Gels of collagen hydrolysate (H) crosslinked with dialdehyde starch (DAS) are marked by a strong tendency to aging, which
means a certain problem during their processing into biodegradable packaging materials. Applying casting technology and drying
these materials by heating air-dry films and foils for a limited time (1–4 h) at 105 °C may eliminate the aging problem. Solubility
of heat-treated films in an aqueous environment remains preserved, but depending on how long this temperature acts and on
the DAS content in the film, time of film disintegration prolongs from 1–1.5 h to 1300 h (≈54 days). It is probably caused
by the functional groups initially blocked by sorbed water, which get released to produce hydrogen inter-chain crosslinks.
The decrease in glass transition temperature (Tg) of such films varies with content of water sorbed in films in an interval of 90.2–189 °C.
Authors:Paula Nunes, Marília Bezerra, L. Costa, Juliana Cardoso, R. Albuquerque, M. Rodrigues, Gabriela Barin, Francilene da Silva, and A. Araújo
The purpose of this study was to evaluate the physical–chemical properties of collagen (CL) and usnic acid/collagen-based
(UAC) films, using differential thermal analysis (DTA), thermogravimetry (TG/DTG), infrared spectroscopy (FTIR), and scanning
electron microscopy (SEM). Both films were prepared by casting process using polyethylene glycol 1500 (PEG 1500) as plasticizer.
In the spectrum of UAC, similar bands of the usnic acid are observed, indicating that the polymerization (film formation)
did not affect the stability of the drug. Distinctly, DTA curve of UAC did not show an endothermic peak at 201 °C, indicative
that the drug was incorporated into the polymeric system. These results were corroborated by the scanning electron microscopy
(SEM). The TG/DTG curves of UAC presented a different thermal decomposition profile compared to the individual compounds and
CL. These findings suggest the occurrence of molecular dispersion or solubilization of the drug in the collagen film.
Authors:P. Mokrejs, F. Langmaier, D. Janacova, M. Mladek, K. Kolomaznik, and V. Vasek
The study deals with the effect of chemical and physical modifications on thermal properties and solubility properties of
films based on amaranth flour starch–protein hydrolysate. Biodegradable and edible films were prepared by casting a 25% (w/w)
solution of hydrolysate containing 20% glycerol and various additions of dialdehyde starch (0, 1 and 5%). After thermal exposure
of films at 65 and 95 °C (for 6 and 48 h), thermal properties of films were studied employing differential scanning calorimetry
and thermogravimetric analysis. Film solubility tests were performed in an aqueous environment at 25 °C. Chemical and physical
modifications of films markedly affect their thermal properties and solubility.
Commercially available starch-based biodegradable films were tested for the assessment of biodegradability in accordance with standardised and non-standardised methods providing possibilities to directly monitor microbial activity. A method originating from the measurement process of the biological activity of soils was modified and applied according to the recommendation of international standards to test polymers under controlled composting conditions. Based on the results of our experiments, it is not possible to clearly assess the biodegradability of films based exclusively on the measurements of the produced CO2
Authors:Mai Sao Dam, Lien Le Phuong Nguyen, Tamás Zsom, Géza Hitka, Ildikó Csilla Zeke, and László Friedrich
flour to make biodegradablefilm. The film packaging of 0.15–0.23 mm thickness was applied using immersion, spraying, and film covering technique on sliced and shredded carrot. Biodegradablefilm was able to delay weight loss and whitening of the samples
Authors:Géza Regdon Jr., Diána Hegyesi, and Klára Pintye-Hódi
-coated preparations, e.g. on the study of Eudragit containing polymethacrylate films [ 8 – 11 ], chitosan films [ 12 ], gelatin and poly(vinyl alcohol) containing films [ 13 ], biodegradablefilms [ 14 – 16 ] or cellulose-based films [ 9 , 10 , 17 – 19
Authors:S. C. Mojumdar, C. Moresoli, L. C. Simon, and R. L. Legge
“homogeneity”, volatile mass loss, plasticizer migration, and mechanical and permeation properties during aging of flexible WG films.
Possible applications of protein films
The goal of protein and other biodegradablefilms are simple