Structural modifications of cellulose samples after dissolution into various solvent systems.

Area of Science:

• Polymer Science
• Materials Science
• Organic Chemistry

Background:

• Cellulose dissolution is crucial for its processing into various materials.
• Understanding solvent effects on cellulose structure and properties is essential for optimizing applications.
• Different cellulose sources and solvent systems exhibit varying interactions and outcomes.

Purpose of the Study:

• To investigate the structural modifications of cellulose after dissolution in different solvent systems.
• To evaluate the efficiency and impact of four common cellulose solvent systems on cellulose properties.
• To compare the effects of these solvents on cellulose with varying degrees of polymerization (DP) and crystallinity.

Main Methods:

• Optimization of dissolution conditions for 16 cellulose-solvent systems.
• Turbidity measurements to assess dissolution efficiency.
• Regeneration and analysis of cellulose using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffractometry (XRD).
• Viscosimetry to determine changes in the degree of polymerization (DP).

Main Results:

• For low DP cellulose, most solvents dissolved samples without altering DP, except BMIM[Cl], which caused up to 40% DP decrease and 20% degradation temperature reduction.
• High molecular weight cellulose dissolution was only successful with DMSO/TBAF, preserving molar mass and thermal stability.
• SEM and XRD analyses indicated structural modifications post-regeneration, varying with solvent and cellulose characteristics.

Conclusions:

• Solvent choice significantly impacts cellulose integrity, particularly for high molecular weight samples.
• DMSO/TBAF is a suitable solvent for dissolving high molecular weight cellulose without degradation.
• BMIM[Cl] poses risks of depolymerization and thermal degradation for cellulose, especially at lower molecular weights.