Acrylamide was grafted in low density polyethylene during melt processing in the presence of a free radical initiator using a torque rheometer in a closed system. Effects of processing time, acrylamide and benzoyl peroxide concentrations were studied FTIR studies revealed that the degree of grafting increased by an increase in acrylamide concentration. Maximum grafting was obtained at 7 minutes processing time and 1% (wt/wt) peroxide. Increase in acrylamide concentration led to reduction in melt flow index and increase in apparent melt viscosity.

Introduction: Plastic in any form is harmful to the environment. Its non-degradable nature leads to plastic pollution. Various chemical and biological methods have been attempted to address this issue, but chemical approaches have often resulted in pollution due to the release of toxic gases. Biodegradation is one of the methods that has received much attention in recent years. This study focused on the biodegradation of plastic waste bags using five marine-derived fungal strains isolated from Red Sea.Materials and Methods: The sediment samples were collected from the Red Sea. Samples were subjected to fungal isolation using the serial dilution and spread plate technique. Fungal species isolates were evaluated for degradation activity toward low-density polyethylene (LDPE) strip samples. The degraded plastic strips were analyzed for weight loss, AFM, SEM, and GC-MS to identify degradation byproducts.Results: The results showed that only two fungal strains (Aspergillus terreus (OQ271754) and Alternaria alternata (OQ282860)) exhibited significant degradation activity over 8 weeks, leading to a weight loss of 45.83% and 29.16% in the degraded plastic strips, respectively. AFM and SEM images of the degraded strips by these strains revealed a noticeable change in surface roughness and close attachment of spores compared to control strips. GC-MS analysis of degradation byproducts identified several compounds, with Bis(2-ethylhexyl) phthalate being the major compound. Toxicity testing of this compound on Wheat seeds showed a significant impact on seed germination.Conclusions: This study demonstrates the potential of marine-derived fungi to degrade plastic materials through the action of their secondary metabolites, resulting in significant weight loss and changes in surface texture.

The loss of energy, especially in industrial and residential buildings is one of the main reasons of increased energy consumption. Improving the thermal insulation properties of materials is a fundamental method for reducing the energy losses. Polymeric foams are introduced as materials with excellent thermal insulation properties for this purpose. In the present study, a deep theoretical investigation is performed on the overall thermal conductivity of low-density polyethylene (LDPE) foams. The thermal conductivity by radiation is predicted using two different methods. The most appropriate model is selected through comparing results with experimental data. The results show that the theoretical model has an appropriate agreement with the experimental results. The effects of foam characteristics including foam density, cell size, and cell wall thickness on the overall thermal conductivity are investigated. The results indicate that by decreasing the cell size and increasing the cell wall thickness, the overall thermal conductivity is decreased significantly. Also, there is an optimum foam density in order to achieve the smallest thermal conductivity. The lowest overall thermal conductivity achieved in the studied range is 30 mW/ mK at a foam density of 37. 5 kg. m-3, cell size of 100 μ m, and cell wall thickness of 6 μ m.

The dynamic melt rheology of low and high-density polyethylene/ethylene vinyl acetate copolymer (EVA) blends in different blending ratios were investigated using a parallel plate rheometer. A rheology-based analysis due to Han, reveals that different compositions of both systems show considerable degree of compatibility with identical microstructure, however LDPE/EVA is found to be more compatible originating from similar molecular architecture of the constituents. Also, increasing the EVA content in HDPE/EVA system reduces the degree of compatibility. Furthermore, it is observed that the viscosity of both systems is significantly reduced by increasing the temperature while no changes in morphological state of the blends are observed.

In this study, a biodegradable composite for food packaging application was produced. Low density polyethylene as matrix, lingo-cellulosic powder of wheat straw as filler, and MAPE (Maleic Anhydride Polyethylene) and PEG (Polyethylene Glycol 400 and 600) as compatibilizers were used to preparation of these biocomposites. Mechanical characteristics (tensile, three points flexural and impact tests) of samples were performed to produce the best compound regarding the compatibilizers effect. Different weights of filler phase in levels: 70 to 30, 60 to 40, 50 to 50, and 40 to 60 % were used in the composite formulation. Compatibilizers were also applied in three levels of 0, 7, and 10 %. The results showed that the MAPE was the best compatibilizer as to improving the mechanical properties of the compounds. The type of compatibilizer is ineffective on the impact results. All composites were better than the control sample in the flexural tests.

High-density polyethylene (HDPE)/linear low-density polyethylene (LLDPE) blends have been designed by varying the HDPE: LLDPE ratio. The ratio of 70: 30 showed the best combination of tensile properties (19. 53 MPa), melt flow index (MFI) (1. 75 g/10 min) and hardness properties (Shore D 46. 5), and its tensile strength and hardness was greater than those of plain LLDPE, whereas its MFI was greater than that of a plain HDPE. Hence, with the same composition, the composites were made by addition of silica with a ratio of 10–, 40%. Incorporation of silica acts as a reinforcement into the system and improves the structural rigidity and 30% incorporation showed the best performance in terms of tensile (23. 69 MPa), and hardness (Shore D 48) but slightly less MFI (0. 85 g/10 min) of the composites. Incorporating coconut shell charcoal (CSC) not only improves the system’, s performance but also utilizes its waste and properties are measured as tensile strength (22. 33 MPa), maintaining the hardness properties and slight reduction in MFI (0. 77 g/10 min). All blends and composites were processed through extrusion and palletization followed by compression molding. Plain silica, CSC as well as the selected blends and composites were evaluated by FTIR, XRD, and SEM analyses. Hence, the synergistic effect of silica and CSC in the HDPE-LLDPE blend is studied and such a composite can be suitable in automotive applications.

The electron beam radiation technique has been explored as the newest and most effective means of forming chemically active sites on LDPE surface. In this novel work the solventless grafting of HEMA onto LDPE surface was conducted. Thus the prepared active sites were exploited to subsequently solventless graft copolymerization of HEMA onto LDPE by high energy electron beam radiation (10 MeV) at dose range of 10 up to 200 kGy at atmospheric pressure in air, in the absence of solvent. As HEMA could not wet LDPE surface, its synthesized tacky polymer was used for coating and subsequent grafting purposes. LDPE Film and sheet surfaces were impregnated with the prepared adhesive and then were irradiated. The FTIR spectra of poly(HEMA-g-LDPE) showed that the concentration of characteristic bands of C=O in ester groups, C-OH in hydroxyl groups and –C-O in ether carbon bonds increased with increasing dose as well as the percentage of grafting significantly increased up to 60%. The hydrophilicity of the grafted surface considerably increased compared to that of the ungrafted ones as the contact angle measurements showed a 72% decrease. Furthermore, the yields of gel content measurement were obtained and the topology of the surface and cross-section of poly(HEMA-g-LDPE) films and the sheets were studied by means of SEM. Moreover, the mechanism of achieving up to 70% cross-linked network in semi-crystalline solid LDPE is discussed.