title: Effect of PEO molecular weight on the miscibility and dynamics in epoxy/PEO blends.
abstract: In this work, the effect of poly(ethylene oxide) (PEO) molecular weight in blends of epoxy (ER) and PEO on the miscibility, inter-chain weak interactions and local dynamics were systematically investigated by multi-frequency temperature modulation DSC and solid-state NMR techniques. We found that the molecular weight (M(w)) of PEO was a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interactions between PEO and ER. A critical PEO molecular weight (M(crit)) around 4.5k was found. PEO was well miscible with ER when the molecular weight was below M(crit), where the chain motion of PEO was restricted due to strong inter-chain hydrogen bonding interactions. However, for the blends with high molecular weight PEO (M(w) > M(crit)), the miscibility between PEO and ER was poor, and most of PEO chains were considerably mobile. Finally, polarization inversion spin exchange at magic angle (PISEMA) solid-state NMR experiment further revealed the different mobility of the PEO in ER/PEO blends with different molecular weight of PEO at molecular level. Based on the DSC and NMR results, a tentative model was proposed to illustrate the miscibility in ER/PEO blends.
authors.affiliation: Patent Examination Cooperation Center of the Patent Office, SIPO, Beijing, P. R. China.
authors.forename: Shoudong
authors.initials: S
authors.lastname: Lu
authors.affiliation: Key Laboratory of Functional Polymer Materials, Ministry of Education; College of Chemistry and School of Physics, Nankai University, 300071, Tianjin, P. R. China.
authors.forename: Rongchun
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Key Laboratory of High Performance Polymer Materials and Technology, Ministry of Education, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, 210093, Nanjing, P. R. China. wangxiaoliang@nju.edu.cn.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Functional Polymer Materials, Ministry of Education; College of Chemistry and School of Physics, Nankai University, 300071, Tianjin, P. R. China. spclbh@nankai.edu.cn.
authors.forename: Pingchuan
authors.initials: P
authors.lastname: Sun
authors.affiliation: Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Lv
authors.affiliation: Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China.
authors.forename: Qingjie
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Research Institute of Petroleum Exploration & Development, PetroChina, 100083, Beijing, P. R. China.
authors.forename: Ninghong
authors.initials: N
authors.lastname: Jia
keywords: Soft Matter: Polymers and Polyelectrolytes