Glass-like polymer fiber and preparation method thereof
阅读说明：本技术 一种类玻璃高分子纤维及其制备方法 (Glass-like polymer fiber and preparation method thereof ) 是由 杨曙光 刘泽新 薛冰 朱丽萍 黄浩 刘虎 于 2021-08-18 设计创作，主要内容包括：本发明涉及一种类玻璃高分子纤维的制备方法,是先以含有动态共价键的热交联剂与热塑性聚合物为原料,采用熔融纺丝工艺进行挤出、冷却并卷绕成初生纤维；再将初生纤维进行热交联处理得到类玻璃高分子纤维,动态共价键为硼氧键、动态碳碳双键、碳硫键和亚胺键中的一种以上；且熔融纺丝的温度不高于含有动态共价键的热交联剂的分解温度；挤出前熔融纺丝体系的交联密度小于1*10～(-7)mol·cm～(-3)。制得的类玻璃高分子纤维的交联密度为2.2*10～(-5)～8.6*10～(-)～(5)mol·cm～(-3)；将类玻璃高分子纤维剪断后搭接,并在60～100℃下愈合24～72h后,其拉伸强度和断裂伸长率恢复到剪断前的80％以上。本发明的方法工艺简单,且赋予了聚合物耐溶剂性、自愈合性和可回收性等。(The invention relates to a preparation method of glass-like polymer fiber, which comprises the steps of taking a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; then carrying out thermal crosslinking treatment on the nascent fiber to obtain the glass-like polymer fiber, wherein the dynamic covalent bonds are boron-oxygen bonds, dynamic carbon-carbon double bonds and carbon-sulfur bondsAnd imine bond; the temperature of the melt spinning is not higher than the decomposition temperature of the thermal cross-linking agent containing the dynamic covalent bonds; the melt-spun system before extrusion has a crosslinking density of less than 1 x 10 ‑7 mol·cm ‑3 . The crosslinking density of the prepared glass-like polymer fiber is 2.2 x 10 ‑5 ～8.6*10 ‑ 5 mol·cm ‑3 (ii) a Shearing and lapping the glass-like polymer fibers, and healing the glass-like polymer fibers at the temperature of 60-100 ℃ for 24-72 hours, wherein the tensile strength and the elongation at break of the glass-like polymer fibers are recovered to be more than 80% of those before shearing. The method has simple process, and endows the polymer with solvent resistance, self-healing property, recyclability and the like.)
1. A preparation method of glass-like polymer fibers is characterized by comprising the following steps: firstly, using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; then carrying out thermal crosslinking treatment on the nascent fiber to obtain glass-like polymer fiber;
the dynamic covalent bond is more than one of a boron-oxygen bond, a dynamic carbon-carbon double bond, a carbon-sulfur bond, an imine bond and a trithiocarbonate bond;
the temperature of the melt spinning is not higher than the decomposition temperature of the thermal cross-linking agent containing dynamic covalent bonds; and the cross-linking density of the melt spinning system before extrusion is less than 1 x 10-7mol·cm-3。
2. The method for preparing glass-like polymer fiber according to claim 1, wherein the temperature of melt spinning is 160-265 ℃.
3. The method of claim 1, wherein the thermoplastic polymer is one or more of SBS, SBR, PB, LDPE and PMMA.
4. The method of claim 1, wherein the amount of the thermal crosslinking agent containing dynamic covalent bonds is 1 to 5phr of the thermoplastic polymer;
the thermal cross-linking agent containing dynamic covalent bonds is more than one of dimercapto boric acid ester, sym-triphenylmethylene amino ethanethiol, 1, 3-propanedithiol, p-dioxaborolan dibutyl pyrrole dione, dimercaptodifuran-maleimide addition compound and diene compounds containing trithiocarbonate structural elements;
when the cross-linking agent is 1, 3-propanedithiol, trimethyl sulfonium iodide is also added into the raw materials;
when the cross-linking agent is p-dioxaphenylborane dibutylpyrrole dione, dicumyl peroxide is also added into the raw material.
5. The method for preparing glass-like polymer fiber according to claim 1, wherein the thermoplastic polymer is vacuum dried at 60-80 ℃ for 8-12 hours before the melt spinning process.
6. The preparation method of the glass polymer-like fiber according to claim 1, wherein in the melt spinning process, the screw rotation speed is 60-80 rpm, the melting time of the raw material is 5-15 min, and the extrusion speed is 10-20 rpm.
7. The method for preparing glass-like polymer fiber according to claim 1, wherein the thermal crosslinking treatment is carried out by placing the nascent fiber in a vacuum drying oven for reaction, and the process parameters are as follows: the reaction temperature is 100-130 ℃, the vacuum degree is-0.1-0.08 MPa, and the reaction time is 72-96 h.
8. The glass-like polymer fiber prepared by the method according to any one of claims 1 to 7, wherein the method comprises the following steps: the cross-linking density of the glass-like polymer fiber is 2.2 x 10-5～8.6*10-5mol·cm-3(ii) a Shearing and lapping the glass-like polymer fibers, and healing the glass-like polymer fibers at the temperature of 60-100 ℃ for 24-72 hours, wherein the tensile strength and the elongation at break of the glass-like polymer fibers are recovered to be more than 80% of those before shearing.
9. The glass-like polymer fiber according to claim 8, wherein the glass-like polymer fiber has an elongation at break of 400 to 1000%, a monofilament strength of 18 to 32MPa, and an average monofilament diameter of 0.16 to 0.30 mm; the glass-like polymer fiber is insoluble in a solvent with the temperature of 60-80 ℃, and the solvent is a good solvent of a thermoplastic polymer contained in the glass-like polymer fiber.
Technical Field
The invention belongs to the technical field of polymer fibers, and relates to a glass-like polymer fiber and a preparation method thereof.
Background
At present, plastics and rubbers have become indispensable high molecular materials for human life. However, the conventional thermoplastic polymer has a linear structure, and the mechanical properties and solvent resistance of the conventional thermoplastic polymer are poor, so that the application of the conventional thermoplastic polymer is greatly limited. The introduction of covalently crosslinked networks in these material systems can effectively improve the mechanical properties and solvent resistance of the materials. Crosslinked polymer materials have been widely used in industrial society and production life, for example, tires, shoes, seals, medical implants, shock absorbers, and the like. However, the greatest disadvantage of these conventional crosslinked materials is their poor recyclability and lack of repairability. For example, in document 1 (formulation and morphology of polybutadiene rubber fibers prepared by a method of electrospinning and in-situ photocrosslinking, J. Materials Letters,2011:3076 and 3079), a method for preparing polybutadiene rubber fibers with high form stability is disclosed, and the prepared crosslinked polybutadiene rubber fibers can well maintain the form after being stored in tetrahydrofuran (good polybutadiene solvent) at normal temperature for a long time. However, the fiber prepared by the method adopts the traditional chemical crosslinking, cannot be processed secondarily and is difficult to recover, and on the other hand, a solvent is also needed during electrostatic spinning, so that the environment is greatly influenced; and the prepared fiber is easy to generate adhesion and a special-shaped structure, so that the mechanical property of the fiber is greatly reduced, and the application range of the fiber is limited.
In 2011, Leibler et al constructed a dynamic covalent bond network based on crosslinking of epoxy resin and anhydride, and put forward a new concept of "Vitrimer" for the first time, and the university of qinghua wished to call it as a glass-like polymer, which initiated research in the field of dynamic covalent bond polymer materials. Under the action of external environment stimulation (such as heat, light, force, pH and the like), the breakage and recombination of dynamic covalent bonds in the material can dynamically adjust the topological structure of the macromolecular network; when the stimulus is eliminated, the dynamic covalent bond polymer can show high stability as common covalent bond polymers. However, the introduction of Dynamic covalent bond crosslinking structure into polymer materials in the prior art is generally limited to the use of hot-press molding process to make polymer materials into films, pellets, etc., as in document 2 (polymeric vitamins Based on peroxide Chemistry and Dual Networks with Static and Dynamic Cross-links [ J ] Macromolecules,2019:7102-7113.) Polybutadiene with double-network structure having Dynamic and Static crosslinking characteristics is prepared by radical grafting, all synthetic elastomer glass bodies have better creep resistance and can be processed and recycled repeatedly; however, these products have a low degree of orientation and are difficult to obtain better mechanical properties, thereby limiting their wider application. For example, when used as a composite reinforcement, the fibers can be uniformly distributed in a plastic matrix, resulting in a microstructure with similar Interpenetrating Polymer Networks (IPNs) forming a new composite that surpasses conventional toughened plastics in mechanical properties, particularly toughness and impact strength. Therefore, it is important to develop a glass-like polymer material in a fiber form.
However, conventional crosslinked fibers cannot be recycled and reprocessed, rendering microfibers the largest source of plastic contamination. In addition, when the fiber is prepared, the requirements on the fluidity, viscosity and stability of the raw materials are high, and the fiber is more difficult to form after a large amount of dynamic chemical bonds are introduced for crosslinking. Particularly, when the rubber fiber is prepared, the conditions of adhesion, a bead structure or a special-shaped structure and the like are easy to occur in electrostatic spinning, and the fiber prepared by a melt-blowing method has poor controllability of the dimension, wider diameter distribution and poor fiber continuity.
Therefore, it is important to develop a recyclable and repairable crosslinked polymer fiber material having good mechanical properties and solvent resistance.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a glass-like polymer fiber and a preparation method thereof. The method comprises the following steps: a dynamic covalent bond cross-linking structure is introduced into a spinning raw material, and dynamic covalent bond polymers are polymer materials containing dynamic covalent bonds and comprise linear and cross-linked dynamic covalent bond polymers. Therefore, the invention utilizes the material to improve the mechanical property and solvent resistance of the high molecular material (the uncrosslinked thermoplastic polymer has a linear structure and poor mechanical property, is quickly dissolved in a good solvent, and is obviously improved after crosslinking), and realizes the self-repairing and easy-recycling properties of the high molecular material (common chemical bond crosslinking can cause the high molecular material to be converted into a thermosetting polymer, so that reprocessing and recycling can not be carried out).
In order to achieve the purpose, the invention adopts the following scheme:
a glass-like polymer fiber preparation method, use cross-linking agent and thermoplastic polymer containing dynamic covalent bond as raw materials first, adopt the melt spinning process to extrude, cool and wind into the nascent fiber; crosslinking the nascent fiber to obtain glass-like polymer fiber;
the dynamic covalent bond is more than one of a boron-oxygen bond, a dynamic carbon-carbon double bond, a carbon-sulfur bond, an imine bond and a trithiocarbonate bond;
the temperature of the melt spinning conforms to the processing temperature of the thermoplastic polymer and is not higher than the decomposition temperature of the thermal cross-linking agent containing the dynamic covalent bonds;
the thermoplastic polymer system containing dynamic covalent bonds before extrusion has a crosslinking density of less than 1 x 10-7mol·cm-3(the effective number of network chains per unit volume of crosslinked elastomer, i.e., crosslink density, is an important characteristic parameter of crosslinked polymers crosslink density can be expressed as network chain density (v)e) Crosslink density (. mu.)e) And average molecular mass (Mc) of the segment between the crosslinking points. The network chain density refers to the number of network chains contained in unit volume of the elastomer, and the crosslinking point density refers to the elastomerNumber of crosslinking points per unit volume. These three parameters may be interconverted). The cross-linking density of the melt spinning system before extrusion is more than or equal to 1 x 10-7mol·cm-3When the fiber is extruded, the shape of the strand, the sharkskin, or the like is broken due to the failure to form a stable fluid, and thus the fiber cannot be formed.
As a preferred technical scheme:
in the preparation method of the glass-like polymer fiber, the temperature of melt spinning is 160-265 ℃.
In the above method for preparing glass-like polymer fiber, the thermoplastic polymer is a double bond-containing thermoplastic polymer, such as: one or more of SBS (styrene-butadiene-styrene block copolymer), SBR (styrene butadiene rubber), PB (polybutadiene), LDPE (low density polyethylene) and PMMA (polymethyl methacrylate).
The preparation method of the glass polymer-like fiber is characterized in that the addition amount of the crosslinking agent containing the dynamic covalent bond is 1-5 phr of the thermoplastic polymer; the dosage of the cross-linking agent is too small, and an effective cross-linking network cannot be formed by too low cross-linking density; if the dosage of the cross-linking agent is too much, the cross-linking degree is too high, and a formed cross-linking network is too compact, so that the mechanical property of the polymer is reduced;
the cross-linking agent containing dynamic covalent bonds is more than one of dimercapto boric acid ester (BDB) (containing boron-oxygen bonds), mesitylene methylene amino ethyl mercaptan (containing imine bonds), 1, 3-propanedithiol (containing C-S bonds), p-dioxaborolidine dibutyl pyrrole dione (containing boron-oxygen bonds), dimercapto difuran-maleimide addition products (containing dynamic carbon-carbon double bonds) and diene compounds (containing trithiocarbonate bonds) containing trithiocarbonate structural elements;
when the cross-linking agent is 1, 3-propanedithiol, trimethyl sulfonium iodide is also added into the raw materials; trimethylsulfonium iodide (TMSI) is added in an amount of 2 wt% of the mass fraction of the thermoplastic polymer; TMSI can promote dynamic bond cleavage rearrangement (C-S bonds are dynamically cleaved by methyl exchange with TMSI, thereby detaching from the covalently cross-linked network, creating pendant chains, thereby promoting rearrangement of the network topology).
When the cross-linking agent is p-dioxaphenylborane dibutyl pyrrole diketone, dicumyl peroxide is also added into the raw material; dicumyl peroxide (DCP) is added in an amount of 0.05% by weight based on the mass fraction of the thermoplastic polymer. DCP is an initiator for promoting a crosslinking reaction (an initiator for radical polymerization. the heat resistance and weather resistance of the article can be improved).
According to the preparation method of the glass-like polymer fiber, the thermoplastic polymer is dried in vacuum for 8-12 hours at the temperature of 60-80 ℃ before the melt spinning process.
In the preparation method of the glass-like polymer fiber, in the melt spinning process, the rotating speed of a screw is 60-80 rpm, and the melting time of the raw materials is 5-15 min (set by controlling the crosslinking density); extrusion speed is 10 ~ 20rpm, the spinneret orifice diameter is 0.25mm, winding speed is 15m/min, extrusion speed is too big, thereby the too big fibre shaping difficulty of extrusion pressure can result in to the spinneret orifice diameter undersize, produce and extrude and break, winding speed is too fast can lead to the fibre fracture because of the too big draft ratio, thereby extrusion speed undersize can lead to extruding pressure too little thereby thermoplastic elastomer can't extrude smoothly, winding speed undersize makes the fibre draft insufficient, mechanical properties is relatively poor.
In the preparation method of the glass-like polymer fiber, the thermal crosslinking treatment is to place the nascent fiber in a vacuum drying oven for reaction, and the process parameters are as follows: the reaction temperature is 100-130 ℃, the vacuum degree is-0.1-0.08 MPa, and the reaction time is 72-96 h.
The invention also provides the glass-like polymer fiber prepared by the preparation method of the glass-like polymer fiber, wherein the crosslinking density of a glass-like polymer fiber system in the glass-like polymer fiber is 2.2 to 10-5～8.6*10- 5mol·cm-3(ii) a Shearing and lapping the glass-like polymer fibers, and healing the glass-like polymer fibers at the temperature of 60-100 ℃ for 24-72 hours, wherein the tensile strength and the elongation at break of the glass-like polymer fibers are recovered to be more than 80% of those before shearing.
As a preferred technical scheme:
the glass-like polymer fiber has the breaking elongation of 400-1000%, the monofilament strength of 18-32 MPa (the monofilament strength of the thermoplastic polymer fiber is improved by 3 times (the monofilament strength of the thermoplastic polymer fiber is 6-10 MPa)) and the average monofilament diameter of 0.16-0.30 mm; the glass-like polymer fiber is insoluble in a solvent with the temperature of 60-80 ℃, wherein the solvent is a good solvent of a thermoplastic polymer contained in the glass-like polymer fiber (wherein, when the thermoplastic polymer is low-density polyethylene, the solvent resistance of the low-density polyethylene is good, and the solvent resistance of the crosslinked fiber prepared by the method can be further improved after the crosslinked fiber is prepared, namely, the prepared fiber is not dissolved in the solvent with the temperature of below 80 ℃).
The crosslink density of the present invention was obtained using an equilibrium swelling test (reference: Covalently Cross-Linked Elastomers with Self-Healing and Malleable abilites Enable by boron Ester Bonds [ J ]. ACS appl. Mater. interfaces,2018: 24224-: the crosslink density was determined by equilibrium swelling experiments in toluene, according to the Flory-Rehner equation. The specific operation is to soak the sample to be tested in the good solvent of the thermoplastic polymer for 72 hours at room temperature, and the solvent is replaced every 24 hours. After the swelling is balanced, quickly wiping off the solvent on the surface of the sample by using filter paper, immediately weighing, and then drying in a vacuum oven at the temperature of 60-80 ℃ to constant weight. 3 samples were measured for each sample and the crosslink density was calculated by Flory-Rehner equation.
The mechanism of the invention is as follows:
the single fibers with uniform diameter distribution are obtained by a thermoplastic polymer and a crosslinking agent containing dynamic covalent bonds in a melt spinning mode, the melt spinning process is different from electrostatic spinning, the electrostatic spinning is not influenced by electrostatic action, the obtained fibers have no phenomena of abnormity, bead strings and the like, the melt spinning does not need an organic reagent, the environment is protected, when the crosslinking degree is too high, the thermoplastic polymer crosslinked by the chemical covalent bonds is converted into thermosetting and cannot be processed, and if the thermoplastic polymer containing the dynamic covalent bonds is heated, the topological structure of the thermoplastic polymer is rearranged to enable the thermoplastic polymer to have fluidity (dynamic covalent bond breakage and recombination induce the adjustment of the internal network structure of the polymer), but melt breakage is easy to occur during melt spinning and silk forming cannot be realized.
The invention firstly proposes the adoption of the method of introducing dynamic covalent bonds and simultaneously reducing the crosslinking degree (the crosslinking density is less than 1 x 10)- 7mol·cm-3) The fiber is extruded into filaments, and then secondary crosslinking is carried out, so that the fiber form can be maintained, the glass-like polymer fiber with high crosslinking degree can be obtained, and dynamic chemical bonds in the glass-like polymer fiber can be broken and recombined under the action of external environmental stimuli (such as heat, light, force, pH and the like) so as to induce the polymer network structure in the fiber to carry out dynamic adjustment; when the environmental stimulus is eliminated, the dynamic covalent bond polymer can show high stability, excellent mechanical property and solvent resistance which are similar to the common covalent bond polymer.
Advantageous effects
(1) The preparation method of the glass-like polymer fiber has the advantages of simple process, strong operability, no solvent in the curing process, green and environment-friendly preparation process and suitability for industrial production;
(2) the preparation method of the glass-like polymer fiber successfully spins the thermoplastic polymer into the glass-like polymer fiber by melt spinning by utilizing dynamic chemical bonds, and endows the polymer with certain new properties such as solvent resistance, self-healing property, recoverability and the like.
Detailed Description
The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying the SBS at 60 ℃ for 12 h;
thermal crosslinkers containing dynamic covalent bonds: dimercapto phenyl boronate (the corresponding dynamic covalent bond is a boron oxygen bond).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the addition amount of the dimercapto phenylboronic acid ester is 5phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 190 ℃, the screw rotating speed is 60rpm, the melting time of the raw materials is 5min, the extrusion speed is 15rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 8.5 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 120 ℃, the vacuum degree is-0.1 MPa, and the reaction time is 80 h.
The crosslinking density of the prepared glass-like polymer fiber is 6.1 x 10-5mol·cm-3The elongation at break is 650 percent, the monofilament strength is 29MPa, and the average diameter of the monofilament is 0.25 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 24h to restore the tensile strength to 87% of that before shearing; the elongation at break is recovered to 90 percent before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 2
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying SBR for 8h at 80 ℃;
thermal crosslinkers containing dynamic covalent bonds: sym-triphenylmethylene aminoethanethiol (the corresponding dynamic covalent bond is an imine bond).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein the addition amount of the s-triphenylmethylene aminoethanethiol in the raw materials is thermoplastic2phr of polymer; in the melt spinning process, the melt spinning temperature is 180 ℃, the screw rotating speed is 70rpm, the melting time of the raw materials is 10min, the extrusion speed is 10rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 8 × 10- 8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 110 ℃, the vacuum degree is-0.1 MPa, and the reaction time is 96 h.
The crosslinking density of the prepared glass-like polymer fiber is 3.6 x 10-5mol·cm-3The elongation at break is 920 percent, the strength of the monofilament is 20MPa, and the average diameter of the monofilament is 0.18 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 60 ℃ for 72h, wherein the tensile strength of the glass-like polymer fiber is restored to 84% of that before shearing; the elongation at break is recovered to 86% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 3
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying PB at 70 deg.C for 10 h;
thermal crosslinkers containing dynamic covalent bonds: 1, 3-propanedithiol (the corresponding dynamic covalent bond is a carbon-sulfur bond);
additive: trimethylsulfonium iodide (TMSI) was added in an amount of 2 wt% of the mass fraction of PB.
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the adding amount of the 1, 3-propanedithiol is 1phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 190 ℃, the screw rotating speed is 80rpm, the melting time of the raw materials is 12min, the extrusion speed is 20rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.2 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 130 ℃, the vacuum degree is-0.1 MPa, and the reaction time is 72 h.
The crosslinking density of the prepared glass-like polymer fiber is 2.2 x 10-5mol·cm-3The elongation at break is 1000%, the strength of the monofilament is 18MPa, and the average diameter of the monofilament is 0.3 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 90 ℃ for 48h, wherein the tensile strength of the glass-like polymer fiber is restored to 84% of that before shearing; the elongation at break is recovered to 87% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 4
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying PB at 70 deg.C for 10 h;
thermal crosslinkers containing dynamic covalent bonds: dimercaptodifuran-maleimide adducts (the corresponding dynamic covalent bonds are dynamic carbon-carbon double bonds).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the addition amount of the dimercaptodifuran-maleimide adduct is 4phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 190 ℃, the screw rotating speed is 75rpm, the melting time of the raw materials is 12min, the extrusion speed is 15rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 8.2 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 125 ℃, the vacuum degree is-0.1 MPa, and the reaction time is 85 h.
The crosslinking density of the prepared glass-like polymer fiber is 4.2 x 10-5mol·cm-3The elongation at break is 710%, the strength of the monofilament is 26MPa, and the average diameter of the monofilament is 0.25 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 32h to restore the tensile strength to 85% of that before shearing; the elongation at break is recovered to 86% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 5
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying of PMMA at 80 ℃ for 11 h;
thermal crosslinkers containing dynamic covalent bonds: diene compounds containing trithiocarbonate structural motifs (the preparation method is referred to as DOI:10.1021/ma100378r) (the corresponding dynamic covalent bonds are trithiocarbonate bonds).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the addition amount of the diene compound containing trithiocarbonate structural elements is 3phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 265 ℃, the screw rotating speed is 80rpm, the melting time of the raw materials is 15min, the extrusion speed is 10rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 8.1 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 100 ℃, the vacuum degree is-0.09 MPa, and the reaction time is 80 h.
The crosslinking density of the prepared glass-like polymer fiber is 7.2 x 10-5mol·cm-3The elongation at break is 400 percent, the strength of the monofilament is 19MPa, and the average diameter of the monofilament is 0.16 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 100 ℃ for 24h, wherein the tensile strength of the glass-like polymer fiber is recovered to 90% of that before shearing; the elongation at break is recovered to 91% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 6
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying the mixture of SBS and SBR at 70 deg.C for 9 hr (mass ratio of 1: 1);
thermal crosslinkers containing dynamic covalent bonds: dimercapto phenyl boronate (the corresponding dynamic covalent bond is a boron oxygen bond).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the addition amount of the dimercapto phenylboronic acid ester is 3phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 190 ℃, the screw rotating speed is 60rpm, the melting time of the raw materials is 5min, the extrusion speed is 15rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.9 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 120 ℃, the vacuum degree is 0.1MPa, and the reaction time is 85 h.
The crosslinking density of the prepared glass-like polymer fiber is 5.6 x 10-5mol·cm-3The elongation at break is 800 percent, the strength of the monofilament is 28MPa, and the average diameter of the monofilament is 0.26 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 75 ℃ for 48h, wherein the tensile strength of the glass-like polymer fiber is recovered to 94% of that before shearing; the elongation at break is recovered to 96% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 7
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying SBS at 80 deg.C for 12 hr;
thermal crosslinkers containing dynamic covalent bonds: dimercapto-phenyl borate and s-triphenylmethylene amino ethanethiol with the same mass fraction (corresponding dynamic covalent bonds are boron-oxygen bonds and carbon-sulfur bonds respectively).
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, in the raw materials, the addition amounts of dimercapto boric acid ester and s-triphenylmethylene aminoethanethiol are both 2phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 190 ℃, the screw rotating speed is 60rpm, the melting time of the raw materials is 5min, the extrusion speed is 15rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 8.5 x 10-8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 120 ℃, the vacuum degree is-0.1 MPa, and the reaction time is 72 h.
The crosslinking density of the prepared glass-like polymer fiber is 4.4 x 10-5mol·cm-3The elongation at break is 770%, the strength of the monofilament is 30MPa, and the average diameter of the monofilament is 0.23 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 36h, wherein the tensile strength of the glass-like polymer fiber is recovered to 95% of that before shearing; the elongation at break is recovered to 97% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 8
A preparation method of glass-like polymer fibers comprises the following steps:
(1) preparing raw materials:
thermoplastic polymer (b): vacuum drying the LDPE at 65 ℃ for 11 h;
thermal crosslinkers containing dynamic covalent bonds: p-dioxaphenylborane dibutylpyrrole dione (the corresponding dynamic covalent bond is a boron-oxygen bond);
additive: dicumyl peroxide (DCP) was added in an amount of 0.05 wt% based on the mass fraction of LDPE.
(2) Using a thermal cross-linking agent containing dynamic covalent bonds and a thermoplastic polymer as raw materials, extruding, cooling and winding into nascent fiber by adopting a melt spinning process; wherein, the addition amount of the p-dioxaphenylborane dibutyl pyrrole dione in the raw materials is 5phr of the thermoplastic polymer; in the melt spinning process, the melt spinning temperature is 160 ℃, the screw rotating speed is 65rpm, the melting time of the raw materials is 15min, the extrusion speed is 15rpm, and the crosslinking density of a melt spinning system before extrusion is ensured to be 9.6 x 10- 8mol·cm-3。
(3) Placing the nascent fiber in a vacuum drying oven for reaction to obtain glass-like polymer fiber; wherein the reaction temperature is 120 ℃, the vacuum degree is-0.08 MPa, and the reaction time is 80 h.
The crosslinking density of the prepared glass-like polymer fiber is 8.6 x 10-5mol·cm-3The elongation at break is 780%, the strength of the monofilament is 32MPa, and the average diameter of the monofilament is 0.2 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 100 ℃ for 24h, wherein the tensile strength of the glass-like polymer fiber is recovered to 90% of that before shearing; the elongation at break is recovered to 93 percent before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 80 ℃, wherein the solvent is a good solvent (such as benzene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 9
The preparation method of the glass-like polymer fiber is basically the same as that in example 1, except that the thermoplastic polymer is replaced by SBR which is dried in vacuum for 8 hours at 80 ℃, the melting temperature is adjusted to 180 ℃, and a melt spinning system before extrusion is ensuredHas a crosslinking density of 8.8 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 6.3 x 10-5mol·cm-3The elongation at break is 620%, the strength of the monofilament is 30MPa, and the average diameter of the monofilament is 0.26 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 24h to restore the tensile strength to 85% of that before shearing; the elongation at break is recovered to 87% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene and tetrahydrofuran) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 10
The preparation method of the glass-like polymer fiber is basically the same as that in example 1, except that the thermoplastic polymer is replaced by PB dried for 10 hours in vacuum at 70 ℃, and the crosslinking density of a melt spinning system before extrusion is ensured to be 9.0 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 6.5 x 10-5mol·cm-3The elongation at break is 670%, the strength of the monofilament is 28MPa, and the average diameter of the monofilament is 0.28 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 24h to restore the tensile strength to 87% of that before shearing; the elongation at break is recovered to 89% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 11
The preparation method of the glass-like polymer fiber is basically the same as that in example 2, except that the thermoplastic polymer is replaced by SBS which is dried in vacuum for 12 hours at 60 ℃, the melting temperature is adjusted to 190 ℃, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.6 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 3.4 x 10-5mol·cm-3Elongation at break of 950%, monofilament strength of 19MPa, and average monofilament diameter of0.17mm；
Shearing the glass-like polymer fiber, overlapping, and healing at 60 ℃ for 72h, wherein the tensile strength of the glass-like polymer fiber is recovered to 80% of that before shearing; the elongation at break is recovered to 82% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 12
The preparation method of the glass-like polymer fiber is basically the same as that in example 2, except that the thermoplastic polymer is replaced by PB which is dried for 10 hours in vacuum at 70 ℃, the melting temperature is adjusted to 190 ℃, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.9 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 3.5 x 10-5mol·cm-3The elongation at break is 960 percent, the monofilament strength is 19MPa, and the average diameter of the monofilament is 0.20 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 60 ℃ for 72h, wherein the tensile strength of the glass-like polymer fiber is recovered to 85% of that before shearing; the elongation at break is recovered to 87% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 13
A preparation method of glass-like polymer fiber, which has the same steps as example 3, except that the thermoplastic polymer is replaced by SBS which is dried in vacuum for 12h at 60 ℃, and the crosslinking density of the melt spinning system before extrusion is ensured to be 7.1 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 2.2 x 10-5mol·cm-3The elongation at break is 1000 percent, the strength of the monofilament is 18MPa, and the average diameter of the monofilament is 0.26 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 90 ℃ for 48h, wherein the tensile strength of the glass-like polymer fiber is recovered to 87% of that before shearing; the elongation at break is recovered to 90 percent before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 14
A preparation method of glass-like polymer fiber, which comprises the following steps basically the same as example 3, except that thermoplastic polymer is replaced by SBR vacuum-dried for 8 hours at 80 ℃, the melting temperature is adjusted to 180 ℃, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.4 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 2.3 x 10-5mol·cm-3The elongation at break is 990%, the strength of the monofilament is 18MPa, and the average diameter of the monofilament is 0.27 mm;
shearing the glass-like polymer fiber, lapping, and healing at 90 ℃ for 48h, wherein the tensile strength of the glass-like polymer fiber is recovered to 83% of that before shearing; the elongation at break is recovered to 85% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 15
A preparation method of glass-like polymer fibers comprises the following specific steps which are basically the same as those in example 4, except that thermoplastic polymers are replaced by SBS which is dried in vacuum for 12 hours at 60 ℃, and the crosslinking density of a melt spinning system before extrusion is ensured to be 7.9 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 4.0 x 10-5mol·cm-3The elongation at break is 695%, the strength of the monofilament is 28MPa, and the average diameter of the monofilament is 0.22 mm;
shearing the glass-like polymer fiber, overlapping, and healing at 80 ℃ for 32h, wherein the tensile strength of the glass-like polymer fiber is restored to 88% of that before shearing; the elongation at break is recovered to 89% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.
Example 16
Glass-like polymerThe fiber was prepared by essentially the same procedure as in example 4 except that the thermoplastic polymer was replaced with SBR dried under vacuum at 80 ℃ for 8 hours, the melt temperature was adjusted to 180 ℃ and the crosslink density of the melt-spun system before extrusion was guaranteed to be 8.0 x 10-8mol·cm-3. The crosslinking density of the prepared glass-like polymer fiber is 4.1 x 10-5mol·cm-3The elongation at break is 700 percent, the strength of the monofilament is 27MPa, and the average diameter of the monofilament is 0.23 mm;
shearing the glass-like polymer fiber, lapping, and healing at 80 ℃ for 32h to restore the tensile strength to 87% of that before shearing; the elongation at break is recovered to 89% before shearing; and the glass-like polymer fiber is insoluble in a solvent with the temperature of 60 ℃, wherein the solvent is a good solvent (such as toluene) of the thermoplastic polymer contained in the glass-like polymer fiber.