Phase behavior, crystallization, and nanostructures in thermoset blends of epoxy resin and amphiphilic star-shaped block copolymers

Wang, K., Guo, Q. P., Chen, L., Zheng, S. X. and Halley, P. J. (2006) Phase behavior, crystallization, and nanostructures in thermoset blends of epoxy resin and amphiphilic star-shaped block copolymers. Journal Of Polymer Science Part B-Polymer Physics, 44 6: 975-985. doi:10.1002/polb.20747


Author Wang, K.
Guo, Q. P.
Chen, L.
Zheng, S. X.
Halley, P. J.
Title Phase behavior, crystallization, and nanostructures in thermoset blends of epoxy resin and amphiphilic star-shaped block copolymers
Journal name Journal Of Polymer Science Part B-Polymer Physics   Check publisher's open access policy
ISSN 0887-6266
Publication date 2006
Sub-type Article (original research)
DOI 10.1002/polb.20747
Volume 44
Issue 6
Start page 975
End page 985
Total pages 11
Editor Robert M Briber
Place of publication Hoboken, NJ, U.S.A.
Publisher John Wiley & Sons
Collection year 2006
Language eng
Subject C1
321025 Rehabilitation and Therapy - Hearing and Speech
730303 Occupational, speech and physiotherapy
0303 Macromolecular and Materials Chemistry
0912 Materials Engineering
Abstract This article reports thermoset blends of bisphenol A-type epoxy resin (ER) and two amphiphilic four-arm star-shaped diblock copolymers based on hydrophilic poly(ethylene oxide) (PEO) and hydrophobic poly(propylene oxide) (PPO). 4,4'-Methylenedianiline (MDA) was used as a curing agent. The first star-shaped diblock copolymer with 70 wt% ethylene oxide (EO), denoted as (PPO-PEO)(4), consists of four PPO-PEO diblock arms with PPO blocks attached on an ethylenediamine core; the second one with 40 wt% EO, denoted as (PEO-PPO)(4), contains four PEO-PPO diblock arms with PEO blocks attached on an ethylenediamine core. The phase behavior, crystallization, and nanoscale structures were investigated by differential scanning calorimetry, transmission electron microscopy, and small-angle X-ray scattering. It was found that the MDA-cured ER/(PPO-PEO)(4) blends are not macroscopically phase-separated over the entire blend composition range. There exist, however, two microphases in the ER/(PPO-PEO)(4) blends. The PPO blocks form a separated microphase, whereas the ER and the PEO blocks, which are miscible, form another microphase. The ER/(PPO-PEO)(4) blends show composition-dependent nanostructures on the order of 10-30 nm. The 80/20 ER/(PPO-PEO)(4) blend displays spherical PPO micelles uniformly dispersed in a continuous ER-rich matrix. The 60/40 ER/(PPO-PEO)(4) blend displays a combined morphology of worm-like micelles and spherical micelles with characteristic of a bicontinuous microphase structure. Macroscopic phase separation took place in the MDA-cured ER/(PEO-PPO)(4) blends. The MDA-cured ER/(PEO-PPO)(4) blends with (PEO-PPO)(4) content up to 50 wt% exhibit phase-separated structures on the order of 0.5-1 mu m. This can be considered to be due to the different EO content and block sequence of the (PEO-PPO)(4) copolymer. (c) 2006 Wiley Periodicals, Inc.
Keyword Polymer science
Block copolymer
crystallization
Epoxy resin
Phase behavior
Polymer blends
Poly(ethylene oxide) blends
Unsaturated polyester resin
Polymer blends
Poly(epsilon-caprolactone)-epoxy blends
Semicrystalline mMorphology
Triblock copolymers
Diamine blends
Miscibility
Kinetics
Peo
Q-Index Code C1

 
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Created: Wed, 15 Aug 2007, 09:04:57 EST