Structure image of single crystal of polyethylene

Yin, Li; Chen, Jianfeng; Yang, Xiaoniu; Zhou, Enle

doi:10.1016/s0032-3861(03)00695-5

Cited by 10 publications

(10 citation statements)

References 14 publications

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“…In Figure 3c, Figures S1 and S2 in the Supporting Information, the nanoarchitectures of the PE fibers, particularly the fiber morphology with gear-shaped surface patterns, are shown to be well preserved even after being subjected to a Friedel-Crafts alkylation reaction for 7 d. This finding strongly indicates that the CH 2  backbones of the PE fibers were sufficiently chemically robust to undergo the HXL reaction. This observation is also in good agreement with the results of 13 C SSNMR. To further study the porous structure of the hyper-crosslinked fibers, one of them was thoroughly ground and supported on a grid for TEM analysis.…”

Section: Resultssupporting

confidence: 92%

“…[9] As expected, the vibrations of the -CH 2 -backbone (e.g., 2916, 2848, and 719 cm −1 ) became weaker, owing to the increasing numbers of dark crosslinked VBC layers that covered the PE surface and blocked the IR beam, rather than to damage to the PE core structure. To better demonstrate this point, 13 C solid-state nuclear magnetic resonance ( 13 C SSNMR) was used to investigate the chemical structure of the hypercrosslinked fibers. In Figure 2b, the intensive peaks at 32 ppm assigned to the long alkyl chain are clearly seen in the samples before and after the HXL reaction, strongly indicating that the core structure of the PE fibers was retained without significant change.…”

Section: Resultsmentioning

confidence: 99%

“…Attenuated total reflection-Infrared spectra were measured by a Frontier middle infrared (MIR) system with ATR accessory (PerkinElmer, USA) and 13 Germany). Before analysis, samples were placed in vacuum oven at 50 °C overnight to remove adsorbed water.…”

Section: Characterizationmentioning

confidence: 99%

See 2 more Smart Citations

Fibers with Hyper‐Crosslinked Functional Porous Frameworks

Sheng

Chen

Mahurin

et al. 2018

Macromol. Rapid Commun.

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The incorporation of robust porous frameworks into polymer fibers with handleable morphologies and flexible chemical compositions exhibits significant advantages for device fabrication in a wide range of applications. However, the soft linear polymeric chains of the fibers make the generation of nanopores extremely challenging. Herein, a facile synthetic strategy based on a combination of functional monomer grafting and hyper-crosslinking technology is developed for the porous engineering of polymeric fibers. In this methodology, the nanoporous framework originating from the hyper-crosslinking of aromatic monomers is covalently grafted onto fibers, which is beneficial to retaining their unique fiber morphology and to preserving their excellent mechanical properties. Moreover, this promising protocol can be further extended to the porous functionalization of polymeric matrices with diverse morphologies for target-specific applications.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Fibers with Hyper‐Crosslinked Functional Porous Frameworks

Sheng

Chen

Mahurin

et al. 2018

Macromol. Rapid Commun.

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“…The topology can be tailored by controlling the crystallization kinetics either by dissolution and crystallization or controlled polymerization [2,3,4,5]. The influence of molar mass on the topology of non-crystalline phase has been a subject of interest where the nature of the mobile phase is probed by solid state NMR [6,7].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Distribution of Entanglements in a Nonequilibrium Polymer Melt of UHMWPE: Influence on Crystallization without and with Graphene Oxide

et al. 2016

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Recently, the influence of reduced graphene oxide nanoplatelets (rGON) on the rheological response of polymers has been a subject of interest. In the case of disentangled UHMWPE, it has been shown that the chain-filler interaction in the UHMWPE/rGON composite results into an everlasting non-equilibrium melt state having heterogeneous distribution in entanglement density. In this study, a thermal analysis protocol is used to follow the influence of the non-equilibrium polymer melt on the crystallization kinetics of disentangled UHMWPE with, and without, rGON. The analysis is carried out by means of differential scanning calorimetry (DSC) and the results are supported by rheology. When the disentangled UHMWPE sample, without the filler rGON, is left to crystallize under isothermal condition after melting, two endothermic peaks are observed: the high temperature peak (close to the equilibrium melting point, 141.5 °C) is related to the melting of crystals obtained on crystallization from the disentangled domains of the heterogeneous (nonequilibrium) polymer melt, whereas the low melting temperature peak is related to the melting of crystals formed from entangled domains of the melt. On increasing the annealing time in melt (160 °C), the enthalpy of the lower melting temperature peak increases at the expense of the high melting temperature peak, confirming a transformation of the nonequilibrium polymer melt to a fully entangled equilibrium melt state. However, independent of the equilibrium or non-equilibrium melt state, the recurrence of the high melting temperature peak is observed when the samples synthesized using the single-site catalytic system are left to isothermal crystallization at a specific temperature. The recurrence of the high melting temperature, close to the equilibrium melting point of the polymer, questions the differences in entanglements formed before and after polymerization in these high molar masses. The differences in the topological constraints are likely to influence the difference in melting temperatures of the isothermally crystallized samples. In the presence of rGON, the melting response of disentangled UHMWPE crystallized from its heterogeneous melt state changes; at a specific filler concentration, it is observed that the high endothermic peak remains independent of the annealing time in melt. This observation strengthens the concept that in the presence of the filler, chain dynamics is arrested to an extent that the nonequilibrium melt state having lower entanglement density is retained, facilitating the formation of crystals having high melting temperature. IntroductionThe topology of methylene segments in the non-crystalline region of the semi-crystalline polymer Ultrahigh Molecular Weight Polyethylene (UHMWPE), has a profound influence on the mechanical deformation either uniaxially or biaxially [1]. The topology can be tailored by controlling the crystallization kinetics either by dissolution and crystallization or controlled polymerization [2,3,4,5]. The influence of mo...

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“…The resulting unit cell size was ͑7.13 Å ϫ 5.01 Å ϫ 2.55 Å͒, which is within 4% of the values measured experimentally. 37 All simulations were run at constant energy, volume, and number of atoms. Preliminary testing indicated that a 0.25 fs time step was needed for good energy conservation ␦E / E 0 Ͻ .0001% over the course of several nanoseconds of simulation time.…”

mentioning

confidence: 99%

1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations

et al. 2010

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The thermal conductivity of nanostructures generally decreases with decreasing size because of classical size effects. The axial thermal conductivity of polymer chain lattices, however, can exhibit the opposite trend, because of reduced chain-chain anharmonic scattering. This unique feature gives rise to an interesting onedimensional-to-three-dimensional transition in phonon transport. We study this transition by calculating the thermal conductivity of polyethylene with molecular dynamics simulations. The results are important for designing inexpensive high thermal-conductivity polymers.

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Structure image of single crystal of polyethylene

Cited by 10 publications

References 14 publications

Fibers with Hyper‐Crosslinked Functional Porous Frameworks

Fibers with Hyper‐Crosslinked Functional Porous Frameworks

Heterogeneous Distribution of Entanglements in a Nonequilibrium Polymer Melt of UHMWPE: Influence on Crystallization without and with Graphene Oxide

1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations

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