Structure and Manufacturing Method of Polymer Plant Fiber Composite Materials

Abstract

This invention relates to a polymeric plant fiber composite material structure and its manufacturing method. The composite material comprises a polymeric resin matrix and a plurality of modified plant fibers, which are dispersed in the polymeric resin matrix at a high filling ratio of 50 wt% to 90 wt%. A buffer layer is formed on the outer surface of each plant fiber. This buffer layer is composed of any or a combination of an acidic modifier, a catalytic promoter, an alkaline stabilizer, and a metal lubricant, and is located between the modified plant fiber and the polymeric resin matrix to achieve interfacial grafting, thermal stability, and improved flow. Through the synergistic effect of the above components, the processability and interfacial compatibility under high filling conditions can be effectively improved, allowing the composite material to maintain structural stability in a processing temperature range of 100°C to 260°C, avoiding plant fiber carbonization and melt fracture. This invention also provides a manufacturing method in which acidic modification, catalytic promotion, alkaline stabilization, and lubrication treatments are sequentially performed, followed by mixing with a polymeric resin and processing to form a composite material with excellent material properties and processing stability.

Claims

1. A polymeric plant fiber composite material structure, comprising: a polymeric resin matrix; and a plurality of modified plant fibers dispersed in the polymeric resin matrix, wherein the modified plant fibers account for 50 wt% to 90 wt% of the total weight of the composite material; wherein, A buffer layer is formed on the outer surface of each modified plant fiber. The buffer layer directly covers and bonds to the surface of the modified plant fiber and is located between the modified plant fiber and the polymer resin substrate. The buffer layer is composed of the following components: an acidic modifying component for reacting with the hydroxyl groups on the surface of the modified plant fiber; a catalytic promoting component for promoting interfacial grafting or cross-linking between the acidic modifying component and the polymer resin substrate; an alkaline stabilizing component for neutralizing acidic byproducts generated during high-temperature processing; and a metal lubricating component for reducing the melt viscosity in a highly filled state.

2. The polymeric plant fiber composite material structure as described in claim 1, wherein, The polymer resin substrate is selected from the group consisting of thermoplastic resins, engineering plastics and thermosetting resins; wherein the thermoplastic resins include polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS) and acrylonitrile-butadiene-styrene copolymer (ABS); the engineering plastics include polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET) and polyamide (PA); and the thermosetting resins include polyurethane (PU), epoxy resin and phenolic resin.

3. The polymeric plant fiber composite material structure as described in claim 1, wherein, The acidic modifier is selected from the group consisting of polycarboxylic acids, acid anhydrides, organic sulfonic acids, or mixtures thereof.

4. The polymeric plant fiber composite material structure as described in claim 1, wherein, The buffer layer further comprises a Lewis acid catalyst or a metal peroxide, wherein the Lewis acid catalyst is selected from the group consisting of halides or carboxylates of zinc, aluminum, iron or boron.

5. The polymeric plant fiber composite material structure as described in claim 1, wherein, The alkaline stabilizing component is selected from the group consisting of alkaline earth metal oxides, alkaline earth metal hydroxides, or organic amine compounds.

6. The polymeric plant fiber composite material structure as described in claim 1, wherein, The metal lubricating component contains reactive organic components that can react with the hydroxyl groups on the surface of plant fibers or form an interfacial lubricating layer. These components are selected from the group consisting of long-chain fatty acids with hydroxyl groups, acid anhydrides with unsaturated alkenyl substitutions, or combinations thereof.

7. The polymeric plant fiber composite material structure as described in claim 1, wherein, When the polymer resin substrate is thermosetting polyurethane (PU), the buffer layer can inhibit the foaming phenomenon caused by the side reaction between plant fibers and isocyanate, thereby improving the crosslinking density and structural compactness.

8. A method for manufacturing a polymeric plant fiber composite material structure, comprising the following steps: providing a plurality of plant fibers; acid modification treatment: contacting the plant fibers with an acidic modifier component, causing the acidic modifier component to react with the hydroxyl groups on the surface of the plant fibers to form a surface modified layer; adding a catalytic promoting component: adding a catalytic promoting component to cause an interfacial grafting or cross-linking reaction between the acidic modifier component and a polymeric resin matrix; adding an alkaline stabilizing component: adding an alkaline stabilizing component to neutralize acidic byproducts generated during the reaction and improve thermal stability; adding a metal lubricating component: adding a metal lubricating component to form a lubricating layer on the surface of the plant fibers to reduce melt viscosity, thereby forming modified plant fibers; mixing with a polymeric resin matrix: mixing the modified plant fibers with a polymeric resin matrix, such that the modified plant fibers are dispersed in the polymeric resin matrix at a concentration of 50 wt% to 90 wt%; molding: performing thermoforming or extrusion processing to form the polymeric plant fiber composite material structure.

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