Using $NaBH_4$-diglyme and $NaBH_4-CoCl_2$-diglyme systems Methyl methacrylate was polymerized and copolymerized with styrene.
In $NaBH_4-CoCl_2$-diglyme system its critical catalytic concentration was found when the rate of $[CoCl_2]/[NaBH_4]$ is 4-6 on condition that the concentration of MAA is 4.70 mole/ℓ, the rate of $[CoCl_2]/[MMA]$ is 5.0×$10^{-4}$ and the polymerization temperature is 50℃.
The rate of polymerization was given as follows.
When $[CoCl_2] < 5 \times 10^{-4}$ mole/ℓ,
$R_p=k [MMA]^{1.0} [NaBH_4]^{-0.3} [CoCl_2]^{0.3}$
$when [NaBH_4] > 1.2\times10^{-2}$ mole/ℓ
$R_p=k [MMA]^{1.0} [NaBH_4]^{1.7} [CoCl_2]^{0.3}$
${when [NaBH_4] < 1.2\times10^{-2}$mole/ℓ
The overall activation energy was found as 11.25 kcal/mole.
The change of percent conversion and the number average molecular weight was studied in various conditions of time, temperature and concentration.
The comonomer reactivity ratio of MMA ($M_1$) and styrene ($M_2$) was found as $r_1=0.49$, $r_2=0.76$ respectively by Fineman-Ross equation.
The tacticity of PMMA was heterotactic in $NaBH_4$-diglyme system and syndiotactic in $NaBH_4-CoCl_2$-diglyme system.
From above results, the mechanism of polymerization was discussed and concluded that in $NaBH_4$ system the polymerization was proceeded through the coordination bond between monomer and catalyst and in $NaBH_4-CoCl_2$ system that was initiated through radical mechanism.
Methyl methacrylate의 중합개시제로써 $NaBH_4$와 $NaBH_4-CoCl_2$ 를 사용하여 임계농도를 조사하였으며, 중합속도식과 겉보기 총활성화 에너지를 구하였다. 시간, 온도, 농도에 따른 중합변화율과 분자량의 변화를 조사하였으며 MMA와 styrene의 공중합에서 각 단위체의 반응성비를 구하였다. PMMA의 Tacticity를 조사하여 중합반응의 메카니즘을 관찰하였다.
