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amorphous polymers

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Published: 01 January 1997
Fig. 8 Schematic view of intermolecular order in polymers. (a) Amorphous. (b) Semicrystalline. (c) Uniaxial orientation. (d) Biaxial orientation More
Image
Published: 01 January 2000
Fig. 2 Influence of molecular weight and temperature on the physical state of polymers. (a) Amorphous polymer. (b) Crystalline polymer. Source: Ref 2 More
Series: ASM Handbook
Volume: 23
Publisher: ASM International
Published: 01 June 2012
DOI: 10.31399/asm.hb.v23.a0005676
EISBN: 978-1-62708-198-6
... be either amorphous or semicrystalline. Amorphous polymers tend to have irregularity in their chain structure and often contain large side groups, which prevents the chains from forming ordered structures or crystalline zones. On the other hand, crystalline polymers are more regular and ordered than...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003318
EISBN: 978-1-62708-176-4
..., this region of residual tensile stress is one fourth the size of the monotonic plastic zone described in Eq 13 . Cyclic plastic zones have been observed in several amorphous polymer systems and are important in the inception of cracks under cyclic compression loading ( Ref 13 ). Qualitatively, it is easy...
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 Handbook
Volume: 20
Publisher: ASM International
Published: 01 January 1997
DOI: 10.31399/asm.hb.v20.a0002464
EISBN: 978-1-62708-194-8
... a single chlorine atom onto the PE structure, has a tensile modulus of 2400 to 6500 MPa and a glass transition temperature ( T g ) (amorphous) of 75 to 105 ┬░C. Composition: Molecular Structure Polymer molecules contain multiple repeat units called mers. The number of repeat units can be varied...
Image
Published: 01 January 2000
Fig. 11 Comparison of fatigue crack propagation behavior in the Paris regime for several amorphous and semicrystalline polymers. Note enhanced fatigue resistance of the semicrystalline polymers. Source: Ref 5 More
Book Chapter

Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003541
EISBN: 978-1-62708-180-1
... nature of polymers is responsible for crazing. Without the long chains, it would not be possible to form the fibrils that span the craze and prevent the conversion of the craze into a crack. Although crazing is usually associated with the deformation of amorphous polymers, it has also been observed...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003255
EISBN: 978-1-62708-176-4
... weight polymers, some polar-covalent ceramics, and some metallic alloys. Amorphous structures arise because the mobility of atoms within these materials is restricted such that low energy configurations (crystalline) cannot be reached. To fully describe the nature of glassy materials, it is useful...
Image
Published: 01 January 2001
Fig. 3 Polymer chain orientation. (a) Conventional organic, characterized by chain folds, misalignment, and crystalline and amorphous regions. (b) Para-aramid, characterized by long, straight chains without folds, parallel to the fiber axis, crystalline More
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003023
EISBN: 978-1-62708-200-6
... , the modulus continues to drop until the physical integrity of the polymer is lost (a melting process for semicrystalline polymers; complete liquidlike flow above T g for linear, amorphous polymers; or rubberlike behavior for cross-linked systems). This region of behavior above the transition is called...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003024
EISBN: 978-1-62708-200-6
... shear yielding are noncrystalline, or amorphous, and have no slip planes. For these reasons, the shear bands formed on polymers are generally more diffused or delocalized than the shear bands in metals ( Ref 6 ). It is more common to see extensive necking in polymers than it is to see...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006672
EISBN: 978-1-62708-213-6
..., such as polyethylene terephthalate and polyphthalamide, undergo low-temperature crystallization, representing the spontaneous rearrangement of amorphous segments within the polymer structure into a more orderly crystalline structure. Such exothermic transitions indicate that the as-molded material had been cooled...
Series: ASM Handbook
Volume: 24
Publisher: ASM International
Published: 15 June 2020
DOI: 10.31399/asm.hb.v24.a0006555
EISBN: 978-1-62708-290-7
... extrusion typically is from the class of amorphous thermoplastics, most popularly polylactic acid and ABS. Amorphous polymers are suitable for forming slurries with a rather continuous range of viscosity, as opposed to semicrystalline polymers, which have a sharp transition from solid to melt...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001469
EISBN: 978-1-62708-173-3
... a suitable solvent or by heating the polymer sample. As mentioned previously, only thermoplastics can be joined using the fusion-welding process. The glass transition temperature, T g , in amorphous polymers, and the melting temperature, T m , in crystalline polymers must be exceeded so...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006369
EISBN: 978-1-62708-192-4
... and hydrogen; a-C:H, which is comprised of a lesser amount of sp 3 -hybridized orbitals than ta-C:H; and HC polymers. Fig. 4 Diagram of diamondlike carbon materials based on hydrogen content and sp2- and sp3-hybridized carbon-carbon bonding. a-C, amorphous carbon; ta-C, tetrahedrally bonded amorphous...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002352
EISBN: 978-1-62708-193-1
... description of current theories of intergranular fracture. The theories either focus on the reason for intrinsic grain boundary weakness or on the effect of segregation of embrittling elements. Crazing of Polymers Above the glass temperature, amorphous polymers generally fail by rupture that may...
Book Chapter

By Rebecca Tuszynski
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003011
EISBN: 978-1-62708-200-6
... (rubbery), glassy, or crystalline phase. Elastomers are typically categorized as amorphous (single-phase) polymers having a random-coil molecular arrangement. After being properly compounded and molded into an engineered product, the material at some point will be subject to an external force. When...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003711
EISBN: 978-1-62708-182-5
... of impurity molecules of different shape can result in a solid structure with limited local alignment of molecular unit cells, which, in the extreme, can result in amorphous or glass structures. The basic unit for organics is the polymer. Polymers have large complex atomic alignments, irregular geometry...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006670
EISBN: 978-1-62708-213-6
...Abstract Abstract This article introduces various techniques commonly used in the characterization of semiconductors, namely single-crystal, polycrystalline, amorphous, oxide, organic, and low-dimensional semiconductors and semiconductor devices. The discussion covers material classification...