JPH02110107A - Polystyrene copolymer, and manufacture and use thereof - Google Patents

Abstract

PURPOSE:To produce a copolymer wherein a color can be developed or allowed to disappear by applying an external energy such as light, heat, electricity or pressure by reacting a specific modified polystyrene derivative with an N- hydroxyethylindolium compound. CONSTITUTION:A polystyrene derivative of formula I (wherein R<1> is H, lower alkoxy, etc.; X is halogen; and m/n is 99.9/0.1-0.1/99.9) is reacted with an aldehyde derivative of formula II [wherein A is O, S, etc.; and k is 0-1] to produce a modified polystyrene derivative of formula III. The obtained derivative is reacted with an N-hydroxyethylindolium compound of formula IV (wherein R<2> and R<3> are each lower alkyl; R<4> is H, halogen, lower alkyl, nitro, etc.; R<6> is H or lower alkyl; and Y is an atom or group which can form an anion), thus giving a polystyrene copolymer which is represented by formula V, has an average degree of polymerization of 5,000-200,000, and is useful as a material wherein a color can be developed or allowed to disappear.

Description

[Detailed description of the invention] (b) Industrial application field This invention relates to polystyrene copolymers.

More specifically, the present invention relates to a novel polystyrene copolymer useful as a polymer coloring/fading material.

(b) Prior Art Recently, display elements that utilize color changes caused by reversible electrochemical reactions of chemical substances upon application of voltage have been attracting attention as electrocomic displays (ECDs). In particular, ECDi is less visually dependent than liquid crystal displays and has the same visibility, so it is expected to be put to practical use as a display element.

Various inorganic compounds and commercial compounds have been proposed as chemical substances, ie, electrochromic substances, to be used in such ECD. Among these, WO is an inorganic compound.
5 and N1o○ are representative, and these may have the disadvantage of poor color performance (gloss). On the other hand, hyologen, styryl compounds, etc. are known as finite compounds, but among these, hyologen has the drawbacks of poor color rendering properties and high power consumption.

On the other hand, styryl compounds have the advantages of being easily multicolored, having low power consumption, and having a large dichroic ratio and high color freshness, so they are considered promising for the practical application of ECD. Specifically, various styryl compounds have been proposed as electrochromic materials (Japanese Patent Publication No. 1987-
No. 33307, JP-A No. 6O-5f775, JP-A-58
-48031 publication, etc.).

In addition, since these conventional compounds are monomolecular compounds,
For practical use as an ECD, these compounds must be dissolved in a suitable medium, such as an aqueous solution or an organic solvent, in the presence of a supporting electrolyte or the like. First, when manufacturing cells and the like, they must be finished to prevent liquid leakage, and sufficient safety is required in terms of use.

(C) Problems to be Solved by the Invention This invention seeks to provide a new styryl-based compound, and in particular, a new polymer compound with good electrochromic properties that can be substituted for conventional electrochromic materials. This is what Party B is trying to provide.

(d) Means for Solving the Problems According to the present invention, the following formula (I): (A
) [In the formula, R1 is a hydrogen atom, a lower alkoxy group, a nitro group,
Amine group or lower alkylamino group; R1゜R3 is each a lower alkyl group; R4 is a hydrogen atom, a halogen atom, a lower alkyl group, a nitro group, an ano group, a lower alkoxy group,
Lower alkanoyl group, halogenated lower alkyl group or 1
Class alkanesulfonyl group: A is -0-1-5- or -
A group represented by N- (wherein R5 is a lower alkyl group); Q
is -CHC- or -C)l=CH-CH=C-(
In the formula, R8R8R8 is a hydrogen atom or a group represented by a lower alkyl group; m, n
means the copolymerization ratio, m: n = 99.9: 0
．． A polystyrene copolymer having an average degree of polymerization of 5,000 to 200,000 is provided.

The term "lower" in the lower alkyl group, lower alkoxy group, lower alkanoyl group, and lower alkanesulfonyl group in the definitions of the formulas of this invention refers to carbon atoms of 1 to 6.

In the definition of substituent R1, examples of the lower alkoxy group include metquine, ethquine, propoquine, i-propoquine, butquine, L-butoxy, pendeloxy and the like. lower alkylamino group and 1. Examples include methylamino, ethylamino, propylamino, 1-propylamino, butylamino, butylamino, pentylamino, and the like.

Such R1 is preferably a hydrogen atom or a lower alkoxy group. Further, the suitable substitution position for R1 is the para position or the meta position.

Examples of the lower alkyl group for substituents R7 and R3 include methyl, ethyl, propino, i-propyl, butyl, shi-butyl, and pentyl, and among these, methyl is preferred.

In the definition of substituted MR', examples of the halogen atom include chlorine, iodine, and bromine. As the lower alkyl group, the same ones as the lower alkyl group in the definition of R2 and R3 are applied, and as the lower alkoxy group, the same ones as the lower alkoxy group in the definition of R1 are applied. Lower alkanoyl groups include acetyl, propionyl, butyryl, etc., halogenated lower alkyl groups include chloromethyl, bromomethyl, iodomethyl, dichloromethyl, bromopropyl, etc., and lower alkanesulfonyl groups include methanesulfonyl. , ethanesulfonyl, propanesulfonyl, etc. A suitable substitution position for R' is the 5th or 6th position of the indolium ring.

In addition, in the definition of the group A, the lower alkyl group in R5 of W-N- and the group Q, the group -CHC- and the group -C
H=C)I-CH==C-(up Re
The RO lower alkyl group includes those having the same meaning as the lower alkyl group in R2-R4. As the group A, 0- or methylimino is preferred.

Moreover, in the formula, m and n mean a copolymerization ratio, and indicate a molar ratio when two types of structural units exist in a random or block form. This copolymerization ratio is m + n = 99
．． 9: 0.1 to Q, l: 99.9, and mn=9 in terms of good electrochromic properties.
A ratio of 9:1 to 50:50 is suitable.

On the other hand, the average molecular weight (number average molecular weight) of the copolymer of formula (I) is suitably 5,000 to 200,000 in terms of film-forming properties and ease of production as an electrochromic material;
0000 to 100000 is preferred.

The copolymer of formula (+) of the present invention can be synthesized by introducing an indolinooxazolidine ring into a corresponding polystyrene polymer partially via a styryl group. More specifically, an aldehyde derivative represented by the following formula (b) -÷Cll-CH+V+CH, -CH+-R5 is a lower alkyl group); A modified polystyrene derivative represented by (■): was obtained, and this modified polystyrene derivative (IV) and the following formula (): RI
C) ltX (wherein R' is a hydrogen atom,
Lower alkoxy group, nitro group, amino group or lower alkylamino group;
9.9), and a polystyrene derivative represented by the following formula (III):
Hydrogen atom, halogen atom, lower alkyl group, nitro group,
N represented by a cyano group, lower alkokene group, lower alkanoyl group, halogenated lower alkyl group or lower alkanesulfonyl group; Re is a hydrogen atom or a lower alkyl group; Y represents an atom or group capable of forming an anion) -It can be synthesized by reacting a hydroquine ethyl indolium compound.

The modified polystyrene derivative of formula (IV) obtained by such a synthetic process is itself a novel compound that has not been described in any literature.

The polystyrene derivative of formula (II) which is a raw material in the above synthesis method is obtained by partially introducing a group R1 other than a halogenated methyl group or hydrogen into polystyrene by a known method, or having a halogenated methylstyrene and a group R1. Styrene or substituted styrene can be obtained by copolymerization using known techniques. In this case, the substitution position of the halogenated methyl group may be, for example, the para position and the meta position, or a mixture thereof.

As the aldehyde derivative of formula (III), for example, p
-oxyhenzaldehyde, p-oxycinnamaldehyde, p-methylaminobenzaldehyde, p-methylaminocinnamaldehyde, p-mercaptobenzaldehyde and the like. Among these, p-lower alkylaminocinnamaldehydes such as p-methylaminocinnamaldehyde are made from p-methylaminobenzaldehyde, and acetaldehyde-N
It can be synthesized by subjecting it to a carburizing reaction using -butylimine, or after protecting the N-position hydrogen by acetoquination, subjecting it to a Nikreisen condensation reaction using acetaldehyde, or subjecting it to a Wittig reaction using a ylide. reactor.

The reaction between the aldehyde derivative (I [I) and the polystyrene derivative (ff) is carried out in the presence of a suitable alkaline condensing agent (e.g., sodium hydride) in a polar organic solvent such as trimethylformamide, dimethyl sulfoxide, and trimethylacetamide. This can be done by heating at reflux. The ratio of the compounds of formula (III) and formula (II) to be used is preferably such that the former is used in an amount of 1 to 10 equivalents of the latter. Through this treatment, a condensation reaction between the halogen methyl group of the polystyrene derivative of formula (II) and the substituent at the rose position of the aldehyde derivative of formula (III) proceeds, and a modified polystyrene derivative of formula (IV) is obtained.

The copolymer of the present invention can then be obtained by reacting the modified polystyrene derivative ([V) with the N-hydroquinethylindolium compound (). Formula (V)
Examples of the atom or group capable of forming an anion represented by Y include chloride, bromide, tosylate, verchlorate, and carboxylate. This reaction usually uses a chemical equivalent or a slight excess of the compound of formula (V) corresponding to the aldehyde group in the compound of formula (['/), and these compounds are heated under reflux in a polar organic solvent. The reaction can be carried out under a reaction vessel, and is preferably carried out under an inert gas such as N gas. In this production method, after the condensation reaction between the 2-position methyl group of the indolium compound (V) and the aldehyde group of the modified polystyrene derivative (IV), the ring-closing reaction of the hydroxyethyl group proceeds by deHY-forming. Copolymer (I) is obtained.

The copolymer of the formula (1) of the present invention is a copolymer of the following formula (IV) [wherein R1 is a hydrogen atom, a lower alkokene group, a nitro group, an amino group, or a lower alkylamino group; A is 10--S- or a group represented by -N- (wherein R5 is a lower alkyl group);
is 0 or l;m.

n means copolymerization ratio, m: n = 99.9:
A modified polystyrene derivative represented by 1 having a value of 0.1 to 0.199.9 and the following formula (V[) (wherein, R2 and R3 are each a lower alkyl group; R4 is
Hydrogen atom, halogen atom, lower alkyl group, nitro group,
Reacting an indolino[2,1-b]oxazolidine derivative represented by a cyano group, a lower alkoxy group, a lower alkanoyl group, a halogenated lower alkyl group, or a lower alkanesulfonyl group, R8 represents a hydrogen atom or a lower alkyl group. It can be synthesized by
Indolino J2, which is used as a raw material in this method. +-
b The 3-year-old xazolidine derivative is a known compound (Japanese Patent Publication No. 57-33307).

This reaction is usually carried out using the above-mentioned modified polystyrene derivative (I
V) Tobe-hydroquinethylindolium compound (V)
Do the same thing as the reaction.

(Hereinafter, blank space) The copolymer of the present invention obtained in this way changes color, develops color, and emits color in response to external stimulus energy such as light, heat, ions, electricity, pressure, and radiation, and develops and fades. It can be used as a material. As a more specific example, an ECD can be constructed by interposing this copolymer layer between electrodes for a segment or matrix type ECD. In particular, since this copolymer itself is a polymer compound, it has self-forming properties. Therefore, by applying a solution of this copolymer and supporting electrolyte onto the display electrode surface for ECD, an electrochromic film can be easily produced. Of course, pond film-forming polymers (e.g.
It can also be used in combination with astringents (polystyrene, polymethacrylate, etc.) or polymer electrolytes.

(e) Examples Example 1 Production of polystyrene derivative of formula 11 (■) (where R'=H, Para position substitution mixture, meta:bara = 6.4
) (9,159) was dissolved in methanol (200%), benzoyl peroxide (0,89) was added, and the mixture was stirred for 30 minutes at room temperature under a nitrogen stream and for 5 hours in an oil bath at 65°C. Additional benzoyl peroxide (0.49) was added and the mixture was heated and stirred for 3 hours at the same temperature. After cooling to room temperature, the solvent was distilled off under reduced pressure. Further, unreacted monomers were distilled off on an oil bath at 150°C to obtain a starch syrup-like residue. This was dissolved in chloroform (200zQ) and methanol (1,
5c) was added dropwise little by little. The resulting white powder was collected and dried to obtain the desired polystyrene derivative of formula (b).

The yield was 41.09, the copolymerization ratio m:n #88:12 was determined from the quantitative value of chlorine (3.88%), and the average molecular weight was 1,
8").IR (KBr): 30
00,2900,1600,1485°1445126
0 cm- Note that a polystyrene derivative (fl) in which R1 is a lower alkoke group, an amino group, or a lower alkylamino group can also be synthesized in the same manner using the corresponding styrene substituted product and chloromethylstyrene.

2. Production of modified polystyrene derivative of formula (■) (Step 2
) Copolymer of styrene and chloromethylstyrene obtained by Moeki manufacturing method (copolymerization ratio = 88:12, average molecular weight 1.8X
lO') (11,19) in dimethylformamide (5
0 shoulder Q), and p-N-methylaminobenzaldehyde (4.1 g) was added thereto. Add sodium hydride (1,29) little by little to the above solution while cooling with water, then heat and stir at 0-5°C for 15 minutes, at room temperature for 10 hours, and then at 50-55°C for 21.5 hours. did.

The reaction solution was mixed with methanol (600x□, water (300x)
A pale yellow powder is obtained by filtering the mixture and drying it to obtain a nape-modified polystyrene derivative (average molecular weight ff1=18,000).
11.209 was obtained.

IR(KBr) 3000,2900.1670.15
95.1520°1490, 1445 1370 1
160cm- (Step 3) After washing with water and drying, the title copolymer (average molecular weight 180
00) powder (4,31) was obtained.

IR (Nujol): 1660.1590.151
0.14851160cm-' UV λ max, : 306nm (CH
C2z) Example 2 Styrene obtained in step 2 and p -(N-methyl-N
A copolymer of -(m- or p-vinyl)benzyl)aminobenzaldehyde (copolymerization ratio 88:12) (5,09) was mixed with ethanol (25,000 g) and tetrahydrofuran (5,000 g).
0.

After cooling, the reaction solution was diluted with water (4ooxI2) -meth/-ol (
600m2) of liquid a. The resulting red powder was collected by filtration, dissolved in tetrahydrofuran, and then dissolved in 5% ammonia water (10%
00 mσ) little by little. The precipitated powder was collected by filtration, and N-hydroquinethyl-2 in Step 3 of Example 1 was collected.
, 3,3-trimethylindolium bromide, the title styrylated polystyrene copolymer was prepared in the same manner as in Example 1, except that N-hydroxyethyl-2,3,3,5tetramethylindolium bromide was used. (R
' = H, A = N (CHs) f2 = 1, R
"=R'=R'=CH, average molecular weight 1 gooo) was obtained.

IR (7i/l, mu) + 3050.2950.2
8401665, 1600, 1540, 1490.
1450, 1420.1380.1165cm-'U
Vλmax304nm (CHCQ3) Example 4 Example 3 N-hydroquinoethyl-2,3,3-trimethylindolium bromide was replaced with N-hydroquinoethyl-2,3,3-trimethylindolium bromide.
The title styrylated polystyrene copolymer (R' = H, A = N (Cl(3
)-, &=I, R=R3= CI-i,, R'=902
CH3, average molecular weight 18,000) was obtained.

IR (film) + 3100.2830.166
0°1600, 1520.1490, 1470, 1
450, 1420, 1375.1305.1140
m UVλmax: 305 nm (CHCQ3).

The title styrylated polystyrene copolymer (R
' = H, A = N (CH3)-1C=l.

R'=R'=CH3, R'=NO, average molecular weight 180
00) obtained f2.

IR (film): 3050.2920.160
0.15151490 1450cm-UVλmax: 308nm (CHCl3).

Example 5 By using p-hydroquinohendaldehyde in place of I) -N-methylaminohenzaldehyde used in Working 2 of Example 1, a modified polystyrene derivative (average Molecule ff118000.
IR (Nunoyol) 1685.1600cm-'
), and using this, N
By reacting -hydroquinoethyl-2,3,3-trimethylindolium bromide, the title copolymer (R'=H, A=-0-1Q=1゜R2=R'=(j
(3, R'=H1 average molecular weight 18,000) was obtained.

IR (Nujol): 1660.1600cm-'
UVλmax: 270nm (CHCL3).

Example 6 In place of indolium bromide in Example 5, N-hydroquinethyl-2,3,3-trimethyl-5
The title copolymer (R'=[(1A=-
〇-1!2= 11R'=R'=CH3, R'=CI2
, average molecular weight 18,000).

IR (film): 3050.2930.1690
．． 1600°1510, 1490.1450. l15
0cm-'UVλmax: 268nm (CHCL
3).

Example 7 1, p Preparation of methylaminocinnamaldehyde Diisopropylamine (14,579) in tetrahydrofuran (190
, vρ) solution, a solution of n-butyllithium in tetrahydrofuran (15%) was added dropwise at -10 to -20°C under a nitrogen stream. After cooling the reaction solution to -70'C, acetaldehyde-Nt-butylimine (7,1,49) was added and stirred at the same temperature for 30 minutes. Next, add noethyl chloroposphate (12,42!?) at -70°C, and add 2
After stirring for an hour, the temperature was raised to -10°C over 1.5 hours. After cooling to -65°C again, p-methylaminobenzaldehyde (6,499) was dissolved in tetrahydrofuran (
25iQ) solution was added, the temperature was gradually raised to room temperature, and the mixture was stirred for 15 hours. Water of sulfuric acid (27,239) (
After adding 500x solution and stirring for 8 hours, the pH was adjusted to 10 with 6N sodium hydroxide and extracted with ether. The ether layer was dried with magnesium hydroxide solution after dilution of water, and concentrated under reduced pressure. The residue was applied to a silica gel column. The desired product was obtained in 2.83s+ by elution with N-hexane-ether.

IR (Nujol): 3300.1645.160
0.1580°530cm 2, an example of manufacturing a copolymer of the following formula! Using the styrene-chloromethylstyrene copolymer obtained in Step 1 of Example 1, p-
In place of N-methylaminobenzaldehyde, the above p-
Example except for using N-methylaminocinnamaldehyde! Styrene and p-(N-methyl-N-(m or p-vinyl)benzyl)aminonnamaldehyde copolymer [average molecular ff 118,000.
I R (Nujol) +1660.1590.1515
By using the obtained copolymer and avoiding the reaction in the same manner as in Step 3 of Example 1, the title copolymer (R'=H, A=-N(CH3) -1 (2-2
, R'=R'=CH, , R'=H, average molecular weight 180f
lQ) was obtained.

IR (film): 3050.3000.2930
．． 16001515, 1490. 1450cffi
-'UVλmax: 328nm (CICl3)
.

Example 8 The amounts of styrene and chloromethylstyrene used during copolymerization in Step 1 of Example 1 were changed to obtain a copolymerization ratio m:n=44.
+56, an average molecular weight of 16QOO was obtained, and using this, styrene and p (N-methyl-N-(m or p-vinyl)
copolymer with bennor)aminostyryl-3,3-dimethyl-indolino[2,1-b']oxazolidine (
A copolymerization ratio of 44.56 and an average molecular weight of 16,000 were obtained.

IR (Nunoyor): 1600.1510.1160
．． 1105 Example 9 A styrene-chloromethylstyrene copolymer with a copolymerization ratio m:n=98:2 and an average molecular weight of 16,000 was obtained in the same manner as in Example 8, and this was used to synthesize styrene and p-(N-methyl -N-(m or p-vinyl)bennor)aminostyryl-3,3-dimethyl-indolino[2,1-b]copolymer with oxazoline (copolymerization ratio 44:56,
An average molecular weight of 16,000) was obtained.

[R (nujol): 1600.1480cm-
UV λ max: 305++m (Cl
Cl5) Styrene obtained in Step 2 of Example 1 and p(N
Copolymer of methyl-N(m or p-vinyl)benzyl)aminobenzaldehyde (copolymerization ratio 8812) (38
0H) was dissolved in ethanol (+0R) and tetrahydrofuran (20x (2), and 2.3.3-trimethylindolino[1,2-b cooxazoline (2,
03g) was added thereto and heated under reflux for 15 hours. After cooling, the reaction solution was poured into a mixture of water (400 m2) and ethanol (600 m2), and the resulting precipitate was collected by filtration, washed with water, and dried to obtain the title styrylated polystyrene copolymer (R '＝
H, A-N (CHJ, Q=IR'=R3=CH
, R'=H) (120 g9) was obtained. These are examples first with fR and UV spectra! It was the same as that obtained in step 3.

Evaluation test example (color developing and fading properties) The copolymer 20 of the present invention obtained in Example 9 was
．． 2y(l, dissolved in r T O(2,Ox 2.Oc
m) Place 20μ of this solution on top and rotate with a spinner (
1200 rpm, 100 mm) to form a film, and use this as a transparent electrode. A saturated chloride (lithium) electrode was used as the reference electrode, and a platinum wire was used as the counter electrode. 0.0 as a supporting electrode material.
A 2M solution of tetrachloroammonium perchlorate in acetonitrile was used.

When the potential range is -1.2V to ÷1.5V (vs. saturated sodium chloride electrode, the same applies hereinafter), it is colored red at the potential where an anodic wave is observed, and is discolored at the potential where a cathodic wave is observed. This was repeated. Also, +2. O
It was found that when maintained at V, it gave a majestic absorption wavelength of 550 nm in the visible absorption spectrum, and had no absorption in the visible region at -15V.

The coloring and fading characteristics of each of the copolymers of the present invention obtained in Examples 1 to 7 were evaluated in the same manner. The results are shown in the table below.

As described above, it can be seen that the copolymer of the present invention exhibits good electrochromism, that is, the coloring and fading property, and that it is possible to display various colors by selecting the substituents.

Note that when protons and anions are present around the copolymer of the present invention, light, heat, ions, electricity, pressure,
Changes color, develops color, etc. in response to external stimulation energy such as radiation.
It can produce a rich color.

(f) Effects of the invention The copolymer of formula (+) of this invention can be stabilized reversibly or irreversibly by applying external stimulus energy such as light, heat, ions, electricity, pressure, or radiation. It is capable of color development and fading, and is suitable for use in various display materials, various recording materials, and the like. In particular, it has electrochromic properties that exhibit electrochemical color development and color change, as well as self-forming properties, so it can be used as an electrochromic material for ECD without the need to manufacture a solution-based display cell as in the past. This is extremely useful.

This electrochromic property is considered to be based on the electrochemically reversible ring-opening-ring-closing reaction of the oxazolidine ring in indolinoxapridine bonded via the styryl group in the copolymer of formula (+).

In the copolymer of this invention, the indolinooxazolidine groups are aggregate-regulated through the styryl groups due to the polystyrene chains, so the copolymer has a better response in terms of color development and fading properties than conventional styryl compounds. It can be expected to improve the properties of the polyester, and can also be expected to have multiple colors depending on the selection of the substituent J).

Claims (1)

[Claims] 1. The following formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ... (I) [In the formula, R^1 is a hydrogen atom, a lower alkoxy group, a nitro group, an amino group, or a lower Alkylamino group: R^2, R^3
are each a lower alkyl group; R^4 is a hydrogen atom, a halogen atom, a lower alkyl group, a nitro group, a cyano group, a lower alkoxy group, a lower alkanoyl group, a halogenated lower alkyl group, or a lower alkanesulfonyl group; A is -O- , -S-
Or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^5
is a group represented by a lower alkyl group); Q is -CH=▲There are numerical formulas, chemical formulas, tables, etc.▼ or -CH=CH-CH=
▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^6 is a hydrogen atom or a lower alkyl group); m and n mean the copolymerization ratio, m:n = 99.9:0 .1-0.1:
99.9], and the average degree of polymerization is 5000 to
200,000 polystyrene copolymer. 2. The following formula (II): ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) (In the formula, R^1 is a hydrogen atom, a lower alkoxy group, a nitro group, an amino group, or a lower alkylamino group; is a halogen atom; m and n mean the copolymerization ratio, m:n=99.9:
0.1 to 0.1:99.9) and the following formula (III): ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In the formula, A is - O-, -S- or ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ (in the formula, R^5 is a lower alkyl group); k indicates 0 or 1] is reacted with an aldehyde derivative represented by To obtain a modified polystyrene derivative represented by the following formula (IV): ▲There are mathematical formulas, chemical formulas, tables, etc.▼... (IV) (in the formula, each symbol has the same meaning as in formula (II) or (III)), This modified polystyrene derivative (IV) and the following formula (V): ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ... (V) (In the formula, R^2 and R^3 are each a lower alkyl group; R^
4 is a hydrogen atom, a halogen atom, a lower alkyl group, a nitro group, a cyano group, a lower alkoxy group, a lower alkanoyl group, a halogenated lower alkyl group, or a lower alkanesulfonyl group; R^6 is a hydrogen atom or a lower alkyl group; Y represents an atom or group capable of forming an anion)
- A method for producing a polystyrene copolymer, which comprises reacting a hydroxyethyl yttrium compound to obtain a copolymer represented by the formula (I) of claim (1). 3. Formula (IV) below: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(IV) [In the formula, R^1 is a hydrogen atom, a lower alkoxy group, a nitro group, an amino group, or a lower alkylamino group; A is -O-,
-S- or ▲Mathematical formulas, chemical formulas, tables, etc.▼(In formulas,
R^5 is a lower alkyl group): k is 0 or 1
:m and n mean copolymerization ratio, m:n=99.9:0.
1 to 0.1:99.9] and the following formula (VI): ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(VI) (In the formula. R^2, R^ 3 is each lower alkyl group; R^
4 is a hydrogen atom, a halogen atom, a lower alkyl group, a nitro group, a cyano group, a lower alkoxy group, a lower alkanoyl group, a halogenated lower alkyl group, or a lower alkanesulfonyl group; R^6 represents a hydrogen atom or a lower alkyl group )
A method for producing a polystyrene copolymer, which comprises reacting an indolino[2,1-b]oxazolidine derivative represented by the following formula to obtain a copolymer represented by the formula (I) of claim (1). 4. A coloring/decoloring product made of a polystyrene copolymer represented by formula (I), which changes color, develops color, and decolors in response to external stimulus energy such as light, heat, ions, electricity, pressure, and radiation. material.