Low Density Polyethylene Weight Research Articles

Bacterial Degradation of Low-Density Polyethylene Preferentially Targets the Amorphous Regions of the Polymer.

Low-density polyethylene (LDPE) is among the most abundant synthetic plastics in the world, contributing significantly to the plastic waste accumulation problem. A variety of microorganisms, such as Cupriavidus necator H16, Pseudomonas putida LS46, and Pseudomonas chlororaphis PA2361, can form biofilms on the surface of LDPE polymers and cause damage to the exterior structure. However, the damage is not extensive and complete degradation has not been achieved. The changes in polymer structure were analyzed using Time-domain Nuclear Magnetic Resonance (TD-NMR), High-Temperature Size-Exclusion Chromatography (HT-SEC), Differential Scanning Calorimetry (DSC), and Gas Chromatography with a Flame Ionization Detector (GC-FID). Limited degradation of the LDPE powder was seen in the first 30 days of incubation with the bacteria. Degradation can be seen in the LDPE weight loss percentage, LDPE degradation products in the supernatant, and the decrease in the percentage of amorphous regions (from >47% to 40%). The changes in weight-average molar mass (Mw), number-average molar mass (Mn), and the dispersity ratio (Đ) indicate that the low-molar mass fractions of the LDPE were preferentially degraded. The results here confirmed that LDPE degradation is heavily dependent on the presence of amorphous content and that only the amorphous content was degraded via bacterial enzymatic action.

Screening of Different Fungi Strains Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 for Degradation of Low-Density Polyethylene

Over the past decade, polyethylene (PE) products have become increasingly important in several industries. Their biggest concerns are plastic material degradation resistance and environmental longevity. Therefore, this study aims to find fungi that are capable of degrading low-density polyethylene (LDPE) efficiently. This study uses Gongronella sp. WICC F60, and Cordyceps sp., WICC F61. The fungi were grown on potato dextrose agar for 30 days. Following that, fungal colonies were placed in potato dextrose broth for incubation. The LDPE sample was then cultured with the fungal strain in a minimum salt medium with a 10% inoculum. After 30 days of biodegradation testing, the analysis was done. These studies measured LDPE sample weight loss, pH, and fungal biomass. It was observed that the LDPE sample weight loss increased with time until the end of inclubation. Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 were able to degrade LDPE plastic. Both fungi show an increase in LDPE weight loss. However, Cordyceps sp. WICC F61 shows more efficiency in LDPE degradation compared to Gongronella sp. WICC F60. The LDPE weight loss using Gongronella sp. WICC F60 was 1.07%, which is lower than Gongronella sp. WICC F60's LDPE weight reduction of 5.56%.

Isolation and Characterization of Brucella spp., Low-Density Polyethylene (LDPE) Plastic Degrading Bacteria in Al-Ahsa Region, Saudi Arabia

Plastic pollution is one of the most serious environmental issues, causing severe environmental damage. It is of vital importance to find an efficient and eco-friendly approach to biodegrading plastics. The aim of this study was to isolate and characterize different bacterial isolates from water samples in the Al-Ahsa region of Saudi Arabia. The ability to degrade low-density polyethylene (LDPE) plastic was evaluated using multiple approaches, including changes in the media pH values, weight loss, Fourier transform infrared (FTIR), and gas chromatography–mass spectrometry (GC–MS). The water samples were collected from plastic-contaminated sites in Al-Ahsa, and bacterial isolates were obtained using a mineral nutrient medium (MNM) enriched with LDPE as the only carbon and energy source. Two bacterial isolates (APCK5 and APCZ14) were obtained and they showed potential LDPE degradation, as evidenced by changes in media pH (from 7.0 ± 0.03 to 6.17 ± 0.05 and 6.22 ± 0.03), LDPE weight reduction (8.1 ± 0.63% and 18.85 ± 0.96%, respectively), and FTIR and GC–MS analyses. Based on 16S rRNA gene similarities, APCZ14 and APCK5 were determined to be most closely related to the genus Brucella. APCZ14 exhibited a 99.48% homology with Brucella cytisi, whereas APCK5 showed a 99.33% similarity level to Brucella tritici. In conclusion, both bacterial strains had high efficiency in plastic biodegradation and could be developed for wide use as an eco-friendly method to remove or reduce plastic pollutants from the environment.

EFFECT OF LDPE/CR ADMIXTURE ON THE PROPERTIES OF BITUMINOUS BINDER USED IN PAVING APPLICATIONS

A plastic-elastomer admixture was prepared by blending the recycled low density polyethylene (LDPE) and crumb rubber (CR) recycled from wasted tyres in the presence of tall oil. They are blended in two ratios 1:2 and 1:3, LDPE/CR respectively. In this study two wasted materials, LDPE and CR were taken to improve the properties of base bitumen binder. The CR in the form of powder having particle size less than 0.7 mm, was used blended with melted bitumen at 160-1700C with the help of high speed shear mixer for 1 hour. In the same manner the different compositions were made 3, 5, 8 and 12 percent by weight of LDPE, CR and LDPE/CR combination in both ratios 1:2 & 1:3. These modified blends are characterized in terms of penetration, softening point and viscosity, which found better as compared to base bitumen. The most suitable results are obtained when LDPE, CR and LDPE/CR were used below 8% by weight. The elastic recovery test of 8% by weight of LDPE/CR in the ratio 1:3 meets the requirement of specification and this composition is best suited to be for road constructions.

Melt spinning flow behaviour of high-density polyethylene blended with low-density polyethylene

ABSTRACTThe melt spinning flow behaviour of a high-density polyethylene (HDPE) blended with a low-density polyethylene (LDPE) was studied using a melt spinning technique in temperature ranging from 160 to 200°C and die extrusion velocity varying from 9 to 36 mm s−1. The results showed that the melt apparent extension viscosity of the blends was higher than those of the LDPE and HDPE; the melt apparent extension viscosity decreased with increasing temperature; while the melt apparent extension viscosity increased with increasing extension strain rate when the extension strain rate was lower than 0.2 s−1, and then decreased; the melt apparent extension viscosity reached up to a maximum value when extension strain rate was about 0.2 s−1; the relationship between the melt apparent extension viscosity and the LDPE weight fraction did not follow the mixing rule.

Isolation and identification of low density polythene-degrading bacteria from soil of North West of Algeria

Plas c bags (Low Density Polyethylene (LDPE) belong to the polymers, which plays a very important role in our daily lives by their diversi ed applica on. However, the accumula on of the plas c bags in the environment cons - tutes a serious problem and a real source for visual nuisance, pollu on of soil and marine environments. Furthermore, their biodegradation was the safest method of breakdown that possibly leaves behind less toxic residues and showed poten al of bio-geo chemical cycling of the substrate. The aim of the present work was the characterization of the isolated bacterial strains from a municipal land ll area of Tlemcen, North West Algeria, which were implicated by the biodegrada on ability of the Low Density Polyethylene. The degradation of the Low Density Polyethylene was inves gated by studying the bacterial growth of the isolated, inoculated on a solid culture medium, which was composed of LDPE as the sole carbon source with and with- out a nitrogen source and the selec on was based by the determination of the produced diameter of hydrolysis clear zone on the surface. Furthermore, the isolated, selected degrading Low Density Polyethylene bacterial ML002 has been iden ed by the study of their morphological, biochemical charac- teris cs and the ampli ca on of the fragment, coding the region of ARN 16S. The use of the API system indicated their belonging to the genus Bacillus Cereus, which has reduced the weight of LDPE by 0.26, 1.28, 1.53% a er 30, 90, 120 days respec vely. Furthermore, the amplified of the fragment, coding the region of ARN 16S by the isolated, selected bacterial ML002 indicated a similarity of 99.394% with Bacillus wiedmannii and Bacillus proteolyticus and 99.293% homology with Bacillus toyonensis, Bacillus cereus and Bacillus thuringiensis.

A method for the characterisation of microplastics in sludge

Microplastics (MP) have become a concern owing to their increasing detection in the environment and potential impact on ecosystems. One of the main MP reservoirs is sludge generated during wastewater treatment. Estimates suggest that, through sludge settling, treatment processes remove between 80 and 90 % of MP present in wastewater. Nevertheless, reliable measurements of actual plastics loads retained by sludge are still lacking for management purposes. Hence, our goal was to validate a quick method for MP quantitation in sludge. Recovery tests were conducted with red low-density polyethylene (LDPE) fragments whose sizes ranged between 5 to 1 mm, 1 to 0.5 mm and 500 to 150 μm. For each size fraction, either 10 or 100 LDPE fragments were spiked into wet sludge (50 mL). Subsequent LDPE analysis involved steps such as freeze-drying, sieving, Fenton purification, visual shorting and FTIR identification. When expressed as number of fragments, quantitative (i.e. percentage values between 80 and 100) were obtained regardless of size fraction or initial spiked number. In terms of total spiked LDPE weight, however, recoveries consistently exceeded 100 % because LDPE fragments retained other materials. Such residues contributed to an overestimation of MP by weight up to 33 % of the 500−150 μm fraction.•Method was validated by spiking LDPE fragments.•Recoveries based on MP number showed good precision and accuracy.•Residues attached to MP resulted in overestimated recoveries by MP weight up to 33 %.

Melt Elongation Strength and Drawability of LDPE/LLDPE Blends

Abstract The melt strength behavior and drawability during elongation flow of low density polyethylene (LDPE)/linear low density polyethylene (LLDPE) blends were investigated using the Rheotens test method under temperature ranging from 160 to 200 °C and die extrusion velocity varying from 9 to 36 mm/s. It was found that the blend melt strength decreased with a rise of temperature while increased with increasing the LDPE weight fraction when the extension rate or drawing ratio is constant; the dependence of the blend melt strength on the melt extension temperature roughly obeyed the Arrhenius equation; the dependence of the blend melt strength on the die extrusion velocity roughly obeyed the index equation. The drawing ratio at the melt fracture decreased with increasing the LDPE weight fraction and the die extrusion velocities, while increased with a rise of the melt extension temperature.

Melt elongation flow behaviour of LDPE/LLDPE blends

The extensional rheological properties of low density polyethylene (LDPE)/linear low density polyethylene (LLDPE) blend melts were measured using a melt spinning technique under temperatures ranging from 160 to 200 °C and die extrusion velocities varying from 9 to 36 mm/s. The results showed that the melt elongation stress decreased with a rise of temperature while it increased with increasing extensional strain rate and the LDPE weight fraction. The dependence of the melt elongation viscosity on temperature roughly obeyed the Arrhenius equation, it increased with increasing extensional strain rate and the LDPE weight fraction when the extensional strain rate was lower than 0.5 s−1, and it reached a maximum when the extensional strain rate was about 0.5 s−1, which can be attributed to the stress hardening effect.

Effect of UV Treatment on Optical Properties of Low-Density Polyethylene Films Doped with Eu(TTA)<sub>3</sub>phen Complex

Low-Density Polyethylene (LDPE) films doped with Eu (TTA)3phen complex (TTA=2-thenoyltrifluoroacetone, phen=1,10-phenanthroline) were fabricated by hot-blowing technique for thickness of 100 μm. The films were doped with 0.1 % of Eu (TTA)3phen to the total weight of LDPE and exposed to UV irradiation from deuterium lamp for 5, 10, 20, 40 and 60 hours to investigate the effect of its optical properties. The films were characterized by Spectrofluorometer, UV/VIS Spectrophotometer and FT-IR Spectrometer to measure their emission spectra, lifetimes, transmission transparency and chemical bonding. Photoluminescence of the room-temperature Eu (TTA)3phen doped films consist of typical Eu3+emission transition lines with hypersensitive5D07F2emission band at 610 nm. After 20 hours UV treatment, the peak intensity dropped by 90 % and shortened the luminescent lifetimes from 0.654 ms to 0.305 ms. Longer UV treatment also has accelerated degradation in doped LDPE films shown by significant reducing in absorption peak of FTIR at 3395, 3186 and 1645 cm-1. The results would provide a mechanism to improve the lifetime of the LDPE by utilizing the light-manipulation property of Eu (TTA)3phen complex to absorb UV spectrum and covert into red emission.Keywords: LDPE, rare-earth complex, photoluminescence

Rheological and mechanical properties of poly (ethylene acrylic acid) and low density polyethylene blends

AbstractRheological properties of poly (ethylene‐acrylic acid) (PEA) and low density poly ethylene (LDPE) blends having varied amounts of LDPE from 0 to 100% have been evaluated at different temperatures (115, 120, and 130°C) and shear rates (61.33–613.30 s−1) using a Monsanto processability tester. A reduction in the melt viscosity of the PEA/LDPE blends was noticed with increasing the shear rate. The observed positive deviation in the experimental melt viscosities of the blends is an indication of the synergy present in the blends during melt processing. The activation energy (Ea) of flow calculated using Arrhenius relation for PEA, LDPE, and their respective blends lies in the range 29.98–40.56 kJ mol−1. The experimental activation energy of flow of the blends was higher than that obtained from the additivity rule. Highest activation energy was noticed for the blends containing 60–80% by weight of LDPE in PEA/LDPE blends, which is an indication for the miscibility of the blends at these ratios. The physicomechanical properties such as density, tensile behavior, tear strength, and hardness (Shore A) of PEA, LDPE, and their blends have been evaluated as a function of varying amounts of LDPE. The obtained physicomechanical properties of the PEA/LDPE blends lie in between that of pure polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Implications of LDPE Branching and Mw on Thermal and Mechanical Properties of PP/LDPE Blends

AbstractSummary: The influences of short chain branching (SCB) and molecular (Mw) weight of low density polyethylene (LDPE) on the solid state properties of polypropylene (PP)‐LDPE blends were investigated by mechanical and thermal techniques. DSC analysis of all blends exhibit a double melting peak at all compositions studied thus suggesting that both PP and LDPE crystals exist separately in the solid state. It was found that the SCB and Mw of LDPE influenced the modulus and ultimate tensile strength of the blends. However, elongation at break seems to be independent of the molecular characteristics of the pure homopolymer especially at PP blend composition greater than 50%. LDPE with high SCB showed broader melting peaks. Addition of a small amount of a low Mw LDPE (10%) resulted in a higher elongation at break than a high Mw LDPE. There is likely a correlation between the presence of a new peak in the thermograms of PP‐rich blends and the observed poor elongation at break.

Influences of contents and molecular weights of LDPE on DOP plasticization of PVC

Influences of contents and molecular weights of low-density polyethylene (LDPE) on dioctyl phthalate (DOP) plasticization in the poly(vinyl chloride) (PVC) plastisol (PVC/DOP/AO = 100/30/6.5) were investigated using DMA and DSC. The plasticization effects of DOP on the PVC plastisol were found to decrease with increasing LDPE content. A negligible plasticization effect of DOP on the PVC plastisol was found when the LDPE content was equal to or higher than 75 parts per 100 parts by weight of LDPE and PVC together. Based on thermal fractionation experiments, a favorable interaction between LDPE and DOP was developed during melt blending of LDPE and the PVC plastisol. The present interaction enabled the incorporation of DOP into LDPE and decreased the plasticization effects of DOP on the PVC plastisol. A further decrease in the plasticization effects of DOP on the PVC plastisol by the presence of LDPE was found with increasing LDPE molecular weights. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2548–2555, 2002