ANALYSIS OF THE PHYSICAL AND MECHANICAL PROPERTIES OF A FIBREGLASS COMPOSITE PIPE WITH BINDER MODIFIED BY PLASTICIZERS

This paper considers an approach to improving the service performance of fiberglass composite pipelines under seismic conditions by modifying the thermosetting binder with plasticizing and toughening additives aimed at increasing fracture toughness and reducing the material’s tendency to brittle failure under alternating-sign and impulse actions. The relevance of the study is driven by the fact that conventional pipeline materials (steel, reinforced concrete) have significant limitations when operated in seismically hazardous regions, whereas fiberglass reinforced plastics manufactured by continuous filament winding are characterized by high specific strength, corrosion resistance, and durability, but often demonstrate linear-elastic behavior up to failure. The object of the study was fiberglass composite pipes with a three-layer wall (surface, structurally reinforced, and liner layers). The following binder modifiers were considered: Polyplex; a modifier produced by JSC “Poliplast” (PoliPlast M); and a powder impact modifier of the “core–shell” type Clearstrength® XT100, introduced in different mass percentages. For each formulation, a series of repeated measurements was performed to ensure comparability and statistical evaluation of the results. The experimental program included determination of the initial specific ring stiffness and resistance to initial ring deflection, the initial hoop tensile strength and tensile modulus, the initial axial tensile strength and tensile modulus, as well as Charpy impact toughness in accordance with the applicable standards. Based on the combined indicators, the necessity for multi-criteria selection of binder composition is discussed, enabling preservation of the design stiffness–strength characteristics while improving the dynamic resistance of the material.