High-density Polyethylene Films Research Articles

Isolation and characterization of bio-prospecting gut strains Bacillus safensis CGK192 and Bacillus australimaris CGK221 for plastic (HDPE) degradation.

The present work reports the application of novel gut strains Bacillus safensis CGK192 (Accession No. OM658336) and Bacillus australimaris CGK221 (Accession No. OM658338) in the biological degradation of synthetic polymer i.e., high-density polyethylene (HDPE). The biodegradation assay based on polymer weight loss was conducted under laboratory conditions for a period of 90days along with regular evaluation of bacterial biomass in terms of total protein content and viable cells (CFU/cm2). Notably, both strains achieved significant weight reduction for HDPE films without any physical or chemical pretreatment in comparison to control. Hydrophobicity and biosurfactant characterization were also done in order to assess strains ability to form bacterial biofilm over the polymer surface. The post-degradation characterization of HDPE was also performed to confirm degradation using analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electronic microscopy (FE-SEM) coupled with energy dispersive X-ray (EDX), and Gas chromatography-mass spectrometry (GC-MS). Interestingly strain CGK221 was found to be more efficient in forming biofilm over polymer surface as indicated by lower half-life (i.e., 0.00032day-1) and higher carbonyl index in comparison to strain CGK192. The findings reflect the ability of our strains to develop biofilm and introduce an oxygenic functional group into the polymer surface, thereby making it more susceptible to degradation.

Effect of different nanofillers incorporation on HDPE/LDPE films nanocomposite

The objective of this study was to develop polymeric films of high-density polyethylene (HDPE)/low-density polyethylene (LDPE) that comprise 1 wt% of different nanofillers, that is, either nanofibrillated cellulose (NFC), montmorillonite clay (MMT), or graphene nanoplatelets (GNPs); the polymeric films were developed with and without the inclusion of a coupling agent (CA). The results indicated that all the samples that comprised nanofillers exhibited, at least, an increase of 3 to 25°C compared with that of the matrix and demonstrated higher stability at the beginning of the thermal degradation, as verified using TGA. In the DSC analysis of the samples that contained GNPs had highest crystallinity index (55%), having as the consequent improvement in the mechanical properties and in the oxygen permeation. The incorporation of GNPs provided a 127.71% increase in deformation at break and a lower value in oxygen permeability with 50.06 mL.cm.(cm2.s.cmHg)−1, when compared to the polymeric matrix. It was concluded that all the different nanofillers tested promoted distinct improvements in HDPE/LDPE films nanocomposite. It can be inferred that these modifications are related to the chemical composition, size and morphology of each nanofiller. Thereby, it is indicated that with the use of each nanofiller one must be in accordance with the necessary demand of each composite film.

Preparation of fullerene-containing nanocomposite materials based on high-density polyethylene via environmental crazing and their performance

This work offers a new concept relying on the Rehbinder effect in polymers for the preparation of fullerene-containing nanocomposite materials with added functionality. Tensile drawing of high-density polyethylene (HDPE) films in the solutions of 1,2–dichlorobenzene containing С60-С70 fullerenes (FL) proceeds via the environmental crazing according in the presence of surface active liquids (the Rehbinder effect). Environmental crazing provides the development of a highly developed surface and a mesoporous structure with a uniform distribution of monomeric FL within the HDPE matrix. The content of FL in the FL/HDPE nanocomposite materials can be varied from 1 to 8 wt%. Performance of the FL/HDPE nanocomposite materials (optical properties, thermal stability, mechanical characteristics) was studied by different physicochemical methods (TGA, UV- spectroscopy, tensile tests, etc.). Introduction of FL to HDPE is shown to increase the temperature of thermal degradation onset of HDPE by 30 °C. Rolling as the additional stage off post-treatment allows preparation of the FL/HDPE nanocomposite materials with high mechanical properties. This process can be upscaled using the existing technological equipment for the orientational drawing of polymers. The FL/HDPE nanocomposites with improved thermal resistance and good mechanical properties can be used as innovative optoelectronic materials within a broad temperature interval.

Replacement of conventional packaging with sustainable materials for corn tortillas

This work aimed to evaluate two commercial bio-plastics as sustainable alternatives to high-density polyethylene (HDPE) and paper packaging for corn tortillas. First, the effect of films made of HDPE, a mix of polyesters and thermoplastic starch (TPB), polyhydroxybutyrate (PHB), and two types of paper on the shelf life of corn tortillas was evaluated. Besides, water vapor transmission rate (WVTR), weight gain of packaging materials, overall migration (OM), and biodegradation of TPB and PHB were evaluated. The WVTR at 25 °C and 50% RH of HDPE and PHB films that prevented weight loss (<2.5%) of packaged tortillas was 3.62 and 39.42 gmil/m2day, respectively. In addition, the films were in compliance with the OM limit established by the European Union Regulation (10 mg/dm2). The shelf life of corn tortillas packaged in the HDPE, TPB, PHB, and papers was 18, 2, 17, and 1 day, respectively. Finally, the biodegradation under aerobic soil conditions of TPB and PHB was 41.3% and 36.8%, respectively. These findings revealed that PHB is a viable option for maintaining the corn tortillas’ shelf life and reducing the non-biodegradable waste this staple food generates.

Degradation of High-Density Polyethylene (HDPE) Film by Bacterial Consortium

Degradation of High-Density Polyethylene (HDPE) Film by Bacterial Consortium

Tensile Properties of Luffa Acutangula Reinforced Polymer Composite

In recent years, there has been a growing trend in the popularity of natural fiber-reinforced polymer composites (NFRPC). Numerous researchers have put forward various alternatives to synthetic fibers. Luffa is one of the many natural fibers can be integrated into NFRPCs. Luffa with its unique interconnecting branch (mat/mesh) is suitable for NFRPCs. In this study, luffa reinforced high-density polyethylene (Luffa/HDPE) composite was fabricated using compression molding machine. In the preparation of the fiber, Luffa were cylindrically cut-out and opened into sheets form. The fiber was then laminated with high-density polyethylene (HDPE) film using compression molding method. The proposed fabricated composite consisting of a fiber volume fraction (FVF) of 7%, 14%, 21%, 27% and 30%. Tensile properties of the Luffa/HDPE composite were determined. SEM was used to study the interlamination and delamination of the composite. Tensile test shows that the increase of FVF enhanced the tensile strength of Luffa/HDPE composite. Tensile strength has gradually increased from 7 % to 21 % FVF. Though, tensile strength declines after 21% FVF.

Direct observation of radiation-induced graft polymerization on a polyethylene film

Radiation-induced graft polymerization is widely used in the synthesis of polymeric materials with various functionalities; however, the details of the reaction mechanism are still unresolved. Herein, the initial stage of the graft polymerization reaction was investigated through atomic force microscopy (AFM). We used glycidyl methacrylate (GMA) in methanol (monomer solution) and a high-density polyethylene (HDPE) film with a well-ordered lamellar structure as the substrate. Using polymer film surfaces with a maximum grafting degree of 0.5%, AFM can distinguish between crystalline and amorphous polyethylene (PE) phases as well as a grafted polymer GMA (PGMA) phase. The graft polymerization reaction started from the interface between the crystalline and amorphous PE phases. As the reaction proceeded, the PGMA covered the crystalline PE phase: i.e., the entire surface of the PE film were covered by the PGMA. Further, the crystalline lamellae of the PE film eventually became a scaffold for the formation of aggregates comprising grafted polymer chains alone. The graft polymerization reaction mechanism was explained by comparing the solubility parameters of the monomer solution, substrate, and grafted polymer chains. Understanding the reaction mechanism at a low grafting degree obtained in this study may contribute to enhancing the efficiency of the graft polymerization reaction on any polymeric material.

Enhancing interfacial adhesion through coupling agent incorporation in plywood/ plastic waste composite materials

The objective this study was to fabricate 5-ply boards using virgin and recycled high-density polyethylene (vHDPE and rHDPE) films as formaldehyde-free adhesives, respectively. To enhance the interfacial adhesion between the wood veneer and HDPE film, various loadings (0, 3, 6, 8, and 11 wt%) of polyethylene grafted maleic anhydride (PE-g-MA) were applied as a coupling agent. The physical and mechanical performance of the resulting plywood boards was evaluated using standard test methods, with a UF resin-bonded plywood used as a control for comparison. All materials used were for commercial-scale plywood production. Fourier transform infrared spectroscopy (FT-IR) results provided valuable information about chemical interactions that occurred during the coupling of poplar fibers with HDPE using PE-g-MA. The experimental results showed that the mechanical and physical properties of the plywood boards improved as the amount of coupling agent increased from 0 to 11 wt%. PE-g-MA played a crucial role in the properties of plywood boards made with rHDPE and vHDPE by enhancing the interfacial bonding ability between the HDPE and adjacent veneers, leading to good stress propagation and improved mechanical properties. The properties of samples bonded with vHDPE were significantly more improved than those made with rHDPE, likely due to the presence of color pigments, additives, fillers, and impurities in the rHDPE, which made the coupling agent less effective. In addition, the results demonstrated that the samples made with rHDPE and vHDPE were superior to the plywood bonded with UF resin (control), and the optimal content of the coupling agent was found to be 8 and 11 wt%. These findings suggest that incorporating recycled HDPE films and using coupling agents, such as PE-g-MA, can produce high-quality plywood composite materials with improved mechanical and physical properties, providing an eco-friendly alternative to traditional UF resin-bonded plywood.

Preparation and characterization of plywood panels using recycled HDPE as a formaldehyde-free adhesive: A comparative study

Formaldehyde-based resins such as urea-formaldehyde (UF) are the most widely used adhesives in the plywood industry. However, due to the concerns about formaldehyde toxicity, there is a need to develop formaldehyde-free adhesive materials. Therefore, the present study aimed to minimize or eliminate the harmful effects of UF resin by using recycled high-density polyethylene (HDPE) from post-consumed fruit packing boxes as a nontoxic adhesive. Three-layer plywood panels using poplar veneers and recycled HDPE films were prepared. UF was used as a control adhesive for the comparison. The influence of three variable parameters in terms of HDPE content (from 80 to 320 g/m2), hot-pressing temperature (from 140 to 180 °C), and pressing duration (from 3 to 8 min) on the properties of plywood panels were evaluated. For evaluation, physical properties, namely water absorption (WA), thickness swelling (TS), and mechanical properties, namely modulus of elasticity (MOE), modulus of rupture (MOR), and glue-line shear strength of the samples, were studied. The findings of this work confirmed that HDPE films gave the values of mechanical properties of plywood panels comparable to those obtained with UF adhesive, even though the adhesive content and pressing time were lower than when the UF adhesive was used. The obtained bonding strength values of HDPE-bonded plywood panels ranged from 0.82 to 1.60 MPa and met the requirement for the European Standard EN 314-2. According to FE-SEM micrographs, the fractured surface of plywood panels with 240 g/m2 of HDPE displayed a homogeneous cross-section area, and a large amount of HDPE was attached to the veneer surfaces. It was found that the average mechanical properties tended to increase with an increase in the pressing temperature and time. The type of adhesive had a significant effect on WA and TS. The smallest values of WA and TS were observed in plywood samples using high contents of HDPE films (240 and 320 g/m2). The optimum conditions were an HDPE loading of 240 g/m2, a hot-pressing temperature of 160 °C, and a hot-pressing time of 5 min. The overall results showed that recycled HDPE had enough potential to reuse as a promising adhesive for the environmentally-friendly plywood manufacturing.

Facile fabrication of ultrastrong polyethylene nanocomposite films with low filler content via flow-driven graphene re-dispersion assisted crystallization

Fabrication of polymer films with superb mechanical properties is far from mature compared to that of fibers, hampering the further engineering applications of lightweight polymer materials. Herein, high density polyethylene (HDPE) films reinforced with re-dispersed or refined reduced graphene oxide (rGO) are prepared via a facile melt-stretching strategy. The incorporation of only 0.2 wt% rGO is demonstrated to endow the melt-stretched film (80× stretch ratio) with ultrahigh Young's modulus of 2.9 GPa and tensile strength of 162.2 MPa, which are comparable to many engineering plastics and also significantly superior to the existing HDPE/graphene composites. More importantly, these modulus and strength values are increased by 71 and 65% compared to the neat PE (80×), respectively, far more than the theoretical prediction with the mixing rule. Experimental characterizations indicate that the high-efficient mechanical enhancement is attributed to the strong synergy of melt stretching-driven crystallization and rGO re-dispersion or refinement in constructing the compact and robust shish-kebabs crystal network. Such microstructural characteristics greatly promote the load transfer along the covalently bonded molecular chains, and also from polymer to rigid fillers under loading. Furthermore, the excellent puncture resistance and thermo-mechanical properties of PE/rGO films have been demonstrated. This work provides a feasible way towards scalable manufacturing of high-performance polymer nanocomposite films from general plastics and carbonaceous nanomaterials.

Dopamine-Based Copolymer Bottlebrushes for Functional Adhesives: Synthesis, Characterization, and Applications in Surface Engineering of Antifouling Polyethylene.

Nonpolar materials like polyolefins are notoriously challenging substrates for surface modification. However, this challenge is not observed in nature. Barnacle shells and mussels, for example, utilize catechol-based chemistry to fasten themselves onto all kinds of materials, such as boat hulls or plastic waste. Here, a design is proposed, synthesized, and demonstrated for a class of catechol-containing copolymers (terpolymers) for surface functionalization of polyolefins. Dopamine methacrylamide (DOMA), a catechol-containing monomer, is incorporated into a polymer chain together with methyl methacrylate (MMA) and 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM). DOMA serves as adhesion points, BIEM provides functional sites for subsequent "grafting from" reactions, and MMA provides the possibility for concentration and conformation adjustment. First, the adhesive capabilities of DOMA are demonstrated by varying its content in the copolymer. Then, terpolymers are spin-coated on model Si substrates. Subsequently, the atom transfer initiator (ATRP) initiating group is used to graft a poly(methyl methacrylate) (PMMA) layer from the copolymers, with 40% DOMA content providing a coherent PMMA film. To demonstrate functionalization on a polyolefin substrate, the copolymer is spin-coated on high-density polyethylene (HDPE) substrates. A POEGMA layer is grafted from the ATRP initiator sites on the terpolymer chain on the HDPE films to provide antifouling characteristics. Static contact angle values and Fourier transform infrared (FTIR) spectra confirm the presence of POEGMA on the HDPE substrate. Finally, the anticipated antifouling functionality of grafted POEGMA is demonstrated by observing the inhibition of nonspecific adsorption of the fluorescein-modified bovine serum albumin (BSA) protein. The poly(oligoethylene glycol methacrylate) POEGMA layers grafted on 30% DOMA-containing copolymers on HDPE show optimal antifouling performance exhibiting a 95% reduction of BSA fluorescence compared to nonfunctionalized and surface-fouled polyethylene. These results demonstrate the successful utilization of catechol-based materials for functionalizing polyolefin surfaces.

Exploring the recycling potential of HDPE films reinforced with flax fiber for making sustainable decorative tiles

The goal of the research was to assess the recycling potential of waste high-density polyethylene (HDPE) films taken as reinforcement with natural fibers to fabricate decorative tiles with improved mechanical properties. Initially, the density of the composite was determined. Further, hardness, quasi-mechanical and impact properties were evaluated for the HDPE/natural fiber composite samples by testing the composites tensile, flexural loads and impact. In addition, to evaluate the thermal characteristics of the composite, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) study were performed. Water absorption and sound absorption properties were determined for industry specific applications. Scanning Electron Microscopic analysis (SEM) was performed for analyzing the microstructure and also HDPE matrix and natural fibers bonding exists in the composite. The findings confirmed that adding natural fibers to the HDPE matrix impressively increased both tensile and flexural strengths by up to 25%. The impact strength was also enhanced by up to 38%, whereas the hardness and density values remained relatively unchanged. Improved interfacial bonding between the HDPE matrix and natural fibers had been identified by SEM analysis, which was a factor in the composite material's enhanced mechanical characteristics. These findings suggest that waste HDPE films/natural fibers composite can be effectively recycled to fabricate decorative tiles with improved mechanical properties, thereby offering a sustainable and eco-friendly alternative to traditional decorative tile materials.

Antifungal packaging with coconut oil extract improved the storage of fresh tamarillo fruits

During the post-harvest period, the shelf life of tamarillos can be significantly affected by fungi such as Colletotrichum tamarilloi. Although incorporating fungicides such as lauric acid into packaging can prevent fruit loss, it is necessary to find more readily available sources of antifungal agents. This study demonstrated that incorporating coconut oil hydrolysis products (COHP) into packaging can prevent fungal growth in tamarillos (Solanum betaceum). We found that high-pressure hydrolysis of coconut oil produced COHP with 93.1% w/w organic phase recovery and a high concentration of lauric acid (43.3% w/w). Minimum inhibitory concentration assays of CHOP against four different fungi (Colletotrichum tamarilloi, Fusarium oxysporum f.sp. passiflorae, Fusarium solani, and Fusarium equisetti) confirmed their antifungal properties. Furthermore, we incorporated COHP as an additive in high-density polyethylene (HDPE) films and observed that it inhibited the growth of Colletotrichum tamarilloi by over 80%. Results from in vivo studies showed that the shelf life of both infected and healthy tamarillos was extended by up to three and more than four weeks, respectively.

Biodegradation of polyethylene film by the Bacillus sp. PELW2042 from the guts of Tenebrio molitor (Mealworm Larvae)

The chemical molecular structure of polyethylene (PE) is very stable and extremely difficult to degrade in the environment, thus posing a threat to the environment. In this study, a high-density polyethylene (HDPE)-degrading Bacillus strain PELW2042, was isolated from the gut contents of Tenebrio molitor larvae (yellow mealworms). Results showed that after 42 days of incubation with PELW2042, a large number of pits and cracks were observed on the surface of HDPE film by scanning electron microscopy (SEM). The Fourier Transform-Infrared Spectroscopy (FT-IR) detected absorption peaks near 1700 cm-1 and 1249 cm-1, indicating the formation of carbonyl groups (–CO) and ether groups (–C–O); the X-ray photoelectron spectroscopy (XPS) spectra further demonstrated the generation of new oxygen-containing functional groups. X-Ray Diffraction (XRD) and differential scanning calorimetry (DSC) analyses revealed a 21.63 ± 0.18 % decrease in the relative crystallinity of the HDPE film, indicating that the structure of the HDPE changes. Finally, it was also shown that the weight loss of HDPE film was as high as 17.36 ± 0.56 %. After 42 days of treatment by strain PELW 2042, the molecular weights of the experimental group samples were significantly decreased by 23.31 ± 1.25 % and 30.07 ± 1.37 % for Mw (121700 Da) and Mn (50700 Da), respectively, compared to those of the untreated samples (Mw=158700 Da and Mn=72500 Da). All these results indicate that Bacillus sp. PELW2042 has a high ability to degrade HDPE. This provides a source of strains to accelerate the biodegradation of waste polyethylene plastics.

Utilization of Bacillus cereus strain CGK5 associated with cow feces in the degradation of commercially available high-density polyethylene (HDPE).

The accumulation and mismanagement of high-density polyethylene (HDPE) waste in the environment is a complex problem in the present scenario. Biodegradation of this thermoplastic polymer is a promising environmentally sustainable method that offers a significant opportunity to address plastic waste management with minimal negative repercussion on the environment. In this framework, HDPE-degrading bacterium strain CGK5 was isolated from the fecal matter of cow. The biodegradation efficiency of strain was assessed, including percentage reduction in HDPE weight, cell surface hydrophobicity, extracellular biosurfactant production, viability of surface adhered cells, as well as biomass in terms of protein content. Through molecular techniques, strain CGK5 was identified as Bacillus cereus. Significant weight loss of 1.83% was observed in the HDPE film treated with strain CGK5 for 90days. The FE-SEM analysis revealed the profused bacterial growth which ultimately caused the distortions in HDPE films. Furthermore, EDX study indicated a significant decrease in percentage carbon content at atomic level, whereas FTIR analysis confirmed chemical groups' transformation as well as an increment in the carbonyl index supposedly caused by bacterial biofilm biodegradation. Our findings shed light on the ability of our strain B. cereus CGK5 to colonize and use HDPE as a sole carbon source, demonstrating its applicability for future eco-friendly biodegradation processes.

Imidazolium Salts for Candida spp. Antibiofilm High-Density Polyethylene-Based Biomaterials

The species of Candida present good capability to form fungal biofilms on polymeric surfaces and are related to several human diseases since many of the employed medical devices are designed using polymers, especially high-density polyethylene (HDPE). Herein, HDPE films containing 0; 0.125; 0.250 or 0.500 wt% of 1-hexadecyl-3-methylimidazolium chloride (C16MImCl) or its analog 1-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS) were obtained by melt blending and posteriorly mechanically pressurized into films. This approach resulted in more flexible and less brittle films, which impeded the Candida albicans, C. parapsilosis, and C. tropicalis biofilm formation on their surfaces. The employed imidazolium salt (IS) concentrations did not present any significant cytotoxic effect, and the good cell adhesion/proliferation of human mesenchymal stem cells on the HDPE-IS films indicated good biocompatibility. These outcomes combined with the absence of microscopic lesions in pig skin after contact with HDPE-IS films demonstrated their potential as biomaterials for the development of effective medical device tools that reduce the risk of fungal infections.

Experimental approach of contact mechanics for polyethylene materials with human skin under wet condition

As a lifestyle habit, shoppers like to lick their fingers before opening the polyethylene (PE) shopping bag. In fact, this implies a scientific problem, that is, moisture has an impact on the friction behavior between the plastic bag and the surface of the finger skin. In this study, an experimental method was employed to measure skin friction at three different hydration levels. The high-density polyethylene (HDPE) and low-density polyethylene (LDPE) materials were performed, and photographs of fingertips touching PE films were recorded by a camera. The experimental results showed that the applied normal load is positively correlated with the friction force and negatively correlated with the friction coefficient. And moisture content will increase friction. Specifically, when the fingertip slides on the HDPE film, the friction coefficient of the water-soaked skin is 5.9 times that of the dry skin. It can be inferred that the decrease in modulus of elasticity, as well as volume expansion, leads to an increase in contact area when the skin is wetted with water. This is the main reason for the increase in finger friction. In addition, a negative power function model was established to describe the relationship between the coefficient and the friction conditions by considering the combined effects of hydration level, normal load and material. Abbreviations: CCD: Charge-coupled Device; COF: Coefficient of friction; HbA1C: Hemoglobin A1C; HDPE: High-density polyethylene; LDPE: Low-density polyethylene; PE: Polyethylene; SC: Stratum corneum;

Influence of ultraviolet and chemical treatment on the biodegradation of low-density polyethylene and high-density polyethylene by Cephalosporium strain.

In the present work, the potential of Cephalosporium strain in degrading the pre-treated (ultraviolet irradiation followed by nitric acid treatment) low-density polyethylene and high-density polyethylene films was investigated. Our observations revealed a significant weight reduction of 24.53 ± 0.73% and 18.22 ± 0.31% in pre-treated low-density polyethylene and high-density polyethylene films respectively, after 56days of incubation with the Cephalosporium strain. Changes in the physicochemical properties of the mineral salt medium (MSM) were studied to assess the extent of biodegradation. The pH of the MSM decreased gradually during the incubation period, whereas its total dissolved solids and conductivity values increased steadily. Fourier transform infrared spectroscopy (FTIR) indicated the formation of hydroxyl and C = C groups in biodegraded low-density polyethylene films, while in the case of biodegraded high-density polyethylene films it indicated the [Formula: see text]CH2 stretching. Furthermore, the thermogravimetric analysis (TGA) revealed an enhancement in the thermal stabilities of both the LDPE and HDPE films post the biodegradation. Modifications in the polymer surface morphologies after UV irradiation, chemical treatment, and biodegradation steps were visualized via scanning electron microscopy (SEM) analysis. All our observations confirm the ability of the Cephalosporium strain in biodegrading the pre-treated LDPE and HDPE films.

Degradation of high density polyethylene (HDPE) through bacterial strain from Cow faeces

The prime objective of our research was to assess the efficiency of fecal bacteria Brevibacillus parabrevis CGK45 from cow in the degradation of HDPE plastic films without any physical or chemical pre-treatment. The biodegradation studies were conducted considering various parameters such as percent weight loss and half-life of HDPE film, biomass of surface adhered cells in terms of protein content as well as viability of bacterial biofilm (CFU/cm2) on plastic surface, and hydrophobicity of bacterial culture. The extent of biodegradation was assessed by implementation of various techniques i.e., Field Emission Scanning electron microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). The bacterial strain was identified as Brevibacillus parabrevis CGK45 (Accession number MW965577) by phylogenetic analysis using 16S rRNA gene sequence homology. A significant weight loss (4.03%) in the HDPE film treated with strain CGK45 was observed after 90 days. The SEM analysis visualized remarkable bacterial colonization as well as structural changes in the surface micromorphology on HDPE surface. Furthermore, SEM-EDX analysis showed excellent reduction in the atomic percentage of carbon content (2.2%) whereas FTIR analysis confirmed the conformational shifting of peak and formation of new functional groups [ester (1290 cm−1) and alcohol (1368 cm−1)] apparently due to bacterial biofilm biodegradation. The findings of our investigation provides an insight into the ability of cow dung strain B. parabrevis CGK45 in the colonization and utilization of high density polyethylene as a sole carbon source proving its suitability for future environment friendly degradation studies.

A novel approach for preparation of nanocomposites with an excellent rigidity/deformability balance based on reinforced HDPE with halloysite

An innovative approach, designated as supported activator (SA), allows preparation of high density polyethylene (HDPE)-based highly performant hybrid materials. This procedure makes use of a nano-sized supported methylaluminoxane (MAO)-activator, based on halloysite natural nanotubes (HNT), combined with an in situ supporting concept. The new protocol when compared with a more conventional approach gives rise to higher polymerization activities as well as ultimate materials with better morphological features, greater crystallinity, thicker crystals, and highly increased stiffness. Moreover, a remarkable synergy between rigidity and toughness is attained. The Young’s modulus of a film obtained from the nanocomposite with the highest HNT content increases more than 70 % relatively to a pristine HDPE film, while retaining the limit stretching ability of pristine HDPE (more than 800%). A beneficial impact of using a high aspect ratio support such as HNT in the mechanical properties is also observed, when compared to similar HDPE hybrid materials derived from dendrimer-like silica (DS) nanospheres. Interestingly, polymerization activity, polymer features and derived properties found in the ultimate materials are less impacted by support/filler nature than by preparation method. This fact highlights the crucial role of the synthetic methodology used and corroborates the high potential of the SA route for the preparation of high-performance polyethylene-based nanocomposites with an excellent balance between stiffness and deformability.