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CN-122011555-A - Natural bamboo fiber modified PE composite material and preparation method thereof

CN122011555ACN 122011555 ACN122011555 ACN 122011555ACN-122011555-A

Abstract

The invention relates to a natural bamboo fiber modified PE composite material and a preparation method thereof, belonging to the technical field of composite materials. The composite material comprises a mPE matrix and bamboo fibers treated by a special modified silane coupling agent, wherein the modified silane coupling agent constructs a structure containing long-chain alkyl and branched thioether quaternary ammonium salt on the surfaces of the bamboo fibers, the structure can be fully entangled with mPE, a branched chain of the structure can be used as a template to induce the mPE to form heterogeneous crystallization anchoring at an interface, the thioether bond provides flexible toughening, and the quaternary ammonium salt enhances grafting on the surfaces of the fibers through electrostatic action and endows an anti-corrosion function. The invention obviously enhances the interface combination of the fiber and the mPE, so that the composite material has excellent impact resistance and bending fatigue resistance, can keep high glossiness and high glossiness retention rate after bending, and is particularly suitable for high-end appearance decorative materials.

Inventors

  • LING LEXU
  • YE HUICONG
  • ZHANG RONGCHANG
  • XIE FEI
  • MU DEPING
  • XIE XINGYUN
  • LIANG JIANCHENG

Assignees

  • 江西旭联新材料有限责任公司

Dates

Publication Date
20260512
Application Date
20260319

Claims (7)

  1. 1. The natural bamboo fiber modified PE composite material is characterized by comprising, by weight, 30-45% of modified bamboo fibers, 0.9-1.4% of lubricants, 0.1-0.13% of antioxidants and the balance of mPE resin; The modified bamboo fiber is prepared by coupling natural bamboo fiber with a modified silane coupling agent, wherein the modified silane coupling agent is prepared by the following method: Step A1, premixing a silane coupling agent KH-550, bromoundecene and toluene, adding potassium carbonate and anhydrous magnesium sulfate, heating to 80-100 ℃ under the protection of dry nitrogen, and stirring for reaction for 3-4 hours to prepare an intermediate 1; A2, premixing the intermediate 1, tertiary butyl mercaptan, acetone and absolute ethyl alcohol, adding a photoinitiator 651, mixing, and carrying out ultraviolet irradiation stirring reaction for 1.5-2h at room temperature at the speed of 25-35mW/cm 2 to prepare an intermediate 2; and step A3, uniformly mixing the intermediate 2, methyl iodide and acetonitrile, pressurizing to 4-5bar by using dry nitrogen, heating to 50-60 ℃ and refluxing for 8-10h to prepare the modified silane coupling agent.
  2. 2. The natural bamboo fiber modified PE composite according to claim 1, wherein the dosage ratio of the silane coupling agent KH-550, bromoundecene, potassium carbonate, anhydrous magnesium sulfate and toluene is 10 mmol/20 mmol/1.4-1.8 g/0.5-0.7 g/100-130 mL.
  3. 3. The natural bamboo fiber modified PE composite according to claim 2, wherein the dosage ratio of the intermediate 1, the tertiary butyl mercaptan, the photoinitiator 651, the acetone and the absolute ethyl alcohol is 10 mmol/20-30 mg/50-70 mL/15-30 mL.
  4. 4. The natural bamboo fiber modified PE composite according to claim 3, wherein the dosage ratio of the intermediate 2 to methyl iodide to acetonitrile is 10 mmol/50-70 mmol/40-50 mL.
  5. 5. The modified PE composite for natural bamboo fibers according to claim 4, wherein the modified bamboo fibers are prepared by premixing a modified silane coupling agent and an ethanol aqueous solution, adjusting the pH value to 5 with formic acid, adding the natural bamboo fibers, heating to 60 ℃ and soaking for 8-12h, neutralizing with ammonia water, filtering, washing with water, and drying.
  6. 6. The modified PE composite of natural bamboo fibers according to claim 5, wherein the ratio of the natural bamboo fibers to the modified silane coupling agent to the ethanol aqueous solution is 50g:4.2-5.5g:100-120mL.
  7. 7. The method for preparing the natural bamboo fiber modified PE composite material according to any one of claims 1 to 6, wherein the preparation method is characterized in that the mPE resin, the lubricant and the antioxidant are premixed and then fed from a main feeding port of an extruder, the modified bamboo fiber is fed from a side feeding port, the processing temperature is controlled to be 190-220 ℃, and the composite material is obtained after extrusion and cooling.

Description

Natural bamboo fiber modified PE composite material and preparation method thereof Technical Field The invention belongs to the technical field of composite materials, and particularly relates to a natural bamboo fiber modified PE composite material and a preparation method thereof. Background Polyethylene (PE) is widely used as one of the most productive general-purpose plastics due to its excellent chemical stability, processability and low cost. Metallocene polyethylene (mPE) is a polyethylene prepared by using a metallocene catalyst, and has an extremely high regularity of molecular chains, a narrow molecular weight distribution, and a uniform comonomer distribution. The unique microstructure enables the glass to macroscopically exhibit excellent mechanical properties, particularly extremely high transparency and extremely low haze, while having excellent impact strength and puncture resistance. The bamboo fiber is a green renewable fiber derived from natural bamboo, and the surface of the bamboo fiber has unique natural texture and plain aesthetic feeling, thus the product is endowed with natural and environment-friendly artistic value. The mPE and the bamboo fiber are compounded, and the mPE coating layer can also effectively prevent the bamboo fiber from putrefaction due to moisture absorption and microbial corrosion by combining the excellent mechanical property and high transparency of the mPE and the decoration of the bamboo fiber, fully show the texture of the bamboo fiber, and has wide application prospect in the field of appearance decoration materials (such as indoor decoration plates, furniture veneers, electronic product shells and the like). However, mPE is a nonpolar polymer, and the surface of bamboo fiber is rich in polar groups such as hydroxyl groups, which results in poor interfacial compatibility between the two. In the compounding process, the interface binding force is weak, stress cannot be effectively transmitted, so that the mechanical property of the composite material is deteriorated, and a large number of microscopic defects are formed at the two-phase interface due to the weak interface binding, and the defects become light scattering points, so that the high transparency and high glossiness of the mPE matrix are seriously damaged, the surface of the composite material is dull in luster, and the natural texture and aesthetic feeling of the bamboo fiber cannot be fully displayed. More seriously, when the material is subjected to external forces such as bending, impact and the like, the fiber and the mPE matrix are extremely easy to peel off at the interface, microcrack and blushing are generated, and the optical performance degradation caused by deformation is irreversible, so that the attractive appearance and the use value of the product are permanently influenced. In the prior art, the conventional method for improving the compatibility of the polar fiber and the nonpolar polymer is to adopt a silane coupling agent to carry out surface modification on the fiber, so that the interfacial energy is reduced to a certain extent, and the dispersibility is improved. However, the general coupling modification method has insufficient suitability with the mPE matrix, the root cause is that the mPE molecular chain has high regularity and strong crystallization capability, the combination of the existing alkyl coupling agent and the mPE matrix mainly depends on simple compatibility and limited physical entanglement, and a strong interface anchoring mechanism is lacked. Such weak interactions are not effective in inducing mPE to form a stable crystalline structure at the interface, resulting in limited improvement of the overall mechanical properties of the composite, especially fatigue resistance. Macroscopic appearance is that the strength of the material is not high, whitening, wrinkling and even fracture are easy to occur after repeated bending, and the surface glossiness of the material can be obviously and irreversibly reduced after external force deformation. Disclosure of Invention In order to solve the technical problems in the background art, the invention aims to provide a natural bamboo fiber modified PE composite material and a preparation method thereof. The aim of the invention can be achieved by the following technical scheme: the core creation of the natural bamboo fiber modified PE composite material is to develop a modified silane coupling agent, treat and modify natural bamboo fibers by using the modified silane coupling agent and compound the modified natural bamboo fibers with mPE, so that the interface bonding performance of the modified natural bamboo fibers and mPE is improved, and the modified silane coupling agent specifically comprises the following two aspects: in a first aspect, the present invention provides a modified silane coupling agent for treating bamboo fibers, the preparation method thereof comprising the steps of: Step A1, premixing a silane coup