Styrene과 Methylmethacylate, Methyl Acrylate, 그리고

2-Hydroxypropylacrylate의 공중합 특성

김남석, 설수덕*, 박근호, 정영언**

창원대학교 공업화학과

동아대학교 화학공학과*

부산정보대학 환경위생계열*

Copolymerization of Styrene with  Methylmethacylate, Methyl Acrylate and 2-Hydroxypropylacrylate

Nam Seok Kim, Soo Duk Seul*, Keun Ho Park, Young Eon Cheong***

Department of Chemical Technology, Chang-Won National University

* Department of Chemical Engineering, Dong-A University

** Group Department of Environment & Chemistry, Pusan college of Information Technology

1.Introduction

Copolymerization in a batch reactor has been studied for several decades since it has given lots of useful information about the kinetics or reactivity.  Great care must be taken carrying out investigations of the kinetics and mechanism of solution polymerization. The kinetics are dependent on experimental conditions such as the concentrations of feed monomer, solvent and initiator, the reaction temperature, the reaction time and so on. The basic research on the solution copolymerization of styrene(St.) and Acrylates is of great interest from both a theoretical and a practical standpoint, since the solution polymerization of acrylate monomers is important in the production of low molecular resins. In general, the acrylates are added to impart film-forming characteristics to copolymer. These polymers and copolymers are used as  paints, adhesive and coatings and so on.  In this work, we synthesized copolymers of St. with Acryl;ates Methlmethacrylate, Methyl Acrylate and 2-Hydroxypropylacrylate  with BPO in toluene at 80℃ in a batch reactor and we discuss the   kinetics of copolymerization such as reactivity ratios.

2.Experimental

Batch solution copolymerization was carried out in a 1000 ml, four-necked, round-bottomed flask. The flask was fitted with a condenser, stirrer, thermometer and nitrogen inlet tube, and placed in a constant temperature bath. The experimental procedure was to fill the reactor initially with the desired ratio of the comonomers in the solvent. While the mixture in the reactor was being heated up to the desired temperature, N2 gas was introduced continuously to prohibit the reacted materials from being oxidized during the copolymerization reaction. The initiator was added to the mixture in the reactor when the desired reaction temperature was maintained. The polymerization was continued for 12h with good agitation. The sampling was done at intervals of 60 min. The sample was precipitated by the addition of a large excess of cold methanol. The resulting copolymer was filtered by glass filter(1G3) and dried to a constant weight under high vacuum at room temperature for several days. The copolymer composition was determined by elemental analyzer (Carlo Erba Instrument,EA-1108). The prepared copolymers(St./MMA, St./MA and ST./2-HPA) were identified by Fourier Transform-Infrared Spectroscopy(Nicolet 710). The number- and weight-average molecular weights, Mn and Mw, were estimated by gel permeation chromatography (Waters 150C) with the column system calibrated with polystyrene standards. HPLC grade tetrahydrofuran was used as the carrier solvent. The experimental conditions are summarized in Table 1.

Table 1. Radical copolymerization conditions used  in batch reactor.

Copolymerization conditions
Polymerization Temperature	70 ∼ 90(℃)
Solvent	Toluene
Solvent/Comonomer ratio	4/1 (V/V)
Initiator	Benzoyl peroxide
Initiator concentration	5∼15 (mmol/l)
Reaction time	12 Hrs

3. Results and Discussion

Copolymerization experiments at various initial comonomer feed compositions were carried out in order to estimate the reactivity ratios.

The reactivity ratios were calculated from the the Kelen - T□d□s method, i.e. which is  ;

□ = (r1+r2/□)□- r2/□　                         (1)

where  □=G/(□+F), □=F/(□+F), F=X2/Y,

G=X(Y-1)/Y,  □=(FminxFmax)1/2

X=M1/M2,       Y=m1/m2

By plotting □ values calculated from the experimental data as a function of □, a straight line is obtained, which on extrapolation to □=0 and □=1 gives -r2/□ and r1, respectively, as intercepts. The Kelen - T□d□s  plot in Fig. 1 gives  the reactivity ratios, r1 and r2, in the copolymerization of St. with MMA, MA and 2-HPA. The result means that MMA, MA and 2-HPA have a lower tendency to homopolymerize than St.

(a)

; r1(St.)=0.60, r2(MMA)=0.59

(c)

; r1(St)=0.376,r2(2-HPA)=0.408

Fig. 1. Kelen-T□d□s plot of copolymers

(b)

; r1(St.)=0.87, r2(MA)=0.16

4. Conclusion

The monomer reactivity ratios, r1 and r2 were determined by the Kelen-T□d□s method ; r1(St.)= 0.60, r2(MMA)=0.59 ; r1(St.)= 0.87, r2(MA)=0.16 ; r1(St.)= 0.38, r2(2-HPA)=0.41.

5. Reference

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5. T. Kelen and F. Tudos, J. Macromol. Sci., Chem., A-9, 1(1975).

6. M. Finneman and S. D. Ross, J. Polym. Sci., 66, 1594(1944).