An Efficient Synthetic Route to Well-Defined Theta-Shaped Copolymers

作者：Shi Gang Yin; Pan Cai Yuan^*

来源：Journal of Polymer Science Part A: Polymer Chemistry , 2009, 47(10): 2620-2630.

DOI：10.1002/pola.23347

• atom transfer radical polymerization (ATRP)
• block copolymers
• " click" chemistry
• ring-opening polymerization
• theta-shaped copolymers

A series of well-defined theta-shaped copolymers composed of polystyrene (PS) and poly(epsilon-caprolactone) (PCL) with controlled molecular weight and narrow molecular weight distribution have been successfully synthesized without any purification procedure by the combination of atom transfer radical polymerization (ATRP), ring-opening polymerization (ROP), and the "click" chemistry. The synthetic process involves two steps: (1) synthesis of AB(2) miktoarm star copolymers, which contain one PCL chain terminated with two acetylene groups and two PS chains with two azido groups at their one end, (alpha, alpha'-diacetylene-PCL) (omega-azido-PS)(2), by ROP, ATRP, and the terminal group transformation; (2) intramolecular cyclization of AB(2) miktoarm star copolymers to produce well-defined pure theta-shaped copolymers using "click" chemistry under high dilution. The (1)H NMR, FTIR, and gel permeation chromatography techniques were applied to characterize the chemical structures of the resultant intermediates and the target polymers. Their thermal behavior was investigated by DSC. The mobility decrease of PCL chain across PS ring in the theta-shaped copolymers restricts the crystallization ability of PCL segment.

• 出版日期2009-5-15
• 单位中国科学技术大学