Method for analyzing polymer complex

Abstract

To provide a method for analyzing a polymer complex capable of accurately performing motion analysis of a polymer.SOLUTION: The method for analyzing a polymer complex relates to a method for analyzing a polymer complex using quasi-elastic neutron scattering, the method being characterized in that a sample obtained by swelling the polymer complex with a solvent is subjected to the quasi-elastic neutron scattering.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for analyzing a polymer complex. [Background technology]

[0002] In polymeric material composites containing polymers and other components, for example, in rubber compositions, filler-adsorbed polymers called filler gels are thought to play an important role in the mechanical properties of rubber, and various analyses have been conducted (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-040508 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to solve the above problems and to provide a method for analyzing a polymer composite that can accurately analyze the motion of a polymer. [Means for solving the problem]

[0005] The present invention relates to a method for analyzing a polymer composite using quasi-elastic neutron scattering, characterized in that a sample obtained by swelling the polymer composite in a solvent is subjected to the quasi-elastic neutron scattering. [Effects of the Invention]

[0006] According to the present invention, there is provided a method for analyzing a polymer composite using quasi-elastic neutron scattering, characterized in that a sample of the polymer composite swollen in a solvent is subjected to the quasi-elastic neutron scattering, thereby providing a method for analyzing a polymer composite that can accurately analyze the motion of the polymer. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows the dependence of the toluene volume fraction on the relaxation rate (full width at half maximum) of a polymer. DETAILED DESCRIPTION OF THE INVENTION

[0008] The method for analyzing the polymer composite is a method for analyzing the polymer composite using quasi-elastic neutron scattering, and is characterized in that a sample of the polymer composite swollen in a solvent is subjected to the quasi-elastic neutron scattering.

[0009] As mentioned above, filler-adsorbed polymers (polymers adsorbed to fillers), known as filler gels, are believed to play an important role in the mechanical properties of rubber. This is because, for example, in silica-blended rubber, the mechanical properties of rubber vary significantly depending on the type of binder that bonds the silica and polymer. It is presumed that the binder affects the structure and mobility of the filler gel, which is a filler-adsorbed polymer, and ultimately affects the macroscopic mechanical properties of rubber. However, the relationship between filler gels and the mechanical properties of rubber remains unclear. This is mainly due to the difficulty of analyzing the structure and mobility of filler gels.

[0010] Neutron quasi-elastic scattering is one method that can evaluate the mobility of filler gels. Because neutron quasi-elastic scattering instruments use neutrons as a radiation source, there are only a few of them in use worldwide, and each has its own unique time scale for measurable motion, making them good at capturing relatively fast motion. Therefore, when analyzing filler gels, we have devised a method to match the measurable time constant of the instrument with the time constant of polymer motion by measuring rubber under high-temperature conditions during experiments. However, polymer mobility is very sensitive to temperature, so even small temperature errors can result in differences in mobility, and because the sample size is large, it takes time for the sample temperature to reach a constant value. This has posed a challenge in neutron experiments, where measurement opportunities and time are limited. Therefore, the above-mentioned polymer composite analysis method uses a solvent swelling method, which has the effect of improving polymer mobility instead of temperature, to optimize the time constant of polymer movement for the device. This makes it possible to measure the mobility of filler gels under room temperature conditions with minimal temperature error. This reduces measurement error between samples, enabling highly accurate evaluation of differences in polymer mobility between samples and facilitating comparison between samples.

[0011] In the above-described method for analyzing a polymer composite, a sample obtained by swelling the polymer composite in a solvent is subjected to quasi-elastic neutron scattering.

[0012] The polymer composite is a composite containing a polymer (macromolecule) and other components. The polymer is not particularly limited, and known polymers can be used, for example, known rubber components are preferred. Examples of the rubber component include diene rubbers such as natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), and butyl rubber (IIR). These may be used alone or in combination of two or more. Of these, NR, IR, BR, and SBR are preferred.

[0013] The polymer composite preferably contains a filler, since this allows evaluation of the mobility of the filler gel.

[0014] The filler is not particularly limited, and may be any material known in the rubber field, such as inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica, biochar, and poorly dispersible fillers. Among these, silica and carbon black are preferred, and silica is more preferred, as they allow evaluation of the mobility of the filler gel. The fillers may be used alone or in combination of two or more.

[0015] When the polymer composite contains a filler, the content of the filler is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the polymer component. The upper limit is preferably 150 parts by mass or less, more preferably 120 parts by mass or less. Within the above range, better effects tend to be obtained. When the polymer component is a rubber component, that is, when the polymer composite is a rubber composition, the content of the filler per 100 parts by mass of the rubber component is desirably in the same range.

[0016] The silica that can be used is not particularly limited, and can be, for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrated silica), or other silica commonly used in the tire industry. The raw material for silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from silica-containing products. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. These silicas can be used alone or in combination of two or more types.

[0017] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 The upper limit of the N2SA of silica is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 250m 2 / g or less, more preferably 220m 2 Within the above range, there is a tendency for the effect to be better obtained. In this specification, the N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0018] When the polymer composite contains silica, the content of the silica is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the polymer component. The upper limit is preferably 150 parts by mass or less, more preferably 120 parts by mass or less. Within the above range, better effects tend to be obtained. When the polymer component is a rubber component, that is, when the polymer composite is a rubber composition, the content of silica per 100 parts by mass of the rubber component is desirably in the same range.

[0019] Usable carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace, by hydrothermal carbonization (HTC), or by thermal decomposition of methane, such as in a thermal black process. Commercially available carbon blacks include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Co., Ltd. Carbon black may be used alone or in combination.

[0020] The nitrogen adsorption specific surface area (N2SA) of the above carbon black is 20m 2 / g or more is preferable, and 30m 2 / g or more is more preferable, and 40m 2 / g or more is more preferable. 2 / g or less is preferable, and 150m 2 / g or less is more preferable, and 130m 2 / g or less is more preferable, and 120m 2 Within the above range, the effect tends to be better. In this specification, the nitrogen adsorption specific surface area of ​​carbon black is determined in accordance with JIS K6217-2:2001.

[0021] When the polymer composite contains carbon black, the content of the carbon black is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the polymer component. The upper limit is preferably 150 parts by mass or less, more preferably 120 parts by mass or less. Within the above range, better effects tend to be obtained. When the polymer component is a rubber component, that is, when the polymer composite is a rubber composition, the content of carbon black per 100 parts by mass of the rubber component is desirably in the same range.

[0022] When the polymer composite contains silica, it is preferable that the polymer composite further contains a silane coupling agent. The silane coupling agent is not particularly limited, and those known in the rubber field can be used, such as sulfide-based silane coupling agents such as bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, and bis(4-triethoxysilylbutyl)tetrasulfide, mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, vinyl-based silane coupling agents such as vinyltriethoxysilane, amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane, nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane, and chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

[0023] In the polymer composite, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass or less, more preferably 20 parts by mass or less. Within the above range, better effects tend to be obtained. When the polymer component is a rubber component, that is, when the polymer composite is a rubber composition, the content of the silane coupling agent per 100 parts by mass of silica is desirably in the same range.

[0024] The other components include plasticizers (oil, liquid polymer, resin, etc.), antioxidants, stearic acid, zinc oxide, wax, sulfur, vulcanization accelerators, and the like.

[0025] The polymer composite can be produced by known mixing means, for example, by kneading the components using a rubber kneading device such as an open roll or a Banbury mixer, followed by crosslinking as necessary, to obtain the polymer composite.

[0026] In the sample obtained by swelling the polymer composite in a solvent, a solvent capable of causing swelling (a good solvent) is a solvent that has swelling properties for the polymer. Swelling properties refer to the property of permeating a polymer, and the property of the volume of the polymer increasing as the solvent permeates.

[0027] The solvent (good solvent) capable of swelling the polymer composite is not particularly limited as long as it is capable of swelling the polymer constituting the polymer composite, and may be appropriately selected. Examples include aromatic organic solvents such as benzene and toluene; aliphatic organic solvents such as hexane, heptane, and cyclohexane; halogenated organic solvents such as chloroform, chlorobenzene, and dichlorobenzene; ester-based organic solvents such as ethyl acetate and ethyl propionate; and ether-based organic solvents such as tetrahydrofuran. Other examples include deuterated solvents such as heavy water, deuterated hexane, deuterated toluene, deuterated chloroform, deuterated methanol, deuterated DMSO ((DC)S=O), deuterated tetrahydrofuran, deuterated acetonitrile, deuterated dichloromethane, deuterated benzene, and deuterated N,N-dimethylformamide. These solvents may be used alone or in combination. For example, when a rubber component is used as the polymer component, aromatic organic solvents and deuterated solvents are preferred, deuterated solvents are more preferred, and deuterated toluene is even more preferred.

[0028] The method for swelling the polymer composite with a solvent is not particularly limited as long as it can swell the polymer composite, and any known method can be used. The swelling conditions are preferably conditions that allow the polymer composite to swell uniformly, and it is preferable to place the polymer composite and an arbitrary amount of solvent in a sealed container and swell the entire polymer composite uniformly. "Uniformly swelling the polymer composite" means that the solvent used for swelling is distributed evenly throughout the polymer composite, and the solvent is not unevenly distributed throughout the polymer composite, resulting in a warped polymer composite.

[0029] Generally, when a polymer composite is swollen with a solvent, the polymer composite warps. When such warping occurs, the solvent is not evenly distributed throughout the polymer composite. By allowing the polymer composite and the solvent to coexist for preferably 6 hours or more, more preferably 12 hours or more, the solvent is evenly distributed throughout the polymer composite, the warping is eliminated, and a sample in which the entire polymer composite is uniformly swollen can be prepared.

[0030] The swelling degree S is defined as ((volume of polymer composite) + (volume of compound used for swelling)) / (volume of polymer composite) × 100 (%), where the volume of compound (solvent) used for swelling refers to the volume of compound (solvent) stored in the polymer by the polymer composite.

[0031] The swollen sample is, for example, a sample with a volume of 100 mm 3 When using a polymer composite of 100 mm 3 The swelling degree of 200% when deuterated toluene is added is used, or 200mm 3 It is possible to use a material with a swelling rate of 300% when deuterated toluene is added.

[0032] The swelling degree S may be appropriately set depending on the composition of the polymer composite so as to enable accurate analysis of the polymer motion, but is preferably 50% or more, more preferably 100% or more, and even more preferably 200% or more.

[0033] In the above-mentioned polymer composite analysis method, a sample of a polymer composite prepared by the above-mentioned method or the like is swollen in a solvent and subjected to neutron quasi-elastic scattering for analysis. By combining neutron quasi-elastic scattering and the solvent swelling method for the polymer composite, it is possible to evaluate the mobility of the polymer in the sample even with a neutron quasi-elastic scattering device with a short time constant for measurable movement. In this way, the above-mentioned polymer composite analysis method allows for highly accurate analysis of the movement of the polymer contained in the polymer composite.

[0034] Neutron spectroscopy is a technique for investigating the energy state of atoms and molecules in a sample by bombarding the sample with neutrons and measuring the change in neutron energy before and after scattering when the neutrons are scattered by the atoms and molecules of the sample. One type of neutron spectroscopy utilizes quasi-elastic neutron scattering. While elastic scattering normally does not result in a change in energy, quasi-elastic scattering occurs when a slight change in energy occurs in elastic scattering due to aperiodic fluctuation motion of atoms or molecules caused by some cause. A quasi-elastic neutron scattering instrument (spectroscope) is a measuring device that measures the energy spread of quasi-elastic neutron scattering to investigate the motion mechanisms of atoms and molecules related to aperiodic motion.

[0035] The quasi-elastic neutron scattering device is a known device, such as the J-PARC AMATERAS device (BL14).

[0036] In the above quasi-elastic neutron scattering method, the experimental temperature may be appropriately set, and the method can be carried out at room temperature, etc. The temperature is preferably 275 to 350K, and more preferably 285 to 320K.

[0037] In conventional methods, for example, when subjecting a polymer composite containing a rubber component and a filler to quasi-elastic neutron scattering, measurements had to be performed by changing the temperature to match the measurable time constant of the measurement device with the time of the filler gel movement in the sample. However, by swelling the rubber component in a good solvent, the time constant of the movement can be changed. This allows for comparison of filler gels between samples under conditions where there is no temperature change and temperature-related errors are small. Note that filler gels are formed by the bonding of fillers such as silica with rubber components, and the rubber components surrounding the filler are included in the filler gel. Filler gels are also insoluble in solvents that can dissolve rubber components.

[0038] In the above-mentioned quasi-elastic neutron scattering method, conditions such as the wave number q of measurement, incident neutron energy E, and beam output may be appropriately set so as to enable accurate analysis of the polymer motion.

[0039] In the method for analyzing the polymer composite, the polymer composite is swollen in a solvent and a sample is analyzed using the quasi-elastic neutron scattering method to obtain quasi-elastic neutron scattering data. The obtained quasi-elastic neutron scattering data is then subjected to model analysis using, for example, the following equation (1), to obtain various parameters (Lorentzian function, peak position, full width at half maximum, pre-coefficient of the Lorentzian function, etc.).

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[0040] For example, using the above-mentioned quasi-elastic neutron scattering method, rubber composition samples containing silica swollen in a solvent to various swelling degrees (i.e., rubber composition samples containing filler gel) and rubber composition samples not containing silica swollen in a solvent to various swelling degrees (rubber composition samples without filler gel) were analyzed. The obtained quasi-elastic neutron scattering data were subjected to model analysis using the above-mentioned equation (1) to obtain various parameters for each sample (Lorentzian function, peak position, full width at half maximum, Lorentzian function pre-coefficient, etc.). Next, by examining the relationship between the volume fraction of the solvent contained in the polymer and the obtained full width at half maximum, it was found that when there was no swelling (solvent volume fraction = 0), there was almost no difference in the full width at half maximum between the presence and absence of filler gel. However, as the volume fraction of the solvent contained in the polymer increased, a large difference in the full width at half maximum, i.e., the relaxation rate of the polymer, was observed between the presence and absence of filler gel. In this way, using a polymer composite swollen in a solvent as a sample, it is possible to evaluate the mobility of the filler gel.

[0041] As described above, in the method for analyzing a polymer composite using quasi-elastic neutron scattering, by subjecting a sample prepared by swelling the polymer composite in a solvent to quasi-elastic neutron scattering, it is possible to analyze the mobility of the filler gel, for example, under room temperature conditions with little temperature error. This allows for highly accurate evaluation of differences in polymer mobility between samples, facilitating comparison between samples. [Example]

[0042] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0043] The various chemicals used are explained below. If necessary, the chemicals may be purified according to standard methods. SBR: JSR HPR850 Silica: Evonik VN3 Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Degussa Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator 1: Noccela NS (N-tert-butyl-2-benzothiazylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela D (1,3-diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0044] (Production of rubber composition (crosslinked rubber)) According to the formulation shown in Table 1, the ingredients except for sulfur and vulcanization accelerator were kneaded in a 1.77-liter closed-type Banbury mixer for 3 to 5 minutes until the temperature reached 150°C to obtain a kneaded mixture. Next, the kneaded mixture, sulfur, and vulcanization accelerator were kneaded in an open roll, and the obtained kneaded mixture was vulcanized to obtain a crosslinked rubber.

[0045] [Table 1]

[0046] <Preparation of swollen samples> The crosslinked rubber was sliced ​​to a thickness of 0.1 mm and then cut into 30 mm x 45 mm pieces to prepare crosslinked rubber pieces measuring 30 mm x 45 mm x 0.1 mm. The crosslinked rubber pieces were sealed in a vial together with deuterated toluene, and the swelling degree of the polymer was adjusted to be the same with or without silica (compounds 1 and 2), allowing equilibrium swelling. The rubber was placed along the inner cylinder of a cylindrical aluminum cell under a helium atmosphere and sealed.

[0047] <Neutron Quasi-Elastic Scattering Measurement> The crosslinked rubbers (compounds 1 and 2) were subjected to quasi-elastic neutron scattering measurement and analysis using the following equipment, measurement conditions, and measurement and analysis methods. (Device) J-PARC AMATERAS equipment (BL14) (Measurement conditions) Experimental temperature: 303[K] Measurement wave number q: 0.005 <q<0.3(Å -1 ) Incident neutron energy E: 1.685, 3.133, 7.729 meV MLF beam power: 700kW

[0048] (Measurement / analysis method) The sample (swollen sample) sealed in the cylindrical aluminum cell prepared above was set in the apparatus, and a neutron quasi-elastic scattering experiment was carried out at a temperature of 303 K. The obtained neutron quasi-elastic scattering data was subjected to model analysis using the above equation (1), and various parameters (Lorentz function, peak position, full width at half maximum, pre-coefficient of the Lorentz function, etc.) were obtained.

[0049] Figure 1 shows the FWHM plotted against the toluene volume fraction (φtol) in the polymer for samples with various swelling degrees, namely, Formulation 1 (sample with filler gel) and Formulation 2 (sample without filler gel). Figure 1 shows that when the sample is not swollen (φtol = 0), there is almost no difference in the FWHM between the presence and absence of filler gel. However, as the amount of toluene increases, a large difference in the FWHM, i.e., relaxation rate, is observed between the presence and absence of filler gel. Therefore, by using a polymer composite swollen in a solvent as a sample, it is possible to evaluate the mobility of the filler gel, which was difficult when using a polymer composite that was not swollen in a solvent as a sample.

[0050] <Conventional method> In preparing the swollen sample, the crosslinked rubber was sliced ​​to a thickness of 0.2 mm and then cut into a 30 mm × 45 mm piece to prepare a crosslinked rubber piece measuring 30 mm × 45 mm × 0.2 mm. The crosslinked rubber piece was set in a cylindrical aluminum cell under a helium atmosphere so that the rubber was aligned with the inner cylinder, and the cell was sealed. In the above neutron quasi-elastic scattering measurement, various parameters (Lorentz function, peak position, full width at half maximum, pre-coefficient of Lorentz function, etc.) were obtained in the same manner, except that the sample (unswollen sample) sealed in the cylindrical aluminum cell prepared above was used instead of the swollen sample.

[0051] Even when plotted in the same way as in Figure 1, almost no difference was observed in the full width at half maximum, i.e., relaxation rate, with or without filler gel, making it difficult to evaluate the mobility of the polymer in the filler gel.

[0052] The present invention (1) is a method for analyzing a polymer composite using quasi-elastic neutron scattering, comprising: The method for analyzing a polymer composite is characterized in that a sample obtained by swelling the polymer composite in a solvent is subjected to the quasi-elastic neutron scattering method.

[0053] The present invention (2) is a method for analyzing a polymer composite according to the present invention (1), which analyzes the movement of a polymer contained in the polymer composite.

Claims

1. A method for analyzing a polymer composite using quasi-elastic neutron scattering, comprising: A method for analyzing a polymer composite, comprising subjecting a sample obtained by swelling the polymer composite in a solvent to the quasi-elastic neutron scattering method.

2. The method for analyzing a polymer composite according to claim 1, wherein the movement of a polymer contained in the polymer composite is analyzed.

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