Abstract
Mixtures of safe and renewable solvents can replace hazardous solvents presently being used in the manufacture of engineering plastics. In this work, a methodology is proposed for identifying solvent-pair mixtures for preparing polymer precursors, with poly(amic acid) (PAA) being studied as an example. The methodology uses a chemical safety index, Hansen solubility parameters and Kamlet-Taft solvatochromic parameters of the pure and solvent-pair mixtures to identify hydrogen bond acceptor (HBA)-hydrogen bond donor (HBD) solvent-pair combinations. Ten replacement solvent-pairs for PAA syntheses identified were cyclohexanone-methanol, cyclohexanone-ethanol, cyclopentanone-methanol, cyclopentanone-ethanol, γ-butyrolactone-methanol, γ-butyrolactone-ethanol, γ-butyrolactone-water, γ-valerolactone-methanol, γ-valerolactone-ethanol, and γ-valerolactone-water. Homogeneous PAA solutions could be obtained from HBA-HBD solvent-pair mixtures when their solubility parameters were within 21-29 MPa0.5 and their Kamlet-Taft solvatochromic parameters were π∗ (>0.67) and β (>0.67) for nonaqueous solutions and π∗ (>0.68) and β (>0.59) for aqueous solutions. Replacement solvent-pairs, γ-valerolactone-ethanol, γ-valerolactone-water, and γ-butyrolactone-water gave homogeneous precursor solutions that were comparable with commercial solutions prepared with N-methyl-2-pyrrolidone. The proposed methodology and reported solvatochromic parameters make it is possible to identify other solvent-pair mixtures and new solvent-pairs for preparing polymer precursor solutions used in engineering plastics.
Original language | English |
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Pages (from-to) | 1881-1889 |
Number of pages | 9 |
Journal | ACS Sustainable Chemistry and Engineering |
Volume | 3 |
Issue number | 8 |
DOIs | |
Publication status | Published - 2015 Aug 3 |
Keywords
- Green solvents
- Polyimide
- Polymer
- Precursor solution
- Solvatochromic parameter
ASJC Scopus subject areas
- Chemistry(all)
- Environmental Chemistry
- Chemical Engineering(all)
- Renewable Energy, Sustainability and the Environment