Fabrication of Aliphatic Water-Soluble Polyurethane Composites with Silane Treated CaCO3.

In the present study, composites of water-soluble polyurethane/calcium carbonate (CaCO3) were prepared from a soft segment of hydroxyl-terminated polybutadiene (HTPB) and polyethylene glycol (PEG, average molecular weight = 4000) with aliphatic diisocyanates. The functionality of CaCO3 particles was modified using aminopropyltriethoxysilane (APTES), and was confirmed by Fourier-transform infrared spectroscopy (FTIR). The solubility, hydrophilic properties, and chemical structures of the composites were analyzed by water-solubility tests, contact angle measurements, and FTIR, respectively, and the successful production of the hydrophilic water-soluble polyurethane (WSPU) structure was demonstrated. The adhesion of surface-modified CaCO3 particles to the WSPU matrix and the thermal degradation properties of the neat WSPU and WSPU/CaCO3 composites were studied using field emission scanning electron microscopy (FE-SEM) and thermogravimetric analysis (TGA). The results demonstrated good adhesion of the surface-modified CaCO3 particles along with an improved thermal degradation temperature with the addition of CaCO3 particles to the WSPU matrix.

Thermomechanical Properties of SiC-Filled Polybutylene Succinate Composite Fabricated via Melt Extrusion.

Polybutylene succinate (PBS) composites filled with various mass fractions of silicon carbide (SiC) particles were fabricated via slow melt extrusion. The morphological analysis revealed that the fabrication technique assisted in achieving a good adhesion between the PBS and SiC, along with excellent filler dispersion throughout the PBS matrix. The inclusion of 40 wt.% SiC in the PBS composite afforded a 10 °C increase in the thermal degradation temperature and a 160% enhancement in the thermal conductivity relative to the neat PBS. The crystallization temperature also increased with the inclusion of SiC particles, thus making the composites easier to process. Furthermore, the improvement in the Young's modulus of the PBS composites increased their rigidity and stiffness relative to the neat PBS.

A Study on the Thermal Conductivity of Poly(lactic acid)/Alumina Composites: The Effect of the Filler Treatment.

The excessive utilization of petroleum-based products has given rise to environmental concerns that have led to the shift in the research interest toward recyclable and biodegradable products. Polylactic acid (PLA), an aliphatic polyester that can be obtained from renewable sources, is used in a wide range of applications in different industrial sectors. This study demonstrates the change in the thermal conductivity of 30% alumina filled PLA after a hydrophobic surface modification was applied to the filler. Fourier transmission infrared and X-ray photoelectric spectroscopy results confirmed the successful modification of the alumina particles surfaces. The improvement in the interaction between the modified alumina and PLA matrix was revealed by examining the morphology micrograph obtained by field emission scanning electron microscopy. Since alumina is a highly thermally conductive material, the enhancement in the interfacial adhesion between the filler and matrix leads to an increase of 120% in the thermal conductivity of the PLA/Alumina composite compared to that of the neat PLA. In addition, the PLA/Alumina composite showed an increase in the storage modulus due to the high stiffness of alumina.

Thermal Conductivity and Mechanical Properties of Thermoplastic Polyurethane-/Silane-Modified Al2O3 Composite Fabricated via Melt Compounding.

The increase of miniaturization and rise of powerhouses has caused a need for high-performing thermal interface materials (TIMs) that can transfer heat in electronic packaging. In this study, a thermoplastic polyurethane (PU)/alumina composite was produced via twin extrusion and was suggested as a TIM. The surfaces of the alumina particles were modified by γ-aminopropyltriethoxysilane (APTES) and then evaluated using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) images revealed that the addition of surface-modified alumina was well adhered in the PU matrix. The tensile strength of the composite remained unchanged, while the Young's modulus showed improvement as compared to the pure PU. The elongation at the break decreased as the filler loading increased, due to the brittle behavior of the composite. The viscoelastic elastic property analysis results revealed that there was an increase in the storage modulus of the composite and the glass transition temperature curve shifted to the right. The thermal conductivity of the composite showed that there was an 80.6% improvement in thermal conductivity with the incorporation of 40% APTES-treated alumina particles.

Nonisothermal Crystallization of Surface-Treated Alumina and Aluminum Nitride-Filled Polylactic Acid Hybrid Composites.

This work investigates the nonisothermal crystallization and melting behavior of polylactic acid (PLA), filled with treated and untreated alumina and nano-aluminum nitride hybrid composites. Analysis by attenuated total reflectance Fourier transform infrared spectroscopy revealed that the treated fillers and the PLA matrix developed a good interaction. The crystallization and melting behaviors of the PLA hybrid composites were investigated using differential scanning calorimetry showed that the degree of crystallinity increased with the addition of hybrid fillers. Unlike the untreated PLA composites, the complete crystallization of the treated PLA hybrid composites hindered cold crystallization during the second heating cycle. The crystallization kinetics studied using the Avrami model indicated that the crystallization rate of PLA was affected by the inclusion of filler particles. X-ray diffraction analysis confirmed crystal formation with the incorporation of filler particles. The inclusion of nano-aluminum nitride (AlN) and the increase in the crystallinity led to an improvement of the storage modulus.

Surface Modification of Aluminum Nitride to Fabricate Thermally Conductive poly(Butylene Succinate) Nanocomposite.

Biodegradable polymers and their composites are considered promising materials for replacing conventional polymer plastics in various engineering fields. In this study, poly(butylene succinate) (PBS) composites filled with 5% aluminum nitride nanoparticles were successfully fabricated. The aluminum nitride nanoparticles were surface-modified to improve their interaction with the PBS matrix. Field-emission scanning electron microscopy revealed that the nanocomposites with surface-modified nanoparticles had better interface interaction and dispersion in the polymer matrix than those with untreated nanoparticles. The PBS/modified AlN nanocomposites exhibited maximal thermal conductivity enhancement, 63.7%, compared to the neat PBS. In addition, other thermomechanical properties of the PBS nanocomposites were investigated in this study. The nanocomposites also showed a superior storage modulus compared to the neat PBS matrix. In this work, a PBS nanocomposite with suitable thermal conductivity that can be used in various electronic fields was fabricated.