Long-carbon-fiber-reinforced nylon composite material with electromagnetic shielding function and preparation method thereof

Abstract

The invention discloses a long-carbon-fiber-reinforced nylon composite material with electromagnetic shielding function and a preparation method thereof. The composite material is composed of the following components in percentage by mass: 40-80 wt.% of nylon resin, 20-45 wt.% of long carbon fiber, 2-8 wt.% of alloy powder, 2-10 wt.% of maleic anhydride grafted low-density polyethylene (LDPE-g-MAH) and 0.1-2 wt.% of antioxidant. The preparation method of the composite material comprises the following steps: proportionally and uniformly mixing the nylon, alloy powder, LDPE-g-MAH and antioxidant, carrying came out melt blending on a double screw extruder, and directly extruding the melt into a dipping mold; sending the fiber bundle subjected to surface treatment into the cavity of the dipping mold under the action of tension to sufficiently dip the melt; and pulling the dipped fiber bundle out of the mold, cooling, and granulating to obtain the strip-shaped granules of which the length is 10+/-0.2mm. The composite material disclosed by the invention has the specific function of shielding high/low-frequency electromagnetic waves, and has excellent mechanical properties which are peculiar to long-fiber-reinforced plastics.

Description

technical field [0001] The invention relates to a long fiber reinforced nylon composite material, in particular to a long carbon fiber reinforced nylon composite material with electromagnetic shielding function and a preparation method thereof; the invention belongs to the field of composite material processing and preparation. The nylon composite material prepared by the invention not only has relatively high mechanical properties, but also has a full-band electromagnetic wave shielding function, and is suitable for the manufacture of structures and parts in the field of electronics and electricity. Background technique: [0002] Polyamide (PA), commonly known as nylon, contains polar amide groups capable of forming hydrogen bonds. Nylon resin has excellent mechanical properties, heat resistance, electrical insulation, etc., and is widely used in industry. But at the same time, nylon also has disadvantages such as poor dimensional stability and high water absorption. In so...

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Problems solved by technology

Chinese patent CN102888091A adds alloy powder to nylon to prepare a conductive nylon material with electromagnetic shielding function. Although its electromagnetic shielding function is excellent, the mechanical properties of nylon are reduced by the single addition of metal powder, which is far from meeting the requirements of certain fields, and Metal powder is easy to fall off from the matrix, which greatly affects its performance; Chinese patent CN102344674A uses glass fiber and conductive graphite as the main filler to prepare electromagnetic shielding nylon 6 through salt formation reaction, but the process is complicated and difficult to control

U.S. Patent US7022265 prepares enhanced nylon with electromagnetic shielding function by adding carbon fiber, graphite, zinc oxide whisker, aramid fiber, and thermoplastic polyphenol. Chinese patent CN101717577A prepares electromagnetic shielding nylon 66 by adding three conductive materials: carbon fiber, conductive graphite, and metal fiber. , Chinese patent CN102690514A prepares electromagnetic shielding nylon 610 composite materials by adding carbon fibers, but all of them are prepared by traditional extrusion granulation process, the damage to the fibers is relatively large during processing, and the fiber retention length is short, which not only cannot maximize the reinforcement effect , the electrical conductivity of the composite material is also relatively poor, which also has a certain impact on its electromagnetic shielding function, thus limiting its application in structural materials

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