Shape memory epoxy nanocomposites with carbonaceous fillers and in‐situ generated silver nanoparticles

Abstract

Aim of this work is to develop a novel epoxy based nanocomposite and to analyse its shape memory behavior. In particular, silver nanoparticles are in‐situ generated within an epoxy resin subsequently filled with both carbon black (CB) and carbon nanofibers (NFs) at different ratios and at a total amount of 4 wt%. Differential scanning calorimetry shows how the introduction of both CB and NF induces a slight decrease of the glass transition temperature (Tg) of the samples. The Tg drop due to nanofiller addition determines a decrease of both flexural modulus and stress at yield with respect to the neat resin, especially at elevated CB concentrations, while the presence of Ag nanoparticles plays a positive effect on the flexural properties. The best mechanical properties can be detected at a CF/NF ratio of 50%, coupled with a noticeable decrease of the electrical resistivity down to 102 Ω·cm and an interesting heating capability through Joule effect. The electro‐mechanical shape‐memory characterization under bending configuration demonstrates how it is possible to obtain an almost complete shape recovery after 60 s under an applied voltage of 220 V. POLYM. ENG. SCI., 59:694–703, 2019. © 2018 Society of Plastics Engineers

Thermal Conductivity and Cure Kinetics of Epoxy-Boron Nitride Composites—A Review

“…Linec and Music [29] investigated the effects of the addition of silica of different shape, specific surface area and chemical structure, including crystalline and fused silica, in epoxy moulding compounds and found that T g remained almost constant. Dorigato and Pegoretti [30] introduced both carbon black (CB) and carbon nanofibers (NF) into an epoxy matrix with in situ generated silver nanoparticles and concluded that T g was "slightly reduced"; for example, for 4 wt.% nanofiller the reduction was about 5.5 • C for the CB nanofiller, but only about 2.6 • C for NF. In particular, these authors could not detect any clear trend of T g with the relative proportions of the two carbonaceous nanofillers, in agreement with their earlier observations with various other nanofilled thermosets.…”

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“…Cooling PLA under loads below T g strongly reduces its mobility, thereby fixing the imposed deformation. Finally, when the polymer is heated above T g , the switching domains progressively regain their mobility, and the material returns to its original condition [ 17 , 18 , 19 ].…”