聚醋酸乙烯酯是一種常用於黏著劑的高分子聚合物，而它也是聚乙烯醇的前驅物，只要利用簡單的水解反應，即可將聚醋酸乙烯酯轉換成聚乙烯醇，而聚乙烯醇是一種水溶性的生物可分解高分子材料，常應用於各種生醫材料的開發。但由於醋酸乙烯酯自由基非常不穩定且具有高反應性，容易發生不可逆的鏈轉移與終止反應，導致大量終止鏈產生，限制了它在活性自由基聚合上的發展。
我們利用紫質鈷金屬錯合物在不同溶劑環境下控制醋酸乙烯酯之活性自由基聚合，並發現在無溶劑環境下時，聚醋酸乙烯酯的單體轉換率可高達69%，分子量與單體轉換率呈線性上升且與理論值相符，分子量分布指數低 (Mw/Mn = 1.12 ~ 1.34)。但在不同溶劑環境下時，因為醋酸乙烯酯自由基與溶劑發生鏈轉移反應，所以聚醋酸乙烯酯的分子量會明顯的偏離理論值。當在非配位溶劑環境下進行聚合反應時，我們發現不同的聚合速率常數 (kp) 會改變聚合速率，但在配位溶劑環境時，四氫呋喃會擋住紫質鈷金屬錯合物的反應位向進而影響聚合反應的表現。再來我們在無溶劑環境下，試著改變AIBN的使用量及醋酸乙烯酯對紫質鈷金屬錯合物的比例來觀察聚合反應的變化。當AIBN使用量增加時，會使沉潛期縮短而聚合速率提高，但聚醋酸乙烯酯的分子量有些微的偏差。而改變醋酸乙烯酯對紫質鈷金屬錯合物的比例並不會影響聚合反應的控制效益。接著使用吡啶當作添加劑時，我們發現吡啶的配位會改變活性與休眠物種間的平衡並傾向於活性物種。當25當量的吡啶加入聚合反應時，活性與休眠物種間的平衡常數 (Keq) 會由10-12 變成5.22 × 10-8，代表鈷金屬錯合物引導之自由基聚合的反應機制由等能量鏈轉移變成可逆終止反應。
最後我們利用紫質鈷金屬錯合物在不同溶劑環境下進行丙烯酸甲酯之活性自由基聚合。在非配位溶劑環境時，聚合反應不受影響，而在配位溶劑環境時，如：四氫呋喃、苯甲醚及乙腈，沉潛期明顯的縮短但聚合速率不變，可能是推電子配基會與紫質鈷金屬錯合物配位而擋住反應位向。當使用四氫呋喃當作添加劑時，會些微的縮短沉潛期，但聚合速率與控制效益並沒有明顯的改變。

Cobalt porphyrins mediated vinyl acetate radical polymerization has been performed in different solvent environments and was found that a high monomer conversion (69%) with linear increased molecular weight versus conversion, narrow molecular weight distribution (Mw/Mn = 1.12 ~ 1.34), and little molecular weight deviation could be approached in bulk condition. However, different levels of molecular weight deviation occurred when polymerization was performed in solution, indicating that the control of vinyl acetate radical polymerization was affected by chain transfer to solvent. Besides, non-coordinating solvents caused a difference in polymerization rate mainly due to the different propagation rate constant (kp), but the coordinating solvents such as THF blocked the reaction site of cobalt porphyrins and interfered the whole polymerization behavior. The effect of radical concentration and the ratio of [VAc]0 / [CoII]0 have been also discussed. The higher radical concentration shortened the induction period, increased the polymerization rate and caused a slight deviation of molecular weight. But the control efficiency of cobalt porphyrins to vinyl acetate polymerization was not significantly affected by the ratio of [VAc]0 / [CoII]0. The coordinating effect of pyridine was demonstrated by the shift of equilibrium from dormant organo-cobalt(III) species to active cobalt(II) species. The equilibrium constant (Keq) was changed from < 10-12 to 5.2 × 10-8 when 25 equivalent of pyridine was added into the polymerization so that the major control process was switched from degenerate transfer to reversible termination.
Polymerization of methyl acrylate mediated by cobalt porphyrins has been conducted in different solvents. The polymerization behaviors were similar in non-coordinating solvents. However, the induction period was shortened with coordinating solvents such as acetonitrile, anisole and THF which blocked the reaction site of cobalt porphyrins. When THF was used as an additive, the induction period was slightly decreased, but it showed no effect to the polymerization rate and the controlled efficiency.

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