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amorphous polymers

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Published: 15 May 2022
Fig. 1 Five regions of viscoelastic behavior for a linear, amorphous polymer. Also illustrated are the effects of crystallinity (dashed line) and cross linking (dotted line). More
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Published: 15 May 2022
Fig. 11 Generalized modulus for amorphous and crystalline polymers More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006932
EISBN: 978-1-62708-395-9
... on properties of plastics. It explains the use of high-modulus graphite fibers in amorphous polymers. high-modulus graphite fibers plastics thermal diffusivity thermal expansion thermal stress ENGINEERING PLASTICS, as a general class of materials, are prone to the development of internal stresses...
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Published: 15 May 2022
Fig. 7 Influence of molecular weight and temperature on the physical state of polymers. (a) Amorphous polymer. (b) Crystalline polymer. Source: Ref 7 More
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Published: 15 January 2021
Fig. 18 Schematic picture of spaghetti-bowl appearance of an unoriented amorphous polymer. (a) Prior to plastic strain. (b) After plastic strain; twisting and kinking are reduced and the polymer chains become oriented in the direction of plastic strain. Source: Ref 12 More
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Published: 01 January 2002
Fig. 17 Schematic picture of spaghetti-bowl appearance of an unoriented amorphous polymer. (a) Prior to plastic strain. (b) After plastic strain; twisting and kinking are reduced and the polymer chains become oriented in the direction of plastic strain. Source: Ref 36 More
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Published: 15 May 2022
Fig. 4 Glass transition temperature ( T g ) curves for semicrystalline and amorphic polymers More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006867
EISBN: 978-1-62708-395-9
... solubility parameters exist, the solvent will have no apparent effect. Amorphous polymers absorb chemicals more readily than crystalline polymers, and the rate varies inversely with the degree of crystallinity. Cross-linked polymers will not dissolve but will swell significantly when exposed to chemicals...
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Published: 15 May 2022
Fig. 1 Variation of elastic modulus with the temperature for a typical amorphous polymer. T g is the glass-transition temperature, and the horizontal dashed line shows the effect of slight cross-linking. More
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Published: 15 May 2022
Fig. 4 Modulus versus temperature for typical linear semi-crystalline and amorphous polymers. T g , glass transition temperature; T m , melting temperature; 1, glassy behavior; 2, glass transition; 3, rubbery behavior; 4, viscous fluid behavior More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006934
EISBN: 978-1-62708-395-9
... for homogeneous polymers. The word homogeneous is used to exclude copolymers and blends that undergo microphase separation or phase changes. However, the differences between crystalline and amorphous polymers are identified. The application of this review to the practical problems of failure analysis...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006944
EISBN: 978-1-62708-395-9
... of Polymers under Stress The simple structure of a polymer consists of a random arrangement of chain molecules; such materials are referred to as amorphous polymers or glassy thermoplastics. In amorphous polymers, the chain molecules are randomly intertwined to form the material. The cohesive energy...
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Published: 15 May 2022
Fig. 1 Generic molecular arrangement for an amorphous and a semicrystalline polymer More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006918
EISBN: 978-1-62708-395-9
... Abstract This article reviews generalized test methodologies for fatigue characterization of polymers and examines fatigue fracture mechanisms in different engineering plastics. It provides detailed micromechanistic images of crack-tip processes for a variety of semicrystalline and amorphous...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003550
EISBN: 978-1-62708-180-1
.... With polymer-solvent combinations having solubility parameter differences outside this range, some adsorption of the solvent by the polymer may still occur. When large differences between solvent and polymer solubility parameters exist, the solvent will have no apparent effect. Amorphous polymers absorb...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001391
EISBN: 978-1-62708-215-0
... separation between the cermet and polymer thick-film layers. The condition ranged in severity from its presence as an amorphous layer of contamination to that of total delamination. Gross delamination was consistently observed in the group 3 samples ( Fig. 10 ), indicating that the solder attachment...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006915
EISBN: 978-1-62708-395-9
... in polymers. The chain backbone is shown as a threadlike line. (a) Amorphous. (b) Semicrystalline. (c) Uniaxial orientation. (d) Biaxial orientation Amorphous versus Semicrystalline In the melt or solution, the chains of most polymers exhibit random or amorphous configurations. Upon cooling...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006917
EISBN: 978-1-62708-395-9
... of amorphous plastics are generally less packed and more randomly organized, while semicrystalline materials include regions of tightly and orderly packed polymer molecules together with less-ordered regions ( Fig. 1 ). Fig. 1 Generic molecular arrangement for an amorphous and a semicrystalline polymer...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006941
EISBN: 978-1-62708-395-9
... time-temperature superposition principles is the Williams-Landel-Ferry (WLF) equation ( Ref 8 , 23 ), which applies primarily above the glass transition temperature, T g . Because this treatment was derived for a certain class of plastics known as amorphous polymers, it is to be expected...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006925
EISBN: 978-1-62708-395-9
... of the changes produced in such structural factors as intermolecular bonding and crystallinity. For example, an atactic polymer tends to be a rubbery amorphous material, while an isotactic polymer is more crystalline with more stiffness and melting temperatures. Fig. 6 Stereoisomers in a simple vinyl...