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CN-119161705-B - Modified bamboo fiber full-biodegradable material, preparation method thereof and application thereof in food fresh-keeping

CN119161705BCN 119161705 BCN119161705 BCN 119161705BCN-119161705-B

Abstract

The invention belongs to the technical field of high polymer materials, and discloses a modified bamboo fiber full-biodegradable material which is prepared from PBAT, PLA, modified bamboo powder, a plasticizer and a composite antibacterial agent, and comprises the following steps of S1, performing alkali treatment modification and silane coupling agent modification on the bamboo powder; the preparation method comprises the steps of S2 preparing a composite antibacterial agent by adopting a solid phase reaction method, S3 fully stirring each component with a set amount, S4 performing high-temperature melt extrusion on the mixed component raw materials, cooling and granulating, S5 performing high-temperature casting on the granules to obtain a sheet, and S6 performing plastic suction molding on the sheet. The modified bamboo powder can not only effectively improve the mechanical property of food package, but also reduce the production cost of degradable food package and accelerate the degradation rate of food package, and the composite antibacterial agent is added to endow food package with excellent antibacterial property, which is beneficial to delaying the metabolic process of litchi, thereby remarkably reducing the weightlessness and decay rate of litchi during storage, effectively prolonging the shelf life of litchi, being applicable to fresh-keeping storage of other fruits and having wide applicability.

Inventors

  • ZHOU WUYI
  • XU YUMIN
  • YANG SHUNDE
  • HU SHIYU
  • WANG XING
  • LIN XIANJIAN
  • CAO YONG

Assignees

  • 华南农业大学
  • 广州冠杰环保新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20241011

Claims (7)

  1. 1. The modified bamboo fiber full-biodegradable material is characterized by mainly comprising, by mass, 30-65 parts of polylactic acid, 30-50 parts of polybutylene terephthalate-adipate, 5-15 parts of modified bamboo powder, 2-6 parts of a plasticizer and 1-5 parts of a composite antibacterial agent, wherein the plasticizer is epoxidized soybean oil, and the molecular weight of the plasticizer is 800-1100g/mol; The modified bamboo powder is prepared by placing bamboo powder into an alkaline solution, stirring and reacting for 4-6 hours at the temperature of 50-60 ℃ in a water bath, cooling to room temperature after the reaction is finished, repeatedly washing with water until the water is neutral, drying for 24-36 hours at the temperature of 40-60 ℃, placing the bamboo powder subjected to alkali treatment into an ethanol solution of a silane coupling agent, stirring and reacting for 2-4 hours at the temperature of 300-800 rpm in a water bath at the temperature of 30-50 ℃, drying for 12-24 hours at the temperature of 40-60 ℃, crushing and sieving to obtain the modified bamboo powder; the composite antibacterial agent is prepared by the following steps: (1) Weighing a certain amount of 4-methylpyridine and 1, 3-dibromopropane, adding a proper amount of acetone into a container for dissolution, stirring and refluxing for 24-36 hours at 65-70 ℃, pouring the mixture into the container when the mixture is hot after reaction, sucking the upper liquid by a dropper, adding a proper amount of acetone for washing, standing for layering, sucking the upper liquid, repeating the operation for a plurality of times, adding a proper amount of diethyl ether for washing, standing for layering, sucking the upper liquid, repeating the operation for a plurality of times, naturally volatilizing at a dark place, and then placing the mixture into a vacuum drying oven at 65-75 ℃ for drying for 12-24 hours to obtain white powder [4MePy- (CH 2 ) 3 -4MePy]Br 2 ; (2) Adding a certain amount of [4MePy- (CH 2 ) 3 -4MePy]Br 2 ) and manganese chloride tetrahydrate into a container, adding a proper amount of methanol for dissolution, adding a proper amount of concentrated hydrochloric acid, stirring and refluxing at 80-90 ℃ for 2-4 h, pouring the mixture into the container when the mixture is hot after the reaction, standing and cooling, and naturally volatilizing to obtain light yellow flaky crystal of manganese chloride bipyridine quaternary ammonium salt [4MePy- (CH 2 ) 3 -4MePy][MnCl 4 ], namely the composite antibacterial agent.
  2. 2. The modified bamboo fiber fully biodegradable material according to claim 1, wherein the mass ratio of the bamboo powder to the alkaline solution is 1:12-18, and the mass ratio of the alkali treated bamboo powder to the ethanol solution of the silane coupling agent is 1:5-8.
  3. 3. The modified bamboo fiber fully biodegradable material according to claim 1, wherein the particle size of the modified bamboo powder is 300-800 meshes, the alkaline solution is sodium hydroxide aqueous solution, the concentration of sodium hydroxide is 3-8wt%, the silane coupling agent is KH550, the molecular weight is 200-300g/mol, and the concentration of the silane coupling agent in the silane coupling agent solution is 5-15wt%.
  4. 4. The modified bamboo fiber fully biodegradable material according to claim 1, wherein the molar ratio between 1, 3-dibromopropane and 4-methylpyridine in the step (1) is 1 (2-4).
  5. 5. The modified bamboo fiber fully biodegradable material according to claim 1, wherein the molar ratio of [4MePy- (CH 2 ) 3 -4MePy]Br 2 quaternary ammonium salt) to manganese chloride tetrahydrate in the step (2) is 1 (0.8-1.2).
  6. 6. The modified bamboo fiber fully biodegradable material according to claim 1, wherein the polylactic acid has a melting point of 140-180 ℃, a melt index of 5-25g/10min and a heat distortion temperature of 50-70 ℃.
  7. 7. The method for preparing the modified bamboo fiber fully biodegradable material according to any one of claims 1 to 6, comprising the steps of: (1) Putting the polylactic acid, the polybutylene terephthalate-adipate, the modified bamboo powder, the plasticizer and the composite antibacterial agent into a mixer, stirring for 10-20 minutes at 40-80 rpm, putting the uniformly mixed mixture into a double-screw extruder, controlling the heating temperature of the double-screw extruder to be 158-163 ℃, 163-167 ℃, 167-170 ℃ in three regions, 170-175 ℃ in four regions and 168-173 ℃ in five regions in sequence, rapidly cooling to room temperature after extrusion, granulating, and drying to obtain composite granules; (2) Putting the dried composite particles into a casting machine, controlling the heating temperature of the casting machine to be 160-163 ℃, 163-166 ℃, 166-172 ℃ in a first region, 172-175 ℃ in a fourth region and 175-178 ℃ in a fifth region in sequence, casting to obtain a sheet, and carrying out plastic suction on the sheet to finally obtain the modified bamboo fiber full-biodegradable material.

Description

Modified bamboo fiber full-biodegradable material, preparation method thereof and application thereof in food fresh-keeping Technical Field The invention relates to a modified bamboo fiber full-biodegradable material, a preparation method thereof and application thereof in food preservation, and belongs to the technical field of high polymer materials. Background In recent years, in order to conform to a fast-paced life style, the appearance of disposable foam plastic lunch boxes, fresh-keeping bags, fresh-keeping boxes and other daily products brings a plurality of convenience, and the most commonly used treatment modes of the packaging materials at present are incineration and landfill, so that the packaging materials can cause irreversible pollution to the environment for a long time. Therefore, developing a novel packaging material which is safer, easy to degrade and easy to preserve is an important way for reducing pollution of plastic products, and the use of degradable materials to replace traditional plastics is a great way for solving the problem of plastic pollution. The method aims at further promoting the full-chain treatment of plastic pollution, and the global development initiative of the hand-in-hand implementation of China and the international bamboo rattan organization is initiated together with the initiative of replacing plastic with bamboo, so that an effective solving way is provided for reducing plastic pollution. In order to respond to the call of taking bamboo to replace plastic, biomass energy is fully utilized, natural bamboo powder enters the field of view of scientific researchers, the main components of the natural fiber/polymer composite material are cellulose, lignin, hemicellulose and the like, wherein the cellulose occupies the largest proportion, natural plant fibers are used as fillers or reinforcements, and polymers are used as matrixes, and the natural fiber/polymer composite material has the characteristics of good mechanical property, strong processability and the like. However, the bamboo fiber contains a large number of hydroxyl groups, carboxyl hydroxyl groups and other groups, so that the bamboo fiber has strong polarity, and the interface bonding degree between the natural plant fiber and the plastic matrix is poor, so that the bamboo powder needs to be modified, and the modified bamboo powder is significant in biomass refining and environmental protection because of realizing high-value recycling. Polylactic acid is a nontoxic and non-irritating synthetic polymer material, the raw materials of the polylactic acid are mainly from products of fermentation such as starch and the like, and can be directly subjected to composting or incineration treatment after being used, and finally can be completely decomposed into CO 2 and H 2 O, so that the influence on the environment is very small, the requirement of sustainable development is met, meanwhile, the polylactic acid has biodegradability and thermoplastic properties, so that the polylactic acid is attractive in the packaging material industry, and the polylactic acid has such advantages that the polylactic acid is brittle, has poor impact resistance, low heat deformation temperature and poor heat resistance, and severely limits the large-scale application of the polylactic acid in the aspect of plastic packaging bags. The food antibacterial package combines the packaging material and the antibacterial and antiseptic material together so as to improve the shelf life and the safety of the food, and the limitation of the common antibacterial material is more and more obvious, so that the development of novel antibacterial materials is urgent. The pyridine quaternary ammonium salt has excellent antibacterial performance, can be used as a good hydrogen bond acceptor and can be coordinated and combined with metal halide to form an organic-inorganic hybrid material with excellent catalytic, antibacterial, magnetic and optical properties. Disclosure of Invention Aiming at the problems, the invention provides a modified bamboo fiber full-biodegradable material, which improves the toughness of PLA materials through the modification of bamboo fibers, improves the antibacterial and fresh-keeping properties of the materials through a composite antibacterial agent, and prepares the food packaging material which can be fully biodegradable and has antibacterial properties. In order to achieve the above object, the present invention adopts the following technical scheme: The modified bamboo fiber full-biodegradable material mainly comprises, by mass, 30-65 parts of polylactic acid, 30-50 parts of polybutylene terephthalate-adipate, 5-15 parts of modified bamboo powder, 2-6 parts of a plasticizer and 1-5 parts of a composite antibacterial agent. Preferably, the modified bamboo powder is prepared by placing bamboo powder into an alkaline solution, stirring and reacting for 4-6 hours at the temperature of 50-60 ℃ in a water bath, coo