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1 Oct 1981

Volume 52, Issue 10, pp. 5887-6446

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Statistical distribution analysis of rubber fatigue data

J. L. DeRudder

J. Appl. Phys. 52, 5887 (1981); http://dx.doi.org/10.1063/1.329825 (5 pages)

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Average rubber fatigue resistance has previously been related to such factors as elastomer type, cure system, cure temperature, and stress history. This paper extends this treatment to a full statistical analysis of rubber fatigue data. Analyses of laboratory fatigue data are used to predict service life. Particular emphasis is given to the prediction of early tire splice failures, and to adaptations of statistical fatigue analysis for the particular service conditions of the rubber industry.
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61.41.+e Polymers, elastomers, and plastics
62.20.M- Structural failure of materials

Use of a theoretical equation of state to interpret time‐dependent free volume in polymer glasses

J. G. Curro, R. R. Lagasse, and R. Simha

J. Appl. Phys. 52, 5892 (1981); http://dx.doi.org/10.1063/1.329826 (6 pages) | Cited 30 times

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Many physical properties of polymer glasses change spontaneously during isothermal aging by a process commonly modeled as collapse of free volume. The model has not been verified rigorously because free volume cannot be unambiguously measured. In the present investigation we tentatively identify the free‐volume fraction with the fraction of empty sites in the equation of state of Simha and Somcynsky. With this theory, volume recovery measurements can be analyzed to yield directly the time‐dependent, free‐volume fraction. Using this approach, recent volume measurements on poly(methyl methacrylate) are analyzed. The resulting free‐volume fractions are then used in the Doolittle equation to predict the shift in stress relaxation curves at 23 °C. These predicted shift factors agree with the experimental measurements of Cizmecioglu et al. In addition, it is shown that previous assumptions concerning temperature dependence of free volume are inconsistent with the theory.
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05.70.Ln Nonequilibrium and irreversible thermodynamics
64.10.+h General theory of equations of state and phase equilibria
82.90.+j Other topics in physical chemistry and chemical physics (restricted to new topics in section 82)
36.20.Hb Configuration (bonds, dimensions)

Sub‐sub Tg structural relaxation in glassy polymers

H. S. Chen and T. T. Wang

J. Appl. Phys. 52, 5898 (1981); http://dx.doi.org/10.1063/1.329827 (5 pages) | Cited 26 times

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Structural relaxation in a temperature range from 32 to 62° K glass transition has been investigated, for the first time, for a nearly monodisperse polystyrene using a differential scanning calorimeter and a thermal mechanical analyzer. Low temperature anneals in the vicinity of 320 K stabilize the glassy structure and lead to volume contraction. Upon heating, the annealed samples show an excess endothermic peak and exhibit a gradual expansion associated with structural recovery above the annealing temperature. Significantly, the samples recover the initial heat content and volume without reheating through the glass transition temperature. This sub‐Tg structural relaxation behavior is in many respects distinct from that commonly observed near the glass transition. Kinetics of relaxation processes are also discussed.
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61.43.Fs Glasses
61.43.-j Disordered solids
65.20.-w Thermal properties of liquids
65.40.Ba Heat capacity
65.40.De Thermal expansion; thermomechanical effects

Longitudinal polarization of α‐poly(vinylidene fluoride) by kink propagation

J. D. Clark, P. L. Taylor, and A. J. Hopfinger

J. Appl. Phys. 52, 5903 (1981); http://dx.doi.org/10.1063/1.329828 (3 pages) | Cited 7 times

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The α‐ phase chain of poly(vinylidene fluoride) has a component of dipole moment parallel to the chain axis which can be reversed by propagation of a solitary wave along the chain. Calculations of the energy required to create such a wave in a perfect chain yield larger values than are implied by experiment. This suggests that either head‐to‐tail defects or regions of stress at the lamellar boundary might play an important role in causing the observed dielectric behavior.
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77.22.Ej Polarization and depolarization

Temperature dependence of broadline NMR spectra of water‐soaked, epoxy‐graphite composites

David Lawing, R. E. Fornes, R. D. Gilbert, and J. D. Memory

J. Appl. Phys. 52, 5906 (1981); http://dx.doi.org/10.1063/1.329829 (2 pages) | Cited 7 times

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Water‐soaked, epoxy resin‐graphite fiber composites show a waterline in their broadline proton NMR spectrum which indicates a state of intermediate mobility between the solid and free water liquid states. The line is still present at −42 °C, but shows a reversible decrease in amplitude with decreasing temperature. The line is isotropic upon rotation of the fiber axis with respect to the external magnetic field.
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76.60.-k Nuclear magnetic resonance and relaxation
81.40.-z Treatment of materials and its effects on microstructure, nanostructure, and properties
61.05.Qr Magnetic resonance techniques; Mössbauer spectroscopy (for structure determination only)
81.05.Qk Reinforced polymers and polymer-based composites

The annealing of solution grown crystals of alpha and gamma poly(vinylidene fluoride)

D. T. Grubb and K. W. Choi

J. Appl. Phys. 52, 5908 (1981); http://dx.doi.org/10.1063/1.329830 (8 pages) | Cited 18 times

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Single crystals of poly(vinylidene fluoride) PVF2 have been grown from dilute solution and sedimented to form oriented mats. The product was α‐PVF2 or a mixture of α‐ and γ‐PVF2 and different morphologies were observed for the two phases. Annealed mats exhibited complex melting behavior, due in part to melting and recrystallization. Plots of melting temperature against reciprocal lamellar spacing indicate equilibrium melting points of 443.5 and 457.3 K for rapidly crystallized α‐ and γ‐PVF2 after 1‐h anneal, and fold surface free energies of 15.6 and 27.2 mJm−2 for α‐PVF2 from different solvents, 24.8 mJm−2 for γ‐PVF2. Long annealing times or high annealing temperatures tend to increase the melting point without changing the lamellar thickness probably due to rejection of head‐to‐head defects.
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61.41.+e Polymers, elastomers, and plastics
81.10.Dn Growth from solutions
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials

Depolarization‐current study of low‐density polyethylene containing an antioxidant

D. Ronarc’h and S. Haridoss

J. Appl. Phys. 52, 5916 (1981); http://dx.doi.org/10.1063/1.329831 (5 pages) | Cited 10 times

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Thermally stimulated depolarization currents in low‐density polyethylene containing Irganox 1076 are investigated. The thermal sampling technique has been used to study the elementary processes constituting β and γ relaxations. Irganox 1076 is found to increase the intensity of β and γ peaks and not to change the activation parameters. The participation of the antioxidant in the molecular relaxation processes is discussed.
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72.20.-i Conductivity phenomena in semiconductors and insulators
77.22.Ej Polarization and depolarization

Sub‐Tg annealing studies of advanced epoxy‐matrix graphite‐ fiber‐ reinforced composites

Eric S. W. Kong

J. Appl. Phys. 52, 5921 (1981); http://dx.doi.org/10.1063/1.329832 (5 pages) | Cited 11 times

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Selected mechanical properties of symmetrically (±45°) reinforced 16‐lamina graphite/epoxy composites have been found to be affected by sub‐Tg annealing. Postcured specimens of Thornel 300 graphite/Narmco 5208 epoxy were sub‐Tg annealed at 140 °C for ca. 10, 102, 103, 104, and 105 min, with a prior quenching from above Tg. The ultimate tensile strength strain‐to‐break, and static toughness of the composite materials were found to decrease as a function of sub‐Tg annealing time. No weight loss was observed during the sub‐Tg annealing. The time‐dependent change in properties can be explained on the basis of physical aging which is related to free volume decrease in the non‐equilibrium glassy state of network epoxies. The results imply possible changes in composite properties with service time.
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81.05.Qk Reinforced polymers and polymer-based composites
81.65.-b Surface treatments
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.70.-q Methods of materials testing and analysis

Stretching induced γ→β transition in poly (vinylidene fluoride)

B. Servet, D. Broussoux, and F. Micheron

J. Appl. Phys. 52, 5926 (1981); http://dx.doi.org/10.1063/1.328520 (4 pages) | Cited 4 times

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Transition from unoriented γ to oriented β phases is followed during stretching poly(vinylidene fluoride) at 150 °C, using both x‐ray and small angle light scattering techniques. It is observed that the γ→β transition occurs simultaneously with the morphologic transition from spherulitic to fibrillar state. The threshold draw ratio is λ?2, corresponding to a chain orientation function fH ?0.5; the conversion into β phase is complete at draw ratios λ?4.
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61.50.Ks Crystallographic aspects of phase transformations; pressure effects
64.70.K- Solid-solid transitions

Integral equation method for calculating entropy of confined chains

R. G. Priest

J. Appl. Phys. 52, 5930 (1981); http://dx.doi.org/10.1063/1.328521 (4 pages) | Cited 2 times

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An important aspect of the thermodynamic properties of chain molecules in solids is the amount of entropy that is associated with rotations about bonds. Of particular interest is the high‐pressure hexagonal phase of polyethylene. This system is modeled for the purpose of this calculation as an assembly of chains confined to small cylinders. This paper describes an integral equation approach to the problem that may be viewed as a continuum limit of the transfer matrix technique. Two cases are solved: (1) the freely jointed chain confined to a cylinder small enough to prevent the chain from folding back on itself, and (2) the fixed bond angle chain confined to the same type of cylinder. The result of calculation (2) is discussed in light of a model for the high‐pressure hexagonal phase of polyethylene.
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81.05.Kf Glasses (including metallic glasses)
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
64.70.K- Solid-solid transitions

Conformational defects and associated molecular motions in crystalline poly(vinylidene fluoride)

Andrew J. Lovinger

J. Appl. Phys. 52, 5934 (1981); http://dx.doi.org/10.1063/1.328522 (5 pages) | Cited 11 times

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Electron‐diffraction investigation of single crystals of γ‐poly (vinylidene fluoride) grown from the melt has revealed streaking of 0k0 reflections. The three‐dimensional structure of the spikes was studied by specimen tilting during electron diffraction; streaking is maximized in the b∗c∗ view and disappears in the a∗b∗ view, indicating that the reciprocal‐lattice spikes are directed parallel to c. After exclusion of effects associated with the shape transform of our γ crystals, the streaks are attributed to stacking faults parallel to the ab plane; such faults are consistent with incorporation of α sequences as defects within γ chains during crystallization. Conformational changes between α and γ arrangements are examined using a number of models. The simplest motions (flip‐flops or rigid crankshafts) require simultaneous rotation about two noncolinear axes and are, therefore, less favored than mechanisms involving flexible chain motions as described in this report.
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61.72.J- Point defects and defect clusters
81.10.Aj Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
77.65.-j Piezoelectricity and electromechanical effects
61.66.Hq Organic compounds

Piezoelectricity in γ‐form Nylon 11

J. I. Scheinbeim

J. Appl. Phys. 52, 5939 (1981); http://dx.doi.org/10.1063/1.328523 (4 pages) | Cited 14 times

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X‐ray studies of unpoled and poled γ‐form Nylon 11 films indicate that the polarization mechanism is not due to a field‐induced crystal transformation from the γ to the α form, suggesting the existence of a polar γ form. The temperature dependence of d31 shows no decrease in polarization at the α‐γ transition temperature (∼95 °C), indicating that the hydrogen bonds in the poled film are not able to randomize. These results suggest the possibility that our understanding of the γ‐form structure of Nylon 11 is incomplete.
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85.50.-n Dielectric, ferroelectric, and piezoelectric devices
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.40.Rs Electrical and magnetic properties related to treatment conditions
77.65.-j Piezoelectricity and electromechanical effects

Conformations of polydisperse polymer solutions: Bimodal distribution

J. F. Joanny, P. Grant, P. Pincus, and L. A. Turkevich

J. Appl. Phys. 52, 5943 (1981); http://dx.doi.org/10.1063/1.328524 (6 pages) | Cited 7 times

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We use scaling arguments to construct the ’’phase diagram’’ of an athermal bimodal solution; i.e., a ternary system composed of long chains, short chains, and solvent. Qualitatively, the presence of short chains reduces the effective solvent quality as experienced by the long chains. We obtain asymptotic forms for the radii of gyration of both chains throughout the phase diagram.
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61.41.+e Polymers, elastomers, and plastics
64.75.-g Phase equilibria
82.60.Lf Thermodynamics of solutions
61.05.F- Neutron diffraction and scattering

Conformational and lattice packing analyses of poly(acetylene)

B. J. Orchard, S. K. Tripathy, A. J. Hopfinger, and P. L. Taylor

J. Appl. Phys. 52, 5949 (1981); http://dx.doi.org/10.1063/1.328525 (4 pages) | Cited 2 times

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The intra‐ and inter‐chain structural analyses of proposed poly (acetylene) (PA) valence geometries were performed. The semi‐empirical molecular methods CNDO/2, MINDO/3, and NDDO were used in the intramolecular conformational analysis. A molecular‐mechanics based lattice packing formalism was used to compute the interchain energies. The structures proposed by Baughman and coworkers are predicted to be most stable in observed orthorhombic lattices. The all‐trans chain packs with the lowest energy and the trans‐cisoid structure is more stable than the cis‐transoid. However, a monoclinic set of lattices, not yet observed, are predicted to be about 50% lower in energy than the corresponding orthorhombic lattices for all three chain conformations.
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61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
61.66.Hq Organic compounds

A theory crack healing in polymers

R. P. Wool and K. M. O’Connor

J. Appl. Phys. 52, 5953 (1981); http://dx.doi.org/10.1063/1.328526 (11 pages) | Cited 139 times

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A theory of crack healing in polymers is presented in terms of the stages of crack healing, namely, (a) surface rearrangement, (b) surface approach, (c) wetting, (d) diffusion, and (e) randomization. The recovery ratio R of mechanical properties with time was determined as a convolution product, R = Rh (t)∗ϕ(t), where Rh (t) is an intrinsic healing function, and ϕ(t) is a wetting distribution function for the crack interface or plane in the material. The reptation model of a chain in a tube was used to describe self‐diffusion of interpenetrating random coil chains which formed a basis for Rh (t). Applications of the theory are described, including crack healing in amorphous polymers and melt processing of polymer resins by injection or compression molding. Relations are developed for fracture stress σ, strain ϵ, and energy E as a function of time t, temperature T, pressure P, and molecular weight M. Results include (i) during healing or processing at t<t∞, σ,ϵ∼t1/4, E∼t1/2; (ii) at constant t<t∞, σ,ϵ∼M−1/4, E∼M−1/2; (iii) in the fully interpenetrated healed state at t = t∞, σ,ϵ∼M1/2, E∼M; (iv) the time to achieve complete healing, t∞ ∼M3, ∼exp P, ∼exp 1/T. Chain fracture, creep, and stress relaxation are also discussed. New concepts for strength predictions are introduced.
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81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials
46.50.+a Fracture mechanics, fatigue and cracks

Temperature effect in quasiharmonic infrared bands of stressed polymers

R. S. Bretzlaff and R. P. Wool

J. Appl. Phys. 52, 5964 (1981); http://dx.doi.org/10.1063/1.328527 (6 pages) | Cited 8 times

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The effect of temperature on vibrational frequency shifts in mechanically stressed polymer chains is analyzed. A single chain is modeled as a weakly coupled, one‐dimensional series of anharmonic diatomic oscillators. The anharmonic potential is described as a perturbation of the harmonic potential with cubic and quartic terms. Expressions are derived for the dominant, quasiharmonic contribution to the temperature‐dependent frequency shifting coefficient αc, and distinctions are drawn between the vibrational mode ’’mixing contribution’’ and the ’’anharmonic contribution.’’ αc is derived in terms of the Grüneisen parameter; and the resulting expression is −αc = α0+β0T, where α0 is the extrapolated T = 0 °K value of the frequency shifting coefficient, and β0 is constant. The predicted linear dependence of αc on temperature was found to be in excellent qualitative agreement with experimental studies on stress‐induced infrared frequency shifts versus T in polypropylene.
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78.30.Jw Organic compounds, polymers
46.25.-y Static elasticity

Fatigue of high impact polystyrene and influence of surface treatments

J. A. Sauer, M. Habibullah, and C. C. Chen

J. Appl. Phys. 52, 5970 (1981); http://dx.doi.org/10.1063/1.328528 (7 pages) | Cited 4 times

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The fatigue endurance of unnotched samples of a rubber modified, high impact polystyrene (HIPS) was determined under tension‐compression cycling. The role of the rubber phase inclusions in the fatigue fracture process was further studied by detailed examination of the fracture surfaces by optical methods and by scanning electron microscopy. The observed morphology is compared with that obtained on HIPS samples subject to simple tension bonding and with that obtained on the unmodified polystyrene homopolymer. The dispersed rubber phase particles lead to an increased fatigue crack propagation resistance and, if comparison is made on the basis of the same relative stress, the rubber modified polymer leads also to increased fatigue lifetimes. The influence of various environmental variables such as elevated temperature annealing, surface condition, and surface treatments is discussed. Silicon oil coatings of low viscosity tend to significantly reduce fatigue lifetimes, but lifetimes increase with increased viscosity of oil coating. Significant enhancement in fatigue endurance can be realized by use of elastomeric coatings, such as a thin layer of nitrile rubber.
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62.20.M- Structural failure of materials
61.41.+e Polymers, elastomers, and plastics
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

Viscoplastic behavior of a glass at high pressures

D. L. Questad, K. D. Pae, J. I. Scheinbeim, and B. A. Newman

J. Appl. Phys. 52, 5977 (1981); http://dx.doi.org/10.1063/1.328529 (6 pages) | Cited 8 times

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The glass transition pressure Pg for a polyurethane elastomer (Solithane 113, 50/50 resin‐catalist ratio, manufactured by Thiokol Chemical Co.) is located at 2.5 kbar at room temperature and the glass transition temperature Tg is at −20 °C. Mechanical behavior of the elastomer, namely the tensile and the compressive stress‐strain behavior, in the glassy state as well as in the rubbery state has been determined. The Young’s modulus increases from ∼107 dyn/cm2 in the rubbery state to ∼1010 dyn/cm2 in the glassy state. The tensile fracture strain increases rapidly from 60% at atmospheric pressure to greater than ∼200% at 1 kbar and higher. In the glassy state, the samples exhibit yielding, yield drop, and cold drawing. The yield drop is not accompanied by necking. Rather the samples undergo uniform drawing throughout the entire gage length. A series of sequential loading, unloading, and reloading tests in the plastic range was also conducted in the glassy state. It was observed that the plastic strain recovers as a function of time, that the yield maximum reappeared and grew after a delay time, and that the Young’s modulus in subsequent loadings was higher than the initial values and increased steadily with time. Various loading histories can be completely erased upon returning to a rubbery state by removal of applied pressure. The recovery of the plastic deformation, or the viscoplastic behavior, occurs at essentially the same rate at all pressures tested, and thus the data were superimposable to form a master curve near Pg. A molecular explanation for the various new phenomena observed is given.
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81.05.Kf Glasses (including metallic glasses)
61.41.+e Polymers, elastomers, and plastics
62.20.F- Deformation and plasticity
62.50.-p High-pressure effects in solids and liquids

The poling field and draw dependence of the piezoelectric and pyroelectric response of pressure‐quenched, phase I poly(vinylidene fluoride) films

J. I. Scheinbeim and K. T. Chung

J. Appl. Phys. 52, 5983 (1981); http://dx.doi.org/10.1063/1.329817 (5 pages) | Cited 7 times

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Recent investigations have shown that unoriented phase I poly(vinylidene fluoride) films can be produced by pressure quenching. The poling field dependence of the pyroelectric coefficient Py, the piezoelectric coefficients dp, d31 and e31, and the dielectric response is investigated for poling fields up to Ep = 2.75×106 V/cm. These quantities exhibit a plateau region where the initial rapid increase with increasing Ep decreases. This behavior is similar to that observed for unoriented and biaxially oriented phase II poly(vinylidene fluoride) films. The effect of draw ratio on dp and Py for draw ratios up to 6:1 is also examined. dp increases from 6.5 to 19 pC/N as the draw ratio goes from 1:1 to 6:1 (at constant Ep). Py increases from 1×10−9 to 5×10−9 C/cm2 K.
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85.50.-n Dielectric, ferroelectric, and piezoelectric devices
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.40.Rs Electrical and magnetic properties related to treatment conditions
77.65.-j Piezoelectricity and electromechanical effects

Rheological behavior of progressively shear‐thickening solutions

Steven T. J. Peng and Robert F. Landel

J. Appl. Phys. 52, 5988 (1981); http://dx.doi.org/10.1063/1.329818 (6 pages) | Cited 15 times

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See Also: Erratum

Show Abstract
FM‐9 (the commercial name of an ICI product) in organic solvents or poly(methacrylic acid) (PMMA) in aqueous solution exhibit strong time‐dependent shear‐thickening behavior. The induction time needed for the onset of the thickening depends markedly on shear rate, solvent used, concentration, and molecular weight. Slightly altering the nature of the solvent profoundly affects the behavior. The effects are similar to those obtained by changing the concentration or molecular weight. The nature of thickening behavior is not well understood. The effect will be illustrated (using FM‐9 solutions) as a function of shear rate, concentration, and temperature. Defining a critical shear rate γc as that at which the induction time for thickening becomes so short as to be immeasurable within the resolution of the viscometer, γc for this polymer is found to be inversely proportional to the zero shear‐rate viscosity of the solution for the temperature and concentrations studied.
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62.10.+s Mechanical properties of liquids
66.20.-d Viscosity of liquids; diffusive momentum transport

Some considerations of crazing of polymers: Two‐dimensional quasifracture of polymers

S. S. Chern and C. C. Hsiao

J. Appl. Phys. 52, 5994 (1981); http://dx.doi.org/10.1063/1.329819 (4 pages) | Cited 3 times

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In a tensile stress field, certain polymeric solids deform and develop quasifracture formations. Each such formation is termed a craze. Previous analyses by Knight and Lauterwasser and Kramer have treated a craze by introducing either an assumed or a measured displacement field for the calculation of the stress distribution around the craze profile. In this paper the new phase of oriented polymer molecular bundles within the craze profile has been considered through the use of a linear modulus function for those bundles. Both displacement and stress fields have been calculated. This model developed for studying planar crack has its limitations when it is used for craze investigations. The basic model treatment depends upon classical linear fracture mechanics which is not valid for materials with a zone of craze occurrence. In addition, anisotropic and nonlinear as well as time dependent considerations are difficult to be incorporated into the model analysis.
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62.20.M- Structural failure of materials

Studies of elastic constants of oriented poly(ethylene terephthalate) films using Brillouin scattering

David B. Cavanaugh and C. H. Wang

J. Appl. Phys. 52, 5998 (1981); http://dx.doi.org/10.1063/1.329820 (5 pages) | Cited 6 times

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Brillouin scattering is used to study the elastic behavior of oriented poly(ethylene terephthalate) films. The elastic constants C11, C13, C33, and C44 are determined by measurements of the quasilongitudinal and quasitransverse hypersonic velocities at different angles in the film. The total orientational parameter is calculated for the three draw ratios from the Brillouin hypersonic velocities and are found to be similar to the orientational parameter in the amorphous phase obtained with a different technique.
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78.35.+c Brillouin and Rayleigh scattering; other light scattering
46.80.+j Measurement methods and techniques in continuum mechanics of solids
61.43.Fs Glasses
61.43.-j Disordered solids
62.20.D- Elasticity

Effects of chain orientation of Raman and Brillouin scattering spectra of hydrostatically extruded polypropylene

C. H. Wang and David B. Cavanaugh

J. Appl. Phys. 52, 6003 (1981); http://dx.doi.org/10.1063/1.329821 (5 pages) | Cited 6 times

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Raman and Brillouin scattering techniques have been used to study the effect of chain orientation in uniaxially extruded isotactic polypropylene. The orientation parameters 〈P2〉 and 〈P4〉 are obtained by measuring several Raman scattering intensities associated with the CH2 rocking mode at 841 cm−1. Both 〈P2〉 and 〈P4〉 parameters represent the average of the local orientational distribution of the polypropylene backbone. The Raman scattering result for 〈P2〉 is found in good agreement with the previous study using another vibrational band. The high‐frequency elastic constants C11, C33, C44, and C13 of extruded isotactic polypropylene are determined by Brillouin scattering. The elastic constants of deformed polymers have been related to the orientation parameters determined by Brillouin scattering. The result obtained for 〈P2〉 at high extension using Brillouin scattering is found to be smaller than that of Raman. The result suggests that the pair orientation correlation between segments is important in affecting the hypersonic velocity.
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61.43.Fs Glasses
61.43.-j Disordered solids
78.35.+c Brillouin and Rayleigh scattering; other light scattering
81.40.-z Treatment of materials and its effects on microstructure, nanostructure, and properties
62.20.D- Elasticity

Theory of structure and conformation of polyacetylene

Brian S. Good, P. L. Taylor, and A. J. Hopfinger

J. Appl. Phys. 52, 6008 (1981); http://dx.doi.org/10.1063/1.328574 (3 pages) | Cited 4 times

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An investigation of the structure of polyacetylene is carried out taking into account intrachain interactions. The distribution of torsional angles along the polymer chain is obtained using a transfer integral method. The most stable configuration at low temperature appears to be the cis‐transoid conformation.
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61.43.Fs Glasses
61.43.-j Disordered solids

Dynamics of electrowetting displays

G. Beni and M. A. Tenan

J. Appl. Phys. 52, 6011 (1981); http://dx.doi.org/10.1063/1.329822 (5 pages) | Cited 38 times

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In this paper we analyze the dynamics of a model electrowetting display (EWD) system, derive the operating parameters, and discuss the device performance. To discuss the problem we generalize the Washburn‐Yarnold treatment for the motion of a liquid slug in a capillary tube. It is shown that EWD’s have both memory and voltage threshold, and thus intrinsic matrix addressability. These properties are intimately related to the frictional surface tension forces developed between the metal and the electrolyte. Finally we present a model voltage‐driving scheme for matrix‐addressable EWD’s.
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07.07.Hj Display and recording equipment, oscilloscopes, TV cameras, etc.
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