Kinetic monitoring system for curing reaction and bond exchange reaction of dynamic crosslinking thermosetting resin

Abstract

The utility model belongs to the field of dynamic monitoring of dynamic cross-linked thermosetting resin, and discloses a dynamic monitoring system for curing reaction and bond exchange reaction of the dynamic cross-linked thermosetting resin. Comprising an LCR digital bridge, two groups of clamp suites, a rotational rheometer and a data acquisition system, the rotational rheometer is provided with an environment control chamber furnace, a clamp fastening table and a clamp fastening rod; the data acquisition system comprises a data acquisition card and a computer, and the output end of the data acquisition card is connected to the computer; the two groups of clamp suites are arranged in an up-and-down aligning manner; the two groups of clamp suites are respectively connected to the rotational rheometer through a clamp fastening table and a clamp fastening rod; the environment control cavity furnace is enclosed outside the clamp suite, the clamp fastening table and the clamp fastening rod sleeve; and a communication interface of the rear panel of the LCR digital bridge and a communication interface of the rotational rheometer are respectively connected to the input end of the data acquisition card through data lines. The device can effectively monitor the kinetics of the curing reaction and the bond exchange reaction of the thermosetting resin.

Description

Technical Field

[0001] The utility model belongs to the technical field of monitoring kinetic parameters of dynamically crosslinked thermosetting resins, and particularly relates to a kinetic monitoring system for curing reaction and bond exchange reaction of dynamically crosslinked thermosetting resins. Background Art

[0002] In recent years, a transformative material that combines the characteristics of thermosetting and thermoplastic polymers - dynamically crosslinked thermosetting polymer materials, by introducing dynamic chemical bonds into the polymer crosslinking network, undergoes dynamic bond exchange reactions under external stimuli such as light and heat to carry out crosslinking network topological rearrangement, and can achieve the reshaping, self-healing and recycling of thermosetting polymers and their composites, which has attracted extensive attention in the academic and industrial fields. During the molding and manufacturing process of resin matrix composites, the matrix resin undergoes a curing reaction to form a crosslinking network, which determines the molding processing window of the composite material, affects the microstructure of the material, and ultimately affects the product quality and macroscopic properties. The most significant feature during the curing reaction of thermosetting resins is that the viscosity of the system changes with the reaction, resulting in hindered molecular diffusion, altered reaction rate, thereby affecting the kinetic mechanism and process of chemical reactions, and at the same time affecting the rheological properties of the system. In addition, for the already cured dynamically crosslinked thermosetting resin, the kinetic of the dynamic bond exchange reaction of the crosslinking network is the key to determining its reprocessing, self-healing and recyclable properties. Therefore, it is very important to monitor the curing reaction and bond exchange reaction kinetics of dynamically crosslinked thermosetting resins.

[0003] The curing reaction process of dynamically crosslinked thermosetting resins usually involves multiple reactants simultaneously, especially the intervention of small molecule catalysts. Therefore, the chemical reactions and viscoelastic evolution during the entire curing process are relatively complex. Although conventional thermal analysis and rheological research methods can study the curing kinetics process by measuring the reaction heat enthalpy or viscosity changes under different conditions, they cannot establish a real-time correlation between network formation and evolution and signals. Especially for new types of dynamically crosslinked thermosetting resins, they cannot provide relatively clear data and law references for subsequent molding processes. At the same time, due to the limitations of time and space resolution of traditional research methods based on rheological tests, they cannot reflect the viscoelastic evolution law brought by the formation of crosslinking networks during the real curing process, thus limiting the optimization of composite material molding processes and properties. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a kinetic monitoring system for curing reaction and bond exchange reaction of dynamically crosslinked thermosetting resins.

[0005] To achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0006] A curing reaction and bond exchange reaction kinetics monitoring system for a dynamically cross-linked thermosetting resin comprises an LCR digital bridge, two sets of fixture kits with the same structure, a rotational rheometer and a data acquisition system; the rotational rheometer is equipped with an environmental control chamber furnace, a fixture fastening platform and a fixture fastening rod, the top of the fixture fastening platform and the bottom of the fixture fastening rod are respectively provided with a sleeve integrally formed therewith, and at least two bolt holes are provided around the sleeve;

[0007] The data acquisition system comprises a data acquisition card and a computer, wherein the output end of the data acquisition card is connected to the computer;

[0008] Each set of fixture kits includes a base and a fixture. The base is made of a material that is resistant to high temperature, not easy to oxidize, and does not react with the resin liquid, and the fixture is made of metal; the fixture includes a fixture body, a sample table and a first connecting piece, the sample table and the first connecting piece are respectively fixed on the top and bottom of the fixture body, and the fixture body and the sample table are solid cylinders; the base includes a base body and a second connecting piece, the second connecting piece is fixed on the bottom of the base body, the base body is a solid cylinder, and a cavity is opened inward from the top surface of the center of the base body; the first connecting piece and the second connecting piece are both solid cylinders with a circle of grooves in the middle of the outer side, and the shape and size of the second connecting piece are adapted to the sleeve (to ensure that the second connecting piece can be just embedded in the sleeve), and the cavity is the same shape and size as the first connecting piece A hollow cylinder with a circle of grooves in the middle of the outer side of the adapter (to ensure that the first connecting piece can be embedded in the cavity); a through hole and at least two screw holes are horizontally provided on the side of the base body, the through hole is connected to the inside of the cavity, the screw hole is connected to the groove outside the cavity, and the center height of the screw hole is at the same level as the center height of the groove outside the cavity; a wire is placed at the bottom of the cavity, one end of the wire remains at the bottom of the cavity, and the other end is led out from the through hole; the clamp is nested with the base by the first connecting piece being embedded in the cavity and pressing the wire, and screws matching the clamp are respectively penetrated in the two screw holes, the screws are made of a material that is resistant to high temperature, has high mechanical strength and will not wear the base, the screws pass through the groove outside the cavity and then press against the first connecting piece to fix the clamp on the base;

[0009] The two sets of fixture kits are arranged in a manner that the two sample tables are aligned up and down, and the second connecting pieces of the upper and lower sets of fixture kits are respectively nested in the sleeves of the fixture fastening rod and the fixture fastening platform and fixed by bolts passing through bolt holes to achieve the connection between the fixture kit and the rotational rheometer. The environmental control chamber furnace is surrounded by the fixture kit, the fixture fastening platform and the outside of the fixture fastening rod sleeve; the other ends of the two wires are led out from the through holes and respectively penetrate the environmental control chamber furnace to be connected to the test end of the front panel of the LCR digital bridge; the communication interface of the rear panel of the LCR digital bridge and the communication interface of the rotational rheometer are respectively connected to the input end of the data acquisition card through the first data line and the second data line.

[0010] Preferably, the sleeve is a hollow cylinder, the fixture body, the base body and the sample stage are all solid cylinders, the first connecting member and the second connecting member are both solid cylinders with a groove around the middle of the outer side, and the cavity is a hollow cylinder with a groove around the middle of the outer side and having a shape and size adapted to those of the first connecting member; the solid cylinders of the fixture body and the base body have the same diameter, the solid cylinder of the sample stage has a diameter smaller than that of the solid cylinder of the fixture body, and the solid cylinders of the first connecting member and the second connecting member have the same diameter and are smaller than that of the solid cylinder of the fixture body.

[0011] Preferably, the fixture body, the sample stage and the first connecting member are integrally formed; the base body and the second connecting member are integrally formed.

[0012] Preferably, the central axes of the fixture body, the sample stage and the first connecting member are on the same straight line; the central axes of the base body and the second connecting member are on the same straight line.

[0013] Preferably, the diameter of the bolt hole is adapted to the size of the groove on the outer side of the second connecting member (ensuring that after a bolt adapted thereto is inserted into the bolt hole, the end of the bolt can just be embedded into the groove), and the diameter of the screw hole is adapted to the size of the groove on the outer side of the cavity (ensuring that after a screw adapted thereto is inserted into the screw hole, the end of the screw can just be embedded into the groove).

[0014] Preferably, the number of both the bolt holes and the screw holes is two, the included angle between the two screw holes is 180°, and the included angle between the two bolt holes is 180°.

[0015] Preferably, the central height of the through hole is at the same horizontal height as that of the screw hole.

[0016] Preferably, the through hole is located at the middle position between the two screw holes on the outer side of the base body, that is, the included angle between the through hole and the two screw holes is 90°.

[0017] Preferably, the through hole is a cylindrical hole.

[0018] Preferably, the material of the base is zirconia or aluminum oxide, the material of the fixture is aluminum or stainless steel, and the materials of the screw and the bolt are polyetheretherketone.

[0019] In the present utility model, the LCR digital bridge and the rotational rheometer are both known devices and can be obtained through commercial purchase.

[0020] Beneficial effects:

[0021] (1) The overall system of the present utility model is simple to assemble, stable in operation, high in test resolution and high in precision;

[0022] (2) In the present utility model, a rotational rheometer provides mechanical monitoring signals, and an LCR digital bridge provides electrical signal detection, realizing synchronous monitoring of force - electrical signals and signal complementarity, and more accurately characterizing the curing problem of materials.

[0023] (3) The present utility model can not only monitor the curing reaction kinetics of dynamically crosslinked thermosetting resins and the curing reaction kinetics of resin - based carbon fibers, but also monitor the kinetic process of bond exchange reaction after the materials are cured.

[0024] (4) When using general thermal analysis methods to test the curing reaction kinetics of resin - based carbon fibers, the rigid carbon fibers make sampling difficult, resulting in reduced test accuracy. The electrical signal monitoring system of the present utility model can monitor the curing process of a large number of carbon fiber composites, and better guide the research on the reaction kinetics of resin - based carbon fiber composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : Schematic diagram of the overall structure of the present utility model;

[0026] Figure 2 : Front - view structural schematic diagram of the fixture kit;

[0027] Figure 3 : Front - view structural schematic diagram of the fixture;

[0028] Figure 4 : Front - view structural schematic diagram of the base;

[0029] Figure 5 : Curves of the storage modulus and ionic viscosity of the dynamically crosslinked thermosetting resin varying with time;

[0030] Figure 6 : Curve of the degree of curing of the dynamically crosslinked thermosetting resin varying with time;

[0031] Figure 7 : Curve of the ionic viscosity of the resin - based carbon fiber composite varying with time;

[0032] Figure 8 : Stress relaxation curve of the dynamically crosslinked thermosetting resin;

[0033] Among them, the attached drawing reference numerals are: 1 - LCR digital bridge; 2 - fixture kit, 21 - fixture, 211 - fixture body, 212 - sample stage, 213 - first connecting member, 22 - base, 221 - base body, 222 - second connecting member, 223 - cavity, 224 - cylindrical hole, 225 - screw hole; 3 - rotational rheometer, 31 - environmental control chamber furnace; 32 - fixture fastening rod, 33 - fixture fastening platform, 34 - sleeve; 4 - data acquisition system; 5 - wire; 6 - first data line; 7 - second data line; 8 - uncured resin liquid. Detailed implementation manners

[0034] To make the present utility model clearer and more definite, the following further details the present utility model. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0035] In the following embodiments, the resin liquid involved in the use process and the dynamically crosslinked thermosetting resin and the dynamically crosslinked thermosetting resin-based carbon fiber composite material prepared therefrom are only used as test objects to illustrate how to use the present utility model. The present utility model does not limit the relevant tests only for this resin or resin-based fiber composite material. Other resin or resin-based fiber composite materials of the same type can be tested through the present utility model; the rotational rheometer, brand: TA instruments, model DHR-2, is equipped with an environmental control chamber furnace (also known as an environmental temperature control chamber furnace, environmental control chamber, ETC environmental furnace or temperature controller), a fixture fastening rod and a fixture fastening platform; the LCR digital bridge, brand: Agilent, model: E4980A.

[0036] Embodiment 1

[0037] As Figure 1-4 shown, a curing reaction kinetics monitoring system for a dynamically crosslinked thermosetting resin includes an LCR digital bridge 1, two sets of fixture kits 2 with the same structure, a rotational rheometer 3 and a data acquisition system 4; the rotational rheometer 3 is equipped with an environmental control chamber furnace 31, a fixture fastening rod 32 and a fixture fastening platform 33. At the top of the fixture fastening platform 33 and the bottom of the fixture fastening rod 32, sleeves 34 integrally formed therewith are respectively provided. The sleeve 34 is a hollow cylinder, and two bolt holes are provided on the periphery of the sleeve 34, and the included angle between the two bolt holes is 180°;

[0038] The data acquisition system 4 includes a data acquisition card and a computer, and the output end of the data acquisition card is connected to the computer;

[0039] Each set of fixture kits 2 includes a base 22 and a fixture 21, the base 22 is made of zirconium oxide, and the fixture 21 is made of metal aluminum; the fixture 21 includes an integrally formed fixture body 211, a sample table 212 and a first connecting piece 213, the central axes of the fixture body 211, the sample table 212 and the first connecting piece 213 are on the same straight line, and the sample table 212 and the first connecting piece 213 are respectively located at the top and bottom of the fixture body 211; the base 22 includes an integrally formed base body 221 and a second connecting piece 222, the central axes of the base body 221 and the second connecting piece 222 are on the same straight line, the second connecting piece 222 is located at the bottom of the base body 221, and the bottom The center of the seat body 221 is provided with a cavity 223 from its top surface inwardly; the fixture body 211, the base body 221 and the sample stage 212 are all solid cylinders, the first connecting member 213 and the second connecting member 222 are both solid cylinders with a circle of grooves in the middle of the outer side, and the shape and size of the second connecting member 222 are adapted to the sleeve 34 (to ensure that the second connecting member 222 can be embedded in the sleeve 34), and the cavity 223 is a hollow cylinder with a circle of grooves in the middle of the outer side that is adapted to the shape and size of the first connecting member 213 (to ensure that the first connecting member 213 can be embedded in the cavity 223); the diameters of the solid cylinders of the fixture body 211 and the base body 221 are the same. The diameter of the solid cylinder of the sample stage 212 is smaller than the diameter of the solid cylinder of the fixture body 211, and the diameters of the solid cylinders of the first connecting member 213 and the second connecting member 222 are the same and smaller than the diameter of the solid cylinder of the fixture body 211; a cylindrical hole 224 and two screw holes 225 are horizontally provided on the side of the base body 221, the cylindrical hole 224 is connected to the inside of the cavity 223, and the screw hole 225 is connected to the outer groove of the cavity 223, the center height of the screw hole 225, the center height of the cylindrical hole 224 and the center height of the outer groove of the cavity 223 are at the same horizontal height, the angle between the two screw holes 225 is 180°, and the angle between the cylindrical hole 224 and the two screw holes 225 is 9 0°; the diameter of the screw hole 225 is matched with the size of the groove outside the cavity 223, ensuring that after the screw hole 225 is penetrated with a screw that matches it, the end of the screw can be embedded in the groove; a wire 5 is placed at the bottom of the cavity 223, one end of the wire 5 remains at the bottom of the cavity 223, and the other end is led out from the cylindrical hole 224; the clamp 21 is embedded in the cavity 223 by the first connecting member 213 and presses the wire 5 to achieve nesting with the base 22, and the two screw holes 225 are respectively penetrated with screws that match it, and the material of the screws is polyetheretherketone, and the screws pass through the groove outside the cavity 223 and then press against the first connecting member 213 to fix the clamp 21 on the base 22;

[0040] Two sets of fixture kits 2 are arranged in such a way that the two sample stages 212 are vertically aligned. The second connectors 222 of the upper and lower sets of fixture kits 2 are respectively nested in the sleeves 34 of the fixture fastening rods 32 and the fixture fastening platforms 33, and are fixed by bolts (made of polyether ether ketone) passing through the bolt holes, thereby realizing the connection between the fixture kit 2 and the rotational rheometer 3. The environmental control chamber furnace 31 surrounds the fixture kit 2, the fixture fastening platform 33, and the sleeves 34 of the fixture fastening rods 32. The other ends of the two wires 5 are led out from the cylindrical holes 224 and then respectively penetrate through the environmental control chamber furnace 31 and are connected to the test ends on the front panel of the LCR digital bridge 1. The communication interfaces on the rear panel of the LCR digital bridge 1 and the communication interface of the rotational rheometer 3 are respectively connected to the input end of the data acquisition card through the first data line 6 and the second data line 7.

[0041] When the present utility model monitors the curing reaction kinetics of the dynamically crosslinked thermosetting resin, the usage process is as follows:

[0042] (1) Preparation of the resin solution: Add bisphenol A diglycidyl ether and zinc acetylacetonate into a round-bottom flask, stir in an oil bath at 130 °C for 60 min. After stirring evenly, lower the oil bath temperature to 75 °C. After the temperature stabilizes, add the curing agent glutaric anhydride and stir for 60 min until a homogeneous system is formed to obtain the uncured resin solution 8. Among them, in terms of molar ratio, bisphenol A diglycidyl ether:zinc acetylacetonate:glutaric anhydride = 1:0.05:0.5;

[0043] (2) Drop the uncured resin solution 8 onto the sample stage 212 of the lower fixture kit 2. Since the top surface of the sample stage 212 is flat and the resin solution has a certain viscosity, it forms a hemispherical shape under the action of surface tension. When the upper and lower sample stages 212 are closed, a certain amount of resin solution will remain between the two sample stages 212, and the excess resin solution flows out from the side. Before testing, the excess resin solution on the side of the sample stage 212 needs to be scraped off; Figure 1 The state of the resin solution when the upper and lower sample stages 212 are not closed is shown;

[0044] (3) The environmental control chamber furnace 31 provides a curing temperature of 150 °C for the resin solution. Then, the rotational rheometer 3 provides a mechanical monitoring signal, and the LCR digital bridge 1 provides an electrical signal detection. The data acquisition system 4 effectively displays the changes in the storage modulus in the mechanical mode and the ionic viscosity in the electrical mode of the resin solution over time during the curing process. In the present utility model, the monitored electrical signals are further processed according to formulas (i) to (iv) to calculate the ionic viscosity during the curing process of the resin solution:

[0045] ;

[0046] Among them, ρ is the resistivity with the unit of Ω·m (ohm·meter); σ is the ionic conductivity with the unit of S / m (siemens / meter); ε' and ε" are the real part and the imaginary part of the dielectric constant ε respectively, and ε' is the data measured by the LCR digital bridge 1; ε0 is the vacuum dielectric constant; ω is the angular frequency with the unit of rad / s; f is the test frequency of the LCR digital bridge 1 with the unit of Hz; A is the upper surface area of the sample with the unit of mm 2 , d is the thickness of the sample with the unit of μm; C is the capacitance with the unit of F (farad), which is the data measured by the LCR digital bridge 1; tanδ is the loss tangent angle, which is the test data measured by the LCR digital bridge 1;

[0047] In the present utility model, the resistivity ρ is defined as the ion viscosity (IonVisc) to determine the curing state during the entire curing process. The reason is as follows: σ is the ionic conductivity independent of frequency, and the corresponding resistivity ρ is related to the physical viscosity of the fluid. The crosslinking density characterizing the curing state affects both the physical viscosity and the movement of ions, thereby affecting ρ. In the early stage of the curing process of thermosetting materials, the resin exists as small molecules, making it easy for ions to move. The ionic viscosity usually increases proportionally to the physical viscosity until the physical viscosity reaches infinity after gelation, and the crosslinking reaction continues. The growing crosslinking network shows an increasing hindrance to the movement of ions, and the change in the ion mobility causes a change in the ionic conductivity. The ionic viscosity corresponding to the ionic conductivity can still characterize the curing process after gelation. Therefore, the resistivity ρ (ion viscosity) independent of frequency can be used to determine the curing state during the entire curing process;

[0048] The curves of the storage modulus (mechanical mode) and ion viscosity (electrical mode) of the dynamically crosslinked thermosetting resin monitored by the present utility model versus time are as Figure 5 shown; the results show that: for the mechanical signal, the material is initially a liquid, and as the curing reaction proceeds, the material begins to turn into a solid, resulting in a change in the internal structure of the material during the curing process, thereby increasing the viscoelasticity of the material. Therefore, the storage modulus increases as the curing reaction proceeds; for the electrical signal, the ion mobility and dipole orientation characterize the curing reaction process by causing a change in the dielectric loss or ionic conductivity during curing. In the early stage of curing, the resin exists as small molecules and it is easy for ions to move. As the curing reaction proceeds, the formed crosslinking network hinders the movement of ions. Therefore, the ionic viscosity of the system increases as the curing reaction proceeds; the monitoring results in the mechanical and electrical modes are consistent;

[0049] (4), Process the storage modulus and ion viscosity data according to formulas (vi) to (vii) to obtain the degree of cure in the two modes;

[0050] ;

[0051] Among them, α is the degree of curing; G’ (t α=0 ) is the storage modulus before curing; G’ (t α=1 ) is the storage modulus at complete curing; G’ (t) is the storage modulus at time t ; ρ (t α=0 ) is the ionic viscosity before curing; ρ (t α=1 ) is the ionic viscosity at complete curing; ρ (t) is the ionic viscosity at time t ;

[0052] The curves of the degree of curing of the dynamically crosslinked resin varying with time in two modes are as Figure 6 shown. The results show that: the curing rate of the dynamically crosslinked epoxy resin increases with the increase of the curing time, and it is proved that the curing reaction trends in the two modes of mechanical force and electricity are the same.

[0053] Example 2

[0054] The structure of the monitoring system is the same as that in Example 1. In this example, it is used to monitor the curing reaction kinetics of the dynamically crosslinked thermosetting resin-based carbon fiber composite. The using process is as follows:

[0055] (1). Prepare the prepreg tape component: Prepare the resin solution, and the preparation process is the same as that in step (1) of Example 1; Place a layer of polyester fiber mesh on a polytetrafluoroethylene plate, then place a layer of carbon fiber, and then drop the resin solution. Wait for 20 min. After the resin solution soaks the carbon fiber, place another layer of carbon fiber, pour the resin solution again, wait for 20 min, and finally place another layer of polyester fiber mesh and cover it with a polytetrafluoroethylene plate to obtain the prepreg tape component;

[0056] (2). Cut the prepreg tape component into a circle and make its diameter consistent with the top surface circle diameter of the sample stage 212. Then place the prepreg tape component on the sample stage 212 of the lower fixture set 2 and close the upper and lower sample stages 212;

[0057] (3). The operation is the same as that in step (3) of Example 1.

[0058] The curve of the ionic viscosity of the resin-based carbon fiber composite monitored in this example varying with time is as Figure 7As shown in the figure. The results show that the ionic viscosity of the resin-based carbon fiber composite increases with the increase of the curing time. The reason is that for the curing reaction, it essentially occurs through the collision of small molecules. Since the introduction of carbon fibers increases the resistance to the movement of small molecules, it further hinders the curing reaction of the resin-based carbon fiber composite. As the curing reaction proceeds, the movement of ions becomes more and more difficult, so the ionic viscosity of the system increases with the increase of the curing time.

[0059] Example 3

[0060] The structure of the monitoring system is the same as that in Example 1. In this example, it is used to monitor the kinetics of the bond exchange reaction of the dynamic cross-linked thermosetting resin. The usage process is as follows:

[0061] (1) Unscrew the screws on the base 22, disassemble the assembly of the clamp 21 and the base 22, remove the wire 5 passing through the cylindrical hole 224, and remove the LCR digital bridge 1 and the environmental control chamber furnace 31.

[0062] (2) Reset the two sets of clamp kits 2 in the environmental control chamber furnace 31 in a way that the two sample stages 212 are vertically aligned; the two sets of clamp kits 2 are respectively reconnected to the rotational rheometer 3 by being nested in the sleeves 34 of the clamp fastening rod 31 and the clamp fastening table 32 through the second connectors 222; the communication interface of the rotational rheometer 3 is reconnected to the input end of the data acquisition card through the second data line 7.

[0063] (3) Place the cured dynamic cross-linked thermosetting resin in Example 1 on the sample stage 212 of the lower clamp kit 2, close the upper and lower sample stages 212, provide a mechanical monitoring signal through the rotational rheometer 3, and the data acquisition system 4 effectively displays the change of the mechanical signal of the resin dynamic bond exchange reaction kinetics.

[0064] The stress relaxation curve of the dynamic cross-linked resin monitored in this example is as Figure 8 shown. The stress relaxation behavior of the dynamic cross-linked thermosetting resin is the key to determining the remolding, repair, and physical recycling and reprocessing of such resins. The stress relaxation ability of the dynamic cross-linked network corresponds to the dynamic bond exchange reaction. The bond exchange reaction kinetics of the dynamic cross-linked network can be reflected through the monitored stress relaxation behavior. The test results show that as time increases, the dynamic cross-linked resin exhibits stress relaxation behavior.

Claims

1. A curing reaction and bond exchange reaction kinetics monitoring system for a dynamically cross-linked thermosetting resin, characterized in that: The invention comprises an LCR digital bridge, two sets of fixture kits with the same structure, a rotational rheometer and a data acquisition system; the rotational rheometer is equipped with an environment control chamber furnace, a fixture fastening platform and a fixture fastening rod, the top of the fixture fastening platform and the bottom of the fixture fastening rod are respectively provided with a sleeve integrally formed therewith, and at least two bolt holes are provided around the sleeve; The data acquisition system comprises a data acquisition card and a computer, wherein the output end of the data acquisition card is connected to the computer; Each set of fixture kits includes a base and a fixture. The base is made of a material that is resistant to high temperature, not easy to oxidize, and does not react with the resin liquid, and the fixture is made of metal; the fixture includes a fixture body, a sample table and a first connecting piece, the sample table and the first connecting piece are respectively fixed on the top and bottom of the fixture body, and the fixture body and the sample table are both solid cylinders; the base includes a base body and a second connecting piece, the second connecting piece is fixed on the bottom of the base body, the base body is a solid cylinder, and a cavity is opened inward from the top surface of the center of the base body; the first connecting piece and the second connecting piece are both solid cylinders with a circle of grooves in the middle of the outer side, and the shape and size of the second connecting piece are adapted to the sleeve, and the cavity is the same shape and size as the first connecting piece A hollow cylinder with a circle of grooves in the middle of the outer side thereof; a through hole and at least two screw holes are horizontally provided on the side of the base body, the through hole is connected to the inside of the cavity, the screw hole is connected to the groove outside the cavity, and the center height of the screw hole is at the same level as the center height of the groove outside the cavity; a wire is placed at the bottom of the cavity, one end of the wire is left at the bottom of the cavity, and the other end is led out from the through hole; the clamp is nested with the base by a first connecting piece embedded in the cavity and pressing the wire, and screws matching the clamp are respectively penetrated in the two screw holes, the screws are made of a material that is resistant to high temperature, has high mechanical strength and will not wear the base, the screws pass through the groove outside the cavity and then press against the first connecting piece to fix the clamp on the base; The two sets of fixture kits are arranged in a manner that the two sample tables are aligned up and down, and the second connecting pieces of the upper and lower sets of fixture kits are respectively nested in the sleeves of the fixture fastening rod and the fixture fastening platform and fixed by bolts passing through bolt holes to achieve the connection between the fixture kit and the rotational rheometer. The environmental control chamber furnace is surrounded by the fixture kit, the fixture fastening platform and the outside of the fixture fastening rod sleeve; the other ends of the two wires are led out from the through holes and respectively penetrate the environmental control chamber furnace to be connected to the test end of the front panel of the LCR digital bridge; the communication interface of the rear panel of the LCR digital bridge and the communication interface of the rotational rheometer are respectively connected to the input end of the data acquisition card through the first data line and the second data line.

2. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 1, characterized in that: The sleeve is a hollow cylinder, the clamp body, the base body and the sample stage are all solid cylinders, the first connecting piece and the second connecting piece are both solid cylinders with a circle of grooves in the middle of the outer side, and the cavity is a hollow cylinder with a circle of grooves in the middle of the outer side that is compatible with the shape and size of the first connecting piece; the solid cylinders of the clamp body and the base body have the same diameter, the solid cylinder of the sample stage has a smaller diameter than the solid cylinder of the clamp body, and the solid cylinders of the first connecting piece and the second connecting piece have the same diameter and are smaller than the solid cylinder of the clamp body.

3. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 1, characterized in that: The fixture body, the sample stage and the first connecting piece are integrally formed; the base body and the second connecting piece are integrally formed.

4. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to any one of claims 1 to 3, characterized in that: The central axes of the fixture body, the sample stage and the first connecting member are on the same straight line; the central axes of the base body and the second connecting member are on the same straight line.

5. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin as claimed in claim 1, characterized in that: The diameter of the bolt hole matches the size of the outer groove of the second connecting member, and the diameter of the screw hole matches the size of the outer groove of the cavity.

6. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 1 or 5, characterized in that: The number of the bolt holes and the number of the screw holes are two respectively, the included angle between the two screw holes is 180°, and the included angle between the two bolt holes is 180°.

7. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin as claimed in claim 1, characterized in that: The center height of the through hole is at the same level as the center height of the screw hole.

8. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 7, characterized in that: The through hole is located in the middle between the two screw holes on the outside of the base body.

9. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 1, 7 or 8, characterized in that: The through hole is a cylindrical hole.

10. The curing reaction and bond exchange reaction kinetics monitoring system of a dynamically cross-linked thermosetting resin according to claim 1, characterized in that: The base is made of zirconium oxide or aluminum oxide, the clamp is made of aluminum or stainless steel, and the screws and bolts are made of polyetheretherketone.

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