<i>Structured Polymer Properties</i>

Samuels, Robert J.; Pulver, Martin I.

doi:10.1063/1.3068969

Cited by 133 publications

(97 citation statements)

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“…As the polymer is oriented, the spherulite begins to deform. At low deformations the spherulite deforms elastically as a unit (10). At higher deformations the lamellae begin to slip from their original radial alignment to one in which blocks of lamellae reorient themselves such that the c-axis (main chain axis) of the polymer becomes aligned in the orienting direction (8).…”

Section: Theorymentioning

confidence: 99%

A review of techniques for processing ultra‐high modulus polymers

Bigg

1976

Polymer Engineering & Sci

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Columbus, Ohio 43201Linear crystalline polymers can be processed to high degrees of orientation sufficient to produce dramatic increases in tensile strength and modulus. Three processes have been identified for inducing such orientation: cold drawing, hydrostatic extrusion, and solution spinning. All three processes utilize a high elongational velocity gradient in a critical temperature range to produce a high strength crystalline morphology. Although the molecular supcrstructure may differ in each case, the mechanical properties are similar. An increase in strength is achieved either through the creation of new tie molecules between crystal lamellae or through the creation of an extended chain crystal substructure. Temperature and molecular weight are the prime variables in determining which morphology will develop. The optimum processing temperature for many of the specific techniques is the crystalline dispersion temperature. At this tempcxature, the crystal structure is particularlp atlaptable to forming a new crystal morphology. U1-tradrawn polymers are more Hookean in behavior than isotropic polymers and have properties similar to steel and glass. Polyoxyniethylene has bcen processed most closely to its theoretical strength. Polyethylene, which is the most difficult to process, has achieved the highest modulus of any common polyolefin polymcr, al,out 7 x 10"' Pa.

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Section: Theorymentioning

confidence: 99%

A review of techniques for processing ultra‐high modulus polymers

Bigg

1976

Polymer Engineering & Sci

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“…The properties of crystalline polymers are determined by the relative amount of the amorphous and crystalline phases, crystal modification, the size and perfection of crystallites, the dimensions of spherulites, and by the number of tie molecules [60]. The most important effect of particulate fillers is their ability to act as nucleating agents.…”

Section: Crystalline Matrices Nucleationmentioning

confidence: 99%

Particulate Fillers in Thermoplastics

Móczó

Pukánszky

2017

Fillers for Polymer Applications

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The characteristics of particulate filled thermoplastics are determined by four factors: component properties, composition, structure and interfacial interactions. The most important filler characteristics are particle size, size distribution, specific surface area and particle shape, while the main matrix property is stiffness. Segregation, aggregation and the orientation of anisotropic particles determine structure. Interfacial interactions lead to the formation of a stiff interphase considerably influencing properties. Interactions are changed by surface modification, which must be always system specific and selected according to its 2 goal. Under the effect of external load inhomogeneous stress distribution develops around heterogeneities, which initiate local micromechanical deformation processes determining the macroscopic properties of the composites. INTRODUCTUIONParticulate filled polymers are used in very large quantities in all kinds of applications. The total consumption of fillers in Europe alone is currently estimated as 4.8 million tons (Table 1) [6]. In spite of the overwhelming interest in nanocomposites, biomaterials and natural fiber reinforced composites, considerable research and development is done on particulate filled polymers even today. The reason for the continuing interest in traditional composites lays, among others, in the changed role of particulate fillers. In the early days fillers were added to the polymer to decrease price.However, the ever increasing technical and aesthetical requirements as well as soaring material and compounding costs require the utilization of all possible advantages of fillers.Fillers increase stiffness and heat deflection temperature, decrease shrinkage and improve the appearance of the composites [9][10][11][12][13]. Productivity can be also increased in most thermoplastic processing technologies due to their decreased specific heat and increased heat conductivity [9,10,[14][15][16][17]. Fillers are very often introduced into the polymer to create new functional properties not possessed by the matrix polymer at all like flame retardancy or conductivity [18][19][20][21]. Another reason for the considerable research activity is that new fillers and reinforcements emerge continuously among others layered silicates [7,[22][23][24][25][26][27][28][29], wood flour [30][31][32][33][34][35][36][37], sepiolite [38][39][40][41][42][43][44][45][46][47][48][49], etc.The properties of all heterogeneous polymer systems are determined by the same four factors: component properties, composition, structure and interfacial interactions [9,50]. Although certain fillers and reinforcements including layered silicates, other nanofillers, or natural fibers possess special characteristics, the effect of these four factors is universal and valid for all particulate filled materials. As a consequence, in this paper 3 we focus our attention on them and discuss the most important theoretical and practical aspects of composite preparation and use accordingly. The general rules of h...

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“…The obtained values of the refractive indices n || and n ⊥ of the fibre material can be used to calculate the polarizability per unit volume in case of light polarizing parallel P || and perpendicular P ⊥ to the fibre axis by application of the following Lorantz-Lorenz equation [26]:…”

Section: Polarizability Per Unit Volumementioning

confidence: 99%

Opto-Mechanical Properties of PTFE Fibres Using Phase Shifting Interferometry

Yassien¹,

Bakary²

2014

OPJ

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Polytetrafluoroethylene (PTFE) is one of a class of polymer that has many unique properties, which make it valuable in scores of applications. Here, the molecular alignment effect in fibre drawing and its relation with nonlinear optical properties of the PTFE fibres were studied by means of interferometry. For this propose, the phase shifting Mach-Zehnder interferometer was utilized. The fibre drawing device was attached to the interferometer for measuring the opto-mechanical properties of PTFE fibres. From the recorded interferomgrams the wrapped phase map and its contour line were determined using the phase shifting interferometry (PSI) method. From the contour lines the refractive index, refractive index profile, birefringence, polaryzability and orientation function of the investigated sample were determined at different draw ratios. The PSI method showed good results for enhancing the noisy fringe pattern and for obtaining contour line microinterferograms. This study offers the correlation between the mechanical properties and the structure properties of fibres. Thus, a better structure-property correlation can improve the technical and industry performance of the fibres.

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Structured Polymer Properties

Cited by 133 publications

References 0 publications

A review of techniques for processing ultra‐high modulus polymers

A review of techniques for processing ultra‐high modulus polymers

Particulate Fillers in Thermoplastics

Opto-Mechanical Properties of PTFE Fibres Using Phase Shifting Interferometry

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