Search

CN-121991328-A - Compatilizer for carbon dioxide-based biodegradable mulching film and preparation method thereof, and carbon dioxide-based biodegradable mulching film and preparation method thereof

CN121991328ACN 121991328 ACN121991328 ACN 121991328ACN-121991328-A

Abstract

The invention provides a compatilizer for a carbon dioxide-based biodegradable mulch film and a preparation method thereof, and a carbon dioxide-based biodegradable mulch film and a preparation method thereof, belonging to the technical field of biodegradable plastics. The compatilizer comprises a PPC/PLA segmented copolymer, wherein the PPC/PLA segmented copolymer can play a unique role of a molecular bridge in a blending system, and the structure of the PPC/PLA segmented copolymer and PPC and PLA homopolymer have excellent thermodynamic compatibility, so that the interfacial tension between the PPC and PLA two phases can be obviously reduced, the interfacial cohesive force is enhanced, and the transmission of external field stress between the two components is effectively promoted. The performance test shows that the tensile strength of the biodegradable mulch film prepared by the invention can reach more than 23 MPa, the elongation at break can reach more than 215 percent and can reach up to 344 percent.

Inventors

  • CUI LIN
  • JU HONGYAN
  • GAO FENGXIANG
  • WU RUI
  • WANG XIANHONG

Assignees

  • 中国科学院长春应用化学研究所

Dates

Publication Date
20260508
Application Date
20260325

Claims (10)

  1. 1. A compatibilizer for a carbon dioxide based biodegradable mulch film, the compatibilizer comprising a PPC/PLA block copolymer.
  2. 2. The compatibilizer of claim 1 wherein the PPC/PLA block copolymer has a PPC segment molar content of 75% to 95% and a PLA segment molar content of 2% to 5%.
  3. 3. The compatibilizer according to claim 1 or 2 wherein the PPC/PLA block copolymer has a number average molecular weight of 80 to 170 kg/mol and a molecular weight distribution of 1.5 to 3.5.
  4. 4. A method of preparing the compatibilizing agent according to any one of claims 1 to 3, comprising the steps of: the compatilizer is prepared by copolymerization of carbon dioxide, propylene oxide and lactide under the action of a catalyst.
  5. 5. The carbon dioxide-based biodegradable mulching film is characterized by comprising, by weight, 40-60 parts of PPC, 40-60 parts of PLA and 0.5-2 parts of compatilizer; the compatilizer is the compatilizer of any one of claims 1 to 3 or the compatilizer prepared by the preparation method of claim 4.
  6. 6. The carbon dioxide-based biodegradable mulch film according to claim 5, wherein the PPC has a number average molecular weight of 80 to 220 kg/mol and a molecular weight distribution of 2.1 to 3.2; the number average molecular weight of the PLA is 90-200 kg/mol, and the molecular weight distribution is 1.5-2.5.
  7. 7. The carbon dioxide-based biodegradable mulch film according to claim 5 or 6, wherein the carbon dioxide-based biodegradable mulch film further comprises a functional auxiliary agent; the functional auxiliary agent comprises any one or more of an ultraviolet absorber, an antioxidant or an inorganic filler; the thickness of the carbon dioxide-based biodegradable mulching film is 6-15 mu m.
  8. 8. A method for producing the carbon dioxide-based biodegradable mulch film according to any one of claims 5 to 7, comprising the steps of: S1, mixing PPC, PLA and a compatilizer, and carrying out melt blending, extrusion, cooling and granulation on the obtained mixture in a double-screw extruder to obtain a material; S2, carrying out film forming treatment on the material to obtain the carbon dioxide-based biodegradable mulch film.
  9. 9. The method according to claim 8, wherein the processing temperature of the twin-screw extruder is in the range of 120-170 ℃.
  10. 10. The method of preparation according to claim 8 or 9, wherein the film forming treatment includes, but is not limited to, cast stretch film forming or blow molding film forming.

Description

Compatilizer for carbon dioxide-based biodegradable mulching film and preparation method thereof, and carbon dioxide-based biodegradable mulching film and preparation method thereof Technical Field The invention belongs to the technical field of biodegradable plastics, and particularly relates to a compatilizer for a carbon dioxide-based biodegradable mulching film and a preparation method thereof, and a carbon dioxide-based biodegradable mulching film and a preparation method thereof. Background With the development of modern agriculture, plastic mulching films are widely applied due to the excellent functions of preserving soil moisture, warming, inhibiting grass and the like. However, the traditional mulching films such as Polyethylene (PE) are difficult to degrade in natural environments, and form a long-term threat to soil structures, crop growth and ecological environments. To address this challenge, biodegradable materials are a hotspot for research and application. Poly (propylene carbonate) (PPC) is a carbon dioxide-based biodegradable material having excellent toughness and ductility. PPC not only has good film forming performance, but also has excellent gas barrier property (especially to oxygen and water vapor), and the property is important to maintain microenvironment under plastic film coverage and delay crop root system aging, so that the PPC is regarded as a potential high-performance plastic film substrate. However, PPC itself has disadvantages, mainly its low glass transition temperature, poor thermal stability and insufficient modulus, which results in pure PPC being easily tacky, softened and deformed in use, and strength being difficult to meet the mechanical requirements of farmland operations, limiting its individual application. To improve the performance of PPC, technicians often use degradable materials with complementary properties to blend with them. Polylactic acid (PLA for short) is widely used as a bio-based degradable material with high strength and modulus, and has good performance complementation with PPC. Thus, PPC/PLA blend systems are considered potential systems for preparing high performance degradable mulch films. However, simple physical blending faces the core challenge that the compatibility of PPC and PLA is poor, so that the blended materials are separated, the interfacial binding force is weak, the rigidity advantage of PLA and the toughness advantage of PPC cannot be effectively combined macroscopically, and the mechanical properties of the materials can be reduced. Meanwhile, in the process of preparing the mulching film by a PPC/PLA blending system through a biaxial stretching technology, technical bottlenecks such as film rupture, uneven thickness, optical performance reduction and the like are easily caused in the stretching process due to poor compatibility. Disclosure of Invention In view of the above, the present invention aims to provide a compatilizer for carbon dioxide-based biodegradable mulch film and a preparation method thereof, and a carbon dioxide-based biodegradable mulch film and a preparation method thereof. The compatilizer can play a unique role of a molecular bridge in a blending system, can obviously reduce the interfacial tension between PPC and PLA two phases, strengthen the interfacial adhesion and effectively promote the transmission of external field stress between the two components. In order to achieve the purpose, the invention adopts the following technical scheme: in a first aspect, the present invention provides a compatibilizer for a carbon dioxide based biodegradable mulch film, the compatibilizer comprising a PPC/PLA block copolymer. Preferably, the molar content of the PPC chain segment in the PPC/PLA block copolymer is 75% -95%, and the molar content of the PLA chain segment is 2% -5%. Preferably, the PPC/PLA block copolymer has a number average molecular weight of 80-170 kg/mol and a molecular weight distribution of 1.5-3.5. In a second aspect, the present invention provides a method for preparing the above compatibilizer, comprising the steps of: the compatilizer is prepared by copolymerization of carbon dioxide, propylene oxide and lactide under the action of a catalyst. As a preferred preparation method, the method comprises the following steps: a) Polymerization reaction Sequentially adding a self-made porphyrin aluminum system catalyst, diethyl carbonate, propylene oxide and lactide which are subjected to freeze drying to remove a solvent, and then filling carbon dioxide into a high-pressure reaction kettle subjected to anhydrous anaerobic pretreatment according to calculated amount. Heating to 65-75 ℃, and increasing the pressure in the kettle to 6-7 MPa in the reaction process. And after the set temperature is reached, starting timing, and maintaining the reaction at 65-75 ℃ for 10-12 hours. The 65 to 75 ℃ may be 65 ℃, 66 ℃, 67 ℃, 68 ℃, 69 ℃, 70 ℃, 71 ℃, 72 ℃, 73 ℃, 74 ℃, 75 ℃ or the like. The pressure of 6-7 MPa