Preparation of polyvinylpyrrolidone water-based hybrid coating and its sizing treatment of recycled glass fiber

In order to effectively utilize recycled glass fiber, two polyvinylpyrrolidone water-based hybrid coatings were synthesized under acid catalysis and without adding catalyst using ethyl orthosilicate and coupling agent as precursors and polyvinylpyrrolidone as film-forming agent. The recycled glass fibers were sized separately using the prepared hybrid coatings. The results show that the surface roughness of the recycled glass fibers after the sizing treatment of the hybrid coatings prepared under acid-catalyzed conditions is greater compared with that of the hybrid coatings prepared under the condition of no added catalyst. The single-fiber tensile strengths of the recycled glass fibers after sizing treatment of the hybrid coatings prepared under acid-catalyzed conditions and conditions without added catalysts are (1322.68±98.5) MPa and (1093.84±53.8) MPa, which are increased by 39.8% and 15.6%, compared with the single-fiber tensile strengths of the recycled glass fibers. The interfacial properties of recycled glass fiber and epoxy resin were evaluated by the single fiber fragmentation method. The results show that the interfacial shear strengths of single fiber epoxy resin composites prepared from recycled glass fiber after hybrid coating sizing treatment under acid catalysis conditions and without adding catalysis conditions are 53.5 MPa and 35.7 MPa, respectively, which are 200.5% and 100.8% higher than those of single fiber epoxy resin composites of recycled glass fiber without sizing treatment. Aqueous hybrid coatings prepared under acid-catalyzed conditions are shown to be feasible for recycling glass fibers.