The Effects of Silica-Based Fillers on the Properties of Epoxy Molding Compounds

Abstract

Global design and manufacturing of the materials with superb properties remain one of the greatest challenges on the market. The future progress is orientated towards researches into the material development for the production of composites of better mechanical properties to the existing materials. In the field of advanced composites, epoxy molding compounds (EMCs) have attained dominance among the common materials due to their excellent properties that can be altered by adding different fillers. One of the main fillers is often based on silicon dioxide (SiO2). The concept of this study was to evaluate the effects of the selected silica-based fillers on the thermal, rheological, and mechanical properties of EMCs. Various types of fillers with SiO2, including crystalline silica and fused silica, were experimentally studied to clarify the impact of filler on final product. Fillers with different shape (scanning electron microscope, SEM), along with different specific surface area (specific surface area analyzer, BET method) and different chemical structure, were tested to explore their modifications on the EMCs. The influence of the fillers on the compound materials was determined with the spiral flow length (spiral flow test, EMMI), glass transition temperature (differential scanning calorimetry, DSC), and the viscosity (Torque Rheometer) of the composites.

Thermal Conductivity and Cure Kinetics of Epoxy-Boron Nitride Composites—A Review

“…On the other hand, the following examples are representative of many (probably the majority of) reports which suggest that T g is essentially independent of the filler content in epoxy composites. Linec and Music [29] investigated the effects of the addition of silica of different shape, specific surface area and chemical structure, including crystalline and fused silica, in epoxy moulding compounds and found that T g remained almost constant. Dorigato and Pegoretti [30] introduced both carbon black (CB) and carbon nanofibers (NF) into an epoxy matrix with in situ generated silver nanoparticles and concluded that T g was "slightly reduced"; for example, for 4 wt.% nanofiller the reduction was about 5.5 • C for the CB nanofiller, but only about 2.6 • C for NF.…”

Influence of Filler Content and Filler Size on the Curing Kinetics of an Epoxy Resin

“…Thus, they are widely used as a reinforcement for the plastic industry. In addition, glass beads can be easily and uniformly dispersed throughout the plastic compound and produce smoother flowing compound than with irregular particles [9,10], which ensures that all parts of the electronics are covered with EMC and no short-shot happens even though the filler content is high. In order to improve the bonding between fillers and matrix, the surface of fillers is usually coated with some functional silane as a coupling agent.…”

Remarkable enhancement of thermal stability of epoxy resin through the incorporation of mesoporous silica micro-filler

“…The main exothermic transition appeared in the temperature range of approximately 150–220 °C, due to the addition reactions between the epoxy ring and amines of the hardener, side reactions such as etherification of hydroxyl groups and epoxy groups, homopolymerization of epoxy ring opening, and thermal decomposition of weak bonds, occurred in the high-temperature region [ 6 , 46 ]. These transitions became blunt followed by reduced height of the exothermic peak for epoxy composites than that in control epoxy, implying the affluence of initiation of curing reaction in the epoxy composites by silica particles bearing surface –OH groups [ 47 ]. The inflection point temperature of this exothermic peak was considered as T g [ 6 ].…”