CN-122011297-A - Method for preparing high-performance bamboo fiber/PMMA composite material through high beating and chain transfer agent synergistic regulation

CN122011297ACN 122011297 ACN122011297 ACN 122011297ACN-122011297-A

Abstract

The invention provides a method for preparing a high-performance bamboo fiber/PMMA composite material through high pulping pretreatment and chain transfer agent cooperative regulation, and belongs to the technical field of biomass composite materials. The method comprises the steps of pretreating bamboo fibers with high beating degree, controlling the beating degree to be 60-90 DEG SR, adding a chain transfer agent into a Fenton reaction system, initiating controlled graft polymerization on the surfaces of the bamboo fibers in situ to form PMMA grafted layers with uniform chain length and regular arrangement, removing homopolymers through post treatment to obtain modified bamboo fibers, and finally carrying out melt blending and hot press molding on the modified bamboo fibers and a PMMA matrix to obtain the composite material. According to the invention, through the synergistic effect of precisely regulating and controlling the consumption of the chain transfer agent and the high pulping pretreatment, the transition of the interface structure from 'quantity' to 'quality' is realized, the interface stress transmission efficiency and the tensile strength of the composite material are obviously improved, and the process is green and mild and is suitable for large-scale production.

Inventors

LI QUN
DONG XIAOYU
LIU RONGRONG
LI ZHIQIANG
ZHANG FENGSHAN
LIU YANSHAO

Assignees

天津科技大学

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (9)

1. The preparation process for preparing the high-performance bamboo fiber/PMMA composite material through the synergistic regulation and control of high beating and chain transfer agent is characterized by comprising the following steps of: (1) Pretreating bamboo fiber with high beating degree of 60-90 deg. SR, and drying and scattering to obtain slurry; (2) Dispersing pulped bamboo fiber in water, adding ferrous salt, regulating pH, stirring for a period of time, and squeezing for dehydration; (3) Adding methyl methacrylate monomer and chain transfer agent, then dripping hydrogen peroxide solution, reacting for 0.5-1h at 30-60 ℃ and carrying out Fenton graft polymerization; (4) After the reaction is finished, filtering, washing, performing acetone rope type extraction to remove homopolymer, and drying to obtain modified bamboo fiber with PMMA grafted on the surface; and (3) melting and blending the modified bamboo fiber and a PMMA matrix according to a certain fiber content, granulating, and hot-press molding to obtain the bamboo fiber/PMMA composite material.
2. The process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high beating and chain transfer agent according to claim 1, wherein in the step (1), the beating degree is controlled to be more than 80 DEG SR.
3. The process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high pulping and chain transfer agent according to claim 1, wherein the ferrous salt in the step (2) is ferrous sulfate heptahydrate.
4. The process for preparing high-performance bamboo fiber/PMMA composite material by synergistic regulation and control of high beating and chain transfer agent according to claim 1, wherein the pH in the step (2) is 3-4.
5. The process for preparing the high-performance bamboo fiber/PMMA composite material by synergistic regulation and control of high beating and chain transfer agent according to claim 1, wherein in the step (2), the hydrogen peroxide is used in an amount of 2 mmol.
6. The process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high beating and a chain transfer agent according to claim 1, wherein in the step (3), the chain transfer agent is a mercaptan compound, preferably dodecyl mercaptan.
7. The process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high beating and chain transfer agent according to claim 1 or 3, wherein in the step (3), the amount of the chain transfer agent is 0.3% -1% of the molar amount of the methyl methacrylate monomer.
8. The preparation process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high beating and chain transfer agent according to claim 1, wherein in the step (5), the mass ratio of the modified bamboo fiber to the PMMA matrix is 75:25.
9. The process for preparing the high-performance bamboo fiber/PMMA composite material by the synergistic regulation and control of high pulping and chain transfer agent according to claim 1, wherein in the step (5), the melt blending temperature is 200 ℃, and the hot press molding temperature is 180 ℃.

Description

Method for preparing high-performance bamboo fiber/PMMA composite material through high beating and chain transfer agent synergistic regulation Technical Field The invention belongs to the technical field of biomass composite materials, and particularly relates to a method for constructing a high-performance polymer interface layer on bamboo fibers and preparing a high-performance composite material by means of high-beating pretreatment and accurate regulation of the consumption of chain transfer agent. Background Bamboo fiber is used as a green and renewable reinforcing material and has great potential in replacing the traditional glass fiber. However, its weak interfacial bonding with hydrophobic polymer matrices (e.g. polypropylene, polymethyl methacrylate) is a core bottleneck leading to poor mechanical properties of the composite. In order to solve the problem of interfacial compatibility of the bamboo-plastic composite material, various modification methods are researched and explored. The prior methods for improving the interface mainly comprise physical and chemical treatment (such as alkali treatment and silane coupling), and the methods mainly improve the surface wettability, but fail to establish strong chemical bonding, and have limited interface improvement. The grafting polymerization method (such as radiation grafting and thermal initiation) has the problems of random grafting sites, uncontrollable grafting chain length, uneven distribution and the like, so that the interface layer structure is loose, and the stress transfer efficiency is low. Among them, fenton reaction is used for cellulose modification due to its mild and green conditions. However, the reaction process is mainly homogeneous polymerization, a large amount of polymer is generated in solution instead of the surface of the fiber, so that the grafting efficiency is low, the length and the distribution of a grafting chain are difficult to precisely control, and the formed grafting layer is a brittle coating with loose structure and low stress transmission efficiency. In the prior art, the pretreatment mode of the bamboo fiber is mainly in simple mechanical dispersion or mild chemical treatment, the mechanochemical effect cannot be fully utilized to deeply regulate the internal structure of the fiber, and the exposure of a large number of potential grafting sites is limited. When introducing chain transfer agents, their technical starting point is generally based on their general principle in homogeneous radical polymerization and generally follows the thinking formula "the higher the grafting yield, the better the composite properties". Therefore, development of a modification technology for synergistically regulating and controlling the pulping pretreatment and chain transfer agent of the fiber to realize the leap of the interface structure rather than the accumulation of the pure grafting amount is an urgent need for preparing the high-performance bamboo fiber composite material by breaking through the bottleneck of the prior art. Disclosure of Invention The invention aims to overcome the defects in the prior art, and provides a method for preparing a high-performance bamboo fiber/PMMA composite material by synergistic regulation and control of high beating and chain transfer agent. The core aim is to construct a polymer grafted layer with controllable chain length and regular arrangement on the surface of the bamboo fiber in situ through the cooperation of the pretreatment with high beating degree and the accurate regulation of the chain transfer agent, thereby realizing the fundamental improvement of the interfacial stress transfer efficiency of the composite material, and simultaneously promoting the microfibrillation dispersion of the fiber in the composite material by means of the interlayer permeation of the PMMA with small molecular weight, and realizing the synchronous optimization of the interfacial performance and the macroscopic mechanical property. The invention provides a method for preparing a high-performance bamboo fiber/PMMA composite material through high beating and chain transfer agent cooperative regulation, which comprises the following steps: 1. Pretreatment of bamboo fiber with high beating degree: the bamboo fiber is subjected to high-strength beating treatment in water, and the beating degree is controlled to be 60-90 DEG SR, preferably more than 80 DEG SR. 2. Initiating controlled grafting: a. Dispersing pulped bamboo fiber in deionized water, adding ferrous salt (such as ferrous sulfate heptahydrate), adjusting pH to 3-4, stirring for adsorption, and squeezing for dewatering. B. methyl methacrylate monomer and chain transfer agent are added. The chain transfer agent is preferably a mercaptan compound (such as dodecyl mercaptan), and the molecular weight of the grafted chain can be precisely controlled by controlling the dosage of the chain transfer agent. C. finally, dropwise adding hydrogen peroxid