Preparation of Polyurethane Acrylate Coated Carbon Nanotube Nanocomposites by Emulsion Polymerization

Abstract

The aim of this work was to prepare strong and conductive polyurethane acrylate nanocomposites. First, urethane prepolymers with different molecular weights and hydrophilicities were synthetized. Then, their corresponding polyurethane acrylate nanocomposites were prepared by ultrasonically-assisted emulsion polymerization in the presence of various ratios of urethane prepolymers and acrylate monomers. Thermogravimetric analysis (TGA) and tensile results showed that thermal stability and mechanical properties of polyurethane acrylate samples are significantly dependent on the molecular weight and hydrophilicity of the urethane prepolymer as well as the content of acrylate monomers. Polyurethane acrylate sample (i.e., PUAc-2B50) with optimum mechanical properties and thermal stability were chosen as matrix to prepare nanocomposites in the presence of nanotubes grafted with polymerizable acrylate groups (G-MWNTs). Transmission electron microscope (TEM) revealed that the surface of nanotubes is uniformly coated with polymer nanoparticles. The nanocomposites containing 3 wt% G-MWNTs demonstrated a great modulus up to 374 MPa and excellent strength up to 18.74 MPa. Meanwhile, they indicated remarkable high electrical and thermal conductivities; as the electrical conductivity of the nanocomposites increased by more than twelve orders of magnitude, and thermal conductivity reached to 12.5 times of the neat matrix. The developed nanocomposites hold high potential for diverse applications, such as printable electronic devices, nano-sensors, and heat/electrical induced shape memory polymers.

Effect of Tetrafluorethane and Sulfur Hexafluoride Plasma Treatment on Wettability of Boron Nitride Nano-Sheets

“…Boron nitride (BN) nanostructures are boron nitride (BN) based materials consisting of stacked hexagonal BN layers that are assembled in sheets or tubes (case of BN nano-sheets or BN nanotubes, respectively) with high aspect ratio [1][2][3][4]. These low-dimensional nanostructures are structurally identical to graphene or carbon nanotubes (CNTs) [5,6], and exhibit many fascinating properties for advanced applications [1][2][3][4][5][6][7][8][9]. However, in contrast to graphene or CNTs, which are conductor or semiconductors, BN nanostructures are electrically insulator [5,6].…”

“…These low-dimensional nanostructures are structurally identical to graphene or carbon nanotubes (CNTs) [5,6], and exhibit many fascinating properties for advanced applications [1][2][3][4][5][6][7][8][9]. However, in contrast to graphene or CNTs, which are conductor or semiconductors, BN nanostructures are electrically insulator [5,6]. This makes them a hot research topic in different applications including dielectric substrates, far-ultraviolet light-emitting, high performance electronic devices and smart coating [1][2][3][4][5][6][7][8][9].…”

“…However, in contrast to graphene or CNTs, which are conductor or semiconductors, BN nanostructures are electrically insulator [5,6]. This makes them a hot research topic in different applications including dielectric substrates, far-ultraviolet light-emitting, high performance electronic devices and smart coating [1][2][3][4][5][6][7][8][9]. Concerning smart coating, and except for some BN nanotubes which are super-hydrophobic [10,11], the other BN nanostructures including nano-sheets [12][13][14], and few atomic layers [15], have shown a good hydrophobicity character (with contact angle (CA) around 100-120 • ).…”