EIGHT-ARM STAR-SHAPED THERMOPLASTIC ELASTOMER COPOLYMER AND PREPARATION METHOD THEREFOR

Abstract

An eight-arm star-shaped thermoplastic elastomer copolymer and a preparation method therefor; a polystyrene-polyisoprene lithium compound and a polystyrene/diphenylethylene-polyisoprene lithium compound are synthesized by using active anionic polymerization, and the compounds are used for a coupling reaction with octenyl polyhedral oligomeric silasesquioxane to obtain the copolymer. The method has the characteristics of convenient operation, high reaction efficiency, mild reaction conditions, and few side reactions. The structure and molecular weight of the prepared eight-arm star-shaped polymer are controllable, and the molecular weight distribution is narrow. A polymer segment obtained by the copolymerization of diphenylethylene (DPE) and styrene (St) is used as a hard segment, which enables the eight-arm star-shaped thermoplastic elastomer copolymer to have more outstanding mechanical properties. At the same time, a polymer segment composed of DPE and St units has a higher glass transition temperature than polystyrene, which increases the upper limit usage temperature of the eight-arm star-shaped copolymer.

Claims

1. An eight-arm star-shaped thermoplastic elastomer copolymer, having a structure shown as follow: ##STR00009## wherein, R.sub.1 is ##STR00010## R.sup.2 is ##STR00011## x is from 10 to 200, y is from 2 to 10, z is from 5 to 20, m is from 200 to 600, n is from 10 to 30.

2. A preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 1, comprising the following steps: (1) under nitrogen protection, a lithium compound initiates styrene polymerization to obtain a poly(styryl)lithium(PS-Li); (2) under nitrogen protection, the poly(styryl)lithium(PS-Li) in step (1) initiates diolefin polymerization to obtain a polystyrene-polydiolefin lithium compound; (3) under nitrogen protection, the octavinyl polyhedral oligomeric silsesquioxane reacts with the polystyrene-polydiolefin lithium compound of step (2) to obtain an eight-arm star-shaped thermoplastic elastomer copolymer; or, comprising the following steps: (4) under nitrogen protection, a lithium compound initiates polymerization of styrene and diphenylethylene to obtain polystyrene/diphenylethylene Ethylene lithium compound; (5) under nitrogen protection, the polystyrene/diphenylethylene lithium compound in step (4) initiates diolefin polymerization to obtain a polystyrene/diphenylethylene-polydiolefin lithium compound; (6) under nitrogen protection, the octavinyl polyhedral oligomeric silsesquioxane reacts with the polystyrene/diphenylethylene-polydiolefin lithium compound of step (5) to obtain an eight-arm star-shaped thermoplastic elastomer copolymer.

3. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, in step (1), the molar ratio of the lithium compound to styrene is from (1:10) to (1:200); in step (2), the molar ratio of the poly(styryl)lithium(PS-Li) to the diolefin is from (1:210) to (1:630); in step (3), the molar ratio of the octavinyl polyhedral oligomeric silsesquioxane to the polystyrene-polydiolefin lithium compound is from (1:8.2) to (1:9); in step (4), the molar ratio of the lithium compound, styrene, and diphenylethylene is 1:(10 to 200):(5 to 20); in step (5), the molar ratio of the polystyrene/diphenylethylene lithium compound to the diolefin is from (1:210) to (1:630); in step (6), the molar ratio of the octavinyl polyhedral oligomeric silsesquioxane to the polystyrene/diphenylethylene-polydiolefin lithium compound is from (1:8.2) to (1:9).

4. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, the lithium compound is sec-BuLi or n-butyllithium; the diolefin is butadiolefin or isoprene; the steps (there is no need to use catalysts and catalyst ligands in the reaction process from (1) to (6).

5. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, the polymerization is at room temperature for 6 to 12 hours in step (1), which is at room temperature for 12 to 24 hours in step (2), at room temperature for 1 to 2 hours in step (3), at room temperature for 12 to 24 hours in step (4), at room temperature for 12 to 24 hours in step (5), at room temperature for 1 to 2 hours in step (6).

6. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, after the steps (3) and (6) are reacted, the product is purified separately, including the following steps: Purification of eight-arm star-shaped thermoplastic elastomer copolymer: After the reaction, the reaction liquid is rotated evaporator was concentrated and dropped into anhydrous methanol to precipitate. The precipitate was washed with anhydrous methanol and dried under vacuum, and then dissolved in toluene to obtain a solution. Then, anhydrous ethanol was added dropwise until the solution appeared turbid, and then heated until the solution was transparent, and then stood still. After layering, the lower transparent phase is removed from the solvent and precipitated in anhydrous methanol. The precipitate is filtered and dried to obtain an eight-arm star-shaped thermoplastic elastomer copolymer.

7. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, the reactions in steps (1) to (6) are carried out in a solvent.

8. The preparation method of preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 2, in step (3), the reaction was terminated with anhydrous methanol; in step (6), the reaction was terminated with anhydrous methanol.

9. An application of the lithium compound in preparing the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 1; the lithium compound is sec-butyl lithium or n-butyl lithium.

10. A application of the eight-arm star-shaped thermoplastic elastomer copolymer according to claim 1 in the preparation of polymer materials.

Description

DESCRIPTION OF FIGURES

[0050] FIG. 1 shows the GPC curves of PS (A), PS-PI (B), before purification (C) and after purification (D) of (PS-PI).sub.8POSS in Example 1, the solvent is tetrahydrofuran (THF);

[0051] FIG. 2 shows .sup.1H NMR of PS (A), PS-PI (B), after purification (C) of (PS-PI).sub.8POSS in Example 1, the solvent is CDCl.sub.3;

[0052] FIG. 3 shows FT-IR of PS (A), PS-PI (B), after purification (C) of (PS-PI).sub.8POSS in Example 1;

[0053] FIG. 4 shows thermal weight loss curves of PS (A), PS-PI (B), after purification (C) of (PS-PI).sub.8POSS in Example 1, nitrogen, 10° C./min;

[0054] FIG. 5 shows the stress-strain curve of after purification of (PS-PI).sub.8POSS in Example 1 with the crosshead speed of 50 mm/min;

[0055] FIG. 6 shows the GPC curves of PSD.sub.0.54 (the molar ratio of DPE monomer to St monomer is 0.54 to 1), PSD.sub.0.37 ((the molar ratio of DPE monomer to St monomer is 0.37 to 1) and PSD.sub.0.16 (the molar ratio of DPE monomer to St monomer is 0.16 to 1) in Example 2, the solvent is THF;

[0056] FIG. 7 shows .sup.1H NMR of PSD.sub.0.16 (A), PSD.sub.0.37 (B) and PSD.sub.0.54 (C) in Example 2, the solvent is CDCl.sub.3;

[0057] FIG. 8 shows differential scanning calorimeter (DSC) of PS (A) in Example 1 and PSD.sub.0.16 (B), PSD.sub.0.37 (C) and PSD.sub.0.54 (D) in Example 2, nitrogen, 10° C./min;

[0058] FIG. 9 shows .sup.1H NMR of PSD.sub.0.54-PI (A), PSD.sub.0.37-PI (B), PSD.sub.0.16-PI (C) in Example 2, the solvent is CDCl.sub.3;

[0059] FIG. 10 shows the GPC curves of PSD.sub.0.16 (A), PSD.sub.0.16-PI (B), before purification (C) and after purification (D) of (PSD.sub.0.16-PI).sub.8POSS in Example 2, the solvent is THF;

[0060] FIG. 11 shows the GPC curves of PSD.sub.0.37(A), PSD.sub.0.37-PI (B), before purification (C) and after purification (D) of (PSD.sub.0.37-PI).sub.8POSS in Example 2, the solvent is THF;

[0061] FIG. 12 shows the GPC curves of PSD.sub.0.54 (A), PSD.sub.0.54-PI (B), before purification (C) and after purification (D) of (PSD.sub.0.54-PI).sub.8POSS in Example 2, the solvent is THF;

[0062] FIG. 13 shows the stress-strain curve of (PSD.sub.0.16-PI).sub.8POSS (the molecular weight ratio of PSD to PI is 1 to 4.0) in Example 2 with the crosshead speed of 50 mm/min;

[0063] FIG. 14 shows the stress-strain curve of (PSD.sub.0.37-PI).sub.8POSS (the molecular weight ratio of PSD to PI is 1 to 3.4) in Example 2 with the crosshead speed of 50 mm/min;

[0064] FIG. 15 shows the stress-strain curve of (PSD.sub.0.54-PI).sub.8POSS (the molecular weight ratio of PSD to PI is 1 to 3.2) in Example 2 with the crosshead speed of 50 mm/min;

[0065] FIG. 16 shows the GPC curves of PS, PS-PI, PS-PI-PS in Example 3, the solvent is THF;

[0066] FIG. 17 shows the photo of the PS-PI-PS film formed by solvent volatilization in Example 3;

[0067] FIG. 18 shows the photo of dumbbell-shaped (PSD-PI).sub.8POSS film formed by solvent volatilization in Example 1.

EXAMPLES

[0068] The technical scheme of the present invention is further elaborated in combination with attached Figures and Examples.

Example 1: Preparation of (PS-PI).SUB.8.POSS

[0069] (1) Synthesis of PS-Li: Anionic polymerization at room temperature for 12 h, under nitrogen protection, the monomer of styrene (4.0 mL, 34.9 mmol) stored in ampoule was added into the sec-BuLi (0.7 mL, 0.77 mmol) as initiator, anhydrous benzene (100 mL) as solvent, to obtain the poly(styryl)lithium(PS-Li) solution. 2 mL of PS-Li solution was terminated with methanol, to obtain PS solution for test characterization. If benzene was replaced with the same amount of tetrahydrofuran, the subsequent coupling reaction efficiency of the product PS-Li is very poor, and it is almost impossible to obtain an eight-arm star polymer.

[0070] The PS solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol to obtain pure polymers. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid. All samples have been characterized by GPC, .sup.1H NMR and FT-IR. FIG. 1 (A), FIG. 2 (A) and FIG. 3 (A) respectively show GPC, .sup.1H NMR and FT-IR of PS, which verified the chemical structure of PS. From the .sup.1H NMR, the attribution of the proton peak corresponding to the polymer structure can be found. From the GPC (M.sub.n=3.9 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.05). It can be seen that the peak shape of the PS polymer is symmetrical narrow dispersed.

[0071] (2) Synthesis of PS-PI-Li: Anionic polymerization at room temperature for 12 h, under nitrogen protection, isoprene (15.5 g, 227.2 mmol) and anhydrous benzene (100 mL) was added into the PS-Li solution obtained in the above step (1). 2 mL of PS-PI-Li solution was terminated with methanol, to obtain PS-PI solution.

[0072] The PS-PI solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol to obtain pure polymers. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PS-PI. All samples have been characterized by GPC, .sup.1H NMR and FT-IR. FIG. 1 (B), FIG. 2 (B) and FIG. 3 (B) respectively show GPC, .sup.1H NMR and FT-IR of PS-PI, which verified the chemical structure of PS-PI. From the .sup.1H NMR, the attribution of the proton peak corresponding to the polymer structure can be found. From the GPC (M.sub.n=28.6 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.03). It can be seen that the peak shape of the PS-PI polymer is symmetrical narrow dispersed.

[0073] (3) Synthesis of (PS-PI).sub.8POSS:

[0074] The coupling reaction was carried out at room temperature for 2 hours under nitrogen protection, mixed the PS-PI-Li solution obtained in step (2) above and OVPOSS (73.5 mg, 0.12 mmol) in benzene (10 mL) and the reaction was terminated with anhydrous methanol.

[0075] After the reaction, the reaction solution was concentrated by rotary evaporation and precipitated in cold methanol to obtain crude product. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the pure polymers. The crude product is purified by fractional precipitation to obtain a transparent elastic block solid, which is the eight-arm star-shaped thermoplastic elastomer copolymer.

[0076] All samples have been characterized by GPC, .sup.1H NMR and FT-IR. FIGS. 1 (C) and (D), FIG. 2 (C) and FIG. 3 (C) respectively show GPC of (PS-PI).sub.8POSS crude product. GPC, .sup.1H NMR and FT-IR of the pure product of (PS-PI).sub.8POSS which verified the chemical structure. From the .sup.1H NMR, the attribution of the proton peak corresponding to the polymer structure can be found. From the GPC, the before purification of the crude product there were multiple sets of peak, the peak shape of the after purification of (PS-PI).sub.8POSS is symmetrical narrow dispersed (M.sub.n=168.5 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.12). FIG. 4 shows thermal weight loss curves of PS, PS-PI and (PS-PI).sub.8POSS. Compared with the linear polymer PS-PI, the (PS-PI).sub.8POSS has higher thermal decomposition temperature and better thermal stability. FIG. 5 shows the stress-strain curve of (PS-PI).sub.8POSS. It can be seen from the figure that its elongation at break is 900% and the average breaking strength is 1.2 MPa.

Example 2: Preparation of (PS-PI).SUB.8.POSS with DPE Monomers

[0077] (1) Synthesis of PSD-Li: Take the molar ratio of styrene to diphenylethylene is 1 to 0.16 (St:DPE=1:0.16) for an example.

[0078] Anionic polymerization at room temperature for 12 h, under nitrogen protection, the monomer of styrene (4.0 mL, 34.9 mmol) stored in ampoule was added into the sec-BuLi (0.44 mL, 0.56 mmol) as initiator, anhydrous benzene (100 mL) as solvent, added diphenylethylene(1.2 mL, 6.79 mmol) and styrene (2.6 mL, 22.7 mmol) to obtain PSD.sub.0.16-Li solution. 2 mL of PSD.sub.0.16-Li solution was terminated with methanol, to obtain PSD.sub.0.16-Li solution for test characterization. The PSD solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol, the solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PSD.sub.0.16. The other two samples, PSD.sub.0.37, PSD.sub.0.54 were prepared by this method, and the ratio of raw materials can be changed.

[0079] PSD.sub.0.37: sec-BuLi (0.55 mL, 0.7 mmol), diphenylethylene (2.5 mL, 14.2 mmol), styrene (2.6 mL, 22.7 mmol);

[0080] PSD.sub.0.54: sec-BuLi (0.48 mL, 0.71 mmol), diphenylethylene (2.5 mL, 14.2 mmol), styrene (1.9 mL, 17 mmol).

[0081] The polymer was characterized by .sup.1H NMR and GPC. FIGS. 6 and 7 are GPC and .sup.1H NMR of PSD polymers with different DPE monomers, respectively, verifying the chemical structure of PSD with different monomers molar ratios. From GPC (PSD.sub.0.54, M.sub.n=5.9 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.11, PSD.sub.0.37, n=6.0 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.14, PSD.sub.0.16, M.sub.n=7.6 g.Math.mol.sup.−1, M.sub.w/M.sub.n×1.14), it can be seen that the peak shape of the PS-PI polymer is symmetrical narrow dispersed. From the .sup.1H NMR, the attribution of the proton peak corresponding to the polymer structure can be found. FIG. 8 is the DSC of PSD polymer with different DPE monomers. It can be seen that with the increase of DPE monomers, from 1:0 (A), 1:0.16 (B), 1:0.37 (C) to 1:0.54 (D), the T.sub.g of the polymers are also increased accordingly, that is, the T.sub.g of polymer can be adjusted by changing the content of the DPE monomers.

[0082] (2) Synthesis of PSD-PI-Li: Take the molar ratio of styrene to diphenylethylene is 1 to 0.16 (St:DPE=1:0.16) for an example.

[0083] Anionic polymerization at room temperature for 12 h, under nitrogen protection, added isoprene (13.0 g, 191.0 mmol) and benzene (200 mL) to the PSD.sub.0.16-Li solution obtained in step (1) above, the polystyrene/diphenylethylene-polyisoprene lithium compound (PSD.sub.0.16-PI-Li) solution was obtained. 2 mL of PSD.sub.0.16-PI-Li solution was terminated with methanol, to obtain PSD.sub.0.16-PI solution for test characterization. The PSD.sub.0.16-PI solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol, the solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PSD.sub.0.16-PI. The other two samples, PSD.sub.0.37-PI, PSD.sub.0.54-PI were prepared by this method, and the mass of DPE monomers can be changed.

[0084] PSD.sub.0.37-PI: isoprene (14.43 g, 211.9 mmol);

[0085] PSD.sub.0.54-PI: isoprene (11.7 g, 172 mmol).

[0086] They were characterized by .sup.1H NMR and GPC. FIG. 9, FIG. 10 (B), FIG. 11 (B) and FIG. 12 (B) show .sup.1H NMR and GPC of PSD.sub.0.16-PI, PSD.sub.0.37-PI and PSD.sub.0.54-PI with different DPE monomers verify the chemical structure of PSD-PI. From the .sup.1H NMR, the attribution of the proton peak corresponding to the polymer structure can be found, from the GPC (PSD.sub.0.54-PI, M.sub.n=41.5 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.03, PSD.sub.0.37-PI, M.sub.n=47.2 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.03, PSD.sub.0.16-PI, M.sub.n=56.1 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.03), it can be seen that the peak shape of the PS-PI polymer is symmetrical narrow dispersed.

[0087] (3) Synthesis of (PSD-PI).sub.8POSS: Take the molar ratio of styrene to diphenylethylene is 1 to 0.16 (St:DPE=1:0.16) for an example.

[0088] The coupling reaction was carried out at room temperature for 2 h, under nitrogen protection, mixed PSD.sub.0.16-PI-Li solution obtained in step (2) above and OVPOSS (36 mg, 0.057 mmol) and benzene (10 mL) and the reaction was terminated with anhydrous methanol.

[0089] After the reaction, the reaction solution was concentrated by rotary evaporation and precipitated in cold methanol to obtain crude product. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the pure polymers. The crude product is purified by fractional precipitation to obtain a transparent elastic block solid, which is the (PSD.sub.0.16-PI).sub.8POSS.

[0090] The other two samples, (PSD.sub.0.37-PI).sub.8POSS, (PSD.sub.0.54-PI).sub.8POSS were prepared by this method, and the amount of raw material OVPOSS can be changed.

[0091] (PSD.sub.0.37-PI).sub.8POSS: OVPOSS (50 mg, 0.079 mmol);

[0092] (PSD.sub.0.54-PI).sub.8POSS: OVPOSS (40 mg, 0.063 mmol).

[0093] All samples have been characterized by GPC. FIGS. 10 (C) and (D), FIGS. 11 (C) and (D), and FIGS. 12 (C) and (D), respectively show GPC of (PSD-PI).sub.8POSS crude product and pure polymers. the GPCs verified the chemical structure. From the before purification of the crude product there were multiple sets of peak, the peak shape of the after purification of (PSD-PI).sub.8POSS is symmetrical narrow dispersed. (PSD.sub.0.16-PI).sub.8POSS: M.sub.n=322 kg.Math.mol.sup.−1, =1.11; (PSD.sub.0.37-PI).sub.8POSS: M.sub.n=265.7 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.12; (PSD.sub.0.54-PI).sub.8POSS: M.sub.n=232.6 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.10.

[0094] FIG. 13, FIG. 14, FIG. 15 are respectively correspond to the stress-strain curves of (PSD.sub.0.16-PI).sub.8POSS, (PSD.sub.0.37-PI).sub.8POSS and (PSD.sub.0.54-PI).sub.8POSS, which can be seen from the figure their breaking elongation and breaking strength are: (PSD.sub.0.16-PI).sub.8POSS (2060%, 7.2 MPa); (PSD.sub.0.37-PI).sub.8POSS (1880%, 7.7 MPa); (PSD.sub.0.54-PI).sub.8POSS (1610%, 6.4 MPa). It shows that compared with the (PS-PI).sub.8POSS in Example 1, the (PSD-PI).sub.8POSS incorporating DPE monomers have better mechanical properties.

[0095] The method disclosed by the invention has the advantages of rapid and efficient reaction, mild conditions, fewer side reactions, controllable polymer molecular weight and molecular weight distribution, etc. The obtained eight-arm star-shaped thermoplastic elastomer copolymer has a clear structure; The polymer segment obtained by copolymerization of DPE and St is used as the hard segment, which makes the eight-arm star-shaped thermoplastic elastomer copolymer have more excellent stress-strain characteristics; at the same time, diphenylethylene (DPE) and styrene (St) The polymer segment obtained by copolymerization has a higher glass transition temperature than that of polystyrene, which can increase the upper limit temperature of the star-shaped thermoplastic elastomer copolymer, and the molar ratio of the two monomers can be changed. To adjust the glass transition temperature of the hard segment polymer chain; in particular, the present invention does not require catalysts and catalyst ligands in each step.

Example 3 Preparation of Linear Triblock Thermoplastic Elastomer Copolymer (PS-PI-PS)

[0096] (1) Synthesis of PS-Li: Anionic polymerization at room temperature for 12 h, under nitrogen protection, the monomer of (1.30 mL, 11.4 mmol) stored in ampoule was added into the sec-BuLi (0.12 mL, 0.08 mmol) as initiator, anhydrous benzene (100 mL) as solve styrene nt, to obtain the poly(styryl)lithium(PS-Li) solution. 2 mL of PS-Li solution was terminated with methanol, to obtain PS solution for test characterization.

[0097] The PS solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol to obtain pure polymers. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PS. FIG. 16 shows the GPC of the above PS polymer. From the GPC (M.sub.n=18 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.06). It can be seen that the peak shape of the PS-PI polymer is symmetrical narrow dispersed.

[0098] (2) Synthesis of PS-PI-Li: Anionic polymerization at room temperature for 12 h, under nitrogen protection, isoprene (8.17 g, 120.0 mmol) and anhydrous benzene (200 mL) was added into the PS-Li solution obtained in the above step (1). 2 mL of PS-PI-Li solution was terminated with methanol, to obtain PS-PI solution.

[0099] The PS-PI solution in detached ampoule was concentrated by rotary evaporation and precipitated in cold methanol to obtain pure polymers. The solid was collected and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PS-PI. FIG. 16 shows GPC of PS-PI-Li solution above. From the GPC (M.sub.n=238.7 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.03). It can be seen that the peak shape of the PS-PI polymer is symmetrical narrow dispersed.

[0100] (3) Synthesis of PS-PI-PS:

[0101] Anionic polymerization at room temperature for 12 h, under nitrogen protection, mixed isoprene (1.30 ml, 11.4 mmol) and PS-PI-Li solution obtained in step (2) above and the reaction was terminated with anhydrous methanol to obtain PS-PI-PS solution. After the reaction, the reaction solution was concentrated by rotary evaporation and precipitated in cold methanol and dried at 35° C. in a vacuum oven for 24 h to obtain the white solid PS-PI-PS. FIG. 16 shows GPC of PS-PI-PS solution above. From the GPC (M.sub.n=248.3 kg.Math.mol.sup.−1, M.sub.w/M.sub.n=1.06). It can be seen that the peak shape of the PS-PI-PS polymer is symmetrical narrow dispersed.

[0102] Dissolve PS-PI-PS in Example 3 and (PS-PI).sub.8POSS in Example 1 in a beaker with 40 mL of benzene solvent, stirred for 0.5 h to fully dissolve, and cast in a PTFE square tank, covered the tank slowly evaporate the solvent for 3 days, then placed the square tank in a vacuum oven at 35° C. for 12 hours to fully remove the solvent to obtain PS-PI-PS and (PS-PI).sub.8POSS films; FIG. 17 is photo of the actual PS-PI-PS film, which has poor mechanical properties and cannot be made into a dumbbell-shaped sample for mechanical performance testing; FIG. 18 is a photo of the (PS-PI).sub.8POSS film. A dumbbell-shaped sample can be prepared, corresponding to the test shown in FIG. 5. The sample strip used.