Barrier Materials
Numerous technologies have been developed or are being developed to enhance the barrier of packaging to small gas molecules. For example, external or internal coatings for enhancing the gas barrier of containers have been developed. The coating layer is normally a very high barrier layer, either inorganic or organic, and slows down the diffusion of gases. Implementation of this technology, however, requires coating equipment not normally utilized in the manufacture of packaged beverages and therefore requires substantial capital investment, increased energy usage, and increased floor space. In many beverage packaging plants that are already crowded, the additional space is not an option.
Multi-layered containers have also been developed with a high barrier layer sandwiched between two or more layers. Implementation of this technology also requires substantial capital investment and delamination of the container layers impacts appearance, barrier, and mechanical performance of the containers.
Recent Journal Articles
Oxygen Barrier Properties of New Thermoplastic Natural Rubber Nanocomposites
(1564-1569) Polymer - Plastics Technology and Engineering 50 #15 (2011)
Abstract
Azinia et al , Malaysia and Japan, prepared nanocomposites of linear low-density polyethylene (LLDPE)/natural rubber (NR)/liquid natural rubber (LNR) blend denoted as TPNR with montmorillonite-based organoclay (OMMT) by melt blending. The melt blending of LLDPE/NR/LNR with a composition of 70:20:10 formed blends. For better dispersion of nanoclay in the TPNR blend, MA-PE was used as a coupling agent. The oxygen barrier property of the TPNR blend improved about two-fold by adding only 2 wt% of organoclay. The increase in the barrier property of the blend with the induction in crystallinity indicates the dominant role of organoclay platelets in barrier improvement. 9RDC 11/11/2011)
MORPHOLOGY AND BARRIER PROPERTIES OF SOLVENT CAST NANOCOMPOSITES OF POLYLACTIC ACID WITH CELLULOSE NANOWHISKERS DERIVED FROM ALPHA PURIFIED MICROFIBERS
Sanchez-Garcia and Lagaron (IATA and CSIC, Spain).
(Society of Plastics Engineering Annual Technical Conference, 5/1/2010)
60 to 160 nm long, 10 to 20 nm diameter cellulose nanowhiskers (CNW) was prepared from alpha purified 50 to 100 μm long 10 to 20 diameter cellulose fibers by acid hydrolysis and used with 1 to 5 wt% loading to reinforce polylactic acid (PLA) matrix by solution casting. The cellulose nanowhiskers improved water barrier and oxygen barrier properties due to the impermeability of the cellulose crystals. Purified cellulose nanowhiskers can be potentially used to enhance the barrier properties of thermoplastic biopolyesters in packaging, coatings and membrane applications.