LIGHTWEIGHT REINFORCED THERMOPLASTIC COMPOSITE FLAT SHEETS: WATER-RESISTANT BARRIER PROPERTY AND 3D PRINTABILITY

This paper outlines the production of a lightweight reinforced thermoplastic (LWRT) composite using glass fiber and polypropylene via a wet-laid process. A printable film or water-resistant barrier (WRB) material was laminated onto one surface of the LWRT core, and the composite was then consolidated using calender rolls. This resulted in an LWRT flat sheet or a WRB board with tunable water vapor and liquid water barrier properties. The flat sheets were tested for physical (areal density, ash %, density, and surface energy), mechanical (flexural, flatwise tensile, and film/core adhesion), flame retardancy (FR), water vapor transmission, water resistance, and acoustic properties. Flat sheets with printable film achieved ASTM E84 Class A FR performance, with strong film/core adhesion (> 12 N) and robust Z-direction strength (peak load > 900N). WRB boards demonstrated good adhesion between the WRB material and composite core, with cohesive failure within the WRB during tests. The printable LWRT panel also showed excellent printability and ink adhesion in a digital 3D printing process. The WRB board was water vapor permeable but water impermeable. These LWRT panels have potential applications in recreational vehicles and general building and construction, including use as sidewalls, ceilings, roofing, and sheathing in shear walls.