Chain entanglement, mechanical properties and drawability of poly(lactide)

Grijpma, Dirk W.; Penning, J. P.; Pennings, A. J.

doi:10.1007/bf00652375

Cited by 135 publications

(123 citation statements)

References 49 publications

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“…34 We see that, according to Wu's theories, solid PLLA should describe intermediate brittleductile behavior between that observed for isotactic polystyrene (brittle) and polyethylene (ductile). Grijpma et al (1994) observed substantially brittle behavior for amorphous solid (bulk-polymerised) PLLA in solid tensile and impact tests, 35 and reported characteristic ratios and calculated entanglement densities for their bulk-polymerised PLLA of 11.8 and 0.14 mmol/cm 3 (25°C), 35 respectively. The differences between the estimates provided by Grijpma et al and our work are again largely suspected to be due to differences in calculated amorphous density and melt density values for PLLA samples, and slightly different G n 0 values determined from our dynamic experiments.…”

Section: Characteristic Parametersmentioning

confidence: 96%

“…This value will be used in all calculations below. Further, when this chosen value is compared to that cited by Grijpma et al 35 of approximately 5 ϫ 10 5…”

Section: Effect Of Molecular Weightmentioning

confidence: 96%

“…Little information is cited within the literature, excepting that indirectly provided by Grijpma et al, 35 as to a reference or agreed value of M c for PLLA polymers. Grijpma et al calculated a molecular weight between entanglements (M e ), for PLLA melts of 10,500 g/mol at 200°C.…”

Section: Effect Of Molecular Weightmentioning

confidence: 99%

“…Grijpma et al calculated a molecular weight between entanglements (M e ), for PLLA melts of 10,500 g/mol at 200°C. 35 This value was determined via a similar experimental procedure as used in this work, and using Wu's calculation method. 26 Considering the above relation between M c and M e , this provides for an M c value in the range of 21,000 g/mol.…”

Section: Effect Of Molecular Weightmentioning

confidence: 99%

See 3 more Smart Citations

Rheological properties of poly(lactides). Effect of molecular weight and temperature on the viscoelasticity of poly(l-lactic acid)

Cooper-White

Mackay

1999

J. Polym. Sci. B Polym. Phys.

152

106

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Section: Characteristic Parametersmentioning

confidence: 96%

“…This value will be used in all calculations below. Further, when this chosen value is compared to that cited by Grijpma et al 35 of approximately 5 ϫ 10 5…”

Section: Effect Of Molecular Weightmentioning

confidence: 96%

Section: Effect Of Molecular Weightmentioning

confidence: 99%

Section: Effect Of Molecular Weightmentioning

confidence: 99%

See 2 more Smart Citations

Rheological properties of poly(lactides). Effect of molecular weight and temperature on the viscoelasticity of poly(l-lactic acid)

Cooper-White

Mackay

1999

J. Polym. Sci. B Polym. Phys.

152

106

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“…[10][11][12] The enantiomerically pure PLAs, such as PLLA and PDLA as well as amorphous PLA, deform in a brittle fashion because of the formation of crazes. 13 Crazes are the microcracks bridged by small fibrils and often lead to the catastrophic failure of a polymer.…”

Section: Introductionmentioning

confidence: 99%

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

2007

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The inherent brittleness of polylactide (PLA) poses considerable scientific challenges and limits its large-scale applications. Here, we propose and demonstrate a new industrially relevant methodology to develop a polylactide (PLA)-based nanoblend having outstanding stiffness-toughness balance. In this approach, a hydroxyl functional hyperbranched polymer (HBP) was in-situ cross-linked with a polyanhydride (PA) in the PLA matrix during melt processing. There was formation of new hyperbranched polymer-based cross-linked particles in the PLA matrix. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed the sea-island morphology of PLA-cross-linked HBP blend. The domain size of cross-linked HBP particles in the PLA matrix was less than 100 nm as obtained from TEM. The presence of cross-linked hyperbranched polymer in the PLA matrix exhibited ∼570% and ∼847% improvement in the toughness and elongation at break, respectively, as compared to unmodified PLA. The increase in the ductility of modified PLA was related to stress whitening and multiple crazing initiated in the presence of cross-linked HBP particles. Formation of a networked interface as revealed by rheological data was associated with enhanced compatibility of the PLA-cross-linked HBP blend as compared to the PLA/HBP blend. The cross-linking reaction of HBP with PA was confirmed with the help of Fourier transform infrared spectroscopy (FTIR) and low-temperature dynamical mechanical thermal analysis (DMTA).

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Chain dimensions and entanglement spacings in dense macromolecular systems

Fetters

Lohse

Graessley

1999

J. Polym. Sci. B Polym. Phys.

346

360

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In this article, we reexamine and extend a relationship proposed earlier between entanglement density and chain dimensions in polymer melts. The power‐law equation presented in the earlier work, relating the entanglement molecular weight Me, melt chain density ρ, and the packing length p is tested with additional polymer species. Now included are additional polydienes and their hydrogenated derivatives, the isotactic forms of polypropylene and polystyrene, the essentially syndiotactic form of poly(methyl methacrylate), along with poly(tetrafluoroethylene), poly(vinylmethyl ether), various poly(methacrylates), and polymeric sulfur. We find that within experimental uncertainties, Me/ρ and p are related through an equation (Me/ρ = 218p3) that is insensitive to temperature (25°C ≤ T ≤ 380°C) and which seems to be universal for flexible Gaussian chains in the melt state. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1023–1033, 1999

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Chain entanglement, mechanical properties and drawability of poly(lactide)

Cited by 135 publications

References 49 publications

Rheological properties of poly(lactides). Effect of molecular weight and temperature on the viscoelasticity of poly(l-lactic acid)

Rheological properties of poly(lactides). Effect of molecular weight and temperature on the viscoelasticity of poly(l-lactic acid)

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

Chain dimensions and entanglement spacings in dense macromolecular systems

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