Our calculations show that the elastic stiffness of the model polymeric solid is essentially determined by how far one is removed from its melting point. The main role of the chain connectivity is to destabilize the solid relative to the equivalent solid of hard monomers. Comparison of our results with experimental data on semicrystalline polymers shows order-of-magnitude agreement.

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“…The atoms least involved in the intermolecular interaction, that is, those facing away from the adjacent molecule, were chosen to constrain the torsional angle. As proposed by Hageman et al, 6 to isolate the energy associated with the formation of intermolecular hydrogen bonds, we replaced the NOH groups in PIPD, MePBI, and PPTA with oxygen, such that the propensity to form hydrogen bonds was eliminated. The following steps were involved in calculating the intermolecular hydrogen-bond strength:…”

Section: Simulation Proceduresmentioning

confidence: 99%

“…5 With ab initio computational techniques, the intermolecular hydrogen-bonding energy per PIPD repeat unit was calculated to be Ϫ22.6 kcal/mol. 6 The structure and properties of methyl pendant poly-(p-phenylene benzobisimidazole) (MePBI), which forms a sheetlike arrangement of hydrogen bonds, have been reported elsewhere. 7 The compressive strengths and torsional moduli of MePBI and PIPD are greater than those of other rigidrod polymeric fibers that do not have the capacity to form intermolecular hydrogen bonds.…”

Section: Introductionmentioning

confidence: 99%

The effect of hydrogen bonding on the physical and mechanical properties of rigid-rod polymers

Jenkins

Jacob

Kumar

2000

J. Polym. Sci. B Polym. Phys.

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An ab initio study of the structural and physical properties of a novel rigid-rod polymer: PIPD

Cited by 45 publications

References 18 publications

Bond Scission in a Perfect Polyethylene Chain and the Consequences for the Ultimate Strength

Bond Scission in a Perfect Polyethylene Chain and the Consequences for the Ultimate Strength

Density functional theory for the elastic moduli of a model polymeric solid

The effect of hydrogen bonding on the physical and mechanical properties of rigid-rod polymers

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