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CN-121975176-A - Preparation method of low-density open-cell polymer foam

CN121975176ACN 121975176 ACN121975176 ACN 121975176ACN-121975176-A

Abstract

The invention belongs to the technical field of polymer foaming material preparation, and provides a preparation method of low-density open-cell polymer foam, which comprises the following steps of (1) fully blending a non-water-soluble polymer and a water-soluble polymer template to obtain a blend, forming the blend to obtain a formed blank, wherein the content of the water-soluble polymer template in the blend is 5-wt% -90% wt%, the water-soluble polymer template is solid, (2) placing the formed blank in a reaction kettle, introducing high-pressure gas into the reaction kettle, controlling the temperature and pressure of the reaction kettle to fully saturate the formed blank, then foaming the formed blank by a pressure relief method or a temperature rising method to obtain a first foaming material, and (3) soaking a second foaming material in water, dissolving the water-soluble polymer template in the second foaming material, and drying to obtain the low-density open-cell polymer foam. The method provided by the invention can further reduce the density of the polymer foam on the basis of taking the open-cell structure into consideration.

Inventors

  • Liao xia
  • XU RUYUN
  • WANG BO

Assignees

  • 四川大学

Dates

Publication Date
20260505
Application Date
20260204

Claims (10)

  1. 1. A method of making a low density open cell polymeric foam comprising the steps of: (1) Fully blending a water-insoluble polymer and a water-soluble polymer template to obtain a blend, and forming the blend to obtain a formed blank, wherein the content of the water-soluble polymer template in the blend is 5 wt% -90 wt%, and the water-soluble polymer template is in a solid state; When the water-insoluble polymer is a material which can realize foaming only by forming a three-dimensional network structure through chemical reaction crosslinking, carrying out pre-crosslinking treatment after the blend is molded to obtain a molded blank; when the water-insoluble polymer is a material capable of realizing foaming without chemical reaction crosslinking, the blend is molded to obtain a molded blank; (2) Placing the formed blank body in a reaction kettle, introducing high-pressure gas into the reaction kettle, controlling the temperature and the pressure of the reaction kettle to fully saturate the formed blank body, and then foaming the formed blank body by a pressure relief method or a temperature rising method to obtain a first foaming material; When the water-insoluble polymer adopted in the step (1) is a material which can realize foaming only by forming a three-dimensional network structure through chemical reaction crosslinking, controlling the temperature and the pressure of a reaction kettle to enable the pre-crosslinked water-insoluble polymer in a formed blank body and a water-soluble polymer template to be foamed simultaneously, and performing post-crosslinking treatment on the obtained first foaming material after foaming to obtain a second foaming material; when the water-insoluble polymer adopted in the step (1) is a material capable of realizing foaming without chemical reaction crosslinking, controlling the temperature and the pressure of a reaction kettle to enable the water-insoluble polymer in the formed blank body and a water-soluble polymer template to be foamed simultaneously, and cooling and shaping the obtained first foaming material after foaming to obtain a second foaming material; (3) And soaking the second foaming material in water, dissolving and removing the water-soluble polymer template in the second foaming material by using water, and drying to obtain the low-density open-cell polymer foam.
  2. 2. The method of preparing a low density open cell polymeric foam according to claim 1, wherein step (1) is performed by adding a water-soluble small molecule template which is at least one of a water-soluble sugar and a water-soluble salt in preparing the blend.
  3. 3. The method of preparing a low density open cell polymeric foam according to claim 2, wherein the amount of water soluble small molecular templates used in step (1) is controlled such that the amount of water soluble small molecular templates in the blend is no more than 30 wt%.
  4. 4. The method of preparing a low density open cell polymer foam of claim 1, wherein the water-soluble polymer template is one or more of water-soluble polyethylene glycol, water-soluble polyvinyl alcohol, water-soluble polyacrylic acid, water-soluble polyacrylamide, and water-soluble polyvinylpyrrolidone.
  5. 5. The method of preparing a low density open cell polymeric foam according to any one of claims 1 to 4, wherein the water insoluble polymer is a water insoluble thermoplastic polymer, a water insoluble thermoset polymer, or a blend of a water insoluble thermoplastic polymer and a water insoluble thermoset polymer.
  6. 6. The method of preparing a low density open cell polymer foam according to claim 5, wherein the thermoplastic polymer comprises at least one of polyolefin, polyester, polycarbonate, polymethyl methacrylate, polyamide, polystyrene, and thermoplastic polyurethane, and the thermosetting polymer comprises at least one of epoxy resin, phenolic resin, thermosetting polyurethane, thermosetting rubber, and unsaturated polyester resin.
  7. 7. The method for producing a low-density open-cell polymer foam according to any one of claims 1 to 4, wherein when the step (2) is foaming by a pressure relief method, the pressure of the reaction vessel is controlled to be 1 to 30 MPa, the temperature of the reaction vessel is controlled to be 50 to 180 ℃, and the pressure relief method is operated such that the pressure of the reaction vessel is rapidly reduced to normal pressure after the molded green body is sufficiently saturated, thereby obtaining the first foaming material.
  8. 8. The method for producing a low-density open-cell polymer foam according to any one of claims 1 to 4, wherein when the step (2) is foaming by a temperature-raising method, the pressure of the reaction vessel is controlled to be 1 to 20 MPa, the temperature of the reaction vessel is controlled to be 0 to 50 ℃, the operation of foaming by the temperature-raising method is that after the molded green body is sufficiently saturated, the pressure of the reaction vessel is reduced to normal pressure, the molded green body saturated in the reaction vessel is taken out, and the temperature-raising foaming is performed, thereby obtaining the first foaming material.
  9. 9. The method for producing a low-density open-cell polymer foam according to any one of claims 1 to 4, wherein the saturation time is controlled to be 10min to 24 h in the step (2).
  10. 10. The method of producing a low-density open-cell polymer foam according to any one of claims 1 to 4, wherein in the step (3), the temperature of water used for immersing the second foaming material is 20 to 100 ℃.

Description

Preparation method of low-density open-cell polymer foam Technical Field The invention belongs to the technical field of polymer foaming material preparation, and relates to a preparation method of low-density open-cell polymer foam. Background The polymer foam has light weight, high specific surface area and designable pore structure, so that the polymer foam is focused in the fields of high-efficiency oil-water separation, biomedical tissue engineering, acoustics and the like. The use in these fields places a common core requirement on polymer foams, low density and open cell structure, on the one hand to provide storage space for the substance and on the other hand to ensure substance transport and cell migration. The low density and open cell structure complement each other to form a physical basis for functional application of the polymer foam. However, in engineering practice, the synergistic realization of both features of low density and open cell structure is faced with a great challenge. At present, the preparation methods of polymer foam mainly comprise a chemical foaming agent method, a supercritical fluid foaming method and a template method. Although these mainstream polymer foam production methods are long, they have inherent disadvantages that are difficult to achieve. The chemical foaming agent method has mature process, but the chemical foaming agent can generate toxic byproducts in the decomposition process, has the problems of environmental pollution and poor biocompatibility of products, and is difficult to meet the strict requirements of green manufacturing and biomedical fields on the purity of materials. The supercritical fluid foaming method is environment-friendly, foam with uniform foam pore structure and no impurity residue can be prepared, and low density can be realized by adjusting foaming parameters, but the foam prepared by the method is usually of a closed pore structure and cannot be applied to scenes requiring an open pore structure. The template method is an effective way for preparing the open-cell foam, and the soluble pore-forming agent and the polymer matrix are blended and formed and then leached out, so that the three-dimensional structure of the pore-forming agent is duplicated to form a communicating pore canal, but the pore structure of the foam prepared by the method is seriously dependent on the physical characteristics (such as particle size, shape and the like) and stacking mode of the pore-forming agent, so that the regulation and control flexibility of the pore structure is insufficient, meanwhile, the addition amount of the pore-forming agent has a critical threshold value, and if the addition amount of the pore-forming agent exceeds the critical threshold value, the stability of the cell structure cannot be maintained after the pore-forming agent is leached out, and the cell collapse is caused. Thus, the templating method also has inherent limitations in synergistically achieving low density and open cell structures. Kangkang Zhang et al disclose a method for preparing a highly-connected polycaprolactone porous scaffold by supercritical carbon dioxide foaming-polymer leaching (see Fabrication of highly interconnected porous poly(caprolactone) scaffolds with supercritical CO2 foaming and polymer leaching[J], J Mater Sci (2019)54:5112-5126）.. The method is to blend and press-mold Polycaprolactone (PCL) and polyethylene oxide (PEO), rapidly release pressure and foam after saturation by supercritical carbon dioxide, and remove PEO by water washing to obtain a PCL porous scaffold, which is found in the research, only the PCL phase expands during foaming, the PEO phase does not foam, resulting in limited effect on reducing the overall density of the porous scaffold, making significant densification difficult to achieve, there remains a need for more efficient methods for preparing low density open cell polymer foams that further reduce the density of the polymer foam while compromising the open cell structure. Disclosure of Invention Aiming at the problem that the prior art is difficult to effectively realize both an open-cell structure and low density in the preparation of the polymer foam, the invention provides a preparation method of the low-density open-cell polymer foam, so as to further reduce the density of the polymer foam on the basis of considering the open-cell structure. In order to achieve the above purpose, the invention adopts the following technical scheme: a method of making a low density open cell polymeric foam comprising the steps of: (1) Fully blending a water-insoluble polymer and a water-soluble polymer template to obtain a blend, and forming the blend to obtain a formed blank, wherein the content of the water-soluble polymer template in the blend is 5 wt% -90 wt%, and the water-soluble polymer template is in a solid state; When the water-insoluble polymer is a material which can realize foaming only by forming a three-dimensional netwo