CN-121991492-A - Autonomous healing composition for fiber microcracks with shape memory property

CN121991492ACN 121991492 ACN121991492 ACN 121991492ACN-121991492-A

Abstract

The invention relates to the technical field of polymer compositions, and discloses a fiber microcrack autonomous healing composition with shape memory property, which comprises the following components: a modified polyester containing a thermoreversible dynamic covalent bond, an asymmetric polyether-polyester block copolymer interface modulator; and a thermotropic shape memory polyurethane matrix, wherein the ratio of the melt index of the interface regulator to the melt index of the modified polyester is 1.8-3.2, and the interface regulator is distributed on the periphery of the modified polyester to form core-shell micro domains, the interface regulator forms a low-viscosity flowing layer when the matrix is contracted, the directional migration of the modified polyester to the tip of the fiber microcrack is restrained, the active closure and densification filling of the crack area are realized, the microscopic holes of the repairing area are eliminated, and the mechanical continuity of the composition in a dynamic environment is maintained.

Inventors

LU XICHAO
LU SIQING
ZENG JIE
CHEN TIANBAO
LU ZHIWU

Assignees

湖南科创纺织股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260318

Claims (10)

1. A fibrous microcrack autonomous healing composition having shape memory properties comprising: 5 to 15 parts of a disperse phase component having a melting temperature of A modified polyester containing thermally reversible dynamic covalent bonds; 0.5 to 3 parts of interface regulator, wherein the interface regulator is an asymmetric polyether-polyester segmented copolymer, one end of the interface regulator is a polyether segment containing 1.5 to 3.5 mass percent of isocyanate groups, the other end of the interface regulator is a polycaprolactone segment, and the interface regulator is prepared by Melt index at temperature Melt index at equivalent temperature for the dispersed phase component 1.8 To 3.2 times; And the shape memory polymer matrix is complemented to 100 parts, and the shape memory polymer matrix has a glass transition temperature of And a number average molecular weight of 80000 to 120000, And (3) with Is 5 To 15 ; In the solid phase structure of the composition, the interface regulator is distributed on the periphery of the disperse phase component to form a core-shell micro-domain with the particle diameter of 200nm to 800nm, the polycaprolactone segment of the interface regulator is entangled with the molecular chain of the disperse phase component, and the polyether segment of the interface regulator is compatible with the carbamate segment in the shape memory polymer matrix, and reaches or exceeds the ambient temperature When the interface regulator is used, the interface regulator is firstly converted into a low-viscosity flowing layer so as to restrict the dispersed phase component to directionally fill the microcracks of the fiber under the action of shrinkage restoring stress generated by the shape memory polymer matrix.
2. The composition of claim 1, wherein the shape memory polymer matrix comprises hard segments formed by polycondensation of diphenylmethane diisocyanate and 1, 4-butanediol, and soft segments formed from polyester polyol having a number average molecular weight of 2000 to 4000, wherein the mass fraction of the hard segments is 35% to 42%, and the shape memory polymer matrix exceeds the ambient temperature The shape recovery rate is not less than 95%.
3. The autonomous healing composition for microcracks of fibers with shape memory according to claim 1 wherein the dispersed phase component is a disulfide-modified polycaprolactone obtained by chain extension of polycaprolactone diol with a number average molecular weight of 2000 with an aromatic disulfide, the dispersed phase component has a number average molecular weight of 5000 to 8000 and an internal disulfide content of 0.5 to 1.2mmol/g.
4. The autonomous healing composition of microcracks of fibers with shape memory properties of claim 1 wherein the polyether segments in the interfacial modifier have a number average molecular weight of 1000 to 2000 and the polycaprolactone segments have a number average molecular weight of 1500 to 2500.
5. The composition for autonomous healing of microcracks of fibers with shape memory properties according to claim 1, wherein the composition is prepared by premixing a shape memory polymer matrix, a dispersed phase component and an interfacial regulator, adding the mixture into a co-rotating twin-screw extruder with an aspect ratio of 40:1, and setting the temperature of the extrusion section to 160 ℃ to 190% And the rotating speed of the screw is 180rpm, and the rheological difference between the interface regulator and the disperse phase component is utilized to construct the core-shell micro-domain in the cooling crystallization process.
6. The self-healing composition of fibrous microcracks with shape memory properties of claim 1 wherein, in the presence of a filler, the filler is selected from the group consisting of To the point of Complex viscosity of interface regulator in temperature interval Complex viscosity with dispersed phase component The following logical relationship is satisfied: Wherein the complex viscosity is measured at a frequency of 1rad/s and the strain sweep is in the range of 0.1% to 10%.
7. The composition of claim 1, wherein the interfacial modifier has a polycaprolactone segment and the dispersed phase component having a solubility parameter difference of less than 0.5 (J/cm 3 The absolute value of the difference between the solubility parameters of the polyether segment of the interface regulator and the hard segment of the shape memory polymer matrix is less than 0.8 (J/cm 3) 。
8. The self-healing composition of fibrous microcrack with shape memory properties of claim 1 wherein the temperature is raised to no less than ambient temperature In the repairing action, the shrinkage restoring stress generated by the shape memory polymer matrix drives the dispersed phase component in a molten state to migrate to the tip of the fiber microcrack along the low-resistance fluid channel formed by the interface regulator.
9. The composition for autonomous healing of fiber microcracks with shape memory properties according to claim 1 wherein the composition has a molecular chain packing density of not less than 95% of the intrinsic density of the shape memory polymer matrix in the repaired area after healing of the fiber microcracks and a continuous network of molecular chains is established in the repaired area by the exchange reaction of thermally reversible dynamic covalent bonds.
10. The composition for autonomous healing of microcracks of fibers with shape memory properties according to claim 1 wherein the composition has multiple cycle healing properties and the retention of tensile strength of the composition is not less than 85% of the initial strength after 5 cycles of microcrack generation to healing at the same injury site.

Description

Autonomous healing composition for fiber microcracks with shape memory property Technical Field The invention relates to a fiber microcrack autonomous healing composition with shape memory property, belonging to the technical field of polymer compositions. Background The current self-repairing polymer composition adopts microcapsules to coat a repairing agent or blend low-melting-point components, the repairing agent is triggered and released by utilizing damage and fills cracks by means of capillary force or thermal diffusion, the large length-diameter ratio of fibers is specially characterized in that internal microcracks are in a narrow-depth geometric structure, the tip is provided with a surface tension barrier, the cracks are dynamically opened and closed under a variable-temperature circulation environment, and the physical closing force and the chemical diffusion rate are mismatched in a passive repairing mode, so that the repairing agent is lost or is difficult to permeate into the deep part of the tip. Besides morphological resistance, the micro-rheological driving mechanism also has the defects, for example, chinese patent publication No. CN113845643B discloses a shape memory polyurethane material with dual functions of active oxygen responsiveness and anti-adhesion, the scheme utilizes the dynamic exchange of diselenide bonds to be based on the chemical healing capability of the material, but the repairing action in a fiber structure is limited to isotropic substance diffusion, because no rheological guidance is established at a component phase interface, shrinkage stress generated by the shape recovery of a matrix cannot be converted into directional driving force pointing to crack tips, a molten repairing component randomly permeates into the free volume of the matrix according to the principle of minimum resistance of fluid, the free volume of the matrix cannot be overcome to be densely filled, and when the composite shape memory material and the self-healing component are combined, the matrix restoring force generates isotropic extrusion, the molten repairing component permeates into the free volume of the matrix according to the principle of minimum resistance of fluid, but not directionally migrates to crack holes with larger resistance, the ineffective diffusion reduces repairing efficiency and the density of a repairing area is uneven, and the dynamic load service requirements are difficult to meet. Therefore, how to construct a directional guiding rheology gradient in the composition, so that the macroscopic deformation energy of the matrix can be converted into the driving force for conveying the repairing agent to the crack tip, and the technical problem to be solved by the invention is solved. Disclosure of Invention In order to solve the problems in the background art, the technical scheme of the invention is as follows, a fiber microcrack autonomous healing composition with shape memory property, comprising: 5 to 15 parts of a disperse phase component having a melting temperature of A modified polyester containing thermally reversible dynamic covalent bonds; 0.5 to 3 parts of interface regulator, wherein the interface regulator is an asymmetric polyether-polyester segmented copolymer, one end of the interface regulator is a polyether segment containing 1.5 to 3.5 mass percent of isocyanate groups, the other end of the interface regulator is a polycaprolactone segment, and the interface regulator is prepared by Melt index at temperatureMelt index at equivalent temperature for the dispersed phase component1.8 To 3.2 times; And the shape memory polymer matrix is complemented to 100 parts, and the shape memory polymer matrix has a glass transition temperature of And a number average molecular weight of 80000 to 120000,And (3) withIs 5To 15; In the solid phase structure of the composition, the interface regulator is distributed on the periphery of the disperse phase component to form a core-shell micro-domain with the particle diameter of 200nm to 800nm, the polycaprolactone segment of the interface regulator is entangled with the molecular chain of the disperse phase component, and the polyether segment of the interface regulator is compatible with the carbamate segment in the shape memory polymer matrix, and reaches or exceeds the ambient temperatureWhen the interface regulator is used, the interface regulator is firstly converted into a low-viscosity flowing layer so as to restrict the dispersed phase component to directionally fill the microcracks of the fiber under the action of shrinkage restoring stress generated by the shape memory polymer matrix. Preferably, the shape memory polymer matrix comprises hard segments formed by polycondensation of diphenylmethane diisocyanate and 1, 4-butanediol, and soft segments formed by polyester polyol with a number average molecular weight of 2000 to 4000, wherein the mass fraction of the hard segments is 35 to 42%, and the shape memory polyme