Effects of added SiO₂ nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposites

Abstract

In this study, a unit cell–based micromechanical approach is proposed to analyze the coefficient of thermal expansion of shape memory polymer nanocomposites containing SiO2 nanoparticles. The interphase region created due to the interaction between the SiO2 nanoparticles and shape memory polymer is modeled as the third phase in the nanocomposite representative volume element. The influences of the temperature, volume fraction, and diameter of the SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposite are explored. It is observed that the coefficient of thermal expansion of shape memory polymer nanocomposite decreases with the increase in the volume fraction up to 12%. Also, the results reveal that with the increase in temperature, the shape memory polymer nanocomposite coefficient of thermal expansion linearly increases. The role of interphase region on the thermal expansion response of the shape memory polymer nanocomposite is found to be very important. In the presence of interphase, the reduction in nanoparticle diameter leads to lower coefficient of thermal expansion for shape memory polymer nanocomposite, while the variation of nanoparticles diameter does not affect the coefficient of thermal expansion in the absence of interphase. Based on the simulation results, the shape memory polymer nanocomposite coefficient of thermal expansion decreases as the interphase thickness increases. In addition, the contribution of interphase coefficient of thermal expansion to the shape memory polymer nanocomposite coefficient of thermal expansion is more significant than that of interphase elastic modulus.

Non-Linearity of Thermosetting Polymers’ and GRPs’ Thermal Expanding: Experimental Study and Modeling

“…However, these models are not realized in the non-linearity of polymers’ and composites’ thermal expanding. It is accurate that the inclusion of components with less CTE (mineral additive, graphene tubes, glass, and basalt fibers) results in less CTE of the composite [ 19 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Thus, the greater the linear thermal expansion contribution of the components characterized by the coefficient of linear thermal expansion (CTE), the greater the linearity of the thermal expansion of the composites.…”

Hydrocarbon Resin-Based Composites with Low Thermal Expansion Coefficient and Dielectric Loss for High-Frequency Copper Clad Laminates

“…Conversely, materials with CTE close to that of copper foil have excellent dimensional stability. In previous works, three main ways to reduce the CTE of substrate materials were proposed: firstly, the addition of an inorganic filler with low (such as SiO 2, carbon nanotubes) [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] or negative (such as Hafnium pyrovanadate) CTE [ 28 , 29 ] into the organic matrix; secondly, the addition of a low-CTE organic monomer (such as an alkoxysilyl-functionalized resin) or a negative-CTE organic monomer (such as dibenzocyclooctane) or the use of a resin with a low CTE (such as cyanate ester resin) [ 30 , 31 , 32 , 33 ]; finally, the interpenetration of the network structure by combining a ceramic skeleton with organic matter (such as Al 2 W 3 O 12 ) [ 34 , 35 ]. However, the CTE is not the only factor that should be considered, and other key indicators such as D k and D f should be taken into account either.…”

The Classification of the Stress-Strain Curve Zones on the Basis of their Validity to Study the Shape Memory Effect (SME) Property

“…The shape memory materials are a class of the smart materials which have the ability to return from the fixity temporary shape to the permanent original shape at any point of time by applying the right stimulus to them [1], this is known as the shape memory effect (SME). As examples for this type of smart materials: shape memory polymers (SMPs), shape memory alloys (SMAs), and Shape memory ceramics (SMCs) [2].…”

“…The second step: Retaining (storage) or fixation the deformation (strain) which is called after the fixation process of the fixed temporary shape as one of the following ways [2][ 8] [9][10]:…”