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CN-122011438-A - Preparation method of high-compatibility PBAT bamboo powder composite master batch

CN122011438ACN 122011438 ACN122011438 ACN 122011438ACN-122011438-A

Abstract

The invention relates to the technical field of modification of polymer compositions, and discloses a preparation method of a high-compatibility PBAT bamboo powder composite master batch, which comprises the steps of mixing sulfonated PBAT, PBAT-g-GMA grafts, activated bamboo powder and an auxiliary agent to obtain a mixed dry material; the invention utilizes the viscosity difference between the graft and the matrix in the melting section of double screw extrusion to make the graft melt permeate and fill the micropores of the tube cells in the bamboo powder, and makes the epoxy groups in the graft chemically bond with the sulfonic groups and the hydroxyl groups in the reaction mixing section to form an interface anchoring structure.

Inventors

  • XU WENBO
  • XIE YUNPENG
  • SUN FANGJIE
  • WANG BAIYAO

Assignees

  • 烟台佳合塑胶科技有限公司

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the high-compatibility PBAT bamboo powder composite master batch is characterized by comprising the following steps of: Step 101, mixing 55 to 70 weight percent of sulfonated PBAT, 3 to 8 weight percent of PBAT-g-GMA graft, 25 to 40 weight percent of activated bamboo powder, 0.1 to 0.5 weight percent of lubricant and 0.1 to 0.3 weight percent of antioxidant to obtain mixed dry materials, wherein the sulfonated PBAT is poly (adipic acid)/butylene terephthalate with sulfonic acid groups in a molecular chain, and the activated bamboo powder is bamboo powder fiber with a silane coupling agent coating layer with epoxy groups on the surface; 102, feeding the mixed dry material into a melting conveying section of a double-screw extrusion system, and controlling the set temperature of the melting conveying section to be 140-170 ℃ to enable the mixed dry material to be melted at the set temperature, wherein the melt viscosity of the PBAT-g-GMA graft is lower than that of sulfonated PBAT, so that the PBAT-g-GMA graft in a molten state is filled into pipe cell micropores in the activated bamboo powder; step 103, sending the activated bamboo powder filled with the PBAT-g-GMA graft into a reaction mixing section of a double-screw extrusion system, and under the condition that the set temperature is 170-190 ℃, enabling epoxy groups in the PBAT-g-GMA graft, sulfonic groups in sulfonated PBAT and hydroxyl groups on the surface of the activated bamboo powder to carry out ring-opening esterification reaction, so as to form an interface anchoring structure of chemical bonding between the PBAT-g-GMA graft and the inner walls of micropores in micropores of the tube; Step 104, extruding the reacted melt through a machine head, and sequentially carrying out water cooling and granulating to obtain the high-compatibility PBAT bamboo powder composite master batch.
  2. 2. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein in step 102, the melt mass flow rate of the PBAT-g-GMA graft is larger than that of sulfonated PBAT, and the PBAT-g-GMA graft fills and seals the burr hole channels inside the activated bamboo powder.
  3. 3. The preparation method of the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the particle size of the activated bamboo powder is 800-1200 meshes, the average pore size of micropores of a pipe cell is 0.1-3 μm, and the silane coupling agent coating layer is formed by condensation reaction of 3-glycidoxypropyl trimethoxysilane or 3-glycidoxypropyl methyldiethoxysilane.
  4. 4. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the grafting rate of the PBAT-g-GMA graft is 2% to 5%, the weight average molecular weight of the PBAT graft is 30% to 50% of that of the sulfonated PBAT, and the average filling depth of the PBAT-g-GMA graft in the micropores of the tube cells is not less than 20% of the radial depth of the micropores of the tube cells in step 102.
  5. 5. The preparation method of the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the relation between the molar quantity n EP of epoxy groups in the PBAT-g-GMA graft and the molar quantity n SA of sulfonic acid groups in the sulfonated PBAT is 1.2- EP /n SA -2.5, wherein n EP is the total molar quantity of epoxy groups calculated according to the feeding quantity and the grafting rate of the PBAT-g-GMA graft in the step 101, and n SA is the total molar quantity of sulfonic acid groups calculated according to the feeding quantity and the degree of sulfonic acid group substitution of the sulfonated PBAT in the step 101.
  6. 6. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the degree of substitution of sulfonic acid groups in sulfonated PBAT is 1-3%, and in step 103, the sulfonic acid groups serve as catalytic sites to guide the PBAT-g-GMA grafts to form a crosslinked network inside micropores of the tube cells.
  7. 7. The preparation method of the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the lubricant is selected from zinc stearate, stearic acid amide or polyethylene wax, and the antioxidant is selected from antioxidant 1010 or antioxidant 168.
  8. 8. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the length-diameter ratio of a screw of the double screw extrusion system is 40:1 to 48:1, and the screw of the double screw extrusion system comprises a conveying screw element for plasticizing the mixed dry material and a kneading block element for generating radial extrusion stress in step 103 so as to assist the penetration of components into micropores of the pipe cells.
  9. 9. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the screw rotation speed of the double screw extrusion system is 300r/min to 500r/min so as to promote the ring-opening esterification reaction in the reaction mixing section.
  10. 10. The method for preparing the high-compatibility PBAT bamboo powder composite master batch according to claim 1, wherein the method is characterized by further comprising the step 105 of drying the master batch after dicing in a vacuum drying unit at 45-55 ℃ for 4-6 hours to ensure that the water content of the high-compatibility PBAT bamboo powder composite master batch is lower than 0.1%.

Description

Preparation method of high-compatibility PBAT bamboo powder composite master batch Technical Field The invention relates to a preparation method of a high-compatibility PBAT bamboo powder composite master batch, and belongs to the technical field of modification of polymer compositions. Background In the current production practice of biodegradable polymer composite materials, the composite materials are prepared by melt blending natural plant fibers such as poly (adipic acid)/butylene terephthalate and bamboo powder, which is a common means for realizing low cost and high bio-based content of products, and the composition has wide application value in the fields of green wrapping materials and agricultural mulching films by utilizing the good toughness of polyester matrixes and the rigid supporting effect of the natural fibers, however, as the filling amount of the bamboo powder is increased to more than 30%, the composite system faces the risk of interface bonding failure, the molecular chain of the adipic acid/butylene terephthalate has poor wettability with the surface of the bamboo powder rich in polar hydroxyl due to low density of polar groups, and filler particles are driven by surface energy difference to generate physical aggregation in the melt extrusion process, so that stress concentration occurs at two-phase interfaces, and the mechanical strength and the impact resistance of the products are further reduced. In order to improve interface compatibility, the industry usually adopts a silane coupling agent to modify the surface of bamboo powder or adds maleic anhydride grafts as a compatilizer, the modification mode only forms a transition layer on the outer surface of bamboo powder particles, belongs to surface physical coverage or shallow chemical bonding, because bamboo powder is taken as a typical anisotropic biomass material, a large number of pipe cell micropores and conduit cavities exist in the bamboo powder, high-viscosity polyester melt is extremely difficult to overcome rheological resistance to enter the interior of micro-scale pores under the condition of being limited by the residence time of an extruder, the discontinuity of a shell-core structure causes a large number of surface stress defects which remain unoccupied in the fiber, the conventional modification method is difficult to solve the problem of poor interface bonding, and the development of special chemical auxiliary agents is used for adjusting the polarity of the interface, for example, the Chinese patent with the authorized bulletin number of CN119505212B discloses a PBAT/bamboo powder compatibility and crosslinking integrated auxiliary agent, a preparation method and application, the PBAT-g-AGEMUANTA multielement grafting auxiliary agent is used for constructing a hydrogen bond and chemical bond network at the interface by utilizing the polar groups, deep penetration of the melt is difficult to be realized in actual continuous extrusion production, the polarity is strong, the grafting auxiliary agent is difficult to be separated from the local phase Duan Yi and enters the interface thermal stress concentration before the modification is formed at the periphery of the interface, and the boundary stress concentration is difficult to be formed, and the thermal stress concentration is difficult to be blocked and concentrated at the periphery of the interface stress is difficult to be formed and the modification interface is difficult to be concentrated and the interface is formed and has poor to be subjected to the interface modification effect is difficult to the interface bonding and the interface bonding effect is formed. Therefore, how to utilize natural capillary structures of bamboo powder to guide reactive components to carry out deep penetration, build a geometric anchoring structure crossing phase boundaries and form an interpenetrating network, so that the interface stress transmission efficiency is improved while the high filling rate is maintained, and the technical problem to be solved by the invention is solved. Disclosure of Invention In order to solve the problems in the background technology, the technical scheme of the invention is as follows, the preparation method of the high-compatibility PBAT bamboo powder composite master batch comprises the following steps: Step 101, mixing 55 to 70 weight percent of sulfonated PBAT, 3 to 8 weight percent of PBAT-g-GMA graft, 25 to 40 weight percent of activated bamboo powder, 0.1 to 0.5 weight percent of lubricant and 0.1 to 0.3 weight percent of antioxidant to obtain mixed dry materials, wherein the sulfonated PBAT is poly (adipic acid)/butylene terephthalate with sulfonic acid groups in a molecular chain, and the activated bamboo powder is bamboo powder fiber with a silane coupling agent coating layer with epoxy groups on the surface; 102, feeding the mixed dry material into a melting conveying section of a double-screw extrusion system, and controlling the set