JP2019045196A - Measuring method of coupling amount of monosulfide bond, coupling amount of disulfide bond, coupling amount of polysulfide bond, and coupling amount of filler interface in polymer composite containing filler and sulfur - Google Patents

Abstract

To provide a valuation method with which more exact information is acquired about the coupling amount of a monosulfide bond, the coupling amount of a disulfide bond, the coupling amount of a polysulfide bond, and the coupling amount of a filler interface in a polymer composite containing a filler and sulfur.SOLUTION: A measuring method of the coupling amount of a monosulfide bond, the coupling amount of a disulfide bond, the coupling amount of a polysulfide bond, and the coupling amount of a filler interface in a polymer composite containing a filler and sulfur includes a measuring step for measuring an X-ray absorption spectrum while irradiating the above-mentioned polymer composite with a high-intensity X-ray and changing the energy of the X-ray in the polymer composite containing the filler and sulfur; a calculation (1) step for calculating each ratio of the coupling amount of the monosulfide bond, the coupling amount of the disulfide bond, and the coupling amount of the polysulfide bond from the above-mentioned X-ray absorption spectrum; and a calculation (2) step for calculating all the crosslinking density in the above-mentioned polymer composite and the total coupling amount of the monosulfide bond, and the coupling amount of the filler interface using the swelling compressing method, and a calculation (3) step for calculating the coupling amount of the monosulfide bond, the coupling amount of the disulfide bond, the coupling amount of the polysulfide bond, and the coupling amount of the filler interface from the calculation result of the above-mentioned calculation (1) step and the above-mentioned calculation (2) step.SELECTED DRAWING: None

Description

The present invention relates to a method of measuring the binding amount of monosulfide bonds, the binding amount of disulfide bonds, the binding amount of polysulfide bonds, and the binding amount of a filler interface in a filler- and sulfur-containing polymer composite material.

Investigation of the sulfur cross-linking structure in a sulfur-containing polymer composite material including vulcanized rubber is important in controlling the required performance such as mechanical properties.
Conventionally, as a method of analyzing a sulfur crosslinked structure in a vulcanized rubber crosslinked using a sulfur-containing compound such as a sulfur vulcanizing agent, the crosslinking is selectively cut with a reagent such as LiAlH ₄ or propane 2-thiol, From the degree of swelling at room temperature, the monosulfide bond (R-S ₁ -R), the disulfide bond (R-S ₂ -R), and the polysulfide bond (R-S _n- ) in the vulcanized rubber using the Flory-Rehner equation A swelling compression method for calculating the crosslink density [mol / cm ³ ] of R (n ≧ 3)) has often been used (see, for example, Non-Patent Document 1).

Hideo Nakauchi, 4 others, “The Japan Rubber Association Journal”, 1987, Volume 60, No. 5, p. 267-272

If it is possible to control the sulfur crosslinking structure in a sulfur-containing polymer composite material including a vulcanized rubber crosslinked using a sulfur-containing compound, the performance required for the sulfur-containing polymer composite material such as mechanical properties is further enhanced. It is believed that it becomes possible to finely control, and analysis of the sulfur cross-linking structure in the sulfur-containing polymer composite material is very important in controlling the above-mentioned required performance.

As described above, conventionally, there has been known a method for analyzing the sulfur cross-linked structure in the vulcanized rubber, but in the conventional swelling compression method, monosulfide bond (R-S ₁ -R) in the vulcanized rubber It was supposed that three types of crosslink density (binding amount) of a disulfide bond (R-S ₂ -R) and a polysulfide bond (R-S _n -R (n) 3)) could be calculated.

Here, when a sulfur cross-linking structure in a sulfur-containing polymer composite material including a vulcanized rubber is analyzed using a swelling compression method, in the swelling compression method, polymer components such as rubber are swollen, so entanglement of polymers is caused. The effect can be ignored. On the other hand, when the filler is contained in the sulfur-containing polymer composite material, the bond at the filler interface due to the adsorption or bonding of the polymer component and the filler can not be ignored. It is considered to be a thing.

For example, the vulcanized rubber containing a filler, when subjected to swelling compression method using LiAlH _4, disulfide bonds in the vulcanized rubber by _{LiAlH 4 (R-S 2 -R} ) and polysulfide linkages _{(R-S n} Although -R (n ≧ 3)) is cleaved, the monosulfide bond (R-S ₁ -R) remains uncleaved, but the bond at the filler interface also remains uncleaved. Therefore, when the binding amount of the monosulfide bond is calculated by this method, it is considered that the total binding amount of the binding amount of the monosulfide bond and the binding amount of the filler interface is calculated as the binding amount of the monosulfide bond. Thus, when the sulfur crosslinked structure of the polymer composite material containing the filler and the sulfur is analyzed using the swelling compression method, there is a problem that each bonding amount can not be measured correctly. Therefore, there has been room for improvement in the method for more accurately analyzing the sulfur cross-linking structure of the polymer composite containing filler and sulfur.
In addition, the problem that the sulfur crosslinked structure of the polymer composite material containing a filler and sulfur as described above can not be accurately analyzed by the swelling compression method is that the present inventor has found for the first time.

The present invention solves the above-mentioned problems, and in the filler- and sulfur-containing polymer composite material, the binding amount of monosulfide bond, binding amount of disulfide bond, binding amount of polysulfide bond, and binding amount of filler interface, The purpose is to provide an evaluation method that can obtain more accurate information.

The present invention is a method of measuring the amount of monosulfide bond binding, the amount of disulfide bond binding, the amount of polysulfide bond binding, and the amount of filler interface bonding in a filler- and sulfur-containing polymer composite material, In the measurement method, the polymer composite material is irradiated with high-intensity X-rays, and the X-ray absorption spectrum is measured while changing the energy of X-rays, and from the X-ray absorption spectrum, the binding amount of monosulfide bond, Calculation of calculating each ratio of disulfide bond bond amount and polysulfide bond bond amount (1), using the swelling compression method, the total crosslink density in the polymer composite material, and the monosulfide bond Calculation (2) step of calculating the total bonding amount of bonding amount and bonding amount of filler interface, and calculation results of the calculation (1) and the calculation (2). And a monosulfide bond binding amount characterized by including a calculation step (3) for calculating the binding amount of the monosulfide bond, the disulfide bond binding, the polysulfide bond binding, and the filler interface bonding amount The present invention relates to a method of measuring the amount of disulfide bond binding, the amount of polysulfide bond binding, and the amount of filler interface bonding.

In the measurement step, it is preferable to measure the X-ray absorption spectrum of sulfur near the sulfur K-shell absorption edge by setting the energy range scanned using X-rays to 2400 to 2800 eV.

According to the present invention, the high-intensity X-ray is irradiated to the polymer composite material containing the filler and the sulfur, and the X-ray absorption spectrum is measured while changing the energy of the X-ray. The ratio of the amount of bonded sulfide, the amount of bonded disulfide bond, and the ratio of the bonded amount of polysulfide bond is calculated, and the swelling compression method is used to determine the total content of the polymer composite containing the filler and sulfur. The crosslink density, and the total binding amount of the binding amount of the monosulfide bond and the binding amount of the filler interface is calculated, and from the calculation results, the binding amount of the monosulfide bond, the binding amount of the disulfide bond, the binding amount of the polysulfide bond And, by calculating the amount of bonding at the filler interface, bonding of monosulfide bonds in the filler- and sulfur-containing polymer composite material , Binding of disulfide bonds, bonds of polysulfide bonds, and for binding of the filler surface, it is possible to obtain more accurate information.

The present invention irradiates high-intensity X-rays to a polymer composite material containing a filler and sulfur, and measures an X-ray absorption spectrum while changing the energy of the X-rays. From the X-ray absorption spectrum, monosulfide Calculation (1) step of calculating the ratio of bonding amount of disulfide bonding, bonding amount of disulfide bonding, and bonding amount of polysulfide bond, total crosslink density in the polymer composite material using the swelling compression method, and From the calculation results of the calculation (2) step of calculating the total bonding amount of the bonding amount of the monosulfide bond and the bonding amount of the filler interface, and the calculation (1) and the calculation (2) in the step Containing filler and sulfur including the calculation step (3) for calculating the amount of binding, the amount of binding of disulfide bond, the amount of binding of polysulfide bond, and the amount of binding of filler interface In molecular composites, the amount of binding monosulfide bonds, bonds of the disulfide bonds, bonds of polysulfide bonds, and a method for measuring the binding amount of the filler surface. In the present invention, from the X-ray absorption spectrum obtained in the measurement step, the amount of monosulfide bond binding, the amount of disulfide bond binding, and the amount of polysulfide bond binding in the filler and sulfur-containing polymer composite material The respective crosslink density in the polymer composite containing filler and sulfur and the total bonding amount of the bonding amount of the monosulfide bond and the bonding amount of the filler interface in the polymer composite containing the filler and the sulfur are calculated by the swelling compression method. Calculation of the amount of monosulfide bond, the amount of disulfide bond, the amount of polysulfide bond, and the amount of bond at the filler interface in the filler and sulfur-containing polymer composite material. In the polymer composite containing filler and sulfur, it is possible to The total amount, the amount of coupling a disulfide bond, the amount of binding polysulfide bonds, and for binding of the filler surface, than the conventional can be obtained accurate information.
In addition, the measuring method in this invention may include the other process, as long as the said process is included.

In the measurement step in the present invention, high-intensity X-rays are irradiated on a polymer composite material containing a filler and sulfur (hereinafter, also simply referred to as "sample"), and the X-ray absorption spectrum is changed while changing the X-ray energy. taking measurement. In the measurement step, as a method of measuring an X-ray absorption spectrum, for example, an XAFS (X-ray Absorption Fine Structure: X-ray absorption fine structure near the absorption edge) method may be mentioned.

XAFS method near the sulfur K-shell absorption edge is useful as a method to measure the crosslink density (bond amount) in sulfur-containing polymer composites including rubber materials using sulfur-containing compounds such as sulfur vulcanizing agents It is.
The XAFS method is a method of irradiating X-rays and measuring the amount of X-ray absorption in the targeted atoms, and utilizing the fact that X-ray energy that can be absorbed differs depending on the difference in chemical state (bond), a detailed chemical state (bond ) Can be examined. However, in sulfur-containing polymer composites, sulfur bridges having different sulfur bond lengths such as monosulfide bonds, disulfide bonds, polysulfide bonds, etc. exist, and they have peak energy detected in the spectrum. Further, when zinc oxide is blended, zinc sulfide is also produced, and the spectrum is also observed. As described above, the chemical state of sulfur in the sulfur-containing polymer composite material is complicated, and thus the obtained XAFS spectrum tends to be a broad spectrum as compared with the polymer material not containing a sulfur component. Therefore, more accurate measurement is required for analysis of the sulfur-containing polymer composite material. Therefore, high-luminance X-rays can be used to perform more accurate measurement in the XAFS method.

In the XAFS analysis, X-ray absorption near edge structure (XANES) region, which is a region where a peak up to about 50 eV appears from the absorption edge (energy at which absorption rises), and a loose vibration component of higher energy than that. There is analysis in the EXAFS (Extended X-ray Absorption Fine Structure) area, which is the area in which X appears. In the XANES region, when the sample is irradiated with X-rays near the absorption edge of the targeted atom, electrons in the core level transition to the excited state, so the targeted atom is bound to what atom ( Chemical state is known. On the other hand, in the EXAFS region, inner-shell electrons leave the atomic bond and fly out as photoelectrons. At that time, photoelectrons are expressed as waves, so when there are other atoms nearby, the waves interfere and return. Therefore, information such as the number of atoms around the central atom, atomic species, and interatomic distance can be obtained. In the present invention, the spectrum of the XANES region obtained by the XAFS method near the sulfur K-shell absorption edge can be used as the X-ray absorption spectrum to be subjected to the calculation (1) step described later.

The filler and sulfur-containing polymer composite material to be subjected to the measurement method of the present invention are crosslinked using a sulfur-containing compound such as a sulfur vulcanizing agent, have a sulfur crosslinked structure, and further contain a filler. It is not particularly limited as long as it is a molecular composite material, and, for example, a conventionally known sulfur crosslinked rubber composition can be used, and for example, a rubber composition containing a sulfur containing compound such as a sulfur vulcanizing agent, a rubber component, a filler, and other compounding materials And a vulcanized rubber composition obtained by crosslinking the compound.

Examples of the sulfur-containing compound include sulfur vulcanizing agents such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur and the like.

Examples of the filler include fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide and mica, and zinc oxide.

As the rubber component, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), halogen And diene rubbers such as butyl butyl rubber (X-IIR) and styrene isoprene butadiene rubber (SIBR). In addition, the rubber component may contain one or more modifying groups such as hydroxyl group and amino group. Furthermore, various elastomers can also be used as a rubber component.

Furthermore, as the rubber component, a composite material in which the rubber component and one or more resins are combined can also be used. The resin is not particularly limited, and examples thereof include those widely used in the rubber industry, such as petroleum resins such as C5 aliphatic petroleum resins and cyclopentadiene petroleum resins.

The above-mentioned polymer composite material is appropriately blended with a conventionally known compound in the rubber field such as silane coupling agent, stearic acid, anti-aging agent, wax, oil, vulcanizing agent other than sulfur, vulcanization accelerator, etc. It is also good. Such a rubber material (rubber composition) can be manufactured using a well-known kneading method, a vulcanization method, and the like. As such a rubber material, for example, a vulcanized rubber material for tires (a vulcanized rubber composition for tires) and the like can be mentioned.

As a specific method of measuring an X-ray absorption spectrum while changing the energy of X-rays by irradiating high-intensity X-rays, the following transmission method, fluorescence method, electron yield method and the like are widely used.

(Transmission method)
This is a method of detecting the X-ray intensity transmitted through the sample. A photodiode array detector etc. are used for transmitted light intensity measurement.

(Fluorescent method)
This is a method of detecting fluorescent X-rays generated when the sample is irradiated with X-rays. The detectors include a Lytle detector, a semiconductor detector, and the like. In the case of the transmission method, when X-ray absorption measurement of an element having a small content in the sample is performed, the background becomes high due to the X-ray absorption of the element having a small signal and a large content, and the S / B ratio is poor. It becomes a spectrum. On the other hand, in the fluorescence method (in particular, when an energy dispersive detector or the like is used), it is possible to measure only fluorescent X-rays from the target element, so the effect of the element having a large content is small. Therefore, it is effective when performing X-ray absorption spectrum measurement of an element with a small content. In addition, since fluorescent X-rays have high permeability (small interaction with substances), it becomes possible to detect fluorescent X-rays generated inside the sample. Therefore, this method is most suitable as a method to obtain bulk information next to the transmission method.

(Electron yield method)
It is a method of detecting the current flowing when the sample is irradiated with X-rays. Therefore, the sample needs to be a conductive material. It is also characterized in that it is surface sensitive (information on the order of several nm on the surface of the sample). When the sample is irradiated with X-rays, electrons escape from the element, but since the electrons have a strong interaction with the substance, the mean free path in the substance is short.

As described above, the transmission method is a basic measurement method of XAFS, and is a method of measuring the amount of X-ray absorption by detecting the intensity of incident light and the intensity of X-rays transmitted through the sample. If the concentration of the target compound is a certain level or more (for example, several wt% or more), the measurement is difficult. The electron yield method is a surface sensitive method, and information of several tens of nm on the sample surface can be obtained. On the other hand, the fluorescence method is characterized in that information can be obtained from a part deep from the surface to a certain extent as compared with the electron yield method, and can be measured even if the concentration of the target compound is low. In the present invention, a fluorescence method is suitably used.
Therefore, the fluorescence method will be described more specifically below.

The fluorescence method is a method of monitoring the fluorescent X-rays generated when the sample is irradiated with X-rays, and using the fact that there is a proportional relationship between the amount of X-ray absorption and the intensity of the fluorescent X-rays It is a method to indirectly determine the amount of X-ray absorption from the intensity. When performing a fluorescence method, a method using an ionization chamber and a semiconductor detector such as an SDD (silicon drift detector) or an SSD (silicon strip detector) are often used. Measurement can be performed relatively easily in the ionization chamber, but it is difficult to separate the energy, and scattered X-rays from the sample or fluorescent X-rays other than the target element may enter the sample, which may increase the background. It is necessary to install a solar slit or filter between the sensor and the sensor. When SDD or SSD is used, it is sensitive and energy separation is possible, so that only fluorescent X-rays from the target element can be extracted, and measurement can be performed with good S / B ratio.

The X-ray used in the measurement step preferably has a photon number of 10 ⁷ photons / s or more. This enables highly accurate measurement. More preferably, the number of photons of the X-ray is 10 ⁹ photons / s or more. The upper limit of the number of photons of the X-ray is not particularly limited, but it is preferable to use an X-ray intensity not more than a degree that causes no radiation damage.

The X-ray used in the measurement step preferably has a luminance of 10 ¹⁰ photons / s / mrad ² / mm ² /0.1% bw or more.
The XAFS method requires a continuous X-ray generator for the light source to scan with X-ray energy, and to analyze a detailed chemical state, it measures X-ray absorption spectra of high S / N ratio and S / B ratio. There is a need to. The X-rays emitted from the synchrotron have an intensity of 10 ¹⁰ photons / s / mrad ² / mm ² /0.1% bw or more and are suitable for XAFS measurement because they are continuous X-ray sources . Here, bw indicates the band width of the X-ray emitted from the synchrotron. It is more preferable that the luminance of the X-ray is 10 ¹¹ photons / s / mrad ² / mm ² /0.1% bw or more. The upper limit of the luminance of the X-ray is not particularly limited, but it is preferable to use an X-ray intensity not more than a degree that causes no radiation damage.

As an energy range scanned using the X-ray in the said measurement process, the range of 2400-2800 eV is suitable. By scanning the above range, the X-ray absorption spectrum of sulfur near the sulfur K shell absorption edge can be measured, and information on the chemical state of sulfur in the sample can be obtained. The above energy range is more preferably 2430 to 2700 eV, and still more preferably 2450 to 2600 eV.

In the calculation (1) step in the present invention, the ratio of the amount of monosulfide bond binding, the amount of disulfide bond binding, and the amount of polysulfide bond binding is calculated from the X-ray absorption spectrum obtained in the measurement step.

Specifically, for the standard sample, the X-ray absorption spectrum of the standard sample is measured in the same manner as the measurement step, and the X-ray absorption spectrum of the standard sample and the X-ray absorption spectrum obtained in the measurement step Use to do peak fitting.

As the standard sample, a plurality of compounds having different numbers of sulfur linkages (hereinafter, also referred to as "sulfur sample") are used.

Examples of the sulfur sample include a compound having a monosulfide bond (C-S-C), a compound having a disulfide bond (C-S-S-C), a polysulfide bond (C-S _n -C (nn3) Compounds having) can be used.

As the standard sample, for example, the following compounds can be used, but the standard sample is not limited to the following compounds, and other compounds can be used as long as the sulfur portions are similar.
(Standard sample)
Compound having monosulfide bond: poly (3-hexyl thiophene)
Compound having disulfide bond: Compound having polyethylene glycol polysulfide bond containing disulfide bond: Sulfur

As the measurement conditions and analysis conditions of the X-ray absorption spectrum, for example, the following conditions may be mentioned.
(Device used)
XAFS: Measurement system for the B branch of SPring-8 BL27SU (measurement conditions)
Brightness: 1 × 10 ¹⁶ photons / s / mrad ² / mm ² /0.1% bw
Photon number: 5 × 10 ¹⁰ photons / s
Spectrometer: Crystal spectrometer detector: SDD (silicon drift detector)
Measurement method: Fluorescence energy range: 2460-2500 eV
(XAFS analysis)
We use XAFS analysis integrated software REX2000 made by Rigaku Corporation.

The method of performing peak fitting using the X-ray absorption spectrum of a standard sample obtained in the same manner as the measurement step and the X-ray absorption spectrum obtained in the measurement step is not particularly limited, and conventionally known methods “Observation of Filler-Crosslink Interactions using X-ray Absorption Near Edge Structure (XANES) of the Sulfur K-Edge” (B. Brendebach et al., 1 person, KGK Kautschuk Gummi Kunstatoffe, 2002, No. 55, No. 4, pp. 157-163), containing the filler and sulfur by performing the above peak fitting It is possible to calculate each ratio of the binding amount of monosulfide bonds, the binding amount of disulfide bonds, and the binding amount of polysulfide bonds in the polymer composite material.

In the calculation (2) step in the present invention, using the swelling compression method, the total crosslink density in the filler and sulfur-containing polymer composite material, and the total of the bonded amount of monosulfide bonds and the bonded amount of the filler interface Calculate the binding amount.

As described above, the polymer composite material containing a filler and sulfur, when the swelling compression method using LiAlH _4, disulfide bonds of the polymer composite material by _{LiAlH 4 (R-S 2 -R} ) and Since the polysulfide bond (R-S _n -R (n ≧ 3)) is broken while the bond of the monosulfide bond (R-S ₁ -R) and the filler interface remains unbroken, the polymer The total binding amount of the binding amount of the monosulfide bond and the binding amount of the filler interface in the composite material can be calculated.

That is, although the swelling and compression method can be performed by a conventionally known method, it is preferable to use lithium aluminum hydride (LiAlH ₄ ).

As the swelling compression method, for example, can be carried out by methods disclosed in Non-Patent Document 1, below, implementation of swelling compression method will be described in detail with LiAlH _4.

A test piece of a polymer composite material containing a filler and sulfur is immersed in a swelling solution (for example, a mixed solution of tetrahydrofuran and toluene) to swell, and the swelling compression degree is measured using a thermomechanical analyzer, and Flory-Rehner's By using the equation, the total network density (total crosslink density) is calculated from the degree of swelling and compression of the swollen sample. In addition, a test piece of a polymer composite material containing a filler and sulfur is dipped and swollen in a swelling solution (eg, a mixed solution of tetrahydrofuran and toluene) saturated with LiAlH ₄ , and the swelling and compression degree is measured using a thermomechanical analyzer. Is measured, and the total binding amount of the binding amount of the monosulfide bond and the binding amount of the filler interface is calculated from the degree of swelling and compression of the swollen sample by using the Flory-Rehner equation.

In the calculation (3) step of the present invention, from the calculation results of the calculation (1) step and the calculation (2) step, the bonding amount of monosulfide bond, bonding amount of disulfide bond, bonding amount of polysulfide bond, and filler Calculate the amount of interface bonding. Specifically, it is possible to calculate as follows.

From the “total network density (total crosslinking density)” and the “total binding amount of the binding amount of the monosulfide bond and the binding amount of the filler interface” calculated in the above calculation (2), according to the following formula (1) And “the total ratio of the amount of bonding of monosulfide bonds to the amount of bonding of the filler interface” can be calculated.
Ratio of [binding amount of monosulfide bond + bonding amount of filler interface] (%) =
[Binding amount of monosulfide bond + bonding amount of filler interface] ÷ total crosslinking density (1)

Next, the amount of monosulfide bond binding in the filler- and sulfur-containing polymer composite material is small (ie, the amount of monosulfide bond binding and the amount of disulfide bond binding in the filler- and sulfur-containing polymer composite material In the case of a low ratio of the binding amount of monosulfide bonds to the total binding amount of polysulfide bonds and that of polysulfide bonds), the bonding amount of monosulfide bonds and disulfide bonds in a polymer composite containing filler and sulfur Ratio of monosulfide bond binding amount to total binding amount of amount, polysulfide bond binding amount and filler interface binding amount, total of monosulfide bond binding amount, disulfide bond binding amount and polysulfide bond binding amount The value does not differ greatly from the ratio of the amount of monosulfide bond binding to the amount of binding, Since the error is considered to be small even if it is a value, the “total ratio of the bonding amount of the monosulfide bond and the bonding amount of the filler interface” calculated by the above equation (1) and the above calculation (1 The “ratio of the amount of bonding at the filler interface” can be calculated from the “ratio of the amount of bonding of monosulfide bonds” calculated in the process above, using the following formula (2).
Ratio of [bound amount at filler interface] (%) =
Ratio (%) of [bound amount of monosulfide bond + bound amount of filler interface]-
Ratio of [bound amount of monosulfide bond] (%) (2)
From the above assumption, in the present invention, it is preferable that the polymer composite material containing a filler and sulfur has a small amount of monosulfide bond. Specifically, the ratio of the bonding amount of monosulfide bond calculated in the above calculation (1) step is preferably 40% or less, more preferably 35% or less, and still more preferably 20% or less, 10% or less is still more preferable, and 7% or less is particularly preferable. On the other hand, the lower limit of the ratio of the bonding amount of the monosulfide bond calculated in the above calculation (1) step is not particularly limited, but is usually 2% or more, and preferably 3% or more, for example.

And from the calculation result of said Formula (2), "the amount of binding | bonds of a filler interface" can be calculated by following formula (3).
[Binding amount at filler interface] =
Ratio of [bond amount at filler interface] (%) x total crosslink density ÷ 100 (3)

Further, “crosslinking density derived from sulfur crosslinked structure (sulfur crosslinking density)” obtained by subtracting “the amount of bonding at the filler interface” from the total crosslinking density from the calculation result of the above formula (3) by the following formula (4) It can be calculated.
Sulfur crosslinking density = total crosslinking density-[bond amount of filler interface] (4)

And from the calculation result of the above calculation (1) step, "the amount of bonding of monosulfide bond", "the amount of bonding of disulfide bond" and "the amount of bonding of polysulfide bond" are calculated by the following formulas (5) to (7) can do.
[Binding amount of monosulfide bond] =
Ratio of [binding amount of monosulfide bond] (%) x sulfur crosslinking density ÷ 100 (5)
[Binding amount of disulfide bond] =
Ratio of [bond amount of disulfide bond] (%) x sulfur crosslinking density ÷ 100 (6)
[Binding amount of polysulfide bond] =
Ratio of [binding amount of polysulfide bond] (%) x sulfur crosslinking density ÷ 100 (7)

As described above, in the filler and sulfur-containing polymer composite material of the present invention, the method for measuring the amount of bonded monosulfide bonds, the amount of bonded disulfide bonds, the amount of bonded polysulfide bonds, and the amount of bonded filler interfaces Information on the bonding amount of monosulfide bond, bonding amount of disulfide bond, bonding amount of polysulfide bond, and bonding amount of filler interface in the polymer composite containing filler and sulfur more accurately than ever before It is possible to obtain
In addition, although low fuel consumption performance, wear resistance performance, grip performance, etc. are required for the tire, since these performances are contradictory performances, in order to control mechanical properties and improve these performances, a filler and In the measurement method of the present invention, it is considered that it is important to be able to evaluate by the same method rather than evaluating the bonding of the polymer component and the sulfur cross-linking structure by different methods. Since the sulfur crosslinked structure can be evaluated by the same method, it is considered to be an effective evaluation method in improving the performance.

Although the present invention will be specifically described based on examples, the present invention is not limited to these.

[Preparation of sample]
According to the contents of the following composition, materials other than sulfur and vulcanization accelerator are filled in 1.7L Banbury mixer made by Kobe Steel, Ltd. so that the filling rate is 58%, and until 140 ° C is reached at 80 rpm. It knead | mixed (process 1). Sulfur and a vulcanization accelerator were added to the kneaded product obtained in Step 1 in the following composition, and a rubber sample was obtained by vulcanizing at 160 ° C. for 20 minutes (Step 2).

The composition is 30 parts by mass of natural rubber, 70 parts by mass of styrene butadiene rubber, 30 parts by mass of carbon black, 60 parts by mass of silica, 3 parts by mass of silane coupling agent, 10 parts by mass of oil, 4 parts by mass of antioxidant, wax 2. 5 parts by mass, 3 parts by mass of zinc oxide, 2 parts by mass of stearic acid, 1.2 parts by mass of powdered sulfur, and 1 part by mass of a vulcanization accelerator. The materials used are as follows.
Natural rubber: TSR20
Styrene butadiene rubber: Nippon Zeon Co., Ltd. Nipol 1502
Carbon black: Show black N 351 (N ₂ SA: 71 m ² / g) manufactured by Cabot Japan Ltd.
Silica: Ultrasil VN3 manufactured by Degussa
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa
Oil: Japan Energy Co., Ltd. Process X-140
Anti-aging agent: Nouchi 6C (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Co., Ltd.
Wax: Nippon Seiwa Co., Ltd. Ozo Ace 0355
Zinc oxide: Ginkgo R manufactured by Toho Zinc Co., Ltd.
Stearic acid: Koji powder sulfur (containing 5% oil) manufactured by NOF Corporation: 5% oil treated powder sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. (soluble sulfur containing 5% by mass of oil)
Vulcanization accelerator: Noccellar CZ (N-cyclohexyl-2-benzothiazylsulfenamide) manufactured by Ouchi Emerging Chemical Industry Co., Ltd.

(Comparative example 1)
[Swelling compression method]
A test piece (2 cm × 2 cm, thickness 1 mm) of the obtained rubber sample was immersed in a solution in which tetrahydrofuran and toluene were mixed at a ratio of 1: 1 for one day to swell. With respect to this swollen sample, the degree of swelling and compression was measured using a thermomechanical analyzer (manufactured by Shimadzu Corporation, product name “TMA-50”). Then, using the Flory-Rehner equation, the total network density (total crosslinking density) (mol / cm ³ ) was calculated from the degree of swelling and compression of the swollen sample.
In addition, it is allowed to swell by immersion for 1 day in a solution in which tetrahydrofuran and toluene are mixed in a ratio of 1: 1 saturated with LiAlH ₄ , and similarly, the swelling and compression degree of the swollen sample is measured, and the Flory-Rehner equation is used. Then, the network density was calculated, and the network density of monosulfide (bound amount of monosulfide bond) (mol / cm ³ ) was obtained according to the conventional interpretation.
Then, the network density of monosulfide was subtracted from the calculated total crosslinking density to calculate the total network density of disulfide and polysulfide (total bonding amount of disulfide bond and polysulfide bond) (mol / cm ³ ).

Example 1
[Swelling compression method]
In the same manner as Comparative Example 1, the total network density (total crosslinking density) was calculated.
In addition, the network density (monosulfide bond binding amount) of monosulfide calculated in Comparative Example 1 is the exact interpretation, the total binding amount (mol / cm) of the monosulfide bond binding amount and the filler interface binding amount ³ )

[Analysis by XAFS method]
The obtained rubber sample was subjected to measurement by the XAFS method near the sulfur K-shell absorption edge to obtain an XAFS spectrum. As a rubber sample, one cut with a microtome to a thickness of 10 μm was used.
The measurement conditions of measurement by the XAFS method are as follows.

(Device used)
XAFS: Measurement system for the B branch of SPring-8 BL27SU (measurement conditions)
Brightness: 1 × 10 ¹⁶ photons / s / mrad ² / mm ² /0.1% bw
Photon number: 5 × 10 ¹⁰ photons / s
Spectrometer: Crystal spectrometer detector: SDD (silicon drift detector)
Measurement method: Fluorescence energy range: 2460-2500 eV

The XAFS spectrum obtained by the above measurement was analyzed under the following analysis conditions.
(XAFS analysis)
Perform peak fitting using the XAFS spectrum of the following standard sample measured in advance using the XAFS analysis integrated software REX2000 manufactured by Rigaku Corporation, and the amount of monosulfide bond, the amount of disulfide bond, and The ratio (%) of the binding amount of polysulfide bond was calculated. The results were as follows.
Ratio of monosulfide bond binding amount: 6.48%
Ratio of disulfide bond binding: 36.57%
Proportion of polysulfide bond: 56.94%

(Standard sample)
Compound having monosulfide bond: poly (3-hexyl thiophene)
Compound having disulfide bond: Compound having polyethylene glycol polysulfide bond containing disulfide bond: Sulfur

[Calculation of each binding amount]
Total crosslink density, total amount of bonded monosulfide bonds and bonded amount of filler interface calculated using [swelling compression method], and bonding of monosulfide bonds obtained from [analysis by XAFS method] Each binding amount was computed from following formula (1)-(7) using each ratio (%) of the amount, the bonding amount of a disulfide bond, and the bonding amount of a polysulfide bond. The results calculated in Comparative Example 1 and Example 1 are shown in Table 1 below.

Ratio of [binding amount of monosulfide bond + bonding amount of filler interface] (%) =
[Binding amount of monosulfide bond + bonding amount of filler interface] (mol / cm ³ ) / total crosslinking density (1)

Ratio of [bound amount at filler interface] (%) =
Ratio (%) of [bound amount of monosulfide bond + bound amount of filler interface]-
Ratio of [bound amount of monosulfide bond] (%) (2)

[Binding amount at filler interface] (mol / cm ³ ) =
Ratio of [bond amount at filler interface] (%) x total crosslink density ÷ 100 (3)

Sulfur crosslink density (mol / cm ³ ) = total crosslink density- [bound amount of filler interface] (4)

[Binding amount of monosulfide bond] (mol / cm ³ ) =
Ratio of [binding amount of monosulfide bond] (%) x sulfur crosslinking density ÷ 100 (5)

[Binding amount of disulfide bond] (mol / cm ³ ) =
Ratio of [bond amount of disulfide bond] (%) x sulfur crosslinking density ÷ 100 (6)

[Binding amount of polysulfide bond] (mol / cm ³ ) =
Ratio of [binding amount of polysulfide bond] (%) x sulfur crosslinking density ÷ 100 (7)

From the results of Table 1, while the bonding amount at the filler interface can not be calculated in Comparative Example 1, it is possible to calculate in Example 1. Moreover, since the bonding amount of the monosulfide bond is calculated to be large in Comparative Example 1 as compared with Example 1, and there is a possibility of misinterpretation in comparison with mechanical physical properties etc., the method of the present invention Is very effective. Thus, the polymer composite material containing the filler and the sulfur is irradiated with high brightness X-rays, and the measurement step of measuring the X-ray absorption spectrum while changing the energy of the X-rays; Calculation (1) step of calculating the ratio of bonding amount of disulfide bonding, bonding amount of disulfide bonding, and bonding amount of polysulfide bond, total crosslink density in the polymer composite material using the swelling compression method, and From the calculation results of the calculation (2) step of calculating the total bonding amount of the bonding amount of the monosulfide bond and the bonding amount of the filler interface, and the calculation (1) and the calculation (2) in the step Containing filler and sulfur, including a calculation step (3) of calculating the amount of binding, the amount of binding of disulfide bond, the amount of binding of polysulfide bond, and the amount of binding of filler interface In Example 1 in which the method of measuring the bonding amount of monosulfide bond, bonding amount of disulfide bond, bonding amount of polysulfide bond, and bonding amount of filler interface in a polymer composite material is implemented, the filler and sulfur are contained. It was possible to obtain more accurate information than before with regard to the binding amount of monosulfide bond, the binding amount of disulfide bond, the binding amount of polysulfide bond, and the binding amount of filler interface in a polymer composite material.

Claims (2)

A method for measuring the binding amount of monosulfide bonds, the binding amount of disulfide bonds, the binding amount of polysulfide bonds, and the binding amount of a filler interface in a polymer composite containing a filler and sulfur,
The measuring method comprises: measuring the X-ray absorption spectrum while irradiating the high-molecular weight composite material with high-intensity X-rays and changing the energy of the X-rays;
Calculation step (1) of calculating each ratio of the amount of monosulfide bond, the amount of disulfide bond, and the amount of polysulfide bond from the X-ray absorption spectrum
Calculation step (2) of calculating total crosslinking density and total bonding amount of bonding amount of monosulfide bond and bonding amount of filler interface in the polymer composite material using a swelling compression method;
From the calculation results of the calculation (1) step and the calculation (2), calculation of calculating the bonding amount of monosulfide bond, bonding amount of disulfide bond, bonding amount of polysulfide bond, and bonding amount of filler interface (3) 2.) A method of measuring the amount of monosulfide bond binding, the amount of disulfide bond binding, the amount of polysulfide bond binding, and the amount of bonding at the filler interface, comprising the steps of: The binding amount of monosulfide bond according to claim 1, wherein the X-ray absorption spectrum of sulfur in the vicinity of the sulfur K-shell absorption edge is measured by setting the energy range scanned using X-rays to 2400-2800 eV in the measurement step. And a method of measuring the amount of disulfide bond binding, the amount of polysulfide bond binding, and the amount of filler interface bonding.