Nylon Oxygen Barrier Tubing Reduces Biofouling in Beer Draught Lines

Beer draught lines are frequently contaminated with biofilm-forming microorganisms, which forces retailers to spend considerable time and money cleaning and replacing lines. In light of this financial burden, draught tubing composition was examined for its role in the prevention of biofouling in beer lines. Three types of draught tubing - vinyl, polyethylene, and nylon barrier - were inoculated with a combination of biofilm-forming microorganisms (Hafnia paralvei, Raoultella planticola, Pediococcus damnosus and Saccharomyces cerevisiae) and used to simulate a bar environment for sixteen weeks. Following simulation, the degree of biofouling in each draught line was determined by spectrophotometry and microscopy. Absorption values and fluorescence images showed that nylon barrier tubing was superior to the other lines at resisting biofilm maturation.These results suggest that tubing composition plays a significant role in the prevention of biofilm formation in beer draught lines and supports the adoption of nylon barrier tubing as an effective strategy against biofouling in a variety of applications.

Phosphonated Poly(ethylene terephthalate) Ionomers as Compatibilizers in Polyester/Polyamide Blends for Packaging Applications

Poly(ethylene terephthalate) (PET) is widely used in the packaging industry. The oxygen barrier properties of PET are acceptable for many food and beverage products, but do not meet the stringent requirements for packaging highly oxygen-sensitive products. Blending PET with aromatic polyamides, such as poly(m-xylyene adipamide) (MXD6), reduces the inherent oxygen permeability of the polyester matrix. Due to the immiscibility of these two parent polymers, a compatibilizer is necessary to achieve an efficient and stable mixing

Polyacrylate Decorating Poly(ethylene terephthalate) (PET) Film Surface for Boosting Oxygen Barrier Property

Polymeric barrier materials are critical in contemporary industries for food, medicine, and chemical packaging. However, these materials, such as PET films, are impeded by the optimization of barrier properties by virtue of molecular design. Herein, a new methyl methacrylate-methyl acrylate-diallyl maleate-maleic acid (MMA-MAc-DAM-MA) was synthesized to tailor the surface properties of PET films for maximizing oxygen barrier properties. During the MMA-MAc-DAM-MA coating and curing process, the chemical structure evolutions of MMA-MAc-DAM-MA coatings were characterized, indicating that the cross-linking conversion and proportion of –COOH groups are critical for the oxygen barrier properties of coatings. The inherent –COOH groups are transformed into designed structures, including intramolecular anhydride, inter-chain anhydride and retained carboxylic acid. Therein, the inter-chain anhydride restraining the activity of coated polymer chain mainly contributes to enhanced barrier properties. The thermal properties of novel coatings were analyzed, revealing that the curing behavior is strongly dependent on the curing temperatures. The impacts of viscosity of the coating solution, coating velocity, and coating thickness on the oxygen permeability (Po2) of the coatings were investigated using a gas permeability tester to explore the optimum operating parameters during practical applications, which can reduce the Po2 of PET film by 47.8%. This work provides new insights on advanced coating materials for excellent barrier performance.

High oxygen barrier chitosan films neutralized by alkaline nanoparticles

The most frequent neutralisation procedure, applied on chitosan (CS) films includes treatment with NaOH base. Such treatment endows CS films with stability in water, yet, same can significantly decrease the film performance. In the present paper, we investigate Mg(OH)2 nanoparticles as a neutralisation agent for CS solutions followed by casting into films. This is combined and compared with classical casting and film drying from non-neutralized solutions followed by NaOH treatment after film formation. The influence on the properties of resulting films is investigated in detail and large differences are found for structure and barrier properties. The stable, opaque-to-transparent CS films (depending on Mg(OH)2 content and post-treatment) were obtained by facile casting method of neat CS or CS–Mg(OH)2 dispersions, in the complete absence of cross-linkers and plasticizers. FTIR data demonstrate the Mg(OH)2 and NaOH deprotonation effect, and strongly suggest intensive H-bonding interaction between CS and Mg(OH)2. X-ray photoelectron spectroscopy showed differences in the hydroxide content and protonation of CS nitrogen. The reduction of surface roughness and increase of homogeneity, the tensile strength and elongation, as well as thermal stability and excellent oxygen barrier properties were measured for CS enclosing the Mg(OH)2 nanoparticles. Further treatment with 1 M NaOH causes re-packing of CS polymer chains, improving the crystallinity and water vapour barrier properties, degrading the mechanical properties by increasing the films brittleness and increasing the char formation due to reduced thermal stability. Graphic abstract

A Study on the Oxygen Permeability Behavior of Nanoclay in a Polypropylene/Nanoclay Nanocomposite by Biaxial Stretching

Polypropylene (PP) has poor oxygen barrier properties, therefore it is manufactured in a multi-layer structure with other plastics and metals, and has been widely used as a packaging material in various industries from food and beverage to pharmaceuticals. However, multi-layered packaging materials are generally low in recyclability and cause serious environmental pollution, therefore we have faced the challenge of improving the oxygen barrier performance as a uni-material. In this work, PP/nanoclay nanocomposites were prepared at nanoclay contents ranging from 0.8 to 6.4 wt% by the biaxial stretching method, performed through a sequential stretching method. It was observed that, as the draw ratio increased, the behavior of the agglomerates of the nanoclay located in the PP matrix changed and the nanoclay was dispersed along the second stretching direction. Oxygen barrier properties of PP/nanoclay nanocomposites are clearly improved due to this dispersion effect. As the biaxial stretching ratio and the content of nanoclay increased, the oxygen permeability value of the PP/nanoclay nanocomposite decreased to 43.5 cc·mm/m2·day·atm, which was reduced by about 64% compared to PP. Moreover, even when the relative humidity was increased from 0% to 90%, the oxygen permeability values remained almost the same without quality deterioration. Besides these properties, we also found that the mechanical and thermal properties were also improved. The biaxially-stretched PP/nanoclay nanocomposite fabricated in this study is a potential candidate for the replacement of the multi-layered packaging material used in the packaging fields.

Effects of talc, kaolin and calcium carbonate as fillers in biopolymer packaging materials

We compared the performance of bio-based and biodegradable polymers for packaging applications. Cost-effective inorganic fillers (talc, kaolin and calcium carbonate) were first melt-compounded with polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT) and poly(hydroxy butyrate-co-valerate) (PHBV). Following this, injection- and compression-molded specimens were produced to test the effect of filler loading (0–30 wt%) in relation to the morphological, thermal, mechanical and barrier properties of the composites. All the fillers were homogeneously dispersed in the polymer matrices and suitable polymer–filler adhesion was observed for talc and kaolin. The elastic modulus increased at the expense of a reduced tensile and elongation. The most significant improvements in water vapor and oxygen barrier properties were achieved with talc in PLA, PBAT and PHBV films. Overall, the results point to the promise of the introduced compositions for food packaging materials.