Method for testing complex viscosity of polyphenylene sulfide resin

Abstract

The invention provides a method for testing complex viscosity of polyphenylene sulfide resin, and belongs to the technical field of polyphenylene sulfide resin detection. According to the method, the PPS resin raw powder is tabletted at the temperature of 21-25 DEG C and the pressure of 0.5-2 MPa to prepare the PPS resin sheet, and then the complex viscosity of the PPS resin raw powder is tested by using the rotational rheometer, so that the accuracy of the complex viscosity test of the PPS resin raw powder can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyphenylene sulfide resin detection, and particularly relates to a method for testing the complex viscosity of polyphenylene sulfide resin. Background Art

[0002] Polyphenylene sulfide, abbreviated as PPS, is one of the special engineering plastics, with excellent properties such as high temperature resistance, corrosion resistance, radiation resistance, flame retardancy, etc., and is widely used in the fields of electronics, automobiles, machinery, textiles, etc. In the PPS modification industry, effective evaluation and monitoring of PPS resin raw materials are necessary means to ensure the stable implementation of the modification process, and it is convenient to prevent product quality difference problems caused by performance deviation of raw materials from the source. The difference in the molecular weight and molecular chain structure of PPS resin results in different complex viscosities. Accurately measuring the complex viscosity is an effective method for evaluating and monitoring the performance of PPS resin raw materials. Using the parallel plate fixture of a rotational rheometer to measure the complex viscosity of PPS resin has the advantages of easy cleaning, labor saving, time saving, and less sample consumption; currently, in this method, the appearance of the tested samples is almost all sheets or particles, which are obtained by melting and extruding PPS raw powder at high temperature and granulating. However, the bond energy of the C-S bond in the PPS molecular structure is relatively low, and it is easy to undergo chain oxidation and cleavage at high temperature, generating free radical active chains. The active chains initiate the successive cleavage of other chains, and the chains combine with each other to produce crosslinking and branching, resulting in a change in the PPS molecular structure. At this time, the complex viscosity measured for the sheet or particle can no longer represent the PPS raw powder. Therefore, directly measuring the complex viscosity of PPS resin raw powder without any high-temperature heat treatment can more reliably evaluate and monitor it. Since there is a carrier gas flowing through the heating furnace cavity of the rotational rheometer, if the PPS resin raw powder is directly laid flat on the lower parallel plate fixture and heated and melted, it will be blown throughout the heating furnace cavity. Reducing the carrier gas flow rate and then increasing the carrier gas flow rate after the raw powder melts can improve this problem. However, when the carrier gas flow rate is too low, the atmosphere in the furnace cavity is almost air, and PPS resin still has the possibility of undergoing oxidative degradation crosslinking reaction during melting at a higher temperature, resulting in a decrease in the accuracy of the finally measured complex viscosity. Therefore, it is necessary to establish a method for accurately measuring the complex viscosity of polyphenylene sulfide resin raw powder. Summary of the Invention

[0003] The purpose of the present disclosure is to overcome the deficiencies of the prior art and provide a method for testing the complex viscosity of polyphenylene sulfide resin, which can accurately measure the complex viscosity of polyphenylene sulfide resin raw powder.

[0004] To achieve the above purpose, the technical solution adopted by the present disclosure is: The present invention provides a method for testing the complex viscosity of polyphenylene sulfide resin, including the following steps:

[0005] S1: Place the PPS resin raw powder in a tablet press mold, and press it for 8 - 12 s at a temperature of 21 - 25 °C and a pressure of 0.5 - 2 MPa to obtain a PPS resin sheet;

[0006] S2: Place the PPS resin sheet in the center of the flat fixture of a rotational rheometer, heat it to melting to form a PPS melt;

[0007] S3: Set the strain ε and angular frequency ω for the test, and conduct a complex viscosity - angular frequency sweep test; repeat the test at least 3 times, and judge the accuracy of the complex viscosity of the PPS resin based on the complex viscosity - angular frequency curves of multiple tests.

[0008] In some embodiments, the gap between the flat fixtures of the rotational rheometer is 0.5 - 0.7 mm.

[0009] In some embodiments, the strain ε is 2 - 3%.

[0010] In some embodiments, the angular frequency ω is 0.1 - 100 rad / s.

[0011] In some embodiments, in step S3, after the flat gap reaches the set value, the sample is kept at a constant temperature for 2.5 - 3.5 min.

[0012] In some embodiments, the thickness of the PPS resin sheet is 4 - 6 mm.

[0013] In some embodiments, the heating atmosphere is nitrogen.

[0014] Compared with the prior art, the beneficial effect of the present disclosure is: After the PPS resin raw powder is pressed into a PPS resin sheet at a temperature of 21 - 25 °C and a pressure of 0.5 - 2 MPa in the present invention, and then the rotational rheometer is used to test the complex viscosity of the PPS resin raw powder, the accuracy of the complex viscosity test of the PPS resin raw powder can be improved. Description of the Drawings

[0015] Figure 1 is the appearance diagram of PPS resin sheets prepared under different pressing pressures;

[0016] Figure 2 is the complex viscosity - angular frequency curve of PPS resin sheets prepared under different pressing pressures;

[0017] Figure 3 is the partial enlarged view of the complex viscosity - angular frequency curve of PPS resin sheets prepared under different pressing pressures;

[0018] Figure 4 is the complex viscosity - angular frequency curve of the PPS resin raw powder when the strain is 0.1%;

[0019] Figure 5 Complex viscosity - angular frequency curves of PPS resin samples obtained by different pretreatment methods. Detailed implementation manners

[0020] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the understanding of the disclosed content of the present disclosure is more thorough and comprehensive.

[0021] As used herein, the terms:

[0022] "Prepared from..." is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non - exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements does not necessarily limit to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or device.

[0023] The connecting word "consisting of" excludes any unstated element, step or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0024] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. For example, when the range "1 - 5" is disclosed, the described range should be interpreted to include ranges "1 - 4", "1 - 3", "1 - 2", "1 - 2 and 4 - 5", "1 - 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0025] In these embodiments, unless otherwise specified, the parts and percentages are by mass.

[0026] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass of component A is a parts by mass and the mass of component B is b parts by mass, it means the mass ratio of component A to component B is a:b. Or it means the mass of component A is aK and the mass of component B is bK (K is any number representing the multiplication factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0027] "And / or" is used to indicate that one or both of the described situations may occur. For example, A and / or B includes (A and B) and (A or B).

[0028] The PPS resin raw powder of the present invention refers to the PPS resin that has not undergone any modification or heat treatment.

[0029] To solve the problem of low accuracy in testing the complex viscosity of PPS resin raw powder in the prior art.

[0030] The present invention provides a method for testing the complex viscosity of polyphenylene sulfide resin, comprising the following steps:

[0031] S1: Place the PPS resin raw powder in a tablet press mold, and press for 8 - 12 s at a temperature of 21 - 25 °C and a pressure of 0.5 - 2 MPa to obtain a PPS resin tablet;

[0032] S2: Place the PPS resin tablet in the center of the plate fixture of a rotational rheometer, and heat it to melting in a heating atmosphere to form a PPS melt;

[0033] S3: Set the strain ε and angular frequency ω for testing, and conduct a complex viscosity - angular frequency sweep test; repeat the test at least 3 times, and judge the accuracy of the complex viscosity of the PPS resin according to the complex viscosity - angular frequency curves of multiple tests.

[0034] In different embodiments, the pressure for pressing can be, but is not limited to, 0.5 MPa, 0.6 MPa, 0.8 MPa, 1.0 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, 2 MPa.

[0035] In different embodiments, the time for pressing can be, but is not limited to, 8 s, 9 s, 10 s, 11 s, 12 s.

[0036] After the PPS resin raw powder is made into a PPS resin sheet by pressing, the complex viscosity of the PPS resin raw powder is then measured using a rotational rheometer, which can improve the accuracy of measuring the complex viscosity of the PPS resin raw powder. Among them, the pressing conditions are one of the key factors affecting the accuracy of measuring the complex viscosity of the PPS resin raw powder. If the pressing pressure is too small, the boundaries between the PPS resin raw powder particles are clear, and it is difficult to form a PPS resin sheet, which is not conducive to subsequent testing. If the pressing pressure is too high, pre-oxidation of the PPS resin raw powder will occur, resulting in a decrease in the accuracy of measuring the complex viscosity of the PPS resin raw powder.

[0037] In some embodiments, the gap between the parallel plate fixtures of the rotational rheometer is 0.5 - 0.7 mm, for example, it can be but is not limited to 0.5 mm, 0.6 mm, 0.7 mm.

[0038] In some embodiments, the strain ε is 2 - 3%, for example, it can be but is not limited to 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%.

[0039] The gap between the parallel plate fixtures of the rotational rheometer and the strain ε are values finally determined after a large number of experiments. They can not only ensure the normal progress of detecting the complex viscosity of the PPS resin raw powder, but also ensure that the sample is in the linear viscoelastic region during the measurement of the complex viscosity of the PPS resin raw powder, obtaining accurate complex viscosity values; and those skilled in the art cannot obtain them through a small number of experimental times.

[0040] In some embodiments, in step S3, after the plate gap reaches the set value, the sample constant temperature time is 2.5 - 3.5 min, for example, it can be 2.5 min, 3 min, 3.5 min.

[0041] In some embodiments, the thickness of the PPS resin sheet is 4 - 6 mm, for example, it can be but is not limited to 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm.

[0042] The present invention reads the complex viscosity values corresponding to multiple angular frequencies through the complex viscosity - angular frequency sweep curve.

[0043] In some embodiments, the heating atmosphere is nitrogen.

[0044] Example 1

[0045] This example tests the influence of different pressing pressures on the accuracy of measuring the complex viscosity of the PPS resin raw powder.

[0046] Sample to be detected: Domestic PPS resin raw powder (produced by Zhejiang NHU Co., Ltd., model 3418).

[0047] Instrument for detection: Rotational rheometer (TA Instruments, Inc., USA, model Discovery HR-2).

[0048] The test method includes the following steps:

[0049] S1: Place the PPS resin raw powder in the mold of an infrared press. The addition amount of the PPS resin raw powder is 2 / 3 of the depth of the cavity of the infrared press mold. Under a temperature of 23°C and a specified pressure, apply constant pressure for 10 s to obtain a PPS resin sheet with a thickness controlled at 4 - 6 mm. Prepare 8 groups of PPS resin sheets according to different pressing pressures, denoted as "PPS-0.5MPa", "PPS-1.0MPa", "PPS-2.0MPa", "PPS-3.0MPa", "PPS-4.0MPa", "PPS-5.0MPa", "PPS-7.0MPa", "PPS-10MPa", for standby;

[0050] S2: Place the PPS resin sheet in the center of the flat plate fixture of the rotational rheometer. Heat it to 300°C for melting under a nitrogen atmosphere. The gap of the flat plate fixture is 0.5 mm. After the flat plate gap value reaches the set value, keep the sample at a constant temperature for 3 min to form a PPS melt;

[0051] S3: Set the test strain ε = 2%, and the test angular frequency ω = 0.1 - 100 rad / s. Conduct a complex viscosity - angular frequency sweep test at a constant melting temperature; after each group of samples is tested, clean the parallel plate fixture and use the non - melted PPS resin to test the next sample.

[0052] Figure 1 is the appearance diagram of the PPS resin sheets prepared under different pressing pressures. From Figure 1 it can be seen that when the pressing pressure is relatively low, the boundaries between the PPS resin raw powder particles are clear. As the pressing pressure increases, the edges between the PPS resin raw powder particles gradually become blurred and merge into one; it shows that when the pressing pressure is high, the PPS resin raw powder particles are deformed and broken, resulting in a shortening of the distance between the PPS resin raw powder particles, an increase in the contact area, and at the same time, the van der Waals force between the particles comes into play, generating a large number of new surfaces.

[0053] Figure 2 is the complex viscosity - angular frequency curve of the PPS resin sheets prepared under different pressing pressures, Figure 3 is Figure 2 the partial enlarged view when the angular frequency is 1 - 100 rad / s in Figure 2 、 Figure 3It can be seen that when the tableting pressure is lower than 2 MPa, the complex viscosity - angular frequency curves of the PPS resin raw powder hardly change and are relatively similar; when the tableting pressure is greater than 2 MPa, as the tableting pressure increases, the complex viscosity - angular frequency curves of the PPS resin raw powder show an overall upward trend. The possible reason is that heat is generated by the friction between the PPS resin raw powder particles and between the particles and the die wall, resulting in a local temperature increase, which causes pre - oxidation of the PPS resin raw powder, manifested as an increase in complex viscosity; this leads to a decrease in the test accuracy of the complex viscosity.

[0054] Example 2

[0055] The linear viscoelastic region refers to the region where, within a certain strain or stress range, the structure of the sample undergoes elastic deformation and the deformation can be completely recovered, and the strain - stress law conforms to the sine - wave law, that is, when a sinusoidally varying stress or strain is input, the strain or stress output by the material response should also be sinusoidally varying. Only the viscoelastic parameters measured within the linear viscoelastic region have clear physical meanings. When performing a strain or stress sweep, the region where the modulus is basically unchanged, that is, the region where the stress is proportional to the strain, is the linear viscoelastic region. In the angular frequency sweep test for obtaining the complex viscosity of a material at a certain temperature, the magnitude of the strain and the gap between the parallel - plate fixtures are two important factors affecting whether the material is in the linear viscoelastic region and the accuracy of its complex viscosity value. For resins with different viscosities, the appropriate strain range values and parallel - plate fixture gap values are different. In this example, strain sweep tests of PPS resin raw powders with three different viscosities at different parallel - plate gap values were performed. By analyzing whether the stress output by the material response under various strains is sinusoidally varying, a procedure suitable for accurately measuring the complex viscosity of PPS resin raw powders with various viscosities was explored.

[0056] Samples to be detected: Three domestic PPS resin raw powders with different viscosities (the sample with the model number 3418 produced by Zhejiang NHU Co., Ltd. is marked as "high viscosity"; the model number 3450 is marked as "medium viscosity"; the model number 3490 is marked as "low viscosity").

[0057] The test method includes the following steps:

[0058] S1: Place the PPS resin raw powder in an infrared tableting machine mold. The addition amount of the PPS resin raw powder is 2 / 3 of the depth of the infrared tableting machine mold cavity. Keep the pressure constant at 2.0 MPa for 10 s at a temperature of 23 °C to obtain a PPS resin tablet.

[0059] S2: Place the PPS resin tablet in the center of the parallel - plate fixture of a rotational rheometer. Heat it to 300 °C for melting in a nitrogen atmosphere. The gap between the parallel - plate fixtures is 0.5 - 1.0 mm. After the parallel - plate gap reaches the set value, keep the sample at a constant temperature for 3 min to form a PPS melt.

[0060] Prepare 18 groups of PPS resin samples according to different flat gap values, denoted as "high viscosity - 0.5mm", "high viscosity - 0.6mm", "high viscosity - 0.7mm", "high viscosity - 0.8mm", "high viscosity - 0.9mm", "high viscosity - 1.0mm", "medium viscosity - 0.5mm", "medium viscosity - 0.6mm", "medium viscosity - 0.7mm", "medium viscosity - 0.8mm", "medium viscosity - 0.9mm", "medium viscosity - 1.0mm", "low viscosity - 0.5mm", "low viscosity - 0.6mm", "low viscosity - 0.7mm", "low viscosity - 0.8mm", "low viscosity - 0.9mm", "low viscosity - 1.0mm";

[0061] S3: Set the test strain ε = 0.1 - 100%, the test angular frequency ω = 10 rad / s, and conduct a modulus - strain sweep test at a constant melting temperature; after each group of samples is tested, clean the parallel plate fixture and use the un - melted PPS resin to test the next sample.

[0062] By analyzing the modulus - strain curves of the PPS resin raw powder at different flat gap values, observe whether the stress output by the material response at each strain belongs to sinusoidal variation, thereby judging whether the PPS resin raw powder is in the linear viscoelastic region at this strain, and whether the complex viscosity value measured during angular frequency sweep at this strain is accurate and meaningful. The results are shown in Table 1. Table 1 shows the strain ε range values corresponding to the sinusoidal variation of the stress output by the material response of PPS resins with different viscosities at different flat gap values. From the experimental data in Table 1, it can be seen that the linear viscoelastic region of the high - viscosity PPS resin is wider, and the corresponding linear viscoelastic region can be obtained under various flat gap value conditions. By analyzing the strain ε ranges corresponding to the high - viscosity and medium - viscosity PPS resins at different flat gap values, it can be seen that as the flat gap value increases, the strain ε range decreases; in addition, as the viscosity of the PPS resin decreases, the range of the linear viscoelastic region decreases. For the low - viscosity PPS resin, when the flat gap value is higher than 0.7mm, the hysteresis loop at any point on the curve does not show sinusoidal variation, indicating that when performing a complex viscosity - angular frequency sweep test for viscosity at this flat gap value, the appropriate strain ε parameter value cannot be input into the test program, and thus accurate viscosity data cannot be measured. Based on the above conclusions, controlling the flat gap value within 0.5 - 0.7mm and the strain ε within 2 - 3% can be applicable to the accurate measurement of the viscosities of PPS resins with various viscosities.

[0063] Table 1

[0064]

[0065] Example 3

[0066] This example tests the influence on the accuracy of the complex viscosity measurement of the PPS resin raw powder when the strain is 0.1%.

[0067] Sample to be tested: Domestic PPS resin raw powder (produced by Zhejiang NHU Co., Ltd., model number 3418).

[0068] Instrument for testing: Rotary rheometer (TA Instruments, USA, model Discovery HR-2).

[0069] The test method includes the following steps:

[0070] S1: Place the PPS resin raw powder in the infrared press mold. The addition amount of the PPS resin raw powder is 2 / 3 of the depth of the cavity of the infrared press mold. Keep the pressure constant at 2.0 MPa for 10 s at a temperature of 25 °C to obtain a PPS resin sheet with a thickness controlled at 4 - 6 mm. Prepare three groups of samples, denoted as "3418 - 0.5% - 1", "3418 - 0.5% - 2", and "3418 - 0.5% - 3".

[0071] S2: Place the PPS resin sheet in the center of the parallel plate fixture of the rotary rheometer and heat it to 300 °C for melting in a nitrogen atmosphere. The gap of the parallel plate fixture is 0.5 mm. After the gap of the parallel plate fixture reaches the set value, keep the sample at a constant temperature for 3 min to form a PPS melt.

[0072] S3: Set the strain ε = 0.1% for the test and the angular frequency ω = 0.1 - 100 rad / s, and conduct a complex viscosity - angular frequency sweep test at a constant melting temperature; after each group of samples is tested, clean the parallel plate fixture and then use the un - melted PPS resin to test the next sample, and measure three times in parallel. The test results are as Figure 4 shown.

[0073] Figure 4 When the strain is set to 0.1%, it is the complex viscosity - angular frequency sweep curve of the PPS resin raw powder. Analyzing the complex viscosity - angular frequency curve in the figure, it can be seen that when the applied strain is too low, the complex viscosity curve shows serrations in the low - frequency region, and the stress change output by the material response at each angular frequency on the whole curve does not show a sinusoidal change, indicating that the material is not in the linear viscoelastic region at this time, and the measured complex viscosity value is not accurate.

[0074] Comparative Example 1

[0075] This comparative example tested the influence of different pretreatment methods on the accuracy of the complex viscosity test of PPS resin.

[0076] Sample to be tested: A certain domestic PPS resin raw powder (produced by Zhejiang NHU Co., Ltd., model number 3418).

[0077] Instruments for detection: Rotary rheometer (TA Instruments, USA, model Discovery HR-2).

[0078] Different markings are made according to different pretreatment methods, as follows:

[0079] For samples without any pretreatment, take 3 samples, which are respectively denoted as "direct melting-1", "direct melting-2", and "direct melting-3".

[0080] The preparation method of the samples pretreated by extrusion granulation is as follows: Add the original PPS resin powder into a twin-screw extruder, and melt and extrude granulation under the conditions of a temperature of 270 °C and a screw speed of 350 rpm; Take 3 samples, which are respectively denoted as "extrusion granulation-1", "extrusion granulation-2", and "extrusion granulation-3";

[0081] The preparation method of the samples pretreated by tabletting is as follows: Place the original PPS resin powder in the die of an infrared tabletting machine. The addition amount of the original PPS resin powder is 2 / 3 of the depth of the cavity of the infrared tabletting machine die. Keep the pressure constant at 2.0 MPa for 10 s at a temperature of 23 °C to obtain a PPS resin sheet with a thickness controlled at 4-6 mm; Take 3 samples, which are respectively denoted as "tabletting-1", "tabletting-2", and "tabletting-3".

[0082] Place the PPS samples prepared by the extrusion granulation and tabletting pretreatment methods in the center of the plate fixture of the rotary rheometer, and heat to 300 °C for melting in a nitrogen atmosphere; When directly melting, first close the nitrogen, place the samples without any pretreatment in the center of the plate fixture of the rotary rheometer, and then open the nitrogen after heating to 300 °C for melting; The gap of the plate fixture is 0.5 mm. After the gap between the plates drops to the set value, keep the sample at a constant temperature for 3 min to form a PPS melt;

[0083] S3: Set the strain ε = 2% for the test, the angular frequency ω = 0.1 - 100 rad / s for the test, and perform a complex viscosity - angular frequency sweep test at a constant melting temperature; After each group of samples is tested, clean the parallel plate fixture and then use the unmolten PPS resin to test the next sample. The test results are shown in Table 2 and Figure 5 .

[0084] Table 2 Average values of complex viscosities of PPS resin samples obtained by different pretreatment methods at different frequencies

[0085]

[0086] Figure 5The complex viscosity - angular frequency curves of PPS resin samples obtained by different pretreatment methods. The original PPS resin powder is melted in an air environment under high - temperature conditions while being subjected to the strong shear force applied by a twin - screw extruder, and finally, through extrusion and pelletizing, samples for on - machine testing are obtained. From Table 2 and Figure 5 the experimental data, it can be seen that the three - test curves of the extruded and pelletized original PPS resin powder have good coincidence. In the angular frequency range of 0.1 - 1 rad / s, the complex viscosity decreases with the increase of the angular frequency, showing an obvious shear - thinning phenomenon. This indicates that during the sample preparation stage, oxidation degradation, cross - linking, branching and other reactions occurred in the original PPS resin powder, and the molecular weight increased to some extent. For the directly melted PPS resin, not only is the coincidence of the three - test curves poor, but also in the angular frequency range of 0.1 - 1 rad / s, the complex viscosity also decreases with the increase of the angular frequency, also showing an obvious shear - thinning phenomenon. This is because the actual atmosphere in the furnace cavity is air when the nitrogen is turned off, and coupled with high - temperature melting, a certain degree of oxidation degradation, cross - linking, and branching reactions occurred in the original PPS resin powder, resulting in its test curve being similar to that of the extruded and pelletized sample. However, for the original PPS resin powder pretreated by pressing tablets in the temperature range of 21 - 25 °C, not only is the coincidence of the three - test curves excellent, but also no shear - thinning phenomenon appears in the angular frequency range of 0.1 - 1 rad / s. This indicates that the resin maintains stable performance throughout the sample preparation stage. At this time, the complex viscosity value obtained by testing can best represent the original resin powder, and the method has the advantages of accuracy and reliability.

[0087] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A method for testing the complex viscosity of polyphenylene sulfide resin, characterized in that: The following steps are involved: S1: placing the PPS resin raw powder in a tablet press mold, and tableting at a temperature of 21-25° C. and a pressure of 0.5-2 MPa for 8-12 seconds to obtain a PPS resin tablet; S2: Place the PPS resin sheet in the center of the flat plate fixture of the rotational rheometer and heat it to melt in a heating atmosphere to form a PPS melt; S3: Set the test strain ε and angular frequency ω, and perform a complex viscosity-angular frequency sweep test; repeat the test at least 3 times, and determine the accuracy of the complex viscosity of the PPS resin based on the complex viscosity-angular frequency curves of multiple tests.

2. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: The plate fixture gap of the rotational rheometer is 0.5-0.7 mm.

3. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: The strain ε is 2-3%.

4. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: The angular frequency ω is 0.1-100 rad / s.

5. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: In step S3, after the gap between the plates reaches the set value, the sample constant temperature time is 2.5-3.5 minutes.

6. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: The thickness of the PPS resin sheet is 4-6 mm.

7. The method for testing the complex viscosity of polyphenylene sulfide resin according to claim 1, characterized in that: The heating atmosphere is nitrogen.

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