Synthesis of Silicone Elastomers Containing Silyl-Based Polymer-Grafted Carbonyl Iron Particles: An Efficient Way To Improve Magnetorheological, Damping, and Sensing Performances

High temperatures and humidity could alter the field-dependent rheological properties of MR materials. These environmental phenomena may accelerate the deterioration processes that will affect the long-term rheological reliability of MR materials such as MR elastomer (MRE). This study therefore attempts to investigate the field-dependent rheological characteristics of MRE with corroded carbonyl iron particles (CIPs). The corroded CIPs were treated with hydrochloric acid (HCl) as a way of providing realistic environments in gauging the CIPs reaction towards the ambient conditions. The corroded CIPs along with silicone rubber as a matrix material were used in the fabrication of the MRE samples. To observe the effect of HCl treatment on the CIPs, the morphological observations of MREs with non-corroded and corroded CIPs were investigated via field emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometer (XRD). In addition, the magnetic properties were examined through the vibrating sample magnetometer (VSM), while the field-dependent rheological characteristics such as the storage modulus of MRE with the corroded CIPs were also tested and compared with the non-corroded CIPs. The results showed that the corroded CIPs possessed hydrangea-like structures. In the meantime, it was identified that a sudden reduction of up to 114% of the field-dependent MR effect of MRE with the corroded CIPs was observed as a result of the weakened interfacial bonding between the CIPs and the silicon in the outer layers of the CIPs structure.

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Encapsulation of Carbonyl Iron Particles with Poly(Vinyl Butyral) and their Magnetorheology

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.334-335.193 ◽

2007 ◽

Vol 334-335 ◽

pp. 193-196

Author(s):

Jae Lim You ◽

B.J. Park ◽

I.B. Jang ◽

Hyoung Jin Choi

Keyword(s):

Magnetic Field ◽

Carbonyl Iron ◽

Magnetic Particles ◽

Mineral Oil ◽

Iron Particles ◽

Carrier Liquid ◽

Mr Fluids ◽

Fluid Systems ◽

Ft Ir ◽

Vinyl Butyral

To enhance dispersion stability of magnetorheological (MR) fluids, hybrid magnetic particles of carbonyl iron (CI)/ poly(vinyl butyral) (PVB) with core/shell microstrcutre (CI-PVB) were prepared, since pure magnetic CI based MR fluid systems show severe sedimentation of the CI particles due to the large density mismatch with the carrier liquid and difficulties in redispersion after caking. The composite particles of CI-PVB have a lower density than that of the pure CI particles, while exhibiting almost original magnetic property of the CI. Both CI and CI-PVB particles were dispersed in mineral oil (20 vol%) and their MR characteristics were examined via a rotational rheometer with a magnetic field supplier. Various characterizations of the CI-PVB particles were performed via SEM, TEM and FT-IR. Both yield stress and flow curve of shear stress as a function of shear rate of the MR fluids were investigated under applied magnetic field strengths.

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Performance of Magnetorheological Elastomer Based Silicone/SAIB

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.772.61 ◽

2018 ◽

Vol 772 ◽

pp. 61-65

Author(s):

Muntaz Hana Ahmad Khairi ◽

Saiful Amri Mazlan ◽

Ubaidillah ◽

Siti Aishah Abdul Aziz ◽

Norhiwani Mohd Hapipi

Keyword(s):

Rheological Properties ◽

Silicone Rubber ◽

Carbonyl Iron ◽

Excitation Frequency ◽

Rubber Matrix ◽

Iron Particles ◽

Magnetorheological Elastomer ◽

Magnetorheological Elastomers ◽

Mr Effect ◽

Strain Dependent

This study introduces a sucrose acetate isobutyrate (SAIB) as an additive of magnetorheological elastomers (MREs) to be added in silicone rubber matrix and carbonyl iron particles (CIPs) as their filler. The CIPs were fixed at 60 wt% and two types of MREs sample were fabricated which are isotropic and anisotropic. Rheological properties related to shear storage modulus were measured using a rheometer (MCR 302, Anton Paar). The experimental results demonstrated that the magnetorheological (MR) effect of anisotropic MREs-based Silicone/SAIB was 126 % as compared to isotropic MREs-based Silicone/SAIB, 64%. The fabricated MREs samples were frequency and strain dependent. The relative MR effect for both samples showed decreasing trend with the increment of strain amplitude and excitation frequency.

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