Films For Packaging Applications Research Articles

Carboxymethylation of alkali extracted xylan for preparation of bio-based packaging films

This study describes the synthesis of carboxymethylxylan (CMX) and investigates its suitability as a film for packaging applications. High-purity polymeric xylan was extracted from commercial bleached birch kraft pulp and converted to CMX with three different degrees of substitution (DSs). The water vapor sorption, mechanical, and barrier properties of the films prepared from CMX were tested. Increasing DS of CMX films resulted in an increase in elongation at break and a decrease in tensile strength and Young's modulus. The DS also affected the barrier properties of the films. CMX films with higher DS showed improved (reduced) oxygen permeability (OP), and the water vapor permeability (WVP) increased with DS. It was demonstrated that the carboxymethylation of xylan recovered from industrial side-streams and its conversion to packaging films could be a viable option to valorize xylan.

Properties of linear poly(lactic acid)/polyethylene glycol blends

AbstractPoly(lactic acid) (PLA) has great potentials to be processed into films for packaging applications. However, film production is difficult to carry out due to the brittleness and low melt strength of PLA. In this investigation, linear PLA (L‐PLA) was plasticized with poly(ethylene glycol) (PEG) having MW of 1000 g mol−1 in various PEG concentrations (0, 5, 10, 15, and 20 wt%). In relation to plasticizer content, the impact resistance and crystallinity of L‐PLA was increased, whereas a decrease in glass transition temperature and lower stiffness was observed. Nevertheless, the phase separation has been found in samples which contained PEG greater than 10 wt%. The dynamic and shear rheological studies showed that the plasticized PLA possessed lower viscosity and more pronounced elastic properties than that of pure PLA. Both storage and loss moduli decreased with PEG loading at all frequencies while storage modulus exhibited weak frequency dependence with increasing PEG content. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

Influence of γ-irradiation on mechanical and water barrier properties of corn protein-based films

Effect of γ-irradiation on zein, a predominant corn protein, was studied to improve performance of the zein films in packaging applications. This goal has been achieved by irradiating zein film forming solutions with Co 60 gamma rays (10.5 kGy/h) at the doses of 10, 20, 30, and 40 kGy. Gamma-irradiation of zein solutions caused a disruption and/or an aggregation of the zein molecules according to viscosity measurements. Structural changes of the polypeptides were also evaluated by CD spectrometry. The tensile strength of zein films was decreased with increasing radiation doses with a slight increase was noticed at a radiation dose of 20 kGy, while a noticeable increase in elongation was exhibited with increasing radiation dose. However, a slight decrease was noticed at 20 kGy. Alteration of zein molecular conformation by radiation treatment significantly reduced the water vapour permeability. Measurement of Hunter colour values indicated that radiation caused a significant decrease in Hunter b values.

Biodegradable Zein-Based Films: Influence of γ-Irradiation on Structural and Functional Properties

Zein, a predominant corn protein, is an alcohol-soluble protein extracted from corn and is characterized by unique film-forming properties. The characteristic brittleness of zein diminishes its usefulness as a structural material. The objective of this work was to study the effect of gamma-irradiation on improving the performance of zein films in packaging applications. This goal has been achieved by irradiating zein film-forming solutions with various doses of gamma-rays, namely, 10, 20, 30, and 40 kGy at dose rate of 10.5 kGy/h, using a Co(60) gamma-radiation source. The impact of radiation process on the structural properties has been explored through far-UV CD spectral analysis and scanning electron microscopy. Additionally, viscosity changes that reflect the effect of radiation treatment on degradation and/or cross-linking of protein chains have been measured. However, improvements in the performance of zein films as packaging materials that can be accomplished by radiation treatment have been investigated via monitoring of the color, surface density, roughness, mechanical properties (tensile strength and elongation percentage), water uptake, and water barrier properties. The results indicated that gamma-irradiation treatment of the film-forming solution can be used to improve the water barrier properties, as well as color and appearance of the zein films. Moreover, a sterilization effect is considered to be an additional advantage for applying gamma- irradiation.

Photoinduced formation of gold nanoparticles into vinyl alcohol based polymers

Nanocomposites based on vinyl alcohol-containing polymers and nanostructured gold have been efficiently prepared by a UV photo-reduction process. The very fast process provided dispersed gold nanoparticles with average diameters ranging from 3 to 20 nm depending on the host polymer matrix and the irradiation time. Uniaxial drawing of the irradiated Au/polymer nanocomposites favours the anisotropic distribution of packed assemblies of gold particles, providing oriented films with polarization-dependent tunable optical properties. These pronounced dichroic properties suggest that the nanocomposite films could find potential applications as colour polarizing filters, radiation responsive polymeric objects and smart flexible films in packaging applications.

Sodium dodecyl sulfate treatment improves properties of cast films from soy protein isolate

The manufacture of edible/biodegradable films or coatings can potentially add value to soy protein. This study was conducted to determine the effect of sodium dodecyl sulfate (SDS) on selected physical properties of glycerin-plasticized soy protein isolate (SPI) films. Films were cast from heated (70 °C for 20 min), alkaline (pH 10) aqueous solutions of SPI (5 g/100 ml water), glycerin (50% w/w of SPI), and SDS (0, 5, 10, 20, 30, or 40% w/w of SPI). Tensile strength (TS), elongation at break (E), moisture content (MC), total soluble matter (TSM), water vapor permeability (WVP), and color values ( L, a, and b) were determined after conditioning film specimens at 25 °C and 50% relative humidity (RH) for 2 days. SDS reduced ( P<0.05) film TS by as much as 43% for films with 40% SDS (6.2 vs. 10.9 MPa for control SPI films). In contrast, film E increased ( P<0.05) notably with addition of SDS even at 5%. Films with SDS had smaller ( P<0.05) MC and larger ( P<0.05) TSM values than control SPI films. Films containing 10% or more SDS had lower WVP values than control SPI films by as much as 50%. Increased yellowness, evidenced by greater ( P<0.05) + b color values, was noted for films with high amounts (20, 30, or 40%) of SDS. Changes in tensile, solubility, and water vapor barrier properties of SPI films due to the addition of SDS were largely attributed to disruption of hydrophobic associations among neighboring protein molecules as the non-polar portions of the SDS molecules attached onto hydrophobic amino acid residues within the film structure. It was demonstrated that adding anionic surfactant SDS to film-forming solutions prior to casting could greatly modify the properties of SPI films. In particular, SDS improved the water vapor barrier ability and the extendibility of SPI films, both desirable attributes when assessing the potential of such films for packaging applications.

Study of blends of nylon 6 with EVOH and carboxyl‐modified EVOH and a preliminary approach to films for packaging applications

Study of blends of nylon 6 with EVOH and carboxyl‐modified EVOH and a preliminary approach to films for packaging applications

Low Temperature Deposition of High Dielectric Constant Thin Films for Decoupling Capacitor Applications

ABSTRACTHigh dielectric constant thin films for packaging applications were studied. Compared with polycrystalline or epitaxial ferroelectric thin films amorphous ferroelectric films are a promising alternative because of their ease of processing and low leakage current. Reactive Partially Ionized Beam deposition (RPIB) offers a new approach to deposit high dielectric constant films at a low substrate temperature. As an example, the growth of amorphous BaTiOs thin films using RPIB deposition is described. The films were characterized in terms of dielectric constant and leakage current. The annealing effects on the film properties are also discussed.

Paper‐like filled polyethylene films

AbstractFilled high‐density‐polyethylene (HDPE) films for packaging applications have been developed. These films are of low permeability, are water and grease resistant, and can be heat‐sealed like HDPE films but have stiffness, deadfold, cuttability, and appearance similar to those of paper. The films are produced in thicknesses of 10 to 100 + μm by the standard film blowing technique. The effect of the filler type, resin parameters, and film blowing process variables on the resultant filled film properties is discussed. The commercialization of filled films and the market acceptance of the products is also briefly elaborated upon.