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molecular orientation

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Published: 15 May 2022
Fig. 9 Graphic representation of the concept of molecular orientation More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006935
EISBN: 978-1-62708-395-9
... processes on plastic parts and the material properties is presented. The article presents process effects on molecular orientation. It also illustrates the thinking that goes into the selection of processes for size, shape, and design factors. Finally, the article describes how various processes handle...
Image
Published: 15 May 2022
Fig. 10 Stress optical sensitivity examination of part with high molecular orientation More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006916
EISBN: 978-1-62708-395-9
... molecular orientation plastics residual stresses PLASTIC PARTS will generally fail as a result of one of five major causes: material, design, manufacturing, environmental conditions, and user abuse. Manufacturing-related failures can result from any one of three general categories: processing...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006662
EISBN: 978-1-62708-213-6
... discusses the sampling techniques and applications of IR spectra as well as the molecular structure information it can provide. The discussion begins with a description of the general principle of IR spectroscopy. This is followed by a section on commercial IR instruments. Sampling techniques...
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
... Abstract This article discusses the most fundamental building-block level, atomic level, molecular considerations, intermolecular structures, and supermolecular issues. It contains a table that shows the structures and lists the properties of selected commodity and engineering plastics...
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001735
EISBN: 978-1-62708-178-8
... Abstract Infrared (IR) spectroscopy is a useful technique for characterizing materials and providing information on the molecular structure, dynamics, and environment of a compound. This article provides the basic principles and instrumentation of IR spectroscopy. It discusses the sampling...
Book Chapter

By Paul J. Walsh
Series: ASM Handbook
Volume: 21
Publisher: ASM International
Published: 01 January 2001
DOI: 10.31399/asm.hb.v21.a0009241
EISBN: 978-1-62708-195-5
.... Precursor manufacture is accomplished by spinning the PAN polymer into filaments using variants of standard textile fiber manufacturing processes. The PAN fibers are white in color, with a density of approximately 1.17 g/cm 3 (0.042 lb/ in 3 ) and a molecular structure comprised of oriented, long chain...
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
... forces or hydrogen bonding). Morphology develops as a result of structural aspects of a polymer, such as crystal size and distribution in semicrystalline polymers, molecular orientation from melt processing, size/shape/distribution of fillers/reinforcements, and the degree of phase separation...
Series: ASM Handbook
Volume: 13B
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v13b.a0003844
EISBN: 978-1-62708-183-2
... pull it into a close and symmetrical alignment, areas of crystallinity may develop within a polymeric structure. Molecular orientation of most paints and coatings, when dried, consists of closely symmetrical, crystalline-oriented molecular structures within a larger, randomly oriented, amorphous...
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
..., and addresses related considerations such as melt viscosity and melt strength, crystallization, orientation, die swell, melt fracture, shrinkage, molded-in stress, and polymer degradation. composition elastic modulus engineering plastics polymer properties polymer structure shear rate...
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
... at elevated temperatures. This deformation produces molecular orientation, which is accompanied by internal stresses. If cooling is rapid enough, these stresses are frozen in, along with orientation. This results in anisotropic physical properties and a propensity for dimensional instability. The third...
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
... 4 ). It is suggested that when a stress is applied, free volume can increase in local regions where the polymer is under stress. In fact, molecular orientation, such as that created by polymer flow, plays a significant role in this phenomenon. If stress is applied parallel to the orientation...
Series: ASM Handbook
Volume: 21
Publisher: ASM International
Published: 01 January 2001
DOI: 10.31399/asm.hb.v21.a0003441
EISBN: 978-1-62708-195-5
... epoxies, one sees low strain and a steep curve all the way to failure. In the case of thermoplastics, strain is usually greater, but a unique behavior is observed before failure. This phenomenon is the special involvement and the changes in molecular orientation that are known as yield. At the yield...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006931
EISBN: 978-1-62708-395-9
... of crystallinity, molecular orientation, cross linking, phase separation, structural or morphological changes resulting from processing, and chemical composition in polymer blends, graft polymers, and copolymers.” Polymer composites have also been studied by DMA. The tan δ spectra of impact-modified PP related...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003571
EISBN: 978-1-62708-180-1
... against a smooth metal surface, friction is high in the beginning but drops to a lower value after some sliding. Because of the presence of frictional stress and heat, the PTFE molecular chains are oriented in the direction of sliding and a transfer film is deposited onto the counterface. The molecular...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003025
EISBN: 978-1-62708-200-6
... Abstract Mechanical properties are often the most important properties in the design and selection of engineering plastics. Temperature, molecular structure, crystallinity, viscoelasticity, and effects of environment, fillers and reinforcements are considered as the basic factors affecting...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006933
EISBN: 978-1-62708-395-9
... distribution, crystallinity, tacticity, molecular orientation, and fusion. These characteristics have a significant impact on the properties of the molded article. Additionally, plastic resins are formulated with additives such as reinforcing fillers, plasticizers, colorants, antidegradants, and process aids...
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
... molecular weight, branching leads to a decrease in T m . Therefore, the orientation of high-molecular, linear chains can lead to an exceptionally high T m . For example, UHMWPE, with almost perfect chains, displays the highest T m of the different PE grades with a T m of approximately 150 °C (300...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003006
EISBN: 978-1-62708-200-6
... helmets; and ultrahigh molecular weight polyethylene (UHMWPE), used to make ice hockey dasher boards and pen tips. Thermosets, on the other hand, once reacted and cured, cannot be re-formed by any means that will not break the covalent bonds and destroy the polymer. Examples of thermosets include...