Dynamics and Breakup of Viscoelastic Liquids (A Review)

Рожков, А. Н.

doi:10.1007/s10697-006-0001-7

Cited by 24 publications

(10 citation statements)

References 69 publications

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“…Controlling the dynamics and breakup of thermal inkjet drop formation of lowviscosity liquid by means of small amounts of polymeric additives were investigated. [18][19][20] Dilute solutions of polyacrylamide in a water-glycerin (50/50) mixture were used in the study. Depending on polymer molecular weight and concentration, three variants of behavior were observed: (1) the jet tail fragmented into several secondary drops; (2) the entire tail flowed into the leading drop without loss, forming a single drop; and (3) the drop ejected from the nozzle returned to the nozzle under the action of elastic internal stresses in the tail.…”

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confidence: 99%

Drop-on-demand drop formation of polyethylene oxide solutions

2011

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The dynamics of drop-on-demand (DOD) drop formation for solutions containing polyethylene oxide (PEO) have been studied experimentally. Using a piezoelectrical actuated inkjet printhead with the nozzle orifice diameter of 53 lm, experiments were conducted for a series of PEO aqueous solutions with molecular weights ranging from 14 to 1000 kg/mol, polydispersity from 1.02 to 2.5, and concentrations from 0.005 to 10 wt. %. The addition of a small amount of PEO can have a significant effect on the DOD drop formation process, increasing breakup time, decreasing primary drop speed, and decreasing the number of satellite drops in some cases. The effects depend on both molecular weight and concentration. At lower molecular weights (14 and 35 kg/mol), the effect of PEO over the dilute solution regime is insignificant even at concentrations large enough that the solution does not fall in the dilute regime. As PEO molecular weight increased, the effects became significant. For monodispersed PEO solutions, breakup time and primary drop speed closely correlated with effective relaxation time but not for polydispersed PEO. Effective relaxation time depended greatly on molecular weight distribution. Viscosity-average molecular weight, used in calculating effective relaxation time for polydispersed PEO solutions, did not adequately account for high molecular fractions in the molecular weight distribution of the polydispersed PEOs. A mixture rule was developed to calculate the effective relaxation times for aqueous solutions containing mixtures of monodispersed PEO, and breakup times and primary drop speeds correlated well with effective relaxation times. For our experiments, DOD drop formation was limited to Deborah number .

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confidence: 99%

Drop-on-demand drop formation of polyethylene oxide solutions

2011

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“…[112] Another implication of the frictional loading theory is that there must be a critical strain rate for chain scission to occur, in line with the previously discussed experimental results. The critical strain rate (̇) is found to scale with molecular weight according to Equation (12). [109] In the case of QSSF the exponent (k) has a value of 2 as can be inferred from Equation (11).…”

Section: Mechanical Degradation Of Polymers -18 -mentioning

confidence: 97%

“…[10,11] The enhanced extensional viscosity (or elasticity) of polymer solutions is believed to cause the larger drop size. [12] Increases in other rheological properties such as dynamic surface tension, [3,13] and to a lesser extent static surface tension and zero shear rate viscosity have also been reported to increase spray drop size. [14][15][16] There currently exist an extensive range of commercial drift control adjuvants (DCAs), a selection of which is presented in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Polymeric Drift Control Adjuvants for Agricultural Spraying

Lewis

Evans

Malic

et al. 2016

Macro Chemistry & Physics

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---------The movement of a pesticide or herbicide to an off-target site during agricultural spraying can cause injury to wildlife, plants and contamination of surface water. This phenomenon is known as spray drift and can be controlled by spraying during favorable environmental conditions, and by using low drift nozzles and drift control adjuvants (DCAs). Polymeric DCAs are the most common type of DCA and function by increasing the droplet size produced during spraying. There are, however, two main drawbacks of polymeric DCAs; they are prone to mechanical degradation during spraying which reduces their performance and they can produce oversized drops which reduces the efficacy of the spray. In this review, existing DCA technology is reviewed including the mechanism through which they function.This then provides a platform for the discussion of novel polymeric architectures which have currently not been applied in DCA formulations.-2 -

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“…12,13,15,16 The behavior of viscoelastic fluids under these conditions has received rather less attention. 14,17,18 A fuller discussion of previous relevant work is available from these references; it is the purpose of the present paper to focus on the possibility that the observation of periodic atomization patterns produced by the oblique collision of two viscoelastic liquid jets, i.e., the fishbone patterns, might be used to access rheological information which is relevant to the behavior of the same polymer-containing fluid when it is jetted from a piezoelectric drop-on-demand printhead.…”

Section: Introductionmentioning

confidence: 99%

A New Method to Assess the Jetting Behavior of Drop-on-Demand Ink Jet Fluids

Jung¹,

Hoath²,

Martin³

et al. 2011

jist

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We present a new experimental method to assess the jetting performance of fluids for use in drop-on-demand (DoD) ink jet printheads. The oblique collision of two continuous liquid jets leads to the formation of a thin oval liquid sheet bounded by a thicker rim which disintegrates into ligaments and droplets. Under certain conditions the flow structure exhibits a remarkably symmetrical "fishbone" pattern composed of a regular succession of longitudinal ligaments and droplets. For a series of model elastic fluids containing polystyrene (PS) in diethyl phthalate (DEP), and also for solutions of polyethylene oxide (PEO) in glycerol/water, ejected from nozzles with an internal diameter of 0.85 mm, the shape of the fishbone pattern varies strongly with polymer concentration. The same fluids were also used in a Xaar piezoelectric DoD print head to characterize their jetting performance in terms of the maximum ligament length, a crucial parameter in determining the printability of the fluid. There are close similarities between the ligament collapse behaviors in both experiments. Good correlation was found between the maximum included angle of the fishbone pattern and the maximum ligament length in the jetting experiments, which suggests that a test based on oblique impinging jets may be useful in the development of fluids for ink jet printing.

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Dynamics and Breakup of Viscoelastic Liquids (A Review)

Cited by 24 publications

References 69 publications

Drop-on-demand drop formation of polyethylene oxide solutions

Drop-on-demand drop formation of polyethylene oxide solutions

Polymeric Drift Control Adjuvants for Agricultural Spraying

A New Method to Assess the Jetting Behavior of Drop-on-Demand Ink Jet Fluids

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