Hybridization of hexagonal boron nitride nanosheets and multilayer graphene: Enhanced thermal properties of epoxy composites

M. Wasim Akhtara,b*, Jong Seok Kimb, Muddassir Ali Memona, Muhammad Moazam Balocha

a Department of Metallurgy and Materials Engineering, Mehran University of Engineering & Technology, Jamshoro, Pakistan.b

School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju 54896, Republic of Korea..

Corresponding author: waseem.akhtar@faculty.muet.edu.pk

Supporting Information

Table S-1 : Physical properties of epoxy and curing agent

Specifications of chemicals

Epoxy Resin “Kukdo YD-128”

Specific Gravity (25 °C) 1.17

Viscosity (25 °C) [cps] 11,500-13,500

Epoxy Equivalent Weight EEW (g/eq) 184-190

Curing Agent (Hardener) “Aliphatic Amine modified Hardener KH-602”

Viscosity (cps at 25 °C) 50-250

Total Amine Value (mgKOH/g) 670-730

Use Level (phr) 25 (YD-128=186g/eq))

Table S-2 : Calculated activation energies at various conversions of the decomposition by Flynn–Wall–Ozawa method.

Conversion Neat-Epoxy H-BSG-Epoxyα Ea rb Ea rb

0.10 80.74 0.97838 89.19 0.99827

0.15 86.87 0.99484 96.31 0.99254

0.20 87.24 0.99927 99.16 0.99824

0.30 85.64 0.99758 97.45 0.98745

0.40 85.25 0.99756 100.48 0.98527

0.50 85.14 0.99642 107.44 0.99504

0.60 82.50 0.99248 123.67 0.99379

0.70 80.70 0.97867 146.0 0.98744

Average 84.26 107.46

a The unit of activation energy E is kJ/mol.b The correlation coefficient is represented by r.

Figure S-1 Survey spectra of GP-MLG and SM-BNNS

Figure S-2: (a) Specific heat capacity of MLG-Epoxy, BNNS-Epoxy and H-BSG-Epoxy; (b) Thermal diffusivity of MLG-Epoxy, BNNS-Epoxy and H-BSG-Epoxy; (c) Thermal conductivity of MLG-Epoxy, BNNS-Epoxy and H-BSG-Epoxy; (d) Enhancement in thermal conductivity as a function of filler content.

Figure S-3: Activation energy dependence on degree of curing reaction for neat epoxy and H-BSG epoxy composite. (Ozawa–Flynn–Wall model)

Figure S-4: TEM images of (a) non- functionalized multi-layer graphene (MLG) inset: SAED pattern of corresponding image (a); (b)HR-TEM image of (a); (c) – GPTMS functionalized multi-layer graphene (GP-MLG) ) inset: SAED pattern of corresponding image (c); (d)HR-TEM image of (c).