KR102387499B1 - A analyzing Method for Branch of Polybutadiene - Google Patents

Abstract

The present invention hydrogenates polybutadiene, removes the double bond contained in the polybutadiene main chain, and then prepares an LLDPE analog similar to the LLDPE (Linear Low-density polyethylene) structure made of ethylene-co-1-butene by NMR By measuring the spectrum, an analysis method is provided for quantitatively analyzing the content of the branch bound to the main chain using the NMR spectrum.

Description

A analyzing method for Branch of Polybutadiene

The present invention relates to a method for analyzing branches contained in polybutadiene.

Polybutadiene rubber (BR) consists of a microstructure of 1,4-butadiene (Cis/Trans) and 1,2-butadiene (Vinyl). The factor affecting the physical properties of BR is the ratio of microstructure, and the double vinyl structure shows various contents according to polymerization conditions.

Branches that can be created in BR can be divided into two types. The short chain branch (SCB) of BR means a branch created due to a difference in microstructure, such as a vinyl structure, and a long chain branch (LCB) means that the polymer main chain itself is connected from the branch point of the main chain short or long. .

In general, LCB in BR used for tire manufacturing can improve the process by helping fillers to be incorporated quickly and stably in the rubber matrix during compounding. In addition, highly linear BRs may exhibit cold flow or creep characteristics that flow or are deformed by external forces at room temperature, and it is known that LCB in BR can reduce these phenomena.

An object of the present invention is to provide a quantitative analysis method of LCB (long chain branch) and SCB (short chain branch) contained in polybutadiene.

In order to solve the problem of the present invention,

hydrogenating polybutadiene; and

It provides a method for analyzing polybutadiene branches, which includes quantitatively analyzing the contents of LCB (long chain branch) and SCB (short chain branch) included in the hydrogenated polybutadiene using an NMR spectrum.

According to an embodiment, the NMR spectrum may be a ¹³ C-NMR spectrum.

According to an embodiment, the long chain branch (LCB) may be a branch having 6 or more carbon atoms.

According to an embodiment, the hydrogenation of polybutadiene may include removing double bonds by hydrogenating polybutadiene under a hydrogenation catalyst at high temperature and high pressure.

According to one embodiment, the catalyst may include the structure of Formula 1 below.

[Formula 1]

(R _p Z) _r RhX _q

In Formula 1,

R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group, and Z is phosphorus (P), arsenic (As), sulfur (S), or sulfoxide a group (S=O), X is hydrogen or a halide ion, p is an integer from 2 to 3, r is an integer from 2 to 4,

q is an integer from 1 to 3.

According to an embodiment, the hydrogenation reaction is performed by further adding a cocatalyst, and the cocatalyst may have the structure of Formula 2 below.

[Formula 2]

R _p Z

In Formula 2,

R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group, and Z is phosphorus (P), arsenic (As), sulfur (S), or sulfoxide group (S=O), and p is an integer of 2 to 3.

According to one embodiment, in the step of quantitatively analyzing the content of LCB (long chain branch) and SCB (short chain branch) included in the hydrogenated polybutadiene using an NMR spectrum, NMR (Nuclear Magnetic Resonance) spectroscopy and pulse program may be used together.

According to an embodiment, the pulse program may be a ¹ H pulse program or a ¹³ C pulse program.

The present invention hydrogenates polybutadiene, removes the double bond contained in the polybutadiene main chain, and then prepares an LLDPE analog similar to the LLDPE (Linear Low-density polyethylene) structure made of ethylene-co-1-butene by NMR By measuring the spectrum, the content of the branch bound to the main chain can be quantitatively analyzed using the NMR spectrum.

1 shows ¹³ C-NMR spectrum of BR (Polybutadiene rubber).
Figure 2 shows a comparison of ¹ H-NMR spectrum before and after hydrogenation of BR (Polybutadiene rubber).
Figure 3 shows the ¹³ C-NMR spectrum of the LLDPE (Linear Low-density polyethylene) analog obtained from the hydrogenation of BR (Polybutadiene rubber).

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Since the Vinyl structure, which is the SCB (short chain branch) of polybutadiene rubber (BR), is distinguished from the Cis/Trans structure, which is the main chain structure of polybutadiene in ¹ H NMR spectrum, content analysis is possible, but LCB (long chain branch) is BR Since it is indistinguishable from the structure of the main chain of BR itself, qualitative and quantitative analysis of LCB using ¹ H NMR or ¹³ C NMR spectrum is not possible.

In order to solve this conventional problem, the present invention is to provide an analysis method for analyzing the content of branches after hydrogenating polybutadiene rubber.

The present invention is

hydrogenating polybutadiene; and

It provides a method for analyzing polybutadiene branches, which includes quantitatively analyzing the contents of LCB (long chain branch) and SCB (short chain branch) included in the hydrogenated polybutadiene using an NMR spectrum.

The present invention is a LLDPE (Linear Low-density polyethylene) structure composed of ethylene-co-1-butene after removing the double bond included in the polybutadiene main chain by hydrogenating the polybutadiene rubber as shown in the following reaction scheme. After preparing an LLDPE analog similar to

[reaction formula]

In the present invention, by using the LLDPE analog for quantitative analysis, the peaks of SCB and LCB can be separated from the spectrum by using the branched quantitative analysis method of LLDPE, respectively, and in particular, the peaks of the main chains of LCB and LLDPE analogs are Since they can be displayed separately, the LCB content included in polybutadiene can be quantified.

In this case, LCB can be defined as a branch having a C6 branch and more carbon number made by 1-octene comonomer (1-octenecomonomer).

According to an embodiment, the NMR spectrometer that can be used for the quantitative analysis may be a ¹³ C-NMR spectrometer.

The method for quantifying the branching of the LLDPE analog using ¹³ C-NMR spectroscopy is, for example,

The methylene carbon present in the main chain of the LLDPE analog is observed near the chemical shift δ=30 ppm on ¹³ C-NMR, and in the case of branching of C6, the methyl carbon at the branching end may appear near δ=14.26 ppm, branching of C2 In the case of δ=11.34ppm, it can appear. Therefore, in the case of branching of C6, the relative value of the area of the methyl carbon peak that appears near the chemical shift δ = 14.06 ppm to the area of the methylene carbon peak of the main chain observed near δ = 30 ppm can be evaluated for quantitative evaluation. In the case of branching of C2, the relative value of the peak area of the methyl carbon that appears near the chemical shift δ = 11.34 ppm with respect to the area of the peak of the methylene carbon of the main chain observed near δ = 30 ppm can be evaluated for quantitative evaluation. .

According to an embodiment, the hydrogenation of the polybutadiene rubber may include removing double bonds by hydrogenating polybutadiene under a hydrogenation catalyst at high temperature and high pressure.

In this case, in the process for hydrogenating the polybutadiene, the pressure condition may be 30 to 60 bar, and preferably, it may be performed at a pressure of 40 to 60 bar.

In the process for hydrogenating the polybutadiene, the reaction temperature may be carried out at 100 to 150 °C, preferably at 100 to 130 °C, and the reaction time is 20 to 40 hours, preferably 20 to 30 It may be performed over time.

As the catalyst for the hydrogenation, a hydrogenation catalyst generally used for hydrogenation may be used, and more specifically, a catalyst having a structure of the following Chemical Formula 1 may be used.

[Formula 1]

(R _p Z) _r RhX _q

In Formula 1,

R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group,

Z is phosphorus (P), arsenic (As), sulfur (S), or a sulfoxide group (S=O),

X is hydrogen or a halide ion,

p is an integer of 2 to 3,

r is an integer of 2 to 4,

q is an integer from 1 to 3.

As the catalyst having the structure of Formula 1, for example, a preferred catalyst is tris(triphenylphosphine)-rhodium(I)-chloride ((PPh ₃ ) ₃ RhCl), tris(triphenylphosphine)-rhodium ( III)-chloride ((PPh ₃ ) ₃ RhCl ₃ ) and tris(dimethylsulfoxide)-rhodium(III)-chloride, and tetrakis(triphenylphosphine) of formula ((C ₆ H ₅ ) ₃ P) ₄ RhH )-rhodium hydride, and compounds in which the triphenylphosphine moiety is substituted with a tricyclohexylphosphine moiety. The catalyst may be used in a small amount, for example, 0.10 parts by weight to 50 parts by weight, preferably 2.0 parts by weight to 10 parts by weight based on 100 parts by weight of polybutadiene.

In addition, the catalyst may be used together with a co-catalyst, and more specifically, a co-catalyst having a structure of the following Chemical Formula 2 may be used together.

[Formula 2]

R _p Z

In Formula 2,

R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group,

Z is phosphorus (P), arsenic (As), sulfur (S), or a sulfoxide group (S=O),

p is an integer of 2-3.

Preferably, R and Z may be the same as those used in the catalyst.

The promoter may be used in an amount of 0.38 parts by weight to 190 parts by weight, preferably 7.6 parts by weight to 38 parts by weight, based on 100 parts by weight of polybutadiene.

The organic solvent used in the hydrogenation process may be used without limitation as long as it is conventionally used in the hydrogenation process, and for example, straight and branched chain hydrocarbons such as pentane, hexane, heptane and octane, and alkyl-substituted derivatives thereof; alicyclic hydrocarbons such as cyclopentane, cyclohexane and cycloheptane and alkyl-substituted derivatives thereof; aromatic and alkyl-substituted aromatic hydrocarbons such as benzene, naphthalene, toluene and xylene; hydrogenated aromatic hydrocarbons such as tetralin and decalin; At least one organic solvent selected from linear and cyclic ethers such as dimethyl ether, methyl ethyl ether, diethyl ether and tetrahydrofuran may be used, preferably aromatic and alkyl- such as benzene, naphthalene, toluene and xylene. Organic solvents selected from substituted aromatic hydrocarbons may be more suitable.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein.

<Comparative Example 1>

The ¹³ C NMR spectrum of a polybutadiene rubber (BR) containing an SCB having 2 carbon atoms and an LCB having 6 or more carbon atoms was measured and shown in FIG. 1 below.

<Example 1>

BR of Comparative Example 1 was hydrogenated under the conditions shown in Table 1 below to prepare LLDPE (Linear Low-density polyethylene) analogues. ¹ H NMR measurement results of the obtained LLDPE analog are shown in FIG. 2 . From the ¹ H NMR spectrum result of FIG. 2, it can be determined whether the hydrogenation process of BR has been properly performed (whether all hydrogenation), and from this, it can be confirmed whether BR is structurally transformed into an LLDPE analog.

BR 480 mg catalyst (PPh ₃ ) ₃ RhCl 0.03 mmol cocatalyst PPh ₃ 0.40 mmol menstruum Toluene 50 ml Hydrogenation pressure 50 bar Reaction temperature and time 110℃, 24 hrs

In ¹ H NMR of FIG. 2, the methyl group (-CH ₃ ) at the branched end of the hydrogenated BR appears, although small, but in the ¹ H NMR spectrum, the LCB and SCB contents cannot be accurately quantified due to the overlap of the LCB and SCB peaks. and -CH and -CH ₂ groups included in the main chain and branch appear without distinction, so it is difficult to quantitatively analyze the branch with ¹ H NMR alone.

Therefore, in addition to ¹ H NMR, ¹³ C NMR measurement is required for LLDPE quantitative analysis.

For LLDPE quantitative analysis, ¹³ C NMR spectrum of the LLDPE analogue was measured and shown in FIG. 3 below.

In the result of the ¹³ C NMR spectrum of FIG. 3, -CH and -CH ₂ groups of the branch and main chain are distinguished, and the peaks related to LCB and SCB are also displayed separately. Therefore, the LCB content can be quantified by integrating the peaks for the methyl groups at the ends of the LCB and SCB and calculating the relative value for the methylene peak of the main chain. The results of calculating the contents of SCB and LCB using the ¹³ C NMR spectrum of FIG. 3 are shown in Table 2 below.

More specifically, the quantitative analysis of polybutadiene branches from the ¹³ C NMR measurement result of FIG. 3 may be performed using the following calculation method.

When the integral value of the peak of 30 ppm, which is the main chain carbon, is fixed to 1000, the integral value of 11.3 ppm is referred to as A, and the integral value of 14.3 ppm is referred to as B.

1) How to calculate the relative mole ratio between branches

When the integral value of main chain carbon is normalized to 1000, the integral value of each branch represents the relative mole ratio between them.

Therefore, the relative mole ratio between branches can be obtained as in Equation 1 below.

[Equation 1]

SCB : LCB = A : B = 6.76 : 1.68

2) Calculation of the number of branches (X) per 1000 main chain carbons

Since there are a total of 5 carbons contributed by each branch in the main chain (2α+2β+*), the number of carbons in the main chain can be obtained as shown in Equation 2 below.

[Equation 2]

(1000 - A - B ) + 5 * ( A + B )

Therefore, the number of SCBs present per 1000 main chain carbons (X _SCB ) can be obtained as in Equation 3 below,

[Equation 3]

(1000 - A - B ) + 5 * ( A + B ) : A = 1000 : X _SCB X _SCB = 6.54

The number of LCBs present per 1000 main chain carbons (X _LCB ) can be obtained as in Equation 4 below.

[Equation 4]

(1000 - A - B ) + 5 * ( A + B ) : B = 1000 : X _LCB X _LCB = 1.63

3) Calculation of the relative mole ratio (Y) between Ethylene and each branch

Using the number of SCBs and LCBs obtained in Equations 3 and 4 above, the relative mole ratio between ethylene contained in the main chain and each branch can be obtained as shown in Equation 5 below.

[Equation 5]

Y _Et : Y _SCB : Y _LCB = {1000 - 2 * (X _SCB + X _LCB )} / 2 : X _SCB : X _LCB

= 491.84 : 6.54 : 1.63

4) Relative mass ratio between Ethylene and each branch (Z)

Using the relative mole ratio between Ethylene and each branch obtained in Equation 5, the relative mass ratio between Ethylene and each branch can be obtained as in Equation 6 below.

According to ¹³ C NMR, branches of C6 or higher are structurally similar regardless of the number of carbons and show the same chemical shift, so it is impossible to distinguish each of them. Therefore, LCB was considered as a C6 branch and analyzed.

[Equation 6]

Z _Et : Z _SCB : Z _LCB = Y _Et * 28 : Y _SCB * 56 : Y _LCB * 112

= 366.20 : 182.02 : 13771.40

5) Branch wt%

The contents of SCB and LCB included in BR can be analyzed based on the relative mass ratio between ethylene and each branch obtained in Equation 6 above.

The content of SCB can be obtained as shown in Equation 7 below,

[Equation 7]

SCB wt% = Z _SCB / (Z _Et + Z _SCB + Z _LCB ) *100 = (366.20 / 14319.61) * 100

= 2.6 wt%

The content of LCB can be obtained as shown in Equation 8 below.

[Equation 8]

LCB wt% = Z _LCB / (Z _Et + Z _SCB + Z _LCB ) *100 = (182.02 / 14319.61) * 100

= 1.3 wt%

BR Ingredients (wt%) SCB 2.5 LCB 1.3 Ethylene 96.2

In the present invention, by measuring ¹³ C NMR after hydrogenating polybutadiene, a ¹³ C NMR spectrum in which the main chain and branch peaks are separated can be obtained, and from this, the content of long chain branches (LCB) contained in polybutadiene is determined. can be quantified.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (8)

hydrogenating polybutadiene; and
As an analysis method of polybutadiene branch comprising the step of quantitatively analyzing the content of LCB (long chain branch) and SCB (short chain branch) contained in the hydrogenated polybutadiene using an NMR spectrum,
The quantitative analysis includes calculating the relative value for the methylene peak of the main chain by integrating the peak areas for the methyl groups at the LCB and SCB ends,
The hydrogenation of polybutadiene is performed under a hydrogenation catalyst to remove double bonds from polybutadiene,
The method for analyzing polybutadiene branches, wherein the hydrogenation catalyst includes a catalyst of the following Chemical Formula 1 and a cocatalyst of the following Chemical Formula 2:
[Formula 1]
(R _p Z) _r RhX _q
In Formula 1,
R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group,
Z is phosphorus (P), arsenic (As), sulfur (S), or a sulfoxide group (S=O),
X is hydrogen or a halide ion,
p is an integer of 2 to 3,
r is an integer of 2 to 4,
q is an integer from 1 to 3,
[Formula 2]
R _p Z
In Formula 2,
R is a C1-C8-alkyl group, a C4-C8-cycloalkyl group, a C6-C15-aryl group or a C7-C15-aralkyl group,
Z is phosphorus (P), arsenic (As), sulfur (S), or a sulfoxide group (S=O),
p is an integer of 2-3. According to claim 1,
The analysis method of the polybutadiene branch that the NMR spectrum is a ¹³ C-NMR spectrum. According to claim 1,
The LCB (long chain branch) is a branch of polybutadiene branch having 6 or more carbon atoms. delete delete delete According to claim 1,
In the step of quantitatively analyzing the content of LCB (long chain branch) and SCB (short chain branch) contained in the hydrogenated polybutadiene using an NMR spectrum, NMR (Nuclear Magnetic Resonance) spectroscopy and a pulse program are used together Analysis method of polybutadiene branch. 8. The method of claim 7,
The pulse program is a ¹ H pulse program or ¹³ C pulse program, the method of analysis of polybutadiene branches.

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