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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 19, Number 1
JKCSEZ 19(1)
February 20, 1975 

 
Title
Polymerization of Vinyl Monomers Initiated by Cobalt (Ⅱ) Chloride

염화코발트(Ⅱ)에 의한 비닐단위체의 중합
Author
Dong-ho Lee, Tae-oan Ahn

이동호, 안태완
Keywords
Abstract
CoCl2-THF-MMA계에 대한 중합반응을 조사한 결과 다음과 같은 사실을 알았다. 즉 중합시간에 따른 중합변화율이 6~7% 미만의 초기에는 직선적인 관계가 있으나 차차 중합속도가 감소했다가 그 후에는 라디칼중합의 경우와 같이 자동가속화현상을 볼 수 있었다. 개시물인 염화 코발트(II)의 농도가 증가하면 중합속도가 증가했다가 약 3.4×10-4mole/l 이상이 되면 반대로 중합속도는 감소하였다. 그리고 단위체인 MMA의 농도에 따라 중합속도는 1.38의 반응차수를 가지고 증가하였다. 라디칼중합에 대한 억제물인 DPPH를 첨가하면 억제기간이 생기고 이 억제기간은 DPPH의 농도에 따라 증가하였다. 이 중합계에 대한 겉보기 총 활성화 에너지는 13.2kcal/moe임을 알았다. MMA(M1)과 styrene(M2)의 공중합체에 대한 단위체 반응성비는 r1=2.35, r2=0.78이었다. 그리고 이러한 실험결과에서 이 계에 의한 중합개시 매카니즘을 논의하여 디라디칼에 의한 중합이 우세하게 일어난다고 생각되었다.

The polymerization of methyl methacrylate initiated by cobalt(Ⅱ) chloride in tetrahydrofuran has been studied. The conversion was increased liearly with polymerization time at initial stage of 6∼7% conversion and then the rate of polymerization was slightly reduced, and after that the autoacceleration was observed. The rate of polymerization was increased with the concentration of cobalt(Ⅱ) chloride, but at the concentration of cobalt(Ⅱ) chloride higher than 3.4×10-4 mole/l the rate of polymerization was decreased. The rate of polymerization was dependent on the 1.38 power of the concentration of methyl methacrylate. The effect of the radical inhibitor DPPH was observed and the inhibition time was increased with the concentration of DPPH. The apparent overall activation energy was calculated to be 13.2 kcal/mole. In the copolymerization of methyl methacrylate (M1) and styrene (M2), the monomer reactivity ratio was found to be r1 = 2.35, r2 = 0.78. From the above results. the initiation mechanism of polymerization was discussed and it was considered that the polymerization proceeds mainly via diradical mechaism.

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