CN106753192B

CN106753192B - A kind of polysulfide sealant with room temperature self-healing and high elongation

Info

Publication number: CN106753192B
Application number: CN201710027383.5A
Authority: CN
Inventors: 全一武; 高文通
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2017-01-13
Filing date: 2017-01-13
Publication date: 2020-04-03
Anticipated expiration: 2037-01-13
Also published as: CN106753192A

Abstract

A polysulfide sealant with room temperature self-healing properties and high elongation, comprising 100 parts by weight of terminal mercapto group liquid polysulfide rubber, number average molecular weight of 2500-7000, 5-15 parts by weight of epoxy resin, 2-8 parts by weight Parts of aromatic epoxy glycidyl ether-modified liquid polysulfide oligomer, 0.05 to 5 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol; curing conditions: mix well, cure at room temperature for 14 days or Cured at 50℃ for 2 days or 75℃ for 1 day; the tensile strength of the polysulfide sealant after curing is 0.5-1MPa, and the elongation at break is 350-800%; the broken sealant is in contact with each other at room temperature and self-healing For 12 to 72 hours, the tensile strength is 0.45 to 0.95 MPa, and the elongation at break is 320 to 720%. The sealant has room temperature self-healing properties and room temperature reprocessing and recycling properties.

Description

Polysulfide sealant with room-temperature self-repairability and high elongation

Technical Field

The invention relates to a polysulfide sealant with room temperature self-repairability and high elongation, belonging to the technical field of sealants.

Background

The sealant prepared by taking polysulfide rubber as a main base material has good elasticity, water resistance, oxidation resistance, ultraviolet radiation resistance, chemical corrosion resistance and other properties, and is widely applied to the aspects of sealing buildings, oil tanks and the like. The polysulfide sealant material inevitably generates microcracks and local damage inside and outside the polysulfide sealant material due to the influence of external environment and mechanical fatigue in the long-term use process, the tiny defects are difficult to detect and repair, stress concentration points are easy to form, the overall mechanical property is reduced, and the service life is shortened. Therefore, the polysulfide sealant with self-repairing performance is developed, the maintenance and rework operation can be simplified, the material use is prolonged, and the resources are saved. The literature (Macromolecules, 2011, 44 (8): 2536-2541) reports that epoxy-terminated polysulfide resin is reacted with pentaerythritol tetra-3-mercaptopropionate to prepare a polymer with self-repairing properties, the tensile strength and the elongation at break of which are respectively 0.5MPa and 70 percent; the disconnected samples are mutually contacted at the temperature of 60 ℃ and are self-repaired for 30-60 minutes, the tensile strength is 0.35-0.45 MPa, and the elongation at break of the material is 45-65%. The literature (Chemistry of Materials, 2014, 26 (6): 2038-; the disconnected sample is repaired at room temperature for 12-24 hours under the catalysis of tri-n-butylphosphine, the tensile strength is 0.16-0.21 MPa, and the elongation at break is 66-100%. However, the elongation at break of the self-repairing polysulfide polymer material prepared by the method is less than 120 percent and is lower than that of the general polysulfide sealant, so the self-repairing polysulfide polymer material is not suitable to be used as the sealant.

Disclosure of Invention

The invention relates to a polysulfide sealant with room temperature self-repairability and high elongation.

The invention comprises the following components: 100 parts by weight of thiol-terminated liquid polysulfide rubber with a number average molecular weight of 2500-7000; 5-15 parts by weight of epoxy resin, wherein the epoxy resin is one or a mixture of aromatic or alicyclic epoxy resin; 2-8 parts by weight of an aromatic epoxy glycidyl ether modified liquid polysulfide oligomer; 0.05-5 parts by weight of 2, 4, 6-tris (dimethylaminomethyl) phenol (DMP-30) accelerator. Curing conditions are as follows: mixing, and curing at room temperature for 14 days, or at 50 deg.C for 2 days, or at 75 deg.C for 1 day. The sealant has the main properties: the tensile strength is 0.5-1 MPa, and the elongation at break is 350-800%; the disconnected sealants are contacted with each other at room temperature for 12-72 hours, and self-repairing of material performance can be realized, wherein the tensile strength is 0.45-0.95 MPa, the elongation at break is 320-720%, and the self-repairing rate reaches 80-97% (the self-repairing rate refers to the ratio of the tensile strength or the elongation at break after repairing to the tensile strength or the elongation at break of the material before cutting).

Wherein the liquid polysulfide oligomer modified by aromatic epoxy glycidyl ether is synthesized as follows: 100 parts by weight of terminal mercapto group liquid polysulfide rubber, 1000-5000 parts by weight of number average molecular weight, adding 5-20 parts by weight of aromatic epoxy glycidyl ether, uniformly stirring, reacting at 60-80 ℃ for more than 24 hours under the protection of nitrogen, monitoring reactant 2250cm by infrared spectroscopy^-1When the content of the sulfydryl is reduced to be less than 0.5 percent or the strength of the sulfydryl absorption peak is not changed any more, stopping heating, and cooling to obtain the liquid polysulfide oligomer modified by the aromatic epoxy glycidyl ether. The aromatic glycidyl ether is preferably one or a mixture of several of the following compounds.

The room temperature self-repairability principle and the advantages of the polysulfide sealant of the invention are as follows: (1) the room temperature self-repairability of the polysulfide sealant is realized by adding the aromatic epoxy glycidyl ether modified liquid polysulfide oligomer. The main chain of the modified liquid polysulfide oligomer is polysulfide resin which is the same as the main material of the sealant; the end capping agent is aromatic epoxy glycidyl ether and is well compatible with curing agent epoxy resin. After the modified liquid polysulfide oligomer is added, the modified liquid polysulfide oligomer is easy to diffuse in a polysulfide sealant crosslinking network, so that the creep property of a sealant system chain segment is enhanced, the contact exchange probability of disulfide bonds between chain segments of a material section is improved, the formation of a new chain segment of the polysulfide network is facilitated, new crosslinking points are added, the room temperature self-repairability is improved, and the self-repairing rate reaches 80-97%. (2) The tensile elongation of the polysulfide sealant is 350-800%, and compared with the reported polysulfide polymer with self-repairing property, the polysulfide sealant has higher tensile elongation; the tensile elongation of the sealant can be regulated and controlled by changing the addition amount of the liquid polysulfide oligomer, and the application requirements of different occasions are met. (3) The polysulfide sealant of the invention also has room temperature processability: and (3) small fragments of the sealant with the diameter of less than 0.5cm can be remolded into a film at the die pressing temperature of 5-10 MPa for 12-72 hours, so that the reprocessing and recycling of the material are realized. (4) The polysulfide sealant has the advantages of easily obtained raw materials, simple synthesis and mild reaction conditions, and has good application prospect in the preparation of self-repairing materials and recycled materials.

Drawings

FIG. 1 is a schematic view showing that the incision on the surface of the polysulfide sealant of the present invention is placed at room temperature, and the incision gradually disappears and heals.

The polysulfide sealant broken in the attached figure 2 is contacted with each other at room temperature for 48 hours to self-repair, and then is stretched and deformed.

FIG. 3 shows that the small fragment polysulfide sealant forms a film at the die pressure of 5MPa and the room temperature for 36 hours, and the reprocessing and recovery are realized.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Example 1

Preparing a polysulfide sealant: 100 parts of end mercapto liquid polysulfide rubber, 4000 parts of number average molecular weight, 8.5 parts of bisphenol F type epoxy resin, 5 parts of benzyl epoxy glycidyl ether modified liquid polysulfide oligomer and 1 part of DMP-30 accelerator. Curing conditions are as follows: curing at 75 ℃ for 1 day.

Synthesizing a liquid polysulfide oligomer modified by benzyl epoxy glycidyl ether: 100 parts by weight of terminal mercapto group liquid polysulfide rubber, the number average molecular weight is 4000, 8.2 parts by weight of benzyl epoxy glycidyl ether is added, the mixture is uniformly stirred, the mixture reacts for 36 hours at 70 ℃ under the protection of nitrogen, and the reactant is monitored by an infrared spectroscopy at 2250cm^-1And (4) reducing the content of sulfydryl to be less than 0.5%, and cooling to obtain the liquid polysulfide oligomer modified by the benzyl epoxy glycidyl ether.

The mechanical properties of the sample are as follows: tensile strength of 0.65MPa and elongation at break of 498%. Self-repairing performance: the cut samples are contacted with each other at room temperature for 24 hours, and after self-repairing, the tensile strength of the cut samples is 0.63MPa (the self-repairing rate is 96.9 percent), and the tensile elongation is 461 percent (the self-repairing rate is 92.6 percent).

Example 2

Preparing a polysulfide sealant: 100 parts of mercapto-terminated liquid polysulfide rubber, 4000 parts of number average molecular weight, 7.3 parts of bisphenol A type epoxy resin, 2 parts of cyclohexane-1, 2-dicarboxylic acid diglycidyl ester, 6 parts of phenyl epoxy glycidyl ether modified liquid polysulfide oligomer and 1.5 parts of DMP-30 accelerator. Curing conditions are as follows: curing at 50 ℃ for 2 days.

Synthesizing a liquid polysulfide oligomer modified by phenyl epoxy glycidyl ether: 100 parts by weight of end-mercapto liquid polysulfide rubber, the number average molecular weight is 1000, 16.4 parts by weight of phenyl epoxy glycidyl ether is added, the mixture is uniformly stirred, the mixture reacts for 24 hours at 80 ℃ under the protection of nitrogen, the absorption peak intensity of the mercapto group of the reactant is monitored by infrared spectroscopy to be not changed any more, and the liquid polysulfide oligomer modified by the phenyl epoxy glycidyl ether is obtained by cooling.

The mechanical properties of the sample are as follows: tensile strength of 0.51MPa and elongation at break of 747 percent. Self-repairing performance: the cut samples are contacted with each other at room temperature for 48 hours, and after self-repairing, the tensile strength of the cut samples is 0.49MPa (the self-repairing rate is 96.1 percent), and the elongation at break is 668 percent (the self-repairing rate is 89.4 percent).

Example 3

Preparing a polysulfide sealant: 50 parts of end-mercapto liquid polysulfide rubber, 2500 parts of number average molecular weight, 50 parts of end-mercapto liquid polysulfide rubber, 4000 parts of number average molecular weight, 5 parts of bisphenol A type epoxy resin, 6 parts of bisphenol F type epoxy resin, 3 parts of o-tolyl epoxy glycidyl ether modified liquid polysulfide oligomer and 2 parts of DMP-30 accelerator. Curing conditions are as follows: curing at room temperature for 14 days.

Synthesizing o-tolyl epoxy glycidyl ether modified liquid polysulfide oligomer: 100 parts by weight of end-mercapto liquid polysulfide rubber, the number average molecular weight of which is 4000, 7.5 parts by weight of o-tolyl epoxy glycidyl ether is added, the mixture is uniformly stirred at room temperature and reacts for 48 hours at 60 ℃ under the protection of nitrogen, and the reactant is monitored by an infrared spectroscopy at 2250cm^-1Reducing the content of sulfydryl to below 0.5 percent, and cooling to obtain the o-tolyl epoxy glycidyl ether modified liquid polysulfide oligomer.

The mechanical properties of the sample are as follows: tensile strength of 0.71MPa and elongation at break of 437%. Self-repairing performance: the cut samples are contacted with each other at room temperature for 72 hours, and after self-repairing, the tensile strength of the cut samples is 0.64MPa (the self-repairing rate is 90.1 percent), and the tensile elongation is 364 percent (the self-repairing rate is 83.2 percent).

Claims

1. A polysulfide sealant with room temperature self-repairability and high elongation comprises the following components: 100 parts by weight of thiol-terminated liquid polysulfide rubber, 2500-7000 parts by number average molecular weight, 5-15 parts by weight of epoxy resin, 0.05-5 parts by weight of 2, 4, 6-tris (dimethylaminomethyl) phenol, and is characterized by also comprising 2-8 parts by weight of aromatic epoxy glycidyl ether modified liquid polysulfide oligomer; curing conditions are as follows: mixing, and curing at room temperature for 14 days, or at 50 deg.C for 2 days, or at 75 deg.C for 1 day.