CN111793351A

CN111793351A - Polyurethane/vinyl resin IPN damping material and preparation method thereof

Info

Publication number: CN111793351A
Application number: CN202010645432.3A
Authority: CN
Inventors: 李瑜; 孙昭宜; 邓金飞; 饶秋华; 梅志远
Original assignee: Naval University of Engineering PLA
Current assignee: Naval University of Engineering PLA
Priority date: 2020-07-07
Filing date: 2020-07-07
Publication date: 2020-10-20
Anticipated expiration: 2040-07-07
Also published as: CN111793351B

Abstract

The invention discloses a polyurethane/vinyl resin IPN damping material and a preparation method thereof, wherein the IPN damping material is prepared by the reaction of a polyurethane flexible component PU and a vinyl resin rigid component VER; the PU is prepared from polyether polyol with three functional groups, urethane-modified liquefied MDI and 1, 4-butanediol BDO through a one-step synthesis method; the VER is prepared by the ring-opening reaction of epoxy resin and methacrylic acid. The invention adopts a one-step method to synthesize the polyurethane component, thereby omitting the common polyurethane prepolymer synthesis step and solving the problem that the polyurethane prepolymer is easily influenced by substances such as moisture in the environment in the storage process. And the synthesis method of the polyurethane/vinyl resin IPN damping material greatly simplifies the process of the polyurethane-based IPN elastomer and improves the preparation efficiency of the material. The prepared polyurethane/vinyl resin IPN damping material has the advantages of wide temperature range and high damping.

Description

Polyurethane/vinyl resin IPN damping material and preparation method thereof

Technical Field

The invention relates to the technical field of functional materials, in particular to a polyurethane/vinyl resin IPN damping material and a preparation method thereof.

Background

With the development of society, the vibration and noise problems caused by the operation of mechanical equipment are more and more prominent, which not only causes harm to the physical and mental health of people, but also brings certain destructiveness to the stability of the equipment. At present, the kinetic energy generated when mechanical equipment vibrates is converted into heat energy to be dissipated by utilizing the characteristic of higher damping loss of a viscoelastic damping material, so that the method is one of the methods which are widely applied and can effectively solve the problem of vibration noise. Polyurethane is a viscoelastic damping material which is most widely applied, but because the glass transition region of a pure polyurethane material is generally narrow (only 20-30), and the mechanical property is poor, the pure polyurethane material is generally modified by means of blending copolymerization, organic micromolecule hybridization, filler filling, interpenetrating network polymer and the like, so that the damping temperature range of the polyurethane material is widened, and the mechanical property is improved.

Interpenetrating network polymers (IPNs) are elastomers formed by mutually crosslinking and penetrating two or more polymer monomers through polymerization reaction, and forced compatibility and synergistic effect are generated due to the mutual penetration among crosslinking networks, so that the glass transition region of the material can be effectively widened. Currently, a polyurethane/epoxy resin system is selected for preparing the IPN elastomer, the system not only has a wider damping temperature range, but also has the advantages of good mechanical property, low cost and the like, but the epoxy resin has higher viscosity and brings more inconvenience to production. In addition, in the current preparation process of the polyurethane-based IPN elastomer, a prepolymer method is mostly adopted to synthesize polyurethane components, the process is complicated and time-consuming, and the synthesized polyurethane prepolymer is easily deteriorated by the influence of the environment due to higher activity of a terminal-NCO group, so that a plurality of problems are brought to the preparation process. The vinyl resin has lower viscosity than epoxy resin and has excellent mechanical property of epoxy resinAnd, therefore, have received wide attention from researchers.Disclosure of Invention

Based on the defects of the prior art, the technical problem to be solved by the invention is to provide a polyurethane/vinyl resin IPN damping material and a preparation method thereof. The polyurethane/vinyl resin IPN damping material has the advantages of wide temperature range and high damping. The preparation method of the PU is realized by a one-step method, so that the common polyurethane prepolymer synthesis step in the synthesis of the polyurethane-based IPN elastomer is omitted, and the problem that the polyurethane prepolymer is easily influenced by substances such as moisture in the environment in the storage process is solved. The preparation process of the polyurethane/vinyl resin IPN damping material is relatively simple, the process of the polyurethane-based IPN elastomer is greatly simplified, and the preparation efficiency of the material is improved.

In order to solve the technical problem, the invention provides a polyurethane/vinyl resin IPN damping material which is prepared by the reaction of a polyurethane flexible component PU and a vinyl resin rigid component VER; the PU is prepared from polyether polyol with three functional groups, urethane-modified liquefied MDI (U-MDI) and 1, 4-butanediol BDO through a one-step synthesis method; the VER is prepared by the ring-opening reaction of an epoxy resin EP (with an epoxy value of 0.51) and methacrylic acid MAA.

Preferably, the polyurethane/vinyl resin IPN damping material provided by the present invention further comprises a part or all of the following technical features:

as an improvement of the technical scheme, the one-step method of the polyurethane comprises the following steps:

uniformly mixing a certain amount of polyether polyol, BDO and accelerator CUAT-HSF, dehydrating, adding U-MDI, and mechanically stirring uniformly to obtain a polyurethane component PU;

as an improvement of the technical scheme, the damping temperature range of the polyurethane/vinyl resin IPN damping material is-25-40 ℃, and further is-20 ℃.

A preparation method of a polyurethane/vinyl resin IPN damping material comprises the following steps:

the method comprises the following steps: the vinyl resin synthesis procedure was (reference data: peri-moist. epoxy vinyl ester resin (I) classification of epoxy vinyl ester resin, synthesis and curing [ J ] thermosetting resin, 2002,17(6): 31-3):

adding epoxy resin into a three-neck flask provided with a stirrer and a thermometer, heating to 85-90 ℃, then adding p-methoxyphenol, starting the stirrer, adding measured MAA and N, N-dimethylbenzylamine BDMA into a constant-pressure dropping funnel, and slowly dropping into the three-neck flask, wherein the reaction temperature is controlled to be 100-110 ℃; after the MAA is added, sampling every 1h, and continuously measuring the content of the acid value in the reaction system by using a chemical analysis method; when the acid value content in the system reaches a theoretical calculated value, stopping the reaction, cooling to 80 ℃, and adding styrene with different qualities to obtain vinyl resins with different comonomer contents;

step two: the one-step synthesis method of PU comprises the following steps:

uniformly mixing and dehydrating a certain amount of polyether polyol, 1, 4-butanediol BDO and a PU catalyst CUAT-HSF, adding urethane modified MDI, and mechanically and uniformly stirring to prepare PU;

step three: adding an initiator BPO and an initiation accelerator N, N dihydroxyethyl aniline into the vinyl resin synthesized in the step one, and mechanically stirring uniformly to obtain VER; uniformly mixing VER and PU under a vacuum condition, pouring the mixture into a polytetrafluoroethylene mold, curing the mixture for 12 hours at the room temperature of 25 ℃ under the vacuum condition, putting the mixture into an oven, heating the mixture to 80 ℃, and performing heat preservation and curing for 24 hours to obtain the polyurethane/vinyl resin IPN damping material.

As an improvement of the technical scheme, the mass percent of the chain extender BDO in the polyurethane component is 3.71-7.95%, and the mass percent is preferably 4.51%.

As an improvement of the technical scheme, the PU has a-NCO/-OH molar ratio of 1.05-0.75: 1.

as an improvement of the technical scheme, the mass fraction of the styrene in the VER is 40-85%, and preferably 85%.

As an improvement of the technical scheme, the mass ratio of the PU/VER is 70-90: 10-30, preferably 75-80: 20 to 25.

The invention researches the BDO dosage and the-NCO/-OH molar ratio in PU,the styrene content in VER and the PU/VER dosage ratio influence the damping performance and mechanical performance of IPN. The results show that: reduction of BDO content in PU to obtain T of PU/VER IPN elastomer_gMoving to the low temperature direction; the molar ratio of-NCO/-OH is reduced and the effective damping temperature range is broadened. The styrene content in the VER increases and the tan peak rises. The VER ratio in PU/VER IPN elastomers increases, the peak tan value decreases, and the peak tan value is maximum when the PU/VER dosage ratio is 80/20. With the increase of the BDO dosage and the VER component ratio in PU, the strength of the PU/VER IPN elastomer can be increased, the increase of the styrene content in VER can reduce the tensile strength, but the elongation at break can be improved.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the polyurethane/vinyl resin IPN elastomer is prepared by using liquefied MDI as a raw material and synthesizing a polyurethane component by a one-step method, and blending the polyurethane component and vinyl resin, and the liquefied MDI, a cross-linking agent, the vinyl resin component and a catalyst are directly mixed and cured according to a ratio in the preparation process, so that the common polyurethane prepolymer synthesis step in the synthesis of the polyurethane-based IPN elastomer is omitted, and the problem that the polyurethane prepolymer is easily influenced by substances such as moisture in the environment in the storage process is solved.

2. When the polyurethane component is prepared, trifunctional polyether with higher activity and MDI modified by polyurethane are used as raw materials, so that the molding time of the obtained sample is shortened, and the reaction is more complete; the modulus and the strength of the sample at normal temperature (25 ℃) are higher.

3. The preparation method for preparing the polyurethane/vinyl resin IPN damping material is simple and convenient, greatly simplifies the process of polyurethane-based IPN elastomer and improves the preparation efficiency of the material.

4. The polyurethane/vinyl resin IPN damping material has the advantages of wide temperature range and high damping, and the effective damping temperature range can reach 50 ℃.

The invention analyzes the mechanical properties of the IPN elastomer with different proportions by a dynamic thermal mechanical analyzer DMA and an electronic universal tester, summarizes factors influencing the mechanical properties and damping properties of the PU/VER IPN material, optimizes the damping and mechanical properties of the material and obtains the wide-temperature-range high-damping IPN elastomer material.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the contents of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following detailed description is given in conjunction with the preferred embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below.

FIG. 1 is a graph showing the tan-T effect of the amount of chain extender BDO used in PU of a preferred embodiment of the present invention on IPN elastomers;

FIG. 2 is a tan-T effect curve of the molar ratio of-NCO/-OH in PU versus IPN elastomer according to a preferred embodiment of the present invention;

FIG. 3 is a plot of the tan-T effect of VER component comonomer (ST.) content on IPN elastomers for a preferred embodiment of the present invention;

FIG. 4 is a graph showing the tan-T effect of the PU/VER component of a preferred embodiment of the present invention versus an IPN elastomer;

FIG. 5 is a graph showing the effect of BDO dosage as a chain extender on the mechanical properties of an IPN elastomer according to a preferred embodiment of the present invention;

FIG. 6 is a plot showing the effect of the molar ratio of-NCO/-OH in PU according to a preferred embodiment of the present invention on the mechanical properties of an IPN elastomer;

FIG. 7 is a graph of the effect of VER component comonomer (ST.) content on the mechanical properties of an IPN elastomer according to a preferred embodiment of the present invention;

FIG. 8 is a plot of the mechanical property impact of the PU/VER component of a preferred embodiment of the present invention versus an IPN elastomer.

Detailed Description

Other aspects, features and advantages of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.

The preparation method of the polyurethane/vinyl resin IPN damping material comprises the following steps:

the method comprises the following steps: the vinyl resin synthesis steps are as follows:

in order to eliminate the effect of additives on the present study, vinyl resins were synthesized by the following steps: adding epoxy resin into a three-neck flask provided with a stirrer and a thermometer, heating to 85-90 ℃, then adding p-methoxyphenol, starting the stirrer, adding measured MAA and BDMA into a constant-pressure dropping funnel, slowly dropping into the three-neck flask, and controlling the reaction temperature to be 100-110 ℃. After the MAA is added, sampling every 1h, and continuously measuring the content of the acid value in the reaction system by using a chemical analysis method. When the acid value content in the system reaches the theoretical calculated value, stopping the reaction, cooling to 80 ℃, adding styrene with different masses to obtain vinyl resin components with different comonomer contents

Step two: the one-step synthesis method of the polyurethane comprises the following steps:

uniformly mixing and dehydrating metered polyether polyol 3000E, BDO and a catalyst CUAT-HSF, adding U-MDI, and mechanically and uniformly stirring to prepare a polyurethane component PU;

step three: adding the vinyl resin synthesized in the step one into an initiator BPO and an accelerator PEDA, and mechanically stirring uniformly to prepare a vinyl component VER; uniformly mixing the vinyl resin component and the polyurethane component under a vacuum condition, pouring the mixture into a polytetrafluoroethylene mold, curing the mixture for 12 hours at room temperature (25 ℃) under the vacuum condition, putting the mixture into an oven, heating the mixture to 80 ℃, and performing heat preservation and curing for 24 hours to obtain the polyurethane/vinyl resin IPN damping material.

The synthesis mechanism is as follows:

according to the above synthesis method, a series of examples were carried out, the compounding ratio is shown in table 1, and the influence of the amount of chain extender BPO in PU, the-NCO/-OH molar ratio, the content of comonomer styrene in VER and the PU/VER component compounding ratio on the IPN damping performance and mechanical properties was studied, as shown in FIGS. 1 to 8.

Table 1 raw material ratio in each example

Remarking: the dynamic mechanical temperature spectrum was measured by a dynamic thermomechanical analyzer (DMA1, mettler toledo). The selected test mode is a stretching mode, the test frequency is 1Hz, the heating rate is 3 ℃/min, and the temperature scanning range is-40 ℃ to 100 ℃.

FIG. 1 is a graph showing the influence of the amount of chain extender BDO in PU on tan-T of an IPN elastomer;

FIG. 2 is a plot of the tan-T effect of the molar ratio of-NCO/-OH in PU versus IPN elastomer;

FIG. 3 is a plot of the effect of comonomer (ST.) content in VER on tan-T of an IPN elastomer;

FIG. 4 is a graph showing the effect of PU/VER component on IPN tan-T;

FIG. 5 is a curve showing the influence of the amount of chain extender BDO in PU on the mechanical properties of the IPN elastomer;

FIG. 6 is a plot of the effect of the molar ratio of-NCO/-OH in PU on the mechanical properties of IPN elastomers;

FIG. 7 is a graph of the effect of VER component comonomer (ST.) content on the mechanical properties of an IPN elastomer;

FIG. 8 is a plot of the mechanical property impact of PU/VER component ratio on IPN elastomers.

1. Influence of the amount of BDO used as PU chain extender, -NCO/-OH molar ratio on the damping performance of IPN

FIG. 1 is a graph showing the effect of the amount of chain extender BDO in PU on the tan-T of IPN elastomers. As can be seen from the figure, when the amount of the chain extender is reduced, the peak value of tan is shifted toward a low temperature, but tan is decreased_max(damping peak) is basically unchanged (about 0.4), and effective damping temperature range (DTR, tan)>0.3) is basically in the range of 50 ℃, and when the using amount of the chain extender BDO is 4.51 percent of the mass fraction of PU, the DTR covers 0-50 ℃, so that the polyurethane is an excellent normal-temperature damping material. This may be due to the use of small molecule diols with low molecular weightThe reduction of urethane groups generated in the chain segment, the increase of ether group content, the enhancement of internal rotation of the main chain and the good low-temperature flexibility of the chain segment, thereby reducing the glass transition temperature. In addition, with the reduction of the using amount of the chain extender, the proportion of bonds which can rotate on the chain is relatively increased, the rigidity of the molecular chain is reduced, and the deviation of the glass transition temperature to the low-temperature direction is facilitated.

FIG. 2 is a graph showing the effect of the molar ratio of-NCO/-OH in PU on the damping performance of IPN. As can be seen from the graph, when the molar ratio-NCO/-OH was decreased from 1.05 to 0.75, the tendency of the change in the tan peak of IPN was substantially the same as that of FIG. 1, both shifted toward low temperatures, but the difference was that the DTR gradually became wider (increasing from 50 ℃ to 66 ℃). This is probably because the urethane groups in PU are reduced, the rigidity of the molecular chain is reduced, which is beneficial to the deviation of the glass transition temperature to the low temperature direction, and in addition, because the molar ratio of-NCO/-OH is reduced, the degree of network crosslinking is reduced, which is beneficial to the improvement of the interpenetrating efficiency of the two-component network of PU/VER, the microphase separation is increased, and the DTR is widened.

2. Effect of comonomer (ST.) content in VER on the damping Properties of IPNs

FIG. 3 is a graph of the effect of VER comonomer (ST.) content on IPN tan efficiency. As can be seen from the figure, the polyurethane/vinyl IPN damping material gradually has two loss factor peaks changing into one peak, which shows that the IPN gradually changes from the half thermodynamic compatibility to the complete thermodynamic compatibility along with the increase of the styrene content. In addition, tan is shown in the figure_maxIncreased with increasing ST. content, tan when ST. content reached 85%_maxReaching 0.69. This is probably because ST. content is increased, so the VER free radical random copolymerization degree is increased, the molecular chain curling flexibility is increased, and the damping performance is improved.

3. Effect of PU/VER component ratio on IPN damping Performance

FIG. 4 is a graph showing the effect of PU/VER component ratio on the degree of tan of IPN. As can be seen from the figure, when the component ratio is 90/10 to 75/25, the damping peaks in the system are all unimodal, which indicates that the VER hard phase component enters the soft phase in a large amount, and the two components are mixed at a certain molecular level. When the component ratios are 80/20 and 75/25, the DTRs are 56 ℃ and 64 ℃ respectively, and the damping performance is better. The curves in the graph show that as the proportion of the VER component increases, the damping peak value decreases, but the effective damping temperature range is widened, which shows that the interpenetrating efficiency of the two-component network is high, and the microphase separation is large. In addition, the rigid chain segment between networks is increased, and the glass transition temperature is increased to a certain extent. When the component ratio is 70/30, the damping value is low, a wave valley region with low damping value appears, a certain phase separation is generated macroscopically, the respective loss factor peaks of the two components are obvious, the respective damping is shown, the interpenetration degree is poor, and the damping performance of the IPN is poor.

4. Analysis of mechanical Properties

FIG. 5 is a plot of the effect of the amount of chain extender used in the PU component on the Tensile Strength (TS) and elongation at break (Eb) of the PU/VER IPN material. As can be seen from the figure, the tensile strength of the IPN gradually decreases with decreasing amount of chain extender, but the corresponding elongation at break gradually increases. The content of ether groups (-C-O-C-) in the main chain segment is increased due to the increase of the proportion of the soft segment of the polyether polyol in the PU component, so that the molecular chain is more flexible, the elongation is promoted, but the rigidity of the corresponding molecular chain is reduced, and in addition, the molecular weight is reduced along with the reduction of the chain extender, so that the strength is gradually reduced. FIG. 6 is a plot of the effect of the molar ratio of PU component N (NCO)/n (OH) on the tensile strength of IPN versus elongation at break. Although the isocyanate and the chain extender constitute the hard PU segment, they have a different effect on the mechanical properties of the IPN. As shown in the figure, after the-NCO molar ratio is increased to a certain degree, the strength is not obviously changed any more, which is probably because the NCO content is high, the crosslinking degree of the PU network is increased, and the interpenetration between the PU/VER component networks is inhibited to a certain extent, so that the microphase separation is poor, and as also shown in the figure 2, the damping value is reduced due to the microphase separation, thereby being effectively verified.

Fig. 7 is a graph of the effect of comonomer (ST.) content on IPN tensile strength and elongation at break. As can be seen, the tensile strength of the IPN decreases with increasing ST. content, while the elongation at break gradually increases. This may be due to a decrease in the high molecular weight vinyl resin component of the VER network system, resulting in a decrease in the degree of crosslinking of the network, resulting in a decrease in molecular weight and thus in a decrease in strength. Further, the increase in the ST. monomer increases the degree of random copolymerization of the segment, increases the length of the randomly curled segment, and increases the distance of extension and contraction of the curled segment with an increase in stress, thereby increasing the elongation.

FIG. 8 is a plot of the effect of PU/VER component on IPN tensile strength versus elongation at break. It is seen from the figure that when PU/VER is 90/10, the strength is 1.66Mpa at the lowest, and the strength increases rapidly with the increase of VER component proportion, and when PU/VER is 70/30, the strength reaches 9.26Mpa, which shows that the rigid chain segment in VER component and PU component are interpenetrated to a higher degree, a certain hard phase region is formed in PU soft phase, and a certain reinforcing effect is achieved in IPN. Correspondingly, with the increase of stress, the interlocking between the two networks generates a certain motion inhibiting effect, so that the elongation rate is increased, but when PU/VER is 75/25, the elongation rate begins to be reduced, the inhibiting effect between the interpenetrating networks reaches a certain critical point, and the brittle characteristic of a rigid chain segment in a plastic phase region formed by the VER component is displayed, so that the elongation rate is gradually reduced.

In conclusion, the polyurethane/vinyl resin IPN damping material provided by the invention has the following characteristics:

(1) in the PU component, the tensile strength is gradually reduced with the increase of the hard segment content, but the elongation at break is increased to different degrees; an increase in comonomer content in the VER component leads to a linear decrease in the strength of the IPN and a corresponding linear increase in the elongation at break; the tensile strength increases rapidly with increasing proportion of the VER component.

(2) When the using amount of the chain extender is gradually reduced, the Tg peak of the IPN shifts to the low-temperature direction, and the influence on the damping peak value is small; the molar ratio of-NCO/OH is different from that of a chain extender in that when the molar ratio of NCO is reduced, DTR is gradually widened, the maximum range can reach 66 ℃, and the effective damping temperature range is approximately between-30 ℃ and 40 ℃; the VER comonomer content is increased, the damping peak value of the IPN is improved, when the comonomer content is increased to 85 percent, the damping peak value reaches 0.69, and the damping effect is best; the IPN damping peak value is reduced along with the increase of VER component content, when PU/VER is 80/20 and 75/25, the damping peak values are 0.73 and 0.56 respectively, the damping performance is good, and the damping temperature range is approximately-20 ℃.

The raw materials listed in the invention, the upper and lower limits and interval values of the raw materials of the invention, and the upper and lower limits and interval values of the process parameters (such as temperature, time and the like) can all realize the invention, and the examples are not listed.

While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A polyurethane/vinyl resin IPN damping material is characterized in that: prepared by the reaction of a polyurethane flexible component PU and a vinyl resin rigid component VER; the PU is prepared from trifunctional polyether polyol, urethane-modified liquefied MDI and 1, 4-butanediol BDO through a one-step synthesis method.

2. The polyurethane/vinyl IPN damping material according to claim 1, wherein: the one-step method of the PU comprises the following steps:

uniformly mixing and dehydrating a certain amount of polyether polyol, BDO and PU catalyst CUAT-HSF, adding urethane modified liquefied MDI, and mechanically and uniformly stirring to prepare PU.

3. The polyurethane/vinyl IPN damping material according to claim 1, wherein: the damping temperature range of the polyurethane/vinyl resin IPN damping material is-25-40 ℃, and further is-20 ℃.

4. A preparation method of a polyurethane/vinyl resin IPN damping material is characterized by comprising the following steps: the raw material of claim 1 is adopted, and the specific preparation method comprises the following steps:

the method comprises the following steps: preparation of vinyl resins

Step two: the one-step synthesis method of PU comprises the following steps:

5. The method for preparing polyurethane/vinyl resin IPN damping material according to claim 4, wherein: the mass percentage of the chain extender BDO in the polyurethane component is 3.71-7.95%.

6. The method for preparing polyurethane/vinyl resin IPN damping material according to claim 5, wherein: the mass percentage of the chain extender BDO in the PU is 4.51 percent.

7. The method for preparing polyurethane/vinyl resin IPN damping material according to claim 4, wherein: the PU has a molar ratio of-NCO/-OH of 1.05-0.75: 1.

8. the method for preparing polyurethane/vinyl resin IPN damping material according to claim 4, wherein: the mass fraction of styrene in the VER is 40-85%.

9. The method for preparing polyurethane/vinyl resin IPN damping material according to claim 4, wherein: the PU/VER mass ratio is 90-70: 10 to 30.

10. The method for preparing polyurethane/vinyl IPN damping material according to claim 9, wherein: the PU/VER mass ratio is 75-80: 20 to 25.