dear colleagues,i'm looking for papers or any data relative to standard values of water vapor permeability required for packaging films applications. Any help is welcome :)
Hi Dorsaf Cheikh
I recommend for you this article :
"Development of Antimicrobial Packaging Film Made from Poly(Lactic Acid) Incorporating Titanium Dioxide and Silver Nanoparticles
Molecules. 2017;22(7):1170 DOI 10.3390/molecules22071170"
Abstract
Polylactide (PLA)/nano-TiO2 and PLA/nano-TiO2/nano-Ag blends films were prepared by a solvent volatilization method. Compared to pure PLA film, the nano-blend films have low water vapor permeability (WVP) and a poor transparency. With the increase of the NPs in the PLA, the tensile strength (TS) and elastic modulus (EM) decreased, while the elongation at break (ε) increased. SEM analysis indicated a rougher cross-section of the nano-blend films. According to the FTIR analysis, no new chemical bonds were formed in the nano-blend films. By using DSC to examine the crystallization and melting behavior, the result shows that the NPs have no effect on the glass transition (Tg) and melting temperature (Tm), but they caused an increase on the cold crystallization (Tc) and crystallinity (Xc). TGA results show that the addition of nanoparticles significantly improved the thermal stability. The PLA nano-blend films show a good antimicrobial activity against. E. coli and Listeria monocytogenes. Most important, we carried out migration tests, and verified that the release of NPs from the nano-blend films was within the standard limits.
Regards,
Akram
Dear Dorsaf
It all depends on the product you need to pack. For products with low water activity, the ideal is to have a WVTR close to zero. That is why the use of high barrier materials such as aluminum, PVDC, or PHA laminates. On the contrary, for fresh vegetables with high transpiration-water evaporation rates, materials with a low barrier to water vapor are required such as EVOH, nylon, or PLA (WVTR = 0.5 - 8 g m-2 d-1).
Dear all, data are possible to know if the name of the packaging film is known. Worth to know that there existe standard norms for measuring WVP such as ASTM and ISO. Thé attached documents are interesting to check. My Regards
This is a characteristic to be calculated. You should know the area of permeation, the moisture content of the contents (when packed and how much would be acceptable in the consumption) , time to be stored or transported and an estimative of the humidity during storage and transportation. The calculation can also include water absorbers (like sílica gel or vermiculite), if they are present (What is your intention: to prevent the contents drying or to mantain the contents dryed?).The thickness of the packaging material or the layers combination should be adjusted to balance the water flow to the water permeation calculated as above.
Kindly check https://link.springer.com/article/10.1007/s12393-019-09205-z
Also check https://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612011000300029
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