Preparation and characterization of polymer composites containing boron compounds

Topçuoğlu, Elif
Epoxy (EP) is a thermosetting polymer which has high dimensional stability. However, the brittleness, low resistance to impact failure and flammability are some limitations of the epoxy polymer. These properties limit the usage of epoxy in the applications where high mechanical strength and flame retardancy properties are needed. The purposes of this study are to improve both mechanical and flame retardancy properties of epoxy by the addition of boron containing compounds (BCC) mainly boron carbide (B4C), and to characterize the prepared composites in terms of their mechanical, flame retardancy, thermal, electrical properties and morphologies. In this study, as-received boron carbide particles were first characterized in terms of their structural, thermal, electrical properties and morphologies. X-Ray Diffraction (XRD) analysis revealed the presence of B4C. Scanning Electron Microscopy (SEM) showed that the particles are irregular in shape and with the size of 3-8 microns. Epoxy composites containing 0.5, 1, 3, 5 and 8% boron carbide were characterized using Fourier Transform Infrared Spectroscopy (FTIR), tensile and impact tests, Limiting Oxygen Index (LOI), and UL-94 tests, Differential Scanning Calorimetry (DSC) analysis, Thermal Gravimetric Analysis (TGA) and two point probe electrical resistivity measurements. It was determined that epoxy-based composites containing 3% B4C had 44 MPa tensile strength, 13.4 kJ/m2 impact strength and LOI value of 23%. The properties of the epoxy-based composites containing BCC such as zinc borate (ZnB), boric acid (BA), calcium borate (CaB) and melamine phosphate (MP) were investigated using the same characterization techniques. Among all the composites of the study, EP/10MP/3B4C composite exhibited the highest flame retardancy property with a LOI value of 27.5% and V-0 rating in UL-94 test. Impact strength of EP/3B4C composite (13.4 kJ/m2) was found to be higher than that of the neat epoxy (11.1 kJ/m2) and EP/10MP/3B4C composite (6.4 kJ/m2).
Citation Formats
E. Topçuoğlu, “Preparation and characterization of polymer composites containing boron compounds,” M.S. - Master of Science, Middle East Technical University, 2016.