Abstract
The use of mol. iodine I2 in controlled radical polymn., called reverse iodine transfer polymn., represents a new, straightforward way to prep. controlled macromol. architectures. Herein, miniemulsion polymn. of styrene in the presence of mol. iodine was successfully performed. The polymn. of styrene was initiated by bis(4-tert-butylcyclohexyl) peroxydicarbonate at T=60° with dodecyl sulfate sodium salt as surfactant and hexadecane as hydrophobe, yielding a stable and uncolored latex. A certain amt. of iodine reacted with water to form hydroiodic acid, leading to an upward deviation of the exptl. mol. wt. from the theor. value. However, when the iodine lost by hydrolysis was regenerated by continuous addn. of hydrogen peroxide in acidic conditions, it led to the expected mol. wt. (e.g., Mn,SEC = 7900 g mol-1, Mw/Mn = 1.46, styrene conversion=78%, Mn,theoretical=7900 g mol-1). Hence, the mol. wt. of the polymer chains could be accurately controlled by changing the concn. of iodine. Last, a chain extension was successfully performed in seeded emulsion polymn., proving the living character of the polymn.