CN-122011707-A - Reactive compatibilized active polylactic acid packaging material and preparation method and application thereof

CN122011707ACN 122011707 ACN122011707 ACN 122011707ACN-122011707-A

Abstract

The invention belongs to the field of food packaging materials, and particularly relates to a reactive compatibilized active polylactic acid packaging material, and a preparation method and application thereof. The reactive compatibilization, active antioxidant and antibacterial polylactic acid material is prepared by blending and melt extrusion of polylactic acid, tannic acid, polylactic acid and maleic anhydride graft copolymer, and the polylactic acid and maleic anhydride graft copolymer is prepared by blending and melt extrusion of polylactic acid, maleic anhydride and an initiator. Can be used for packaging food or flowers, and has effects of effectively delaying browning, inhibiting microorganism growth, maintaining hardness and quality, and prolonging shelf life. And the raw materials are green and degradable, the process is simple and continuous, the method is suitable for industrial production, and a new way is provided for the development of active functional packages.

Inventors

LI LI
MA WENYA
DING JIAN
FAN MIN
DONG QINGFENG
QIAN KUNPENG

Assignees

上海海洋大学

Dates

Publication Date: 20260512
Application Date: 20260122

Claims (10)

1. The reactive compatibilized active polylactic acid packaging material is characterized by being prepared by blending, melting and extruding polylactic acid, tannic acid and a polylactic acid-maleic anhydride graft copolymer, wherein the polylactic acid-maleic anhydride graft copolymer is prepared by blending, melting and extruding polylactic acid, maleic anhydride and an initiator.
2. The active polylactic acid packaging material according to claim 1, wherein the active polylactic acid packaging material is in the form of a strip, a granule or a film.
3. A preparation method of reactive compatibilized active polylactic acid packaging material is characterized by comprising the steps of blending polylactic acid, tannic acid, polylactic acid and maleic anhydride graft copolymer, and carrying out melt extrusion to obtain the strip-shaped or granular active polylactic acid packaging material.
4. The method of claim 3, wherein the step of preparing the polylactic acid-maleic anhydride graft copolymer comprises blending polylactic acid, maleic anhydride and an initiator, and melt-extruding the blend to obtain the polylactic acid-maleic anhydride graft copolymer.
5. The method according to claim 3, further comprising forming a film of the granular active polylactic acid packaging material by a melt extrusion casting process or a hot press film forming process.
6. The active polylactic acid packaging material according to claim 1 or 2 or the active polylactic acid packaging material prepared by the preparation method according to any one of claims 3 to 5 for use in preparation of packages, or the film-like active polylactic acid packaging material according to claim 2 or the film-like active polylactic acid packaging material prepared by the preparation method according to claim 5 for use in packaging foods or flowers.
7. A package comprising the active polylactic acid packaging material according to claim 1 or 2 or the active polylactic acid packaging material produced by the production method according to any one of claims 3 to 5.
8. The package of claim 7, wherein the package is useful for packaging food or flowers.
9. The package of claim 8, wherein the food product is a breath-skip type food product and the flower is a breath-skip type flower.
10. The package of claim 7, wherein the package is selected from any one of a can, bottle, bag, pouch, roll, box, case, film.

Description

Reactive compatibilized active polylactic acid packaging material and preparation method and application thereof Technical Field The invention belongs to the field of food packaging materials, and particularly relates to an active antioxidant packaging film for in-situ construction of a polylactic acid/tannic acid compatible system through melt extrusion, and a preparation method and application thereof. Background The problem of environmental pollution caused by the non-degradability of petroleum-based plastic packaging materials is increasingly severe, and the development of green degradable alternative materials has become an urgent need in the field of food packaging. Polylactic acid (PLA) is taken as an important bio-based degradable material, has the advantages of renewable sources, good processing performance, high biocompatibility and the like, and is regarded as one of ideal substitutes of traditional plastics. However, the pure PLA film has single function, does not have the active functions of antioxidation, antibiosis and the like, has gas barrier property and mechanical toughness to be improved, and the active ingredients of antioxidation, antibiosis and the like added for improving the active function of the pure PLA film greatly reduce the barrier property and the mechanical toughness, so that the high-end application of the pure PLA film in fresh-keeping packaging of perishable foods such as fresh fruits and vegetables is limited. To impart functionality to PLA films, researchers often blend natural actives (e.g., plant polyphenols, essential oils, etc.) with them. Tannic Acid (TA) is an ideal active additive as a natural polyphenol compound with excellent antioxidant and broad-spectrum antibacterial properties. However, TA is rich in phenolic hydroxyl groups and is a strongly polar substance, while PLA is a non-polar polymer, which is extremely poorly compatible. If directly and simply blended, TA is extremely easy to generate serious phase separation and agglomeration in a PLA matrix, so that holes and interface defects appear in the composite film, the mechanical property and the barrier property of the film are seriously deteriorated, uneven distribution of active ingredients can be caused, the function release is uncontrollable, and even film formation cannot be realized due to serious agglomeration. Therefore, how to improve the interfacial compatibility of PLA with TA is a core challenge to achieve PLA/TA high performance active film preparation. The existing method for improving the incompatible polymer blend system mainly comprises the steps of adding a compatibilizer, chemically modifying a matrix or filler and the like. Chemical modification methods, although remarkable in effect, often have complex synthetic routes, high cost, or involve toxic reagents, and are difficult to meet the dual requirements of safety and economy of food packaging materials. The physical blending and adding of the compatibilizer is simple in process, but most of the compatibilizer and the active ingredients lack specific interaction, the compatibilizer has limited compatibilization effect, and a new incompatible interface can be introduced. The PLA/TA compatible method which is simple in process, high in efficiency and capable of being implemented in large scale is developed, and is important to promoting the practical application of the functional degradable packaging material. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides an innovative reactive melt extrusion compatibilization strategy. In the method, commercial PLA is used as a raw material, and an initiator is utilized to trigger a PLA molecular chain to generate free radicals in the melt extrusion process, and the free radicals and a polar grafting monomer Maleic Anhydride (MAH) undergo an in-situ grafting reaction to generate PLA-g-MAH. The molecular chain of the grafted product has both a non-polar chain segment of PLA and a polar anhydride/carboxyl group of MAH, and can be used as a high molecular bridging agent. And then, carrying out secondary melt blending on the polylactic acid and the PLA matrix and TA, wherein a nonpolar part in the PLA-g-MAH is compatible with the PLA matrix, and a polar part is tightly combined with a phenolic hydroxyl group of the TA through interaction such as hydrogen bond and the like, so that a stable anchoring interface is constructed between the PLA and the TA, the dispersibility and the interfacial binding force of the TA in the PLA matrix are obviously improved, and finally, the PLA/TA active packaging film which has uniform structure, controllable mechanical property and lasting antioxidant/antibacterial function is obtained. The preparation process of the active antioxidant antibacterial packaging film for constructing the polylactic acid/tannic acid compatible system by melt extrusion is simple and continuous, and is suitable for industrial production. The ac