Food packaging fields

Figoli et al. [96,97] reported the preparation of polymeric capsules combining the phase-inversion technique with the membrane process. Polyetheretherketone (PEEKWC) capsules of different size (300-800 micrometer) and morphology (asymmetric with a porous or dense layer) have been prepared. The SEM pictures of the prepared PEEKWC capsules are shown in Figure 21.16. The capsules can find application both in chemical and in food packaging fields [98],... 

Residual amounts of styrene and acrylonitrile monomers usually remain in manufactured batches of styrene-acrylonitrile copolymers. As these copolymers have a potential use in the food packaging field, it is necessary to ensure that the content of both of these monomers in the finished copolymer is below a stipulated level. 

Hasebe, T., et al., 2007. Recent advances in DLC films in medical and food-packaging fields. 

Residual amounts of styrene and acrylonitrile monomers usually remain in manufactured batches of styrene-acrylonitrile copolymers and acrylonitrile-butadiene-styrene terpolymers (ABS), As these copolymers have a potential use in the food packaging field, it is necessary to ensure that the content of both of these monomers in the finished copolymers is below a stipulated level. In a polarographic procedure [9, 10] for determining acrylonitrile (down to 2 ppm) and styrene (down to 20 ppm) monomers in styrene-acrylonitrile copolymer, the sample is dissolved in 0.2 M tetramethylammonium iodide in dimethyl formamide base electrolyte and polarographed at start potentials of -1.7 V and -2.0 V, respectively, for the two monomers. Excellent results are obtained by this procedure. Table 5.3 shows the results obtained for determinations of acrylonitrile monomer in some copolymers by the polarographic procedure. 

Polypropylene, unlike the polyethylenes, is not subject to environmental stress cracking, which gives it an advantage in the food packaging field. It also has a lower density (0.90 g/cm ) than either LDPE or HOPE. Although the impact strength of polypropylene is lower than that of HOPE, especially at temperatures below 0 °C, this can be improved by incorporating various synthetic rubbers into polypropylene or by copolymerisation with ethylene and propylene. 

In the past decades, polymer materials have been continuously replacing more traditional materials such as paper, metal, glass, stone, wood, natural fibres and natural rubber in the fields of clothing industry, E E components, automotive materials, aeronautics, leisure, food packaging, sports goods, etc. Without the existence of suitable polymer materials progress in many of these areas would have been limited. Polymer materials are appreciated for their chemical, physical and economical qualities including low production cost, safety aspects and low environmental impact (cf. life-cycle analysis). 

The enforcement in Denmark of EU Directives on food packaging materials is discussed. Enforcement activities considered include studies of total migration from food contact materials, migration from kitchen-and tableware made of melamine plastics and migration of di(2-ethylhexyl)adipate from plasticised PVC films. Activities which need to be undertaken to increase the effectiveness of enforcement activities in the field of migration are described, including development of selfinspection programmes in industry, European network of enforcement, more rapid analysis and provision of information to the consumer. 2 refs. 

KIP, by contrast, due to the formation of a polymer-anchored benzoyl radical (Scheme 22), caimot release benzaldehyde after photocleavage, thus allowing production of non-yellowing and low-odour coatings [89,91], especially required in the field of food packaging. 

Modern industry has an increasing requirement for new materials with specific properties. Over the last few years, many studies have used new technology with the intention of obtaining nanomaterials which display specific functionality. Antimicrobial nanocomposites are multiphase materials that inhibit microbial development and are desirable for various everyday applications, such as food packaging, water management and medical use. Polymer-metal nanocomposites have specific applications related to their unique properties this important area of nanoscience offers multidisciplinary methods to provide materials for the fields of physical, chemical and materials science in conjunction with areas such as engineering and topology [1]. 

The polypyrrole (Ppy)/dextrin nanocomposite is synthesised via in situ polymerisation and the preparation of this nanocomposite is shown in Figure 5.4. The backbone chain of this nanocomposite polymer contains hydrophobic side chains, which disrupt the microbial cell membrane leading to leakage of the cytoplasm in bacteria including Escherichia coli. Pseudomonas aeruginosa. Staphylococcus aureus and Bacillus subtilis. This material can be implemented in the fields of biomedicine, biosensors and food packaging due to the biodegradable property of dextrin as well as the antibacterial properties of the Ppy [79]. 

The modification of polymers and fibrous surfaces to alter the porosity, wettability and other characteristics of polymeric substrates, will enable the prodnction of implants and biomedical devices which exhibit greater resistance to microbial adhesion and biofilm formation. A nnmber of polymers have been developed that can be incorporated into cellulose and other materials, which will provide significant advances in many fields snch as food packaging, textiles, wound dressings, coating of catheter tnbes and sterile surfaces. 

There is a growing interest in CDs used in preparing food packaging materials. The use of CDs in this field often generates several advantages (a) CDs can reduce... 

It should be noted that, in addition to the possible emission of volatile toxic compounds from plastics and rubber materials, there is also the issue of migration of these compounds (into food) in the field of food packaging, which, at least, can impact the visual impression of packaged products as well as their organoleptic qualities [4],... 

Cathodic process of hydrogen evolution as in the field of food packaging in metal containers, where the evolution of gases causes the swelling of the container and possible explosion... 

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