Barrier Properties of Coated and Laminated Polyolefin Films for Food Packaging

The food packaging industry demands polymer films possessing a defined barrier against permeation of gases, moisture and flavor. The objective of this study was to assess the differences between the barrier properties of coated and un-coated polyolefine films. Eight types of packaging films are prepared by standard industrial procedure by cast film extrusion processing with chill rollers: biaxially oriented polypropylene (BOPP), BOPP coated by acrylic copolymer, metallized BOPP by aluminum, and low-density polyethylene (LDPE). The influence of lamination and metallization on the gas molecules ($CO_{2}$, $O_{2}$ and $N_{2}$) was determined by Lyssy's method. The moisture transparency was assessed according to the gravimetric method. The substantial differences between the barrier properties of the coated and un-coated films were estimated. It was estimated that the lamination process improves the oxygen barrier but not necessarily the moisture barrier, due to the different mechanisms for oxygen and moisture permeability. The obtained barrier properties data were considered from a practical point of view. It was concluded that films based on metallized BOPP has excellent barrier properties and can be used to over wrap food products

The changes of etheric oil content in powdered garlic during storage in different packaging materials

The etheric oil components in garlic are proven to have numerous positive effects on human health, and powdered garlic has long been widely used in both the food industry and private households. In order to prolong the stability of etheric oil components, different combinations of packaging materials are used for the storage of powdered garlic. Since the quality of dehydrated powder depends on the packaging used, the investigation was aimed to determine the effects of packaging material types on etheric oil content in industrially powdered garlic over the storage period. Powdered samples were analysed immediately after production and during long periods of storage (after 30, 90, 120, 180 and 270 days). The investigations were focused on the correlation between packaging materials performances (light, water vapour and air permeability), and the changes of etheric oil and moisture content in powdered garlic. In order to describe the changes in etheric oil content during time, as well as to predict changes in packed powdered garlic, a statistical procedure was applied for all examined packaging materials and curve fitting data were estimated (the least square approach)

INVESTIGATION OF POTENTIONAL USE OF RECYCLED POLY(ETHYLENE TEREPHTHALATE) IN POLYURETHANE SYNTHESIS

This paper presents an outline of developed methods for chemical recycling of postconsumer poly(ethylene terephthalate) (PET) waste bottles. Oligoesters (obtained by chemical recycled PET) with 2,2-bis (hydroxyl methyl) propionic acid, as hydrophobic monomer, and isophorone diisocyanate as cross-linker, in the presence of di-n-dibutyl tin(IV)dilaurate catalyst, were used for polyurethane dispersions. Molecular masses of obtained products were analyzed by gel permeation chromatography. Infra-red spectroscopy was used for molecular structures analysis. Thermal properties were evaluated by using differential scanning calorimetry and thermogravimetric analysis.This paper presents an outline of developed methods for chemical recycling of postconsumer poly(ethylene terephthalate) (PET) waste bottles. Oligoesters (obtained by chemical recycled PET) with 2,2-bis (hydroxyl methyl) propionic acid, as hydrophobic monomer, and isophorone diisocyanate as cross-linker, in the presence of di-n-dibutyl tin(IV)dilaurate catalyst, were used for polyurethane dispersions. Molecular masses of obtained products were analyzed by gel permeation chromatography. Infra-red spectroscopy was used for molecular structures analysis. Thermal properties were evaluated by using differential scanning calorimetry and thermogravimetric analysis

Preparation and Thermal Stability of Elastomers Based on Irregular Poly(urethane-isocyanurate) Networks

The objective of this study was to investigate the thermal stability of poly(urethane-isocyanurate) networks with increasing amount of dangling chains. In order to improve thermal stability of elastomeric materials, networks were prepared by adding some heat resistant isocyanurate rings as a junction points by catalytic cyclotrimerisation of telechelic diisocyanates. The thermal degradation kinetics of samples has been studied by means of high-resolution thermal analyzer SDT Q600 TA Instruments, under nitrogen atmosphere. The activation energy for the two step reactions of thermal decomposition of different species was calculated and compared