4금암모늄염 촉매를 이용하여 Poly(GMA-co-MMA)와 이산화탄소의 부가반응과 Poly methyl methacrylate(PMMA)의 상용성 고찰

박 성영·박 희영·박 대원·하 창식*

부산대학교 화학공학과

*부산대학교 고분자 공학과

Application of Quaternary Ammonium Salt as Catalyst in the Reaction of Poly(GMA-co-MMA) with CO2 and the Its Miscibility Behavior

S. Y. Park·H. Y. Park·D. W. Park·C. S. Ha*

Dept. of Chem. Eng., Pusan National University

*Dept. of Polymer Science and Eng., Pusan National University

1. Introduction

Polymers bearing 5-membered cyclic carbonate groups have been of interest as new polymeric materials for the optical and electric applications, and these polymers can be applied as polymeric polar solvents for inorganic electrolytics and hot dyes in nonlinear optical films. Carbon dioxide plays an important role in the global warm-up. An attractive strategy to deal with this situation is to convert CO2 into valuable substance. Consequently new technologies are being investigated to convert CO2 catalytically1). The synthesis of 5-membered cyclic carbonates under mild conditions in the presence of metal halides or a Phase Transfer Catalyst(PTC) was also reported2).

In general, a vinyl monomer bearing a cyclic carbonate group such as (2-oxo-1,3-dioxalane-4-yl) methyl methacrylate(DOMA) is extremely sensitive to the polymerization and difficult to handle. Thus, the quantitative polymer reaction of epoxide polymers with carbon dioxide can be one of the most effective methods to obtain cyclic carbonate polymers. The polymers containing pendant 5-membered cyclic carbonate groups can also be considered as starting materials for the synthesis of functional polymers. Blends of polymers bearing a cyclic carbonate group with some commercial polymers have also been developed in this laboratory for more versatile application of the polymers.

In this work, therefore, blends of the DOMA containing copolymer with poly(methyl methacrylate)(PMMA) were prepared. Miscibility of the blends was investigated by using differential scanning calorimetry(DSC), Fourier transform infrared(FT-IR) spectroscopy4) as well as optical clarity test5).

2. Experiment

1) Synthesis of Poly(DOMA-co-MMA) by Direct Incorporation of Carbon Dioxide to Poly(GMA-co-EA)

The synthesis of a copolymer of DOMA and MMA(poly(DOMA-co-MMA)) from poly(GMA-co-MMA) and CO2 was carried out using quaternary ammonium salts as shown in Scheme 1. 0.5mmol of catalyst was introduced to a 150ml four-neck semi-batch reactor containing the mixture of 5g of poly(GMA-co-MMA) and 100ml of DMSO, and the solution was heated up to a desired temperature(100℃). Reaction was started by stirring the solution under a slow stream of CO2(10ml/min), and continued for 8h. The copolymer composition of poly(GMA-co-MMA) were first determined from the ratio of area in the copolymer using the 1H-NMR.

Scheme 1. Poly(DOMA-co-EA) synthesis via incorporation of carbon dioxide into  poly(GMA-co-EA).

2) Preparation of Blends

To prepare blend films, weighed amounts of poly(DOMA-co-MMA)(19.4wt.% MMA) and PMMA with a given composition were cast from 10wt% solution in DMF. The films were dried under vacuum for 3 days at room temperature.

3.Reslt and Discussion

1) Synthesis of Poly(DOMA-co-MMA) from Poly(GMA-co-MMA) and Carbon Dioxide

- Structure Identification of Poly(DOMA-co-MMA)

The reaction of poly(GMA-co-MMA) with carbon dioxide was carried at 100oC for 8h in DMSO using 0.5mmol of TOAC as a catalyst under atmospheric pressure. It is known that the rate-determining step of the epoxide-CO2 reaction involves nucleophilic attack of an anion to oxirane ring. Highly nucleophilic Cl- anion in an aprotic solvent is also known to enhance the attack of the anion to epoxide ring of poly(GMA-co-MMA)3). Thus, poly(DOMA-co-MMA) can be synthesized easily by the polymer reaction of poly(GMA-co-MMA) and carbon dioxide using active catalysts. The conversion of epoxide ring in poly(GMA-co-MMA) to the five-membered cyclic carbonate group in poly (DOMA-co-MMA) could be identified by FT-IR and 1H-NMR spectrum as shown in Figures 1 and 2. The IR-spectrum of the poly(DOMA-co-MMA) exhibited an absorption peak at 1800cm-1(C=O of cyclic carbonate), whereas the peak was not observed on the IR spectrum for poly(GMA-co-MMA). 1H-NMR analysis also confirmed the formation of poly(DOMA-co-MMA). The characteristic peaks are as follows : 3.4~3.6(-OCH2-, in side chain), 3.7~3.8(-HCO-, in cyclic carbonate), 4.2~4.3ppm(-OCH2-, in cyclic carbonate).

2) Blends of Poly(DOMA-co-MMA) with PMMA

For the purpose of extending the application of the CO2 fixed polymer, poly(DOMA-co-MMA) was blended with a poly(methyl methacrylate). The degree of miscibility of the poly(DOMA-co-MMA)/PMMA blend was first investigated by an optical clarity test. Table 1 shows all the poly(DOMA-co-MMA) with PMMA blends formed clear films, which seems to mean that the blend are miscible over the whole concentration ranges.

For the detailed study of the miscibility of the polymer blends, the glass transition temperature(Tg) of the blends are measured. Each blend of different poly(DOMA-co-MMA) compositions with PMMA exhibited single glass transition temperature between the two Tgs of the each polymer(Table 1). This result indicates that these blends are miscible over the entire composition ranges.

4.Reference

1. Moon, J. Y., Yang, J. G., Jung, S. M., Park, D. W. and Lee, J. K.,  React..Kinet. & Cat. Lett, 61(2), 315 (1997).

2. Nishikubo, T., Kameyama, A. and Sasano, M., J. Polym Science: Part A, 32, 301-308(1994).

3. Park, D. W., Moon, J. Y., Yang, J. G., Jung, S. M., Lee, J. K., Chang, C.S.,     Studies in Sur. sci. and Cata., 114, 403(1998).

4. Zou Yousi, Lin Donghai, Dai Lizhong, Zhang Jinghui and Pan Ronghua,        Polymer, 38(15), 3947(1997).

5. Woo, N. K., Charles, M. B., J. of Polymer science: Part B, 28,                  1409-14295(1998).

Figure 1. FT-IR spectra of poly(GMA-co-MMA) and poly(DOMA-co-MMA).

Figure 2. 1H-NMR spectrum of poly(DOMA-co-MMA).

Table 1. Optical Clarity and Glass Transition Temperatures of

Poly(DOMA-co-MMA) with PMMA Blends

Poly(DOMA-co-MMA)/PMMA
Composition of Poly(DOMA-co-MMA)	Optical clarity	Tg(oC)	Cp(J/goC)
0.0 0.2 0.4 0.6 0.8 1.0	- Clear Clear Clear Clear -	114.0 110.2 103.5 102.8 95.4 93.8	0.215 0.317 0.366 0.343 0.195 0.291