The mechanical fatigue limit for rubber

Lake, G. J.; Lindley, P. B.

doi:10.1002/app.1965.070090405

Cited by 267 publications

(162 citation statements)

References 10 publications

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“…2a and 2b is quickly lost as the polymer strongly binds with the filler particles, and the composite's mechanical strength is likewise forfeited. 18 Similarly, as the AB content increases in the AB/PVDF composites, the pure polymer phase shrinks due to the formation of the fixed polymer layer on the AB. At the higher AB content of 1:1 AB:PVDF, all of the PVDF is associated with fixed polymer layers on AB particles.…”

Section: Resultsmentioning

confidence: 99%

Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-Ion Electrode Performance

Liu

Zheng

Song

et al. 2012

J. Electrochem. Soc.

227

201

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This paper investigates lithium-ion electrode laminates as polymer composites to explain their performance variation due to changes in formulation. There are three essential components in a positive electrode laminate: active material (AM) particles, acetylene black (AB) particles, and the polymer binder. The high filler content and discrete particle sizes make the electrode laminate a very unique polymer composite. This work introduces a physical model in which AB and AM particles compete for polymer binder, which forms fixed layers of polymer on their surfaces. This competition leads to the observed variations in electrode morphology and performance for different electrode formulations. The electronic conductivities of the cathode laminates were measured and compared to an effective conductivity calculation based on the physical model to probe the interaction among the three components to reveal the critical factors controlling electrode conductivity and electrochemical performance. The data and effective conductivity calculation results agree very well with each other. This developed physical model provides a theoretical guideline for optimization of electrode composition for most polymer binder-based Li-ion battery electrodes. Proper electrode design is critical to meeting both the energy and power performance requirements for any battery application. [1][2][3][4] Polymer binders and conductive additives used in Li-ion batteries, although not electrochemically active, are essential components in the electrodes, along with the active material (AM) that stores lithium ions. Conductive additives such as acetylene black (AB), are used to provide the electronic conductivity from the current collector to the composite, and to provide surface conductivity to the micronsized spherical AM particles. AB is an essential component for all cathodes due to its low cost and unique morphology. 5,6 Primary AB particles fuse to form a branched structure, which allows for a fully percolated filler structure at much lower AB loading than would occur without the branching. 7,8 This electrically conductive medium is needed to provide both long-range conductivity and short-range electron transport to the AM surface. A polymer binder such as polyvinylidine difluoride (PVDF) adheres the AB and AM particles together to form a continuous and robust electric conduction path to the current collector.In designing an electrode, the AM content is preferentially high to maximize the energy density, but the inactive materials AB and PVDF are critical for electron transport and mechanical integrity, respectively. A typical cathode contains 90% AM, 4% AB, and 6% PVDF. 9 The AB content needs to be as low as the electrode design allows and still fulfill its function of providing electrical connection from the laminate to the current collector and amongst the AM particles throughout the laminate. The polymer content also needs to be as low as possible and still meet its design needs of binding the laminate to the current collector and holding all...

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Section: Resultsmentioning

confidence: 99%

Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-Ion Electrode Performance

Liu

Zheng

Song

et al. 2012

J. Electrochem. Soc.

227

201

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“…A peculiar attention has been paid to the quasi equilibrium properties which could be deduced from the network theory and the theory of entropic elasticity applied to quasi ideal networks in which the length distribution of elastically active chains (EAC) would be unimodal. In such cases, a key characteristic is the number of chains crossing a unit area in unloaded state [4]; according to Lake [5], there is a simple relationship with the molar mass M c of EACs: (1) where G IC0 is the threshold tear strength that characterizes fracture free of viscoelastic or strain induced crystallization (SIC) effects. K is mainly related to the rupture energy of a single chain.…”

Section: Introductionmentioning

confidence: 99%

Role of strain induced crystallization and oxidative crosslinking in fracture properties of rubbers

Gac

Broudin

Roux

et al. 2014

Polymer

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tTensile properties and crack propagation properties, especially critical strain energy release rate in mode I, G IC , have been used to investigate fracture properties of elastomers and their relationships with microstructure. These investigations were mainly based on a series of comparisons: first, the behaviour of polychloroprene rubber (CR), undergoing stress hardening due to strain induced crystallization (SIC) and oxidative crosslinking (OCL) was compared with that of chlorinated polyethylene (CPE), which undergoes SIC but not OCL, and with a polyurethane based on hydroxyl terminated polybutadiene (PU) which undergoes OCL but not SIC. Comparisons were also made on CR between fracture behaviour at ambient temperature, where SIC occurs and at 100 C where there is no SIC. Finally, oxidative crosslinking was used to vary in a continuous way the crosslink density in CR and PU, in order to evaluate the role of crosslinking in fracture behaviour. The results reveal the strong contribution of SIC to fracture strength. Crosslinking, even at low conversion, inhibits SIC which explains the sharp decrease of CR toughness in the early period of exposure to oxidation. When SIC has disappeared, it is possible to appreciate the effect of crosslinking on fracture behaviour. This effect, as evaluated from the density of deformation energy at rupture in tension or from G IC value, is almost negligible while the sample modulus increases regularly as a consequence of crosslinking. It appears that the toughness remains almost constant because it is under the influence of two contradictory phenomena: the negative effect of a reduction of ultimate elongation and the positive effect of a modulus increase. Such behaviour can be explained in terms of heterogeneous distribution of the lengths of elastically active chains. After long exposure, the sample behaviour becomes brittle, very high modulus values indicate that the samples approach, presumably in a heterogeneous way, the glassy state.

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“…From studies using small-angle X-ray scattering Cutting Test and transmission electron microscopy, cylindrical Previous studies 12,13 have shown that the meadomains of PS have been observed in neat SBS sured fracture energy is significantly reduced films cast from toluene solution. 15,16 Because when a sharp blade is applied at the tip of a crack.…”

Section: Measurements Of Fracture Energymentioning

confidence: 99%

Fracture energies of styrene-butadiene-styrene block copolymers (II). Strength at high temperatures

Wang

Chang

1997

J. Polym. Sci. B Polym. Phys.

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The mechanical fatigue limit for rubber

Cited by 267 publications

References 10 publications

Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-Ion Electrode Performance

Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-Ion Electrode Performance

Role of strain induced crystallization and oxidative crosslinking in fracture properties of rubbers

Fracture energies of styrene-butadiene-styrene block copolymers (II). Strength at high temperatures

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