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branching polymers

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Image
Published: 01 January 2003
Fig. 2 (a) Simulated cross linked (networked or three-dimensional) structure. (b) Simulated linear polymer molecule. (c) Simulated structure of a branched polymer More
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003006
EISBN: 978-1-62708-200-6
... of polyisoprene Structure Within the Molecule The structure within the molecule may involve stereoisomerism, branching, molecular weight and distribution, end groups and impurities, and copolymerization. Stereoisomers The polymer structures illustrated in Tables 1 , 2 , 3 , and 4 may appear...
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
... The mer unit defines the chemical composition of a polymer, but complete information about the chemical structure of a polymer has several variations of how the mers combine to form a polymer. These variations in structure within the molecule may involve stereoisomerism, branching, molecular weight...
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
... , and melt processing via extrusion generally correlates most closely with M z . Fig. 3 Generic illustration of molecular weight distribution Molecular Architecture Polymer molecules can be linear, branched, or crosslinked into a three-dimensional network. In the bulk, polymers can...
Image
Published: 01 January 1990
Fig. 12 4137 steel bolts (hardness: 42 HRC) that failed by hydrogen-assisted SCC caused by acidic chlorides from a leaking polymer solution. (a) Overall view of failed bolts. (b) Longitudinal section through one of the failed bolts in (a) showing multiple, branched hydrogen-assisted stress More
Image
Published: 01 January 2003
Fig. 12 4137 steel (UNS G41370) bolts (hardness, 42 HRC) that failed by hydrogen-assisted stress-corrosion cracking caused by acidic chlorides from a leaking polymer solution. (a) Overall view of failed bolts. (b) Longitudinal section through one of the failed bolts in (a) showing multiple More
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001278
EISBN: 978-1-62708-170-2
... literature and can be divided into two major groups: high-molecular-weight, low-solids materials and low-molecular-weight, high-solids materials. Two factors are particularly important to good performance in this class of coatings: the branching or cross-link density of the condensation polymer employed...
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
... themselves into an orderly structure. In general, simple polymers (with little or no side branching) crystallize very easily. Crystallization is inhibited in heavily cross-linked (thermoset) polymers and in polymers containing bulky side groups. There are three categories of polymers: thermoplastics...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006930
EISBN: 978-1-62708-395-9
... of branching, and whether there are additives present and to what degree. The results of rheological testing help answer question regarding the processability of a given material for given applications. Rotational Rheometry Rotational rheometry is one common method of characterizing polymer melts...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006865
EISBN: 978-1-62708-395-9
... structure. In general, polymers that have a reasonably regularly ordered chain structure and little or no side branching will crystallize under suitable conditions. Crystallization is inhibited in heavily cross-linked (thermoset) polymers and in polymers that contain bulky side groups. There are three...
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
... and this strongly affects the thermal, mechanical, and rheological properties of plastics as shown in Table 4 . Polymer size is quantified primarily by molecular weight (MW), molecular-weight distribution (MWD), and branching. Effect of molecular weight on polyethylene Table 4 Effect of molecular weight...
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
... , 3 ). When linear or branched thermoplastic polymers are exposed to large enough quantities of solvents having solubility parameters within approximately ±2 H of that of the polymer, dissolution of the polymer will occur. In smaller quantities, these solvents will be adsorbed by the polymer...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006373
EISBN: 978-1-62708-192-4
... ). The friction coefficient passes the minimum, which corresponds to transition from elastic contact (the descending branch of the curve) to plastic (the ascending branch). It is important that the load can vary the temperature of viscoelastic transitions in polymers and thereby the mechanism of friction...
Series: ASM Handbook
Volume: 9
Publisher: ASM International
Published: 01 December 2004
DOI: 10.31399/asm.hb.v09.a0009071
EISBN: 978-1-62708-177-1
... its decomposition temperature ( Ref 2 ). In contrast, thermoplastics, which consist of high-molecular-weight linear or branched polymer chains (not crosslinked), can be reshaped with the application of heat and pressure ( Ref 2 ). In relation to composite materials, the distinction between these types...
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
... . Polymer size is quantified primarily by molecular weight, molecular-weight distribution, and branching. Effect of molecular weight on polyethylene Table 3 Effect of molecular weight on polyethylene Number of –CH 2 –CH 2 – units Molecular weight Softening temperature Character of polymer...
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
... are tabulated in many references; they also can be calculated using the concept of group contributions. ( Ref 2 , 3 ). When linear or branched thermoplastic polymers are exposed to large enough quantities of solvents having solubility parameters within approximately ±2 H of that of the polymer, dissolution...
Series: ASM Handbook
Volume: 5B
Publisher: ASM International
Published: 30 September 2015
DOI: 10.31399/asm.hb.v05b.a0006009
EISBN: 978-1-62708-172-6
... and alcohols must be used for linear polyester manufacturing. A specific amount of tri- or higher functional monomers must be used in the manufacture of branched polyesters ( Ref 3 ). Depending on the choice of components used to build up the polyester, the polymer morphology may be widely changed...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006923
EISBN: 978-1-62708-395-9
... fraction become brittle at temperatures below the T g . During crystallization, the crystallizing polymer has chain segments containing structural irregularities, for example, short-chain and long-chain branches on PE chains. These structural irregularities are routed into the regions of amorphous...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003023
EISBN: 978-1-62708-200-6
..., although there are occasional exceptions to this rule. The yield strength of PP decreases when molecular weight increases. Studies of morphology indicate that high molecular weight and branching reduce crystallinity. Polymers with high intermolecular interaction, such as hydrogen bonding, do not require...
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
..., an increase in mean stress results in faster crack propagation rates. Remarkably, several polymer blends offer improved resistance to crack propagation as the mean stress is increased ( Ref 5 , 13 ). These polymers include ABS, HIPS, PC, branched PE, low-molecular-weight PMMA, and rubber-toughened PMMA...