CN-121975263-A - Remodelable high-toughness phenolic resin and preparation method thereof

CN121975263ACN 121975263 ACN121975263 ACN 121975263ACN-121975263-A

Abstract

The invention provides a repairable high-toughness phenolic resin and a preparation method thereof, the reversible dynamic covalent bond network is constructed through the transurethanization reaction of the phenolic resin, and the nanoparticle reinforced topological cross-linking structure is formed by combining an in-situ hydrolysis technology. The invention not only successfully solves the inherent defects of unrepairable and insufficient toughness of the traditional thermosetting phenolic resin, but also realizes the breakthrough performance of mechanical properties exceeding that of the thermoplastic phenolic resin in a high-temperature environment, and simultaneously endows the material with self-repairing capability, thereby opening up a new path for sustainable application of the high-performance thermosetting resin. The preparation method comprises the steps of S1, preparing silicon dioxide-phenolic resin hybrid resin by a sol-gel method, S2, carrying out vacuum drying treatment on the hybrid resin, carrying out melt blending with a catalyst, then adding isocyanate to react to obtain a prepolymer containing dynamic urethane bonds, and S3, adding a curing agent into the prepolymer, and carrying out heating curing treatment to obtain the remodelable high-toughness phenolic resin.

Inventors

LIAO JUN
WANG DEHUA
HUANG CHI
HU MINGJIE
HU WEI
CHEN HAO

Assignees

湖北航泰科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (10)

1. A preparation method of remodelable high-toughness phenolic resin is characterized by comprising the following steps: s1, preparing silicon dioxide-phenolic resin hybrid resin by a sol-gel method; S2, carrying out vacuum drying treatment on the hybrid resin, and carrying out melt blending with a catalyst; and S3, adding a curing agent into the prepolymer, uniformly mixing, and heating for curing to obtain the remodelable high-toughness phenolic resin.
2. The method for preparing the remodelable, high-toughness phenolic resin according to claim 1, wherein the steps for preparing the silica-phenolic resin hybrid resin are as follows: dissolving novolac resin in absolute ethyl alcohol under the condition of heating and stirring to form homogeneous resin solution; mixing tetraethyl orthosilicate, absolute ethyl alcohol, deionized water, an acid catalyst and an amino silane coupling agent in proportion, and stirring at 25-40 ℃ for pre-hydrolysis reaction to obtain silane hydrolytic sol; Slowly dripping the silane hydrolytic sol into the homogeneous resin solution, continuously stirring and reacting for 2-4 hours, and rotationally evaporating the reaction solution at 50-60 ℃ under the condition of reduced pressure to obtain the silica-phenolic resin hybrid resin.
3. The method for preparing the remodelable high-toughness phenolic resin according to claim 2, wherein the mass fraction of the phenolic resin in the homogeneous resin solution is 30-50 wt%, and the heating and stirring temperature is 50-60 ℃.
4. The method for preparing the remodelable high-toughness phenolic resin as claimed in claim 2, wherein the dosage of the tetraethyl orthosilicate is 5% -20% of the mass of the phenolic resin, the molar ratio of water to the tetraethyl orthosilicate is 4-10, and the volume ratio of the tetraethyl orthosilicate to the absolute ethyl alcohol is 1:4.
5. The method for preparing remodelable high-toughness phenolic resin according to claim 2, wherein the acid catalyst is hydrochloric acid, the amount of the acid catalyst is 0.5% -2% of the mass of tetraethyl orthosilicate, and the prehydrolysis time is 30-120 min.
6. The method for preparing the remodelable high-toughness phenolic resin according to claim 1, wherein the aminosilane coupling agent is KH-550, and the mass of the aminosilane coupling agent accounts for 0.5% -1.5% of the mass of tetraethyl orthosilicate.
7. The method for preparing the remodelable high-toughness phenolic resin according to claim 1, wherein in the step S2, the vacuum drying temperature is 60 ℃, the drying time is 12 h, the catalyst is zinc acetate, the dosage is 1-2% of the mass of the phenolic resin, and the melt blending temperature is 120 ℃.
8. The method for preparing a remodelable high-toughness phenolic resin according to claim 1, wherein the isocyanate is hexamethylene diisocyanate or isophorone diisocyanate, the reaction temperature is 80 ℃, and the ratio of n (-NCO)/n (-OH) is 0.8-1.0.
9. The method for preparing the remodelable high-toughness phenolic resin according to claim 1, wherein in the step S3, the curing agent is hexamethylenetetramine, the amount of the curing agent is 6% -15% of the mass of the phenolic resin, the heating curing treatment is stepped heating curing treatment, and the curing procedures are 100 ℃ per 2h, 120 ℃ per 2h and 150 ℃ per 2h in a vacuum drying oven.
10. The remodelable, high-toughness phenolic resin prepared by the preparation method of any one of claims 1 to 9, characterized in that the remodelable, high-toughness phenolic resin has a remodelable plasticity occurrence condition of temperature >200 ℃.

Description

Remodelable high-toughness phenolic resin and preparation method thereof Technical Field The invention belongs to the technical field of high polymer materials, and particularly relates to a remodelable high-toughness phenolic resin and a preparation method thereof. Background Thermosetting phenolic resins form an irreversible three-dimensional network structure after curing, so that the thermosetting phenolic resins are difficult to recycle by a traditional method, and cannot be remolded by heating like thermoplastic resins, and the characteristic severely limits the sustainable development potential of the thermosetting phenolic resins. Meanwhile, the inherent brittleness of the material leads to poor impact resistance, and cracks and even failures are easy to generate under the extreme environment of rapid temperature change. While temporary processability is imparted to the material by dynamic covalent bond (e.g., urethanization) design, irreversible decay of mechanical strength and heat resistance is often accompanied during the recovery of the structure after remodeling. Aiming at the problem of insufficient toughness, although the toughness and heat resistance of the material can be improved to a certain extent by modifying the nano particles, the interface bonding force between the nano particles and the matrix is weak, the stress concentration is easy to cause, the material is accelerated to fail, and the interface debonding risk is possibly increased due to the mismatch of the thermal expansion coefficients. In addition, phenolic hydroxyl groups in the phenolic resin molecular chain are easy to absorb environmental moisture, so that the mechanical property is deteriorated, and the long-term service stability is affected. Based on the above situation, the invention provides an innovative remodelable high-toughness phenolic resin and a preparation method thereof, and a crosslinking network is reconstructed from a molecular level through a composite modification strategy. Firstly, chemically crosslinking nano particles on phenolic resin groups by utilizing an in-situ hydrolysis technology, secondly, constructing a dynamic covalent network by utilizing a transurethanization technology, realizing cyclic recovery and remolding of phenolic resin by utilizing a collaborative modification strategy, and simultaneously realizing toughening and heat-resistant modification of the phenolic resin. Disclosure of Invention The invention aims to overcome the defects that the existing phenolic resin material is large in brittleness and difficult to recycle, and provides a remodelable high-toughness phenolic resin and a preparation method thereof. The resin has the advantages of high plasticity, high toughness and closed loop recovery capability, and simultaneously has heat resistance and strength. The invention provides the following technical scheme: the invention provides a preparation method of remodelable high-toughness phenolic resin, which comprises the following steps: s1, preparing silicon dioxide-phenolic resin hybrid resin by a sol-gel method; S2, carrying out vacuum drying treatment on the hybrid resin, and carrying out melt blending with a catalyst; and S3, adding a curing agent into the prepolymer, uniformly mixing, and heating for curing to obtain the remodelable high-toughness phenolic resin. The invention adopts the sol-gel method to generate the silicon dioxide nano network in situ in the phenolic resin system, thereby effectively avoiding the phase aggregation and stress concentration caused by simple physical blending. And the subsequent functionalization treatment of the phenolic resin through the transurethanization reaction, the construction of a modified system of the synergistic effect of a nanoparticle topological crosslinked structure and a dynamic covalent bond network, the realization of the recoverability and the self-repairing capability of the phenolic resin on the basis of keeping the original excellent performance, and the remarkable improvement of the toughness of the material are realized. R is isocyanate, and R 1 is a silane coupling agent. Further, the steps for preparing the silica-phenolic resin hybrid resin are as follows: dissolving novolac resin in absolute ethyl alcohol under the condition of heating and stirring to form homogeneous resin solution; mixing tetraethyl orthosilicate, absolute ethyl alcohol, deionized water, an acid catalyst and an amino silane coupling agent in proportion, and stirring at 25-40 ℃ for pre-hydrolysis reaction to obtain silane hydrolytic sol; And slowly dripping the silane hydrolytic sol into the homogeneous resin solution, continuously stirring and reacting for 2-4 hours at 40-60 ℃, and rotationally evaporating the reaction solution at 50-60 ℃ under the condition of reduced pressure to obtain the silica-phenolic resin hybrid resin. Further, the mass fraction of phenolic resin in the homogeneous resin solution is 30-50 wt%, the heating and stirri