Thermoconductive Thermosetting Composites Based on Boron Nitride Fillers and Thiol-Epoxy Matrices

Abstract

In this work, the effect of the addition of boron nitride (BN) fillers in a thiol-cycloaliphatic epoxy formulation has been investigated. Calorimetric studies put into evidence that the kinetics of the curing has been scarcely affected and that the addition of particles does not affect the final structure of the network. Rheologic studies have shown the increase in the viscoelastic properties on adding the filler and allow the percolation threshold to be calculated, which was found to be 35.5%. The use of BN agglomerates of bigger size increases notably the viscosity of the formulation. Glass transition temperatures are not affected by the filler added, but Young’s modulus and hardness have been notably enhanced. Thermal conductivity of the composites prepared shows a linear increase with the proportion of BN particle sheets added, reaching a maximum of 0.97 W/K·m. The addition of 80 μm agglomerates, allowed to increase this value until 1.75 W/K·m.

Study of the synergistic effect of boron nitride and carbon nanotubes in the improvement of thermal conductivity of epoxy composites

“…This seems to indicate that the hydroxyl and acid groups on the surface do not produce any improvement in the interaction. With the addition of 40 wt% of BN, the rigidity is much improved, more than twice that of neat material as observed in previous studies, as the result of the reinforcing role of the filler. The use of both CNTs and BN particles has a complementary effect on the rigidity of the samples, slightly increasing the value with the same trend as the composites with only CNTs as filler, which reach a maximum rigidity at 0.75 wt%.…”

“…Figure shows G ′ and G ″ as functions of ω for all the mixtures. It can be observed at which concentration G ′ is greater than G ″ at low frequencies (<1 rad s −1 ), a sign that the percolation threshold is surpassed . This transition, from liquid‐like behaviour ( G ″ > G ′) to solid‐like behaviour ( G ′ > G ″), is located between proportions of 0.10 and 0.25 wt% of CNTs.…”

“…It can be observed at which concentration G ′ is greater than G ′′ at low frequencies (<1 rad s −1 ), a sign that the percolation threshold is surpassed. 36,44 This transition, from liquid-like behaviour (G ′′ > G ′ ) to solid-like behaviour (G ′ > G ′′ ), is located between proportions of 0.10 and 0.25 wt% of CNTs. It must be considered that this behaviour is characteristic for this epoxy system with this type of particle, the dispersion method applied (sonication) and the temperature at which the mixtures were examined.…”

Effective Mechanical Properties and Thickness Determination of Boron Nitride Nanosheets Using Molecular Dynamics Simulation

“…While the mechanical strength of BNNS is not as high compared to that of its elemental counterpart—graphene [ 3 ], it possesses better thermal and oxidation resistance [ 4 ]. This makes BNNS an attractive alternative to graphene for applications under extreme conditions, such as nanocomposites [ 5 , 6 ], nanoelectronics [ 7 , 8 ], and nanoelectromechanical (NEMS) devices [ 9 , 10 ]. This creates a major initiative in investigating the mechanical strength of BNNS, which will provide valuable information for the design of next-generation BNNS-based nano-devices and components.…”

The Use of Click-Type Reactions in the Preparation of Thermosets

“…Thiol-epoxy curing based on renewable monomers like eugenol [70,71], phloroglucinol [72] or gallic acid [73] has also been recently reported. The thiol-epoxy reaction has been used in the preparation of polymer matrix in nanoclay [74] and boron nitride [75,76] composites. In the latter, the thermal conductivities achieved were higher than in amine-epoxy composites.…”