Supercritical fluid injection molding foaming polylactic acid foam material and preparation method thereof

A technology of supercritical fluids and foam materials, which is applied in the post-treatment and modification of cellulose pulp, can solve the problems of affecting the biological properties of PLA materials, difficult to large-scale industrial application, and reducing the degradability of materials. Melt properties, ease of industrial production, and the effect of improving melt strength

Active Publication Date: 2020-06-16
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the addition of these non-bio-based fillers will affect the biological characteristics of PLA materials and reduce the degradability of materials.
[0004] It is worth noting that the current development of PLA foam materials is still traditional chemical foaming agents and physical foaming agents such as alkanes as foaming agents. The resulting foam has large cell size and poor mechanical properties. In addition, most foaming processes use batch Foaming process is difficult to apply in large-scale industrialization

Method used

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  • Supercritical fluid injection molding foaming polylactic acid foam material and preparation method thereof
  • Supercritical fluid injection molding foaming polylactic acid foam material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] (1) The dried cellulose pulp is put into a mixed liquor whose volume ratio of toluene, acetic acid, perchloric acid and acetic anhydride is 100:80:0.2:1, wherein the mass fraction of cellulose nanofibers is 5%, at room temperature Stir at low temperature for 1 hour to obtain modified cellulose nanofiber slurry, and then wash with ethanol and deionized water in sequence to obtain an aqueous solution of surface-modified cellulose nanofibers.

[0043] (2) PLA with a weight-average molecular weight of 400,000 is added through the main feeding port of the twin-screw extruder, and then the above-mentioned modified cellulose nanofiber aqueous solution is added by the auxiliary feeding port of the extruder, and the high-shear Shear force melt blending, while removing water vapor through the exhaust port on the extruder barrel, repeated extrusion twice, the temperature of the blending barrel for the first extrusion was 99 ° C, and the screw speed was 100 rpm; the second time Ext...

Embodiment 2

[0047] (1) Putting the dried cellulose pulp into toluene, acetic acid, perchloric acid and acetic anhydride in a volume ratio of 100:80:0.4:3, wherein the mass fraction of cellulose nanofibers is 10%, at room temperature Stir for 2 hours to obtain a modified cellulose nanofiber slurry, and then wash with ethanol and deionized water in sequence to obtain a surface-modified cellulose nanofiber aqueous solution.

[0048] (2) PLA with a weight-average molecular weight of 250,000 is added through the main feeding port of the twin-screw extruder, and then the above-mentioned modified cellulose nanofiber solution is added through the auxiliary feeding port of the extruder, and the high-shear Shear force melt blending, while removing water vapor through the exhaust port on the barrel of the extruder, repeated extrusion twice, the temperature of the blending barrel for the first extrusion was 97 ° C, and the screw speed was 130 rpm; the second time The temperature of the extrusion blen...

Embodiment 3

[0052] (1) Putting the dried cellulose pulp into toluene, acetic acid, perchloric acid and acetic anhydride in a volume ratio of 100:80:0.6:5, wherein the mass fraction of cellulose nanofibers is 20%, at room temperature Stir for 3 hours to obtain a modified cellulose nanofiber slurry, and then wash with ethanol and deionized water in sequence to obtain a surface-modified cellulose nanofiber aqueous solution.

[0053] (2) PLA with a weight-average molecular weight of 150,000 is added through the main feeding port of the twin-screw extruder, and then the above-mentioned modified cellulose nanofiber solution is added through the auxiliary feeding port of the extruder, and the high-shear Shear force melt blending, while removing water vapor through the exhaust port on the extruder barrel, repeated extrusion twice, the temperature of the blending barrel for the first extrusion was 95°C, and the screw speed was 160rpm; the second time Extrusion blending cylinder temperature is 160 ...

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Abstract

The invention discloses a supercritical fluid injection molding foaming polylactic acid foam material and a preparation method thereof. The light high-strength polylactic acid foam material is prepared by modifying biological filler cellulose nanofibers, and the crystallization property and melt property of the polylactic acid material are improved by using the cellulose nanofibers as a nucleatingagent. The prepared cellulose nanofiber modified polylactic acid composite material is uniformly mixed with a supercritical fluid foaming agent in a microcellular foaming injection molding machine, and microcellular injection foaming molding is carried out through a mold opening and closing foaming device to obtain the full-bio-based polylactic acid foaming material. The microcellular foaming cellulose nanofiber / polylactic acid composite material which is uniform in cell size, high in cell density and good in performance is prepared, and the preparation method has the outstanding advantages of being high in production efficiency, high in operability, stable, reliable, easy for industrial production and the like.

Description

technical field [0001] The invention relates to the technical field of polymer material processing, in particular to a supercritical fluid injection foamed polylactic acid foam material and a preparation method thereof. Background technique [0002] Polylactic acid (Polylactide, PLA) is a thermoplastic aliphatic polyester with good mechanical properties, processability, transparency and unique barrier properties. PLA is mainly obtained by ring-opening polymerization of lactide, which is derived from starch and sugars in renewable resources such as wheat, corn, grains, rice straw, etc. PLA is completely biodegradable after being used and discarded, and the final decomposition products are carbon dioxide and water. It will not cause any pollution to the environment. It is a green and environmentally friendly material that has attracted widespread attention. It is expected to replace traditional petroleum-based plastics and be widely used in various fields. In recent years, po...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/12C08J5/06C08L67/04C08L1/02D21H11/20
CPCC08J9/122C08J9/0061C08J5/06D21H11/20C08J2203/08C08J2203/06C08J2205/044C08J2367/04C08J2401/02B29B7/48B29B7/92B29B7/94B29B7/603B29B7/845B29B7/726B29B7/7404B29C44/3442B29C44/42B29C44/3446B29K2067/046B29K2201/00C08J2201/03C08J9/0085B32B2307/54B32B2250/40B32B2307/72B32B2266/0264B32B5/18B29B7/20B29B7/90
Inventor 汪龙郑文革任倩张利华吴明辉吴飞罗海斌
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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