Handbook of Engineering Polymeric Materials

Cheremisinoff, Paul N.

doi:10.1201/9781482292183

Cited by 89 publications

(57 citation statements)

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“…The initial increase is maybe due to the availability of free radicals generated for grafting reaction. When the initiator concentration rises above a certain value, increased free radical concentration results in a homopolymerization which diminishes the graft copolymerization [23,47]. This result can be attributed to the fact that free radical generation process will increase with increasing levels of AIBN, which enhances the grafting degrees.…”

Section: Effect Of the Initiator Concentrationmentioning

confidence: 76%

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

Ha¹,

Sơn²

2016

J Chem Eng Process Technol

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Section: Effect Of the Initiator Concentrationmentioning

confidence: 76%

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

Ha¹,

Sơn²

2016

J Chem Eng Process Technol

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“…Weak links can exist in form of side chains, peroxy, carbonyl, hydroxyl group (formed in the process of radical polymerization of propylene), and atactic portions of macromolecular chain could induce the degradation at an earlier stage as these are most susceptible to thermal destruction. 23 However, we see a high proportion of C12-C15 in the product composition (Fig. 7), due to the absence of other fractions (C24 and above).…”

Section: Products Analysismentioning

confidence: 91%

“…PP undergoes random-scission reaction (1) giving rise to one primary radical (R p ) and one secondary radical (R s ). 3,5,23 CAC bonds in PP are weaker than in PE due to the presence of tertiary carbon centers at every second carbon atom in the chain backbone; hence, random scission starts at a lower temperature and thereby increasing the yield of product at 200 C for PP (Fig. 6) as compared with PE.…”

Section: Mechanistic Analysismentioning

confidence: 95%

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Temperature‐dependent pyrolytic product evolution profile for polypropylene

Hujuri

Ghoshal

Gumma

2010

J of Applied Polymer Sci

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The composition of the pyrolysis products of plastics depends on disintegration of the macromolecule into variety of hydrocarbon fractions. In this work, a detailed gas chromatographic study of pyrolysis products of polypropylene (PP) between 200 and 600°C was carried out. The pyrograms have been analyzed in terms of amount of different products evolved at various pyrolysis temperatures. At low pyrolysis temperatures (200–300°C), the yield of lighter hydrocarbons (C5‐C10) is low; it gradually increases until maximum decomposition temperature (446°C) and decreases thereafter. The following reaction types were considered to explain the decomposition mechanism of PP: (a) main chain cleavage to form chain‐ terminus radicals; (b) intramolecular hydrogen transfer to generate internal radicals; (c) intermolecular hydrogen transfer to form both volatile products and radicals; and (d) β‐scission to form both volatiles and terminally unsaturated polymer chains. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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“…Thus, from a qualitative standpoint, the effect of molecular weight is similar to that of the polymer concentration; low molecular weights enable the development of different impact morphologies, while increasing the molecular weight progressively suppresses secondary atomization and breakup/splashing, until only the dry rebound regime can be observed. The similarity between the effects of the molecular weight and of the polymer concentration on the impact morphology is justified because both of these parameters affect the relaxation time of polymer solutions [21][22][23].…”

Section: Resultsmentioning

confidence: 99%

Dilute polymer solution drops impacting on heated surfaces: New impact morphologies and impact regime maps

Lakhanpal¹,

Bertola²

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The impact morphology of dilute polymer solution drops on a heated surface is studied experimentally by means of high-speed imaging, with respect to the following parameters: surface temperature; impact Weber number; polymer concentration; polymer molecular weight. In addition to impact morphologies observed in Newtonian drops (deposition, rebound, secondary atomisation and breakup/splashing), three new impact regimes have been identified: (i) a single satellite droplet ejected in the direction of bouncing but tethered to the main drop by a thin liquid filament; (ii) a splashing-like behaviour (semi-splashing), where the rim instability generates satellite droplets tethered to the lamella by thin liquid filaments; (iii) a spray-like behaviour (semi-spray), where a fine secondary atomisation generated upon impact is quickly absorbed back into the drop globule. Experiments were carried out using drops of aqueous polyethylene oxide (PEO) solutions, with mass concentrations of 100 ppm, 200 ppm and 400 ppm, and PEO molecular weights of 2 MDa, 4MDa, and 8MDa. The impact morphology on a polished aluminium surface with temperatures ranging between 160°C and 400°C was investigated for impact Weber numbers between 20 and 170, taking side view images of impacting drops at a rate of 1,000 frames per second. KeywordsDrop Impact; Heated Surfaces; Polymer Solutions; Impact Regime Map. IntroductionThe dynamics of liquid drops impinging on a heated surface is a phenomenon of interest in many areas of engineering, including spray cooling, inkjet printing for advanced manufacturing applications, quenching of alloys in the steel industry and nuclear reactor safety. Despite several decades of research, this phenomenon is understood only to a limited extent and requires further research; specifically, the development of impact regime maps (IRMs) is of practical interest because they provide a consolidated understanding of the impact behaviour and represent a tool of practical use in the design of nozzles, print heads, etc. A quantitative and comprehensive IRM also presents an important test case for the development and validation of theoretical models describing specific features, such as transitions between different impact regimes. Currently, an extensive body of literature on the behaviour of Newtonian drops impacting on heated surfaces exists. The first IRM produced [1] identified most of the impact regimes, however lacked clear quantitative description on the initiation and extent of these regimes. This work was soon followed by a detailed investigation that allowed production of three distinct IRMs corresponding to Weber numbers of 20, 60 and 220 and for surface temperatures ranging from 100° to 300°C [2]. Although this work included substantial information on the spreading behaviour of a drop and its heat transfer characteristics, the IRMs were far from being fully comprehensive, particularly lacking information on all possible impact regimes that can be realised as well as the transitional boundaries. This was partly ...

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Handbook of Engineering Polymeric Materials

Cited by 89 publications

References 0 publications

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

Temperature‐dependent pyrolytic product evolution profile for polypropylene

Dilute polymer solution drops impacting on heated surfaces: New impact morphologies and impact regime maps

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