Table 4 Comparison of PVA foils containing SKL-C1 and EKL-C1 lignin nanoparticles.
From: Lignin nanoparticle-enhanced PVA foils for UVB/UVC protection
Property | Pure PVA (Ref) | PVA with SKL-C1 (Spruce) | PVA with EKL-C1 (Eucalyptus) | Significance |
|---|---|---|---|---|
UV Transmittance (UVA/UVB/UVC) | High transmittance (poor UV blocking) | Partial UVA shielding, near-complete UVB/UVC blocking at 15% LNP | Near-complete UVA/UVB/UVC blocking at 15% LNP | EKL-C1 foils provide superior UV shielding, especially in UVA, critical for packaging light-sensitive materials |
Surface Roughness (AFM) | Ra = 0.411 nm, Rq = 0.522 nm | Ra = 0.647 nm, Rq = 1.26 nm at 15% LNP | Ra = 0.452 nm, Rq = 0.791 nm at 15% LNP | EKL-C1 foils have smoother surfaces due to better dispersion, reducing aggregation and enhancing material quality |
Colorimetric Properties (CIELAB) | L* = 53.54, a* = 0, b* = 0 | Increased yellowness (b* = 1.52 at 15% LNP), L* = 53.03 | Increased redness (a* = 0.13), slight yellowness (b* = 0.66 at 15% LNP), L* = 53.40 | Minimal color change with EKL-C1, better aesthetic suitability for packaging; linear correlation (r = 0.99 for b* in EKL-C1) enables manufacturing control |
LNP Dispersion (TEM) | N/A | Uniform spherical nanoparticles, some aggregation | More uniform, minimal aggregation | EKL-C1’s linear structure (S-units) reduces aggregation, improving compatibility with PVA matrix |
Thermal Stability (TGA) | Three-stage degradation (100 °C, ~ 395 °C, ~ 430 °C) | Similar degradation trend, slight Tmax shift | Slightly enhanced Tmax and charring ability due to aromatic units | EKL-C1 improves thermal stability and fire resistance, enhancing durability for practical applications |
FTIR (Hydroxyl Stretching Shift) | 3298 cm⁻¹ | Blue shift to 3314 cm⁻¹ at 15% LNP | Blue shift to 3316 cm⁻¹ at 15% LNP | Strong hydrogen bonding between LNPs and PVA, slightly more pronounced with EKL-C1, indicating better integration |
