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CN-121991495-A - Polyurethane-based light composite material and preparation method thereof

CN121991495ACN 121991495 ACN121991495 ACN 121991495ACN-121991495-A

Abstract

The invention belongs to the technical field of compositions of high molecular compounds, and discloses a polyurethane-based light composite material and a preparation method thereof. The composite material realizes pH response triggering and space positioning nucleation in a microfluidic chip by introducing a bio-based dynamic foaming regulator based on a carboxymethylated tannic acid derivative to act together with a microfluidic nucleation guide liquid, so that a highly uniform closed cell structure is formed. The density of the obtained material is The compression strength is high in batch stability, low in heat conductivity coefficient, free of halogenated hydrocarbon and environment-friendly. The invention provides a polyurethane-based light composite material with controllable structure, stable performance and environmental friendliness and a preparation method thereof. The method realizes the accurate molding of the cell structure from a nucleation source through the synergistic effect of the bio-based dynamic foaming regulation and control system and the microfluidic nucleation guiding technology, breaks through the inherent problem of the traditional foaming technology between uniformity and greenness, and provides a technical means for the green manufacturing of the high-performance light composite material.

Inventors

  • CHENG XI
  • WU MIN
  • CHENG ZHENGWEI
  • GU JING
  • ZHU WENLIN
  • CHEN ZHIMIN

Assignees

  • 湖北博兴复合材料股份有限公司

Dates

Publication Date
20260508
Application Date
20260410

Claims (10)

  1. 1. A polyurethane-based light weight composite, characterized in that the composite is composed of the following components: A polyol component, an isocyanate component, a biobased dynamic foaming regulator, a microfluidic nucleation guide liquid, a catalyst, a surfactant and optional reinforcing filler; the biobased dynamic foaming regulator is a tannic acid derivative modified by carboxymethylation, wherein not less than 3 carboxymethyl functional groups are introduced into the molecular structure of the tannic acid derivative, and the tannic acid derivative shows reversible protonizing-deprotonating transformation behavior in an aqueous phase environment with the pH value of 4.0 to 6.5; The microfluidic nucleation guide liquid is an aqueous dispersion system containing sodium bicarbonate microcrystals.
  2. 2. The polyurethane-based light weight composite of claim 1, wherein the polyol component is a polyether polyol or a polyester polyol.
  3. 3. The polyurethane-based light weight composite of claim 1 wherein the isocyanate component is diphenylmethane diisocyanate or a modified prepolymer thereof having an isocyanate group content of from 28.0% to 32.0%.
  4. 4. The polyurethane-based light composite material according to claim 1, wherein the catalyst is a composite system of an organobismuth catalyst and triethylenediamine in a mass ratio of 3:1 to 5:1, and the surfactant is a siloxane-polyether block copolymer.
  5. 5. The polyurethane-based light weight composite material according to claim 1, wherein the composite material performs space-time accurate control on a microbubble nucleation process through a microfluidic chip, the microfluidic chip comprises a main mixing channel, nucleation guide branches and a pressure balance cavity, the nucleation guide branches are led out from the side wall of the main mixing channel in a periodic array mode, and a nucleation microcavity with the diameter of 10 microns is arranged at the tail end of each branch, and the microcavity distance is 500 microns.
  6. 6. The polyurethane-based lightweight composite material as claimed in claim 1, wherein the bio-based dynamic foaming regulator has a carboxymethyl substitution degree of 0.8 to 1.2 and is added to the composite material in an amount of 0.5 to 2.0% by weight.
  7. 7. The polyurethane-based light composite material according to claim 1, wherein sodium bicarbonate microcrystals in the microfluidic nucleation guide liquid are subjected to surface silanization treatment, and 3-aminopropyl triethoxysilane is grafted on the surfaces of the sodium bicarbonate microcrystals.
  8. 8. The polyurethane-based light-weight composite material according to claim 1, wherein the microfluidic chip is made of polydimethylsiloxane or polymethyl methacrylate, and the runner layer is treated by oxygen plasma.
  9. 9. The polyurethane-based light composite material according to claim 1, wherein the reinforcing filler is nano cellulose whisker or fumed silica, the addition amount of the reinforcing filler is 0.1-1.0% by weight, the nano cellulose whisker is subjected to TEMPO oxidation treatment, the surface of the nano cellulose whisker is provided with carboxyl groups, and the fumed silica is subjected to hexamethyldisilazane treatment.
  10. 10. A process for the preparation of a polyurethane-based light weight composite material according to any one of claims 1 to 9, comprising the steps of: Mixing a polyol component, a bio-based dynamic foaming regulator, a catalyst, a surfactant and optionally a reinforcing filler to form a component A; Taking isocyanate component as B component, taking aqueous dispersion system containing sodium bicarbonate microcrystal as C component; synchronously injecting the component A and the component B into a main mixing channel of the microfluidic chip according to the volume ratio of 1:1.05 to 1:1.15, and independently injecting the component C into a nucleation guide branch; and after the nucleation triggering is completed in the microfluidic chip, the prepolymerization system is led out and cured and formed.

Description

Polyurethane-based light composite material and preparation method thereof Technical Field The invention belongs to the technical field of compositions of high molecular compounds, and relates to a polyurethane-based light composite material and a preparation method thereof. Background Polyurethane-based light composite materials have been widely used in the fields of building energy conservation, transportation, aerospace, high-end packaging and the like because of the advantages of excellent specific strength, high heat insulation performance, designability and the like, and become key components in modern light-weight material systems. In the preparation process of the material, the uniformity of the microscopic cell structure and the stability of the macroscopic mechanical property are directly determined by the foaming process, so the foaming process is regarded as a core technical link. For a long time, physical foaming agents (such as halogenated hydrocarbon compounds) are commonly used in industry as gas phase sources, and foam cell nucleation and growth are realized through volatilization and phase change of the physical foaming agents in a polymerization reaction system. The method effectively combines process controllability and cost effectiveness under early technical conditions, particularly shows good engineering adaptability in large-scale continuous production, and has obviously promoted the industrialization process of the polyurethane foam material. However, with the deepening of the green manufacturing concept and the continuous improvement of the requirements of the terminal application scene on the consistency of the material performance, the thermodynamic driving mechanism relied on by the traditional physical foaming technology gradually exposes the inherent limitations. The volatilization rate of halogenated hydrocarbon foaming agents in the system is highly dependent on the local temperature field and concentration gradient, so that the micro-bubble nucleation process lacks space-time synchronism, and further the significant dispersion of the cell size distribution is initiated. The heterogeneity of the microstructure is directly mapped into local density fluctuation on a macroscopic scale, so that the stress transmission path of the material is disordered when the material bears compressive load, and the compressive strength shows uncontrollable batch-to-batch fluctuation or even intra-batch fluctuation, thereby limiting the application of the material in high-reliability structural members. Moreover, the halogenated hydrocarbon remained in the matrix is difficult to completely remove, and can be slowly released in the later stage of material service, thus forming a potential threat to the ecological environment. Disclosure of Invention In order to achieve the aim of the invention, the invention provides a polyurethane-based light composite material and a preparation method thereof. The polyurethane-based light composite material realizes high uniformity of a cell structure and batch stability of mechanical properties on the premise of not depending on a halogenated hydrocarbon physical foaming agent by introducing a plant polyphenol derivative-based bio-based dynamic foaming regulation and control system and combining a microfluidic chip to implement space-time precise control on a microbubble nucleation process, and simultaneously remarkably improves the environmental compatibility and process controllability of the material. The polyurethane-based light composite material consists of a polyol component, an isocyanate component, a biobased dynamic foaming regulator, a microfluidic nucleation guide liquid, a catalyst, a surfactant and optional reinforcing filler. The bio-based dynamic foaming regulator is a tannic acid derivative modified by carboxymethylation, wherein not less than 3 carboxymethyl functional groups are introduced into the molecular structure of the tannic acid derivative, the tannic acid derivative shows reversible protonation-deprotonation transformation behavior in an aqueous phase environment with the pH value of 4.0 to 6.5, the microfluidic nucleation guiding liquid is an aqueous dispersion system containing sodium bicarbonate microcrystals, the microcrystal grain size distribution of the aqueous dispersion system is 1.0 to 5.0 micrometers, and the concentration of the aqueous dispersion system is 5.0 to 15.0 weight percent. The polyol component is polyether polyol or polyester polyol with the number average molecular weight of 2000-6000, the isocyanate component is diphenylmethane diisocyanate or modified prepolymer thereof, the isocyanate group content of the diphenylmethane diisocyanate or modified prepolymer is 28.0-32.0%, the catalyst is a composite system of an organobismuth catalyst and triethylene diamine, the mass ratio of the organobismuth catalyst to the triethylene diamine is 3:1-5:1, and the surfactant is a siloxane-polyether segmented copolymer