Compared to other polymers like PET, PP etc. LDPE has very poor oxygen diffusion barrier properties. Enhancement of barrier properties in the case of PET / PP is very good just by surface modification / thin barrier film deposition but not getting reduction in OTR values more than approx. 10 - 15 times in the case of LDPE.
If anyone here have done similar work on LDPE films please share your experience. It would be very much helpful for my studies.
Hi Ravinder, Thank you very much for your reply.
I understand that diffusion is a bulk phenomena and LDPE is has more free volume but certain surface treatment can enhance the barrier properties of such polymers. If we can stop oxygen ingress from the surface itself we can make it high barrier material. Many research has reported this. But we are facing problem with LDPE specially may be due there is roughness difference with other polymers probably. So wanted to know if anyone else has tried with LDPE and faced the similar problem.
Commercially it is solved by using multilayer films, including EVOH (ethlyene vinyl alcohol) orpolyamide and tie layer resin layers. In pipes EVOH is also used (coextrusion). Otherwise PVDC (polyvinlyidene) chloride and other low oxygen permeability plastics are used. It is also possible to apply SiOx ororther relatd layers to improve barrier properties. Layered nanosilicates also work a to certain degree.
Yes Purvi, the fact is when the integrity of the coating layers is same, i.e. free of connected porosity, cracks, the films applied as same as multilayer mode and same thickness, the permeability properties of poly (ethylene terephthalate), low- and high-density polyethylenes and polypropylene across the coating films rank according to surface roughness and the LDPE got the higher roughness then the higher permeability. I think the work of M.S Hedenqvist etal. is highly support the hypothesis of roughness factor.
Best regards
https://www.researchgate.net/publication/237945439_Barrier_properties_of_SiOx-coated_polymers_Multi-layer_modelling_and_effects_of_mechanical_folding
Article Barrier properties of SiOx-coated polymers: Multi-layer mode...
thank you sir, will go through the full text once I get it. This would be indeed a supporting document for my study.
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