Thin Films Testing

Ta, Christine, and Jonathan Bones. Journal of Chromatography A 1492 (2017): 49-54.

Single-use plastic films are widely utilized in bioprocessing; however, their potential to release extractables poses a concern for product safety and cell culture integrity. This study employed an ultra-performance liquid chromatography with ultraviolet detection (UPLC-UV) method to detect and quantify bDtBPP and oxidized Irgafos 168 in three bioprocessing bag films. Using a CSH fluoro phenyl column with UV detection at 220 nm, the method demonstrated high sensitivity (limits of detection: 16–60 μg L^-1), repeatability (%RSD ≤ 1.8), and linearity (R² ≥ 0.9992).

The extractables study revealed the presence of bDtBPP (50–190 μg L^-1) and oxidized Irgafos (30–210 μg L^-1) in all three films, whereas the leachables study detected no significant levels. Chromatographic analysis also indicated additional unidentified compounds, necessitating further mass spectrometric analysis. Small-scale extractions provided a more accurate assessment of concentration per film area, demonstrating film C to be the least suitable for bioprocessing due to its higher bDtBPP content.

These findings highlight the critical role of extractables testing in selecting biocompatible films for single-use bioprocessing. The validated UPLC-UV method offers a reliable approach for pre-screening plastic films, ensuring minimal contamination risks and safeguarding cell culture integrity.

Farhan, Abdulaal, and Norziah Mohd Hani. Food Hydrocolloids 64 (2017): 48-58.

Edible packaging films offer a sustainable alternative to conventional plastic films, particularly in food packaging applications. This study evaluated the mechanical and barrier properties of semi-refined kappa-carrageenan (SRC) films plasticized with glycerol or sorbitol at varying concentrations (20–30%, w/w). The incorporation of plasticizers significantly enhanced the tensile strength and elongation at break of SRC films, demonstrating improved flexibility and durability compared to unplasticized films.

Water sorption kinetics revealed that plasticized films absorbed water rapidly within the first 20–40 minutes and reached equilibrium, with glycerol-containing films exhibiting higher water uptake due to its greater hydrophilicity. Despite high moisture absorption, all plasticized films remained structurally intact, suggesting strong hydrogen bonding within the SRC matrix. Increased plasticizer concentrations also improved film transparency, seal strength, and reduced oil permeability, enhancing their suitability for food packaging applications. Notably, sorbitol-plasticized films exhibited superior oxygen barrier properties and smoother morphology, as confirmed by scanning electron and atomic force microscopy.

These findings underscore the potential of SRC-based edible films as biodegradable packaging materials with enhanced mechanical and barrier properties. Their stability in moist conditions highlights their applicability as absorbent pads for packaged meat, poultry, and seafood, as well as protective films for fresh-cut fruits and vegetables. The results emphasize the importance of optimizing plasticizer concentrations to tailor film properties for specific food packaging needs.

Liu, Sitong, et al. "Quantitative detection of plasticizer migration in starch/polyvinyl alcohol film with UV-Vis and GC-MS/MS." Polymer 312 (2024): 127596.

The migration of plasticizers in starch/polyvinyl alcohol (PVA) films is a critical factor influencing their stability and safety in packaging applications. This study investigates the migration behavior of urea and formamide plasticizers under UV irradiation, employing GC-MS/MS and UV-Vis spectroscopy for precise quantification.

Results revealed that formamide migration in starch/PVA films increased gradually, reaching equilibrium by day 6. Notably, An-SPF-UF films exhibited a lower formamide migration ratio (4.5%) compared to An-SPF-F (8.3%), attributed to a more compact hydrogen-bonded network restricting molecular movement. Similarly, the urea migration ratio differed significantly between An-SPF-U and An-SPF-UF. An-SPF-U displayed an accelerated migration after two days of UV aging, reaching a peak of 6.2% after 30 hours of immersion, whereas An-SPF-UF demonstrated delayed migration, plateauing at 3.2%. The enhanced stability of An-SPF-UF was attributed to the synergistic interaction between urea and formamide, which facilitated UV-induced cross-linking and the formation of a dense network structure.

These findings highlight the importance of evaluating plasticizer migration in biodegradable films to optimize their durability and functional properties in food packaging. The study underscores that modifying starch/PVA films with synergistic plasticizers can improve structural integrity and reduce migration, enhancing their applicability as sustainable packaging materials.