Prepolymers of poly( ethylene oxide) (Pre-PEO) were synthesized by reacting azoisobutyronitrile ( AIBN) with poly( ethylene glycol) ( PEG), and their structures were characterized by IR and UV. The molecular weight of pre-PEO was related to the feed ratio and reaction time. These prepolymers can be
Poly(ethylene glycol)-block-poly(butyl acrylate). II. Characterization and properties
β Scribed by Meidong Lang; Guo Zhang; Xinfang Chen; Na Feng; Shuhua Li
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 316 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0021-8995
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β¦ Synopsis
Poly(ethylene glycol)-block-poly(butyl acrylate) synthesized by radical polymerization in a one-step procedure were characterized by gel permeation chromatography, infrared, 1 H-NMR spectroscopy, and differential scanning calorimetry (DSC). The crystalline property, emulsifying property, and phase transfer catalytic effect in the Williamson reaction were studied. It was found that the crystallinity of the copolymer increased with an increase in both the content and molecular weight of poly(ethylene oxide) (PEO) sequences. DSC curves showed two distinct crystallization temperature due to the heterogeneous nucleation and homogeneous nucleation crystallization. The casting solvent significantly affected the morphology and crystallinity of the solvent cast films. Both the emulsifying volume and the phase transfer catalytic efficiency in the Williamson reaction increased with the amount and PEO content of the block copolymers used, but decreased with an increase in the molecular weight of PEO sequences.
π SIMILAR VOLUMES
Poly( 1-caprolactone) -poly(ethylene glycol) -poly( 1-caprolactone) triblock copolymers (PECL) covering a wide range of poly(ethylene glycol) (PEG) lengths were synthesized with alkali metal alkoxide derivatives of poly(ethylene glycol). The effects of various factors, such as amount of the initiato