Weather-resistant plant fiber-reinforced air duct with multi-layer wall, and preparation method thereof

A method for preparing a weather-resistant plant fiber-reinforced air duct with a multi-layer wall, wherein the method comprises any one of the following methods:

• method 1, comprising the following steps:
• mixing plant fibers with a toughened phenolic foam material at a mass ratio of (25-35):100, and then subjecting the mixture to a first emulsification to obtain a surface fiber foam material;
• mixing plant fibers with a toughened phenolic foam material at a mass ratio of (5-15):100, and then subjecting the mixture to a second emulsification to obtain a core fiber foam material;
• paving and laminating the surface fiber foam material and the core fiber foam material, and conducting closed-cell foaming to obtain a plant fiber-reinforced thermal insulation layer;
• with the method of paving and laminating, stacking an outer isolation layer, the plant fiber-reinforced thermal insulation layer, a moisture-proof layer and a sealing layer in sequence from bottom to top to obtain a wall material for the weather-resistant plant fiber-reinforced air duct with a multi-layer wall;
• and assembling the wall material for the weather-resistant plant fiber-reinforced air duct with a multi-layer wall into a square weather-resistant plant fiber-reinforced air duct with a multi-layer wall;
• wherein, during the stacking, a coupling agent, vinyl resin and a fiber-based plasticized adhesive are successively coated on the previous layer for the stacking of the next layer;
• and the square weather-resistant plant fiber-reinforced air duct with a multi-layer wall has the outer isolation layer as an inner wall and the sealing layer as an outer wall;
• or with the method of paving and laminating, stacking an outer isolation layer, the plant fiber-reinforced thermal insulation layer, a moisture-proof layer and a sealing layer on a cylindrical mold in sequence from inside to outside to obtain a circular weather-resistant plant fiber-reinforced air duct with a multi-layer wall;
• wherein, during the stacking, a coupling agent, vinyl resin and a fiber-based plasticized adhesive are successively coated on the previous layer for the stacking of the next layer;
• and
• method 2, comprising the following steps:
• wrapping an outer isolation layer around the core of an air duct mold;
• winding glass fibers impregnated with an epoxy resin system around the surface of the outer isolation layer to form a glass fiber-epoxy resin layer on the outer isolation layer;
• while glass fibers are wound without interruption, winding plant fibers impregnated with a toughened phenolic foam material around the glass fiber-epoxy resin layer to form a glass fiber-epoxy resin and plant fiber-phenolic resin composite layer;
• stopping the winding of glass fibers, winding plant fibers impregnated with a toughened phenolic foam material around the transition layer without interruption to form a plant fiber-phenolic resin layer, and conducting closed-cell foaming and finally to obtain a plant fiber-reinforced thermal insulation layer;
• wrapping a moisture-proof layer around the surface of the plant fiber-reinforced thermal insulation layer;
• and
• winding glass fibers impregnated with an epoxy resin system around the moisture-proof layer to form a sealing layer on the surface of the moisture-proof layer.