The effect of nano- and micron-scale filler modified epoxy matrix on glass-fiber reinforced polymer insulator component behavior

Abstract

Glass-fiber reinforced polymer (GFRP) composite rods with epoxy matrix filled with electrically nonconducting particles find widespread use in high-voltage electrical insulator applications. The service loads require a range of different, minimum material property values, e.g. toughness, tensile, or compressive strength, but also component-specific performance, e.g. pull-out friction of surface crimped metal fittings or electric breakdown strength. The contribution discusses selected examples of the effects of different particle filler types on the properties of filled epoxy resin as well as on the behavior of GFRP rods with such a matrix. In all investigated systems CaCO3 was used as micron-sized filler, complemented by different amounts of either nanosilica or core-shell rubber (binary filler), or by both, nanosilica and core-shell rubber (ternary filler). With ternary filler combinations at a content of 36 wt%, fracture toughness GIC was improved in nanocomposite epoxy plates and in GFRP rods by 60% and 100%, respectively compared to a matrix with 20 wt% CaCO3 (used as reference system). The glass transition temperature Tg for some ternary systems dropped from 160 °C (for neat epoxy), to approximately 140 °C, the maximum allowed drop in Tg in view of requirements from further processing steps of the electrically insulating components. The ternary fillers yield transfer of the improvements of fracture properties from epoxy nanocomposite plates into the GFRP rods beyond that of the system with CaCO3 filler only. Compressive strength of the GFRP rods was improved by about 20% only for the binary nanosilica and CaCO3 filler, and was not significantly enhanced with the ternary systems. That combination, however, did not yield improvements in toughness beyond the CaCO3-filled nanocomposite plates and rods. With the range of filler types and contents investigated here, it was hence not possible to simultaneously optimize both, fracture toughness and compressive strength of the GFRP insulator rods.

In-Service Delaminations in FRP Structures under Operational Loading Conditions: Are Current Fracture Testing and Analysis on Coupons Sufficient for Capturing the Essential Effects for Reliable Predictions?

“…For GFRP composites with nano-and micro-size-filler-modified epoxy matrix, there is evidence that improving fracture toughness or delamination resistance by adding nanoand micro-scale particles to the epoxy matrix results in the degradation of another property, the compressive strength. Both properties could not be improved simultaneously with the same particle modification of the matrix [112], again indicating the complexity of potential synergistic effects. In view of observed synergistic effects in controlled laboratory tests that improve or degrade the delamination resistance performance of CFRP composites, it seems quite challenging to identify all potential synergistic effects in realistic service environments.…”

A Review on Basalt Fiber Composites and Their Applications in Clean Energy Sector and Power Grids

“…An insulating pull rod is one of the important components of an SF 6 insulated circuit breaker, which mainly plays the role of supporting, transmitting forces, controlling line on-off switching, and insulating. Due to the frequent opening and closing times of circuit breakers, the insulating pull rod is required to have not only high insulation and mechanical properties but also strong fatigue resistance [73]. Insulating pull rods were first formed by curing epoxy-resin-impregnated GF, but these had the disadvantages of high weights, brittleness, and lack of wear resistance.…”

Optimization of Technological Parameters of the Process of Forming Therapeutic Biopolymer Nanofilled Films

“…Many studies are devoted to the development of the composition of nanofilled polymer materials [ 44 ] and coatings [ 45 , 46 , 47 ], their application in various fields of technology [ 48 ], and the reuse of polymers after processing [ 49 , 50 , 51 ]. For the rational choice of the composition of nano-containing polymer materials and technological modes of their manufacture [ 52 , 53 ], tests were performed under different types of loads [ 54 ].…”