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branching polymers

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Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2013
DOI: 10.31399/asm.tb.ems.t53730099
EISBN: 978-1-62708-283-9
... Abstract This chapter discusses the structural classifications, molecular configuration, degradation, properties, and uses of polymers. It describes thermoplastic and thermosetting polymers, degree of polymerization, branching, cross-linking, and copolymers. It also discusses glass transition...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2012
DOI: 10.31399/asm.tb.ffub.t53610327
EISBN: 978-1-62708-303-4
... Abstract This chapter covers the fatigue and fracture behaviors of ceramics and polymers. It discusses the benefits of transformation toughening, the use of ceramic-matrix composites, fracture mechanisms, and the relationship between fatigue and subcritical crack growth. In regard to polymers...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780146
EISBN: 978-1-62708-281-5
... but is inversely related to the size of the absorbate. The rate of diffusion is decreased by the presence of branches, pendant groups, or cross links. Solubility parameters are useful for amorphous and some semicrystalline polymers. Crystallinity can yield behavior that appears anomalous. The...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780003
EISBN: 978-1-62708-281-5
... stereoisomerism, branching, molecular weight and distribution, end groups and impurities, and copolymerization. Polymer size is quantified primarily by molecular weight (MW), molecular-weight distribution (MWD), and branching. These factors are briefly described in this section with more details given in the next...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2020
DOI: 10.31399/asm.tb.bpapp.t59290035
EISBN: 978-1-62708-319-5
... mixture of crystalline, amorphous, and branched structures Another variation in properties arises from the level of chain branching. Branched polymers are difficult to crystallize and exhibit lower density. For example, polyethylene has a density of 0.855 g/cm 3 if it is branched. The branches...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780329
EISBN: 978-1-62708-281-5
... Abstract This article provides a basic review of polymer photochemistry as it relates to the weatherability of engineering plastics, considering the chemistry induced by exposure to sunlight in open air. Elementary aspects of weatherability chemistry that are discussed include the light...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300301
EISBN: 978-1-62708-323-2
... plate of spaghetti, they are termed linear polymers ( Fig. 11.3 ), and weak van der Waals forces hold the chains together. Rubbers/elastomers usually have chemical bonds between chains; they have a branched structure. There can be interpenetrating polymer chains when more than one polymer makes up a...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780199
EISBN: 978-1-62708-281-5
... Abstract This article describes the general aspects of and practical problems of failure analysis of creep, stress relaxation, and yielding for homogeneous polymers. The effect of temperature and strain rate on the relationship between yield point and elastic modulus and the aging effect that...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780105
EISBN: 978-1-62708-281-5
... weight distribution. Figure 13 shows that the complex melt viscosity decreases more immediately, although gradually, with a broadening of the distribution, and that the G ′ increases. The same trend can be observed for short-chain branching in the polymer architecture, which is discussed in the...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780295
EISBN: 978-1-62708-281-5
... Abstract In an attempt to explain the stresses encountered in the plastics industry, this article first defines the different types of internal stresses in amorphous polymers. Each type of thermal stress is then discussed in detail, with reference to the mechanism of generation and the effect...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780404
EISBN: 978-1-62708-281-5
... macroscopic appearance, and the examination and interpretation of the features of fracture surfaces. In addition, the article considers several cases of field failure in various polymers to illustrate the applicability of available analytical tools in conjunction with an understanding of failure mechanisms...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780115
EISBN: 978-1-62708-281-5
... Abstract This article covers the thermal analysis and thermal properties of engineering plastics with respect to chemical composition, chain configuration, and/or conformation of the base polymers. The thermal analysis techniques covered are differential scanning calorimetry, thermogravimetric...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780238
EISBN: 978-1-62708-281-5
.... Remarkably, several polymer blends offer improved resistance to crack propagation as the mean stress is increased ( Ref 5 ). These polymers include ABS, HIPS, PC, low-density or branched PE, low-molecular-weight PMMA, and rubber-toughened PMMA ( Table 1 ). Hertzberg postulated that the strain energy normally...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.tb.scm.t52870573
EISBN: 978-1-62708-314-0
... Abstract This chapter discusses the types of fibers and matrix materials used in ceramic matrix composites and the role of interfacial coatings. It describes the methods used to produce ceramic composites, including powder processing, slurry infiltration and consolidation, polymer infiltration...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2012
DOI: 10.31399/asm.tb.lmub.t53550569
EISBN: 978-1-62708-307-2
..., continuous fiber ceramic composites, and carbon-carbon composites. It also describes a number of ceramic-matrix composite processing methods, including cold pressing and sintering, hot pressing, reaction bonding, directed metal oxidation, and liquid, vapor, and polymer infiltration. ceramic-matrix...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780028
EISBN: 978-1-62708-281-5
... varied, 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. Table 4 Effect of molecular weight on polyethylene...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780305
EISBN: 978-1-62708-281-5
... the waste essentially determines whether the service life objective is met. The engineer who wishes to work with thermoplastics in a given environment needs to consider particular questions and problems: Why certain environments promote crazing in polymers under stress How to identify...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780089
EISBN: 978-1-62708-281-5
... , 1972 , p 1953 – 1958 10.1002/app.1972.070160809 23. Batzer H. , and Zahir S.A. , Studies in the Molecular Weight Distribution of Epoxide Resins. II . Chain Branching in Epoxide Resins, J. Appl. Polym. Sci. , Vol 19 , 1975 , p 601 – 607 10.1002/app.1975.070190221 24...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2012
DOI: 10.31399/asm.tb.lmub.t53550325
EISBN: 978-1-62708-307-2
... exceptions to this rule. The yield strength of polypropylene decreases when molecular weight increases. Studies of morphology indicate that high molecular weight and branching reduce crystallinity. Polymers with high intermolecular interactions, such as hydrogen bonding, do not require high molecular weight...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300391
EISBN: 978-1-62708-323-2
... and lubrication) 10.31399/asm.hb.v18.9781627081924 • Wells J.G. , Lubrication Fundamentals , Marcel Dekker Inc. , New York , 1980 Greases are semisolids containing a lubricant. The lubricant is usually a mineral oil but may be a synthetic oil, a polymer (such as...