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An interfacial adhesion improvement between low-density polyethylene (LDPE) and aluminum (Al) foil is an important challenge in designing multilayered packaging (TetraPak packaging type) due to insufficient inherent adhesion between both untreated materials. Therefore, extra adhesive layers are often used. The hydrophobic character of LDPE is responsible for poor adhesion to Al and can result in delamination. This study deals with the comparative study of the bulk modification of LDPE with various commercially available adhesive promoters with different chemical compositions to increase LDPE's adhesive characteristics and ensure good adhesion in LDPE/Al laminates. A copolymer of ethylene and methacrylic acid; a terpolymer of ethylene, maleic anhydride, and acrylic ester; or maleated polyethylene (PE) were used as adhesive promoters, and their effect on adhesion improvement of LDPE to Al was investigated. The best adhesion improvement was observed in LDPE-modified samples with maleated PE, while 0.1 wt.% additive content significantly increased peel resistance (from zero to 105 N/m). An additional increase in additive content (0.5 wt.%) in LDPE led to stronger adhesion forces than the cohesion forces in Al foil. Adding 0.5 wt.% of maleated PE into LDPE improved the LDPE/Al laminates' adhesion and can be applied in multilayered lamination applications. [ABSTRACT FROM AUTHOR]

Low-density polyethylene (LDPE) modified by atmospheric dielectric surface barrier discharge plasma in oxygen was investigated to improve surface properties and adhesion of LDPE to more polar polymers. The process of plasma modification was investigated using several methods-surface energy measurements, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The surface energy of LDPE increased significantly after activation by oxygen barrier plasma even at very short time of modification. The FTIR-ATR spectra manifested the presence of carbonyl functional groups on the surface of polymer pre-treated by oxygen barrier plasma. It was shown by SEM, and AFM, that the topography of modified LDPE was significantly changed and the surface of modified polymer exhibited higher roughness in comparison with unmodified polymer. The surface energy of treated LDPE diminished in the course of ageing especially during the first 10 days after modification by barrier plasma. Hydrophilicity of the modified LDPE surface was stabilized by photochemical post-functionalization with 2,2,6,6-tetramethylpiperidin-4-yl-diazoacetate. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Low-density polyethylene (LDPE) belongs to commodity polymer materials applied in biomedical applications due to its favorable mechanical and chemical properties. The main disadvantage of LDPE in biomedical applications is low resistance to bacterial infections. An antibacterial modification of LDPE appears to be a solution to this problem. In this paper, the chitosan and chitosan/pectin multilayer was immobilized via polyacrylic acid (PAA) brushes grafted on the LDPE surface. The grafting was initiated by a low-temperature plasma treatment of the LDPE surface. Surface and adhesive properties of the samples prepared were investigated by surface analysis techniques. An antibacterial effect was confirmed by inhibition zone measurements of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The chitosan treatment of LDPE led to the highest and most clear inhibition zones (35mm2 for E. coli and 275mm2 for S. aureus). [Copyright &y& Elsevier]

Polyethylene (PE) is one of the most widely used polymers in many industrial applications. Biomedical uses seem to be attractive, with increasing interest. However, PE it prone to infections and its additional surface treatment is indispensable. An increase in resistance to infections can be achieved by treating PE surfaces with substances containing antibacterial groups such as triclosan (5-Chloro-2-(2,4-dichlorophenoxy)phenol) and chlorhexidine (1,1'-Hexamethylenebis[5-(4-chlorophenyl)biguanide]). This work has examined the impact of selected antibacterial substances immobilized on low-density polyethylene (LDPE) via polyacrylic acid (PAA) grafted on LDPE by low-temperature barrier discharge plasma. This LDPE surface treatment led to inhibition of Escherichia coli and Staphylococcus aureus adhesion; the first causes intestinal disease, peritonitis, mastitis, pneumonia, septicemia, the latter is the reason for wound and urinary tract infections. [ABSTRACT FROM AUTHOR]

The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak provides stability and strength to food packaging, ensures protection against outside moisture, and maintains the nutritional values and flavors of food without the need for additives in the food products. However, a poor adhesion of LDPE to Al, due to its non-polar surface, is a limiting factor and extra polymeric interlayers or surface treatment is required. Plasma-assisted grafting of the LDPE surface with different molecular weight compounds of polyethylene glycol (PEG) was used to improve LDPE/Al adhesion. It was found that this surface modification contributed to significantly improve the wettability of the LDPE surface, as was confirmed by contact angle measurements. The chemical composition changes after plasma treatment and modification process were observed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). A surface morphology was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Adhesion characteristics of LDPE/Al adhesive joints were analyzed by the peel tests. The most significant adhesion improvement of the PEG modified LDPE surface was achieved using 10.0 wt.% aqueous (6000 M) PEG solution, while the peel resistance increased by approximately 54 times in comparison with untreated LDPE. [ABSTRACT FROM AUTHOR]

This study deals with removing crude oil droplets from colloidal oil in water emulsions. The target was the development of efficient adsorbents for the tertiary treatment of industrial-produced water (PW). The novel adsorbent was designed from recycled low-density polyethylene (LDPE) powder grafted by the cationic polymer. The cationic polymer was synthesized directly on the LDPE surface by plasma-induced radical polymerization. A positively charged adsorbent was chosen due to the negative character of oily droplets to enhance separation efficiency in treating oil-water emulsions. The separation was performed in both batch and filtration modes. Absorption/adsorption uptake capacities showed a sigmoidal S-shape that was analyzed using the Sips model and compared with the newly developed empirical model. Both models showed a remarkable coincidence in the description of experimental data. The separation efficiency of the novel adsorbent was also tested in a filtration mode mimicking a commonly used deep-bed filtration technology. The comparison of the separation efficiency for various sorbents indicated a supreme performance of novel adsorbent. This study demonstrates the potential of a relatively cheap, prepared commodity-based adsorbent for the purification of emulsified oily polluted water in both batch and filtration configurations. This study also contributes to the recycling of polyethylene waste because LDPE attracts meager interest in recycled LLDPE due to many obstacles to reusing LDPE waste for its reprocessing as packaging materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of porous, hydrophobic, and oleophilic hydrocarbon foams. • Utilization of paraffinic waste from petrochemical industry. • Removal of free oils by porous, polymeric foams. • Theoretical description of sorption processes. This study focuses on preparing porous, hydrophobic, and oleophilic hydrocarbon-based foams applicable for removing free oils from water surfaces. Paraffinic waste material generated during industrial production of low-density polyethylene (Qatar Petrochemical Company) was used for the preparation of foamy, elastic structures through crosslinking of short aliphatic chains by dicumyl peroxide and foaming by 1,1′-azobiscarbamide. The porosity of the foam determined by computer microtomography was 58.9%, and the bulk density was 0.42 g.cm −3. The sorption ability of the foam was tested using diesel oil, motor oil, and heavy crude oil. The absorption capacity of foam was characterized as the ratio between the mass of oil absorbed by the foam and the mass of a neat foam (S w) and as the ratio between the volume of oil absorbed by the foam and the volume of a neat foam (S v). The absorption capacities of the new foam reported in this study (referred to here as Qwax foam) are 6.6 ± 0.3 g/g, or 3.3 ± 0.2 cm3/cm3 for diesel oil, 3.9 ± 0.4 g/g or 1.9 ± 0.3 cm3/cm3 for motor oil, and 3.4 ± 0.2 g/g or 1.4 ± 0.4 cm3/cm3 for crude oil. To compare the sorption ability of Qwax foam with some standard foams, the absorption capacities of highly porous commercial polyurethane (PU) and melamine (MA) foams were investigated under the same conditions. These foams showed much higher sorption capacity considering the S w parameter as a reference; however, there was a lower sorption capacity compared to parameter S v. In the last paragraph, the suitability and the relevancy of parameters S w and S v for a comparison of the absorption capacity of foams were theoretically analyzed. [ABSTRACT FROM AUTHOR]