Effect of polar interactions on the magnetorheology of silica-coated magnetite suspensions in oil media

Pacull, Julien; Gonçalves, Stephanie; Delgado, A.V.; Durán, J.D.G.; Jiménez, Marı ́a L.

doi:10.1016/j.jcis.2009.04.083

Cited by 26 publications

(15 citation statements)

References 20 publications

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“…All investigated SMPNCs contained the same type of silica coated magnetite nanoparticles (AdNano MagSilica 50, Degussa, Hanau, Germany) with a mean aggregate size of 90 nm, a mean domain size of 20-26 nm, and a magnetic domain content of 50-60 wt% [15,26]. The Magsilica nanoparticles are assumed as (super)-paramagnetic [27].…”

Section: Applied Shape-memory Polymer Nanocomposites (Smpncs)mentioning

confidence: 99%

Modeling the heat transfer in magneto-sensitive shape-memory polymer nanocomposites with dynamically changing surface area to volume ratios

Heuchel

Razzaq

Kratz

et al. 2015

Polymer

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Abstract:Magneto-sensitive shape-memory polymer nanocomposites (SMPNCs) enable non-contact actuation of a shape-memory effect (SME) by inductive heating in an alternating magnetic field (AMF). Hereby, the achievable temperature (T max ) at fixed magnetic field strength and frequency is depending on the amount and type of incorporated magnetic fillers as well as on surface area to volume (S/V) ratio of the test specimen.Here we present a heat transfer model for predicting T max of SMPNCs samples with different S/V ratios when exposed to an AMF. The obtained temperature difference between sample and surrounding in an AMF of constant magnetic field strength decreases at uni-axial deformation with the square root of the stretching ratio. The model was validated with magnetically heating experiments of two different SMPNC systems (comprising crystallizable or amorphous switching segments) containing the same magnetic nanoparticles, while the magnetic field strength (H) was varied from 7 to 27 kA·m -1 at a fixed frequency of 258 kHz.The experimentally achieved temperatures at deformations up to 50% could be predicted with an accuracy below 6%. Finally the model was applied in a principle design study of a device consisting of a rolled SMPNC stripe, which was stepwise opened by increasing H. The modeling approach might be helpful to predict the temperature profiles of SMPNCs which were heated by other mechanisms, e.g., radiofrequency or near IR.

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Section: Applied Shape-memory Polymer Nanocomposites (Smpncs)mentioning

confidence: 99%

Modeling the heat transfer in magneto-sensitive shape-memory polymer nanocomposites with dynamically changing surface area to volume ratios

Heuchel

Razzaq

Kratz

et al. 2015

Polymer

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“…Narendra Kumar et al -eXPRESS Polymer Letters Vol.6, No.1 (2012) [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] …”

Section: Recovery By Environmental Heatingmentioning

confidence: 99%

“…In the current study, we explored, whether the shape-memory properties of triple-shape nanocomposites achieved by thermal and indirectly by magnetical stimulation of SME could be adjusted by variation of the applied programming protocols. Magnetically-induced triple-shape nanocomposites, with different switching segment ratios and various nanoparticle contents (2.5, 5 and 10 wt%) were synthesized from crystallizable poly(!-caprolactone) diisocyanatoethyl methacrylate (PCLDIMA; M n = 8300 g!mol -1 , T m,PCL = 55°C), crystallizable poly(ethylene glycol) monomethyl ether monomethacrylate (PEGMA; M n = 1000 g!mol -1 , T m,PEG = 38°C) and silica coated magnetite nanoparticles (SNP), named CLEGC, [39,40] according to a procedure previously described in ref. [41].…”

mentioning

confidence: 99%

Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Kumar¹,

Kratz²,

Behl³

et al. 2012

Express Polym. Lett.

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Shape-memory polymers (SMP) and composites thereof belong to the class of actively moving polymers, which have the capability of storing one (dualshape) [1][2][3][4][5][6], two (triple-shape) [7][8][9][10][11][12][13] or multiple (multiple-shape) [14] stable temporary shapes and recover their original or other temporary shapes when exposed to an external stimulus. The field of SMP research has developed rapidly over the last years [6,[15][16][17][18][19][20][21][22][23][24][25] and it has become apparent that these functional polymers are motivating novel applications. Thermo-sensitive SMP contain physical or chemical network-points, which determine their original shape, while each temporary shape is fixed by switching domains associated to a thermal transition temperature T trans , that can be a glass transition (T g ) or a melting transition (T m ) [16,17]. The process for programming of a temporary shape is called 'shapememory creation procedure' (SMCP) and can be realized e.g. by deforming the material to an extension of ! m at T > T trans and cooling to T < T trans while keeping the deformation, which then is fixed temporarily by solidification of the related set of switching domains [26]. The recovery of the original shape is named shape-memory effect (SME), which is typically induced by increasing the environmental temperature (T env ) [3,5,27,28] Abstract. Thermo-sensitive shape-memory polymers (SMP), which are capable of memorizing two or more different shapes, have generated significant research and technological interest. A triple-shape effect (TSE) of SMP can be activated e.g. by increasing the environmental temperature (T env ), whereby two switching temperatures (T sw ) have to be exceeded to enable the subsequent shape changes from shape (A) to shape (B) and finally the original shape (C). In this work, we explored the thermally and magnetically initiated shape-memory properties of triple-shape nanocomposites with various compositions and particle contents using different shape-memory creation procedures (SMCP). The nanocomposites were prepared by the incorporation of magnetite nanoparticles into a multiphase polymer network matrix with grafted polymer network architecture containing crystallizable poly(ethylene glycol) (PEG) side chains and poly(!-caprolactone) (PCL) crosslinks named CLEGC. Excellent triple-shape properties were achieved for nanocomposites with high PEG weight fraction when two-step programming procedures were applied. In contrast, single-step programming resulted in dual-shape properties for all investigated materials as here the temporary shape (A) was predominantly fixed by PCL crystallites.

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“…Magnetorheological (MR) fluids generally consist of micron-sized magnetic particles dispersed in a non-magnetic fluid, such as mineral oil or silicone oil [1][2][3][4][5][6] . They have the unique ability to undergo a rapid and reversible change from a liquid-like to a solid-like state within milliseconds upon the application of an external magnetic field, showing dramatic and tunable transitions in rheological properties [7][8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

Magnetorheology of a Carbonyliron Microsphere Suspension with a Halloysite Additive and Its Damping Force Characteristics

Kwon

Hong

Phu

et al. 2015

Ind. Eng. Chem. Res.

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A carbonyl iron (CI)-based magnetorheological (MR) suspension was prepared with halloysite nanoclay particles as an additive. MR properties of the suspension were investigated using a rotational rheometer with a parallel plate geometry equipped with a magnetic field supply under a range of external magnetic field strengths. From sedimentation ratio test to assess the dispersion stability, the addition of halloysite particles to the CI suspension was found to improve the sedimentation problem. The MR fluids containing both pure CI and CI/halloysite were employed into a custom-designed MR damper, and their damping characteristics, such as damping force as a function of time, displacement and velocity, were examined experimentally because the vibration attenuation using mechanical damper systems is one of the main applications of the MR fluids. Under the same magnetic field strength, the damping characteristics of the two MR fluids were found to be related directly to their yield stresses.

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Effect of polar interactions on the magnetorheology of silica-coated magnetite suspensions in oil media

Cited by 26 publications

References 20 publications

Modeling the heat transfer in magneto-sensitive shape-memory polymer nanocomposites with dynamically changing surface area to volume ratios

Modeling the heat transfer in magneto-sensitive shape-memory polymer nanocomposites with dynamically changing surface area to volume ratios

Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Magnetorheology of a Carbonyliron Microsphere Suspension with a Halloysite Additive and Its Damping Force Characteristics

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