Effect of leaf fiber modification methods on mechanical and heat-insulating properties of leaf fiber cement-based composite materials

Using plant leaves as eco-friendly heat-insulating building materials, five poplar leaf modification methods were employed to improve the compatibility between leaf fibers and cement-based materials in composites. Mechanical properties, water absorption and heat-insulating properties of leaf fiber cement-based composite materials (LFCCM) containing unmodified and modified leaf fibers were analyzed. The results indicated that pure acrylic emulsion spray was the best fiber processing method in terms of mechanical properties of LFCCM, followed by sodium silicate solution spraying; water dipping was also recommended and the strength of LFCCM with lye fiber dipping performed the worst. The optimal fiber treatment method of improving thermal insulation properties of LFCCM was lye dipping, followed by pure acrylic polymer emulsion spraying and sodium silicate solution spraying had the worst performance. With a thermal conductivity < 0.250 W/(m.K), LFCCM is an ideal heat-insulating material. Overall, considering strength and thermal conductivity, pure acrylic polymer emulsion spraying is an optimal treatment method of leaf fibers.