Synthesis and characterization of stereotriblock polybutadiene containing crystallizable high trans-1,4-polybutadiene block by barium salt of di(ethylene glycol) ethylether/triisobutylaluminium/dilithium
✍ Scribed by Xuetao Zhang; Yang Li; Chunqing Zhang; Yanming Hu; Shunxi Song; Huanhuan Guo; Yurong Wang
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 284 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
A series of high trans-1,4-low-cis-1,4-high trans-1,4-stereotriblock polybutadienes (HTPB-b-LCPB-b-HTPBs) were synthesized through a sequential anionic polymerization of butadiene (Bd) initiated by barium salt of di(ethylene glycol) ethylether/triisobutylaluminium/dilithium (BaDEGEE/TIBA/DLi). The polymers consisted of elastic low-cis-1,4-polybutadiene (LCPB) chemically bonded with crystallizable high trans-1,4-polybutadiene (HTPB). The block ratios (HTPB:LCPB:HTPB) were designed at 25:50:25 (molar ratio) and finally determined by SEC. The microstructures and sequences of the specimens were investigated by FTIR and NMR. The resultant HTPB-b-LCPB-b-HTPBs consisted of LCPB block with 52.5% trans-1,4 content and HTPB block with 55.9-85.8% trans-1,4 content. According to differential scanning calorimetry (DSC), HTPB-b-LCPB-b-HTPB showed a significant cold crystallization which was discussed in terms of entanglement concept. The cold crystallization temperature (T cc ) decreased whereas the melting temperature (T m ) increased with the increasing trans-1,4 content of HTPB block.