Fillers In Low Density Polyethylene Research Articles

Ultraviolet Shielding Performance of Coconut Coir as a Filler in Low-Density Polyethylene (LDPE) Plastic Mulch

Plastic mulch is a layer of material applied to the soil surface to maintain moisture retention in the soil by preventing evaporation, reduce weed growth by blocking sunlight from reaching underlying weeds, and optimize fertilizer use by minimizing nutrient loss to the environment. However, the degradation of low-density polyethylene (LDPE), a thermoplastic commonly used for mulching, into microplastics due to exposure to UV radiation. This research explored the potential of coconut coir, a natural fiber with a high lignin content ranging from 30 to 46%, as a UV protective agent. The objective was to develop biodegradable plastic-based mulch composites that have better resistance to UV exposure by incorporating coir as a filler material in LDPE-based composites. Different ratios of coconut fiber were used (10%, 20%, 30%, and 40%), and Maleic anhydride grafted polyethylene (PE-g-MAH) was used as a binder at 2% of total weight mixed with LDPE in a rheomixer (80 rpm, 120°C for 10 min). The resulting plastic mulch bio-composites were evaluated for thermal, mechanical, UV resistance, and biodegradability properties. The results showed that the higher addition of coconut coir resulted in a decrease in the thermal and mechanical characteristics of the composite. However, the addition of higher coconut coir in the composite at 40% can provide an increase in the composite's resistance to ultraviolet light exposure, and the properties are easily degraded by the environment (biodegradable).

Effective Attenuation of Electromagnetic Waves by Synergetic Effect of α-Fe2O3 and MWCNT/Graphene in LDPE-Based Composites for EMI Applications.

In this study, a polymer nanocomposite is synthesized using magnetic and conducting fillers for enhanced electromagnetic interference (EMI) shielding. Alfa-ferrite (α-Fe2O3) nanoparticles with minimal multiwalled carbon nanotube (MWCNT) as low as 5 weight % in combination with variable concentrations of graphene nanoplatelets (GNP) are used as fillers in low-density polyethylene (LDPE) polymer matrix. Nanofillers and the polymer matrix are characterized by various techniques such as XRD, SEM, color mapping, EDAX, TGA, etc. The EMI shielding efficiency of the LDPE-based nanocomposites is tested using Vector Network Analyzer (VNA). The results showed that composite with LDPE:MWCNT:GNP:α-FO-50:5:40:5 displayed enhanced EMI shielding (in X-band (8.2-12.4 GHz) compared to other concentrations studied. This is due to the superior ohmic, dielectric, and magnetic losses at this particular composition and to the synergism amongst the filler. An attenuation of 99.99% was achieved for 5% α-Fe2O3. The mechanistic aspects of the shielding are discussed using permittivity, conductivity, and attenuation.

Approach in Macadamia integrifolia residue based low‐density polyethylene composites on mechanical and thermal performance

AbstractMacadamia nutshell residues are generated in large quantities, around 70%–77% for each ton produced, and it is a waste material with high techno‐economic potential. This work purpose a sustainable alternative to valorize macadamia nutshell residues (MN) as reinforcing in low‐density polyethylene (LDPE) composites through melt mixing, using different fiber contents (0, 5, 10, and 20 wt%), and investigate the influence of fibers (residues) in composites by mechanical tests and thermal analysis. The fibers addition has significantly increased the composites' stiffness compared with neat LDPE, causing a reduction of toughness and resilience, leading to lower impact energy absorption. The LPDE/MN20% composite obtained the best tensile and flexural mechanical performance, resulting in a maximum modulus, which implies an increase of 36.9% and 77.6% compared with the neat LDPE. The addition of macadamia fibers on the composites acted as nucleation points of spherulites, which promoted an increase in the crystallization degree. Consequently, better performance of mechanical properties was observed in the green composites. Thus, the macadamia nutshell residues present a promising future as filler in LDPE for enhancing composites' thermal and mechanical properties.

PREPARATION AND CHARACTERIZATION OF MAGNESIUM/ALUMINIUM LAYERED DOUBLE HYDROXIDE AS FILLER IN LOW-DENSITY POLYETHYLENE COMPOSITE

Polymer had been widely used in industries nowadays. However, the properties of the polymer itself are limited to a particular application. This study describes synthetic clay, layered double hydroxide (LDH), as a filler in low-density polyethylene (LDPE) composite. LDHs of magnesium/aluminium-dodecyl sulfate (Mg/Al-DS) and its grafted with triethoxymethylsilane (TEMS), (TEMS-g-Mg/Al-DS) were synthesized through co-precipitation and salinization reaction methods. The presence of alkyl group, v(C-H) in both LDH had confirmed through Fourier transform infrared (FTIR). The appearance of peaks in FTIR spectra within the absorbance range of 2800 – 2930 cm-1 indicates a successful surface modification of LDH, supported by the changes of interlayer spacing and the presence of carbon from X-ray diffractogram and CHNS elemental analysis, respectively. The synthesized LDH was mixed with LDPE via melt intercalation method. The LDH modification resulted in higher interaction and compatibility between the LDPE matrix and LDH by the formation exfoliated type of nanocomposites, as suggested by XRD analysis.

Thermoset powder coating wastes as filler in LDPE – Characterization of mechanical, thermal and morphological properties

In this study, three different electrostatic powder coating wastes of thermoset structure were used as fillers for low-density polyethylene (LDPE). The mechanical, thermal, and morphological properties of these composites materials are reported. The thermoset powder coating wastes were hydrolyzed using water and alcohol, and then 10%, 20%, and 30% by weight of the deactivated wastes were mixed with LDPE, first in a mechanical dry mixer, and subsequently homogenized by melt compounding in an extruder at about 160 °C. Standard tensile test bars and plate-shaped samples were produced from these homogeneous compounds by injection molding. The effects of adding hydrolyzed powder coating wastes on the properties of LDPE were determined by mechanical, thermal, and morphological tests. Tensile strength and perforation threshold of the sample filled with powder coating wastes decreased to some extent compared to un-filled sample. However, an increase in izod impact and bending strengths has been observed. The results of this investigation demonstrate that powder coating wastes with thermoset structure can be used as fillers in LDPE.

Nanocomposites of polyethylene and ternary (Mg + Zn/Al) layered double hydroxide modified with an organic UV absorber

In this research work, ternary (Mg + Zn:Al; M2+:M3+ = 2:1) layered double hydroxides (LDH) intercalated with nitrate and p-aminobenzoate anions were synthesized through the co­precipitation method at constant alkaline pH. These materials were characterized by several instrumental techniques and used as functional fillers in low-density polyethylene (LDPE), obtaining homogeneous nanocomposites by means of injection molding. In the samples prepared with percentages of 0.5, 2, 4, 6 and 10% by weight in relation to LDPE, maintenance or slight improvement of the mechanical properties was observed for all samples. In the LDPE nanocomposites the UV absorption showed to be higher than neat polyethylene. Weathering experiments performed with the neat LDPE and LDPE nanocomposites containing 5% of maleic anhydride and 5% of LDH intercalated with p­aminobenzoate demonstrated a decrease of oxidation product generated due to ultraviolet radiation absorption because the organic intercalated specie, indicating that the ternary LDH is a potential filler to protect polymers from UV radiation degradation.

A study on the dielectric response of polyethylene-metal oxide nanocomposites for electrical insulation in HVDC cables

Abstract Metal oxide nanoparticles such as MgO and SiO2 have been investigated as fillers in low density polyethylene. The surface modification of the oxide nanoparticles were done with functional methyl, ethyl, hexadecyl or octylsilane. The distribution and dispersion of the nanoparticles in the LDPE is determined by SEM (Scanning Electron Microscopy). Studies were carried out by measuring surface resistivity, volume resistivity. Fourier Infrared spectrometer for identifying the functional groups. Dielectric response studies were carried out using spectroscopic techniques like Dielectric spectroscopy (dielectric loss angle, permittivity, capacitance measurements as a function of frequency from few mHz upto 1 kHz). The surface and volume resistivity of nanocomposites have increased by one order compared to neat LDPE samples. Higher concentrations of nanoparticles have resulted in lower withstanding stresses probably due to decrease in crystallinity with filling concentration. TMMS treated nanoparticle composite show better performance compared PEMAH treated nanocomposite. The dielectric response study on nanocomposites show there is no change in permittivity upto 1 Hz, but slightly increase in value below 1 Hz and upto 0.001. It is presumed that large amount of charges migrate into and go through the LDPE. On the contrary Nano composites can inhibit the charges to inject into the interior of the composite and make most of the charges gather on the surface of the sample.

Rheological properties of low-density polyethylene filled with hydrophobic Co(Ni)-Al layered double hydroxides

Abstract Cobalt/aluminum and nickel/aluminum layered double hydroxide (LDH - M+2:Al molar ratio of 3:1) were intercalated with dodecylsulphate (DDS), laurate (LAU), stearate (STE) and palmitate (PAL) and used as filler in low-density polyethylene (LDPE) in percentages between 0.2 and 7.0wt%. After injection molding, the samples were submitted to morphological characterization by scanning electron microscopy (SEM), analysis of thermal behavior by differential scanning calorimetry (DSC) and investigation of rheological properties. All Co/Al-LDPE samples showed the formation of a high temperature polymer crystal domain, induced by the LDH filler. The rheological properties indicated in general a reduction of shear modulus due to incompatibility between some regions of LDH and LDPE, which promoted phase separation. However, interaction with the LDH surface indicated higher affinity of the Ni/Al-LDH for the LDPE compared to Co/Al-LDH, forming permanent networks.

Fly ash used as a reinforcing and flame-retardant filler in low-density polyethylene

In this study, the possibility to modify low density polyethylene (PE-LD) with fly ash (FA) was tested. Four series of PE-LD composites filled with 1, 5, 20 or 50 wt % of FA were prepared by injection molding. The samples in each of the series differed in particle size of the filler used (0—15 μm, 15—30 μm, 30—60 μm). The influence of amount and the particles size of filler on morphology, mechanical properties, thermal stability and flammability of the composites were investigated. The results show that composites with the addition of FA in the amount up to 20 wt % are characterized by good mechanical properties and processability, and also smaller than the pure PE-LD, flammability.

Zinc layered hydroxide salts: intercalation and incorporation into low-density polyethylene

In this study, polymer composites using low-density polyethylene (LDPE) and layered hydroxide salts (LHS) were synthesized. The following compositions of LHS were obtained Zn5(OH)8(An-)2/n.yH2O, where A was varied in order to obtain hydrophilic (A = NO3-) or hydrophobic (A = DDS- - dodecyl sulfate or DBS- - dodecyl benzene sulfonate). Synthesis was carried out by co-precipitation in alkaline medium and drying, being followed by characterization via Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. A variable amount of filler was then incorporated into the LDPE via extrusion, which was then injection molded to obtain specimens for evaluating tensile properties (Young's modulus, tensile strength, strain at break and toughness). For comparison, the sodium salts of the surfactants (NaDDS and NaDBS) were also used as fillers in LDPE. The X-ray diffraction results indicated that the hydrophobic LHS were exfoliated in the polymer matrix, whereas the hydrophilic LHS was only delaminated. In the LDPE composites, melting and crystallization temperatures were nearly constant, along with the crystallinity indexes. The mechanical properties were mainly varied when the organophilic LHS was used. Overall, fillers based on LHS, especially those containing hydrophobic anions, may be interesting alternatives in the production of reinforced thermoplastics.

Study of lignin dispersion in low-density polyethylene

A maximum of 20% (w/w) lignin was used as a filler in low-density polyethylene (LDPE), together with 3–6% maleic anhydride-grafted LDPE as compatibilizer and 3–10% copper(II) sulphate pentahydrate (CuSO4·5H2O) as lignin’s dispersing agent. The resulting composites were investigated for both their mechanical properties and their melting point following the ASTM standards as well as their behaviour was compared with neat LDPE. The results reveal that addition of compatibilizer significantly improved the mechanical properties of lignin, yielding closer values to those of neat LDPE. In fact, the addition of 3% maleated polyethylene induced a 37% increase of the Young’s modulus, whilst 3% CuSO4·5H2O provides a good lignin dispersion. The above observations are further supported by the scanning electron micrographs of the blend specimens. Finally, the differential scanning calorimetry analysis revealed that the melting temperature and the crystallinity of LDPE slightly increase with the addition of 3% CuSO4·5H2O.

Silver-coated copper nanowires with improved anti-oxidation property as conductive fillers in low-density polyethylene

Silver-coated copper nanowires (AgCuNWs) are prepared by chemical plating method with copper nanowires (CuNWs) and Ag-amine reagent. The prepared AgCuNWs with silver content of 66.52 wt.%, diameter 28–33 nm exhibited improved anti-oxidation behaviour. The silver coating on AgCuNWs can effectively reduce the formation of copper oxide under room temperature. The temperature at which nanowires begin to gain weight can be improved from 85 to 230°C and the maximum weight gain can be decreased from 20.3% to 3.2% by applying silver coating. The volume electrical resistivity of the AgCuNWs filled low-density polyethylene nanocomposites is lower than that of the CuNWs filled low-density polyethylene nanocomposites with same volume percentage of fillers because the silver content in the AgCuNWs is not oxidised during compression moulding. © 2012 Canadian Society for Chemical Engineering

THE EFFECT OF ACETIC ACID ON PROPERTIES OF COCONUT SHELL FILLED LOW DENSITY POLYETHYLENE COMPOSITES

Natural lignocellulosics have an outstanding potential as reinforcement in thermoplastics. Coconut shell is one of natural lignocellulosic material. In this study, coconut shell (CS) was use as filler in low density polyethylene (LDPE) composites. The effect of surface treatment of coconut shell (CS) with acetic acid (acetylation) on mechanical properties, thermal properties and morphology were studied. The acetylation treatment has improved the tensile strength, elongation at break and Young's modulus of LDPE/CS composites. Thermogravimetric analysis (TGA) results show that the acetylated composites has better thermal stability compared to untreated composites at 600 °C. Differential scanning calorimetry (DSC) analysis showed that the esterification treatment increases the crystallinity of LDPE/CS composites. It was found that coconut shell acts as a nucleation agent in the presence of acrylic acid. The scanning electron microscopy (SEM) study of the tensile fracture surface of acetylated composites indicates that the presence of acetic acid increased the interfacial interaction.

Sorption of toluene from aqueous solutions with polyethylene and cellulose powders and composite materials made from them

Toluene is sorbed on LDPE (low-density polyethylene) and PC (powdered cellulose) by different mechanisms. Addition of cellulose as a disperse filler in LDPE increases the sorption capacity of pure LDPE powder by 2.0–2.5 times.

The effect of blending lignin with polyethylene and polypropylene on physical properties

Lignin, a natural polymer was used as a filler in low-density polyethylene and polypropylene up to 30wt%. The influence of lignin blending on processing stability, mechanical properties and light and long-term heat degradation are described for both polymer blend types. It was shown, that there is a different degradation behaviour between polyethylene-lignin and polypropylene-lignin blends. The lignin concentration influenced both the tensile strength and melt flow index.

Lignin-filled polyolefins

Dry lignin powder was used as a filler in low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) up to 30% w/w. The tensile strength reduced for all polymers. Impact properties were almost unaffected for PP but reduced for the other two polymers, Use of five parts of ethylene acrylic acid copolymer (EAA) and 0.5 parts of titanate coupling agent improved mechanical properties considerably. The melt viscosity increased steadily with increasing amounts of lignin. Electrical properties showed improved electrical resistance. The color of the resulting compound could be evaluated only up to a 10% lignin level, beyond which the compounds became very dark. At lower concentrations, samples of HDPE showed a more reddish tinge, while at higher concentrations, all samples showed a green–blue tinge. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1321–1326, 1999

Some properties of cassava mesocarp carbohydrates-low density polyethylene blends

Cassava mesocarp carbohydrate and its modified form were used as fillers in low density polyethylene to give plastic films that were biodegradable. It was found that the tensile strength of the films decreased with an increase in the amount of the filler incorporated. The water absorption results of the films showed that modification of the cassava mesocarp carbohydrate made it hydrophobic and therefore more compatible with the polyethylene.

Studies on Chenopodium quinoa and Amaranthus paniculatas starch as biodegradable fillers in LDPE films

Starches from newer food sources such as Amaranthus paniculatas and Chenopodium quinoa were studied for their possible role as biodegradable fillers in low density polyethylene (LDPE) films. Such starches have a unique feature of having an extremely small granule size (< 1 micron), which helps in better dispersion in polymeric films. In countries, where polymers are expensive, these starches could be used as inexpensive fillers. The effect of incorporating 3–15% corn starch, Amaranthus paniculatas and Chenopodium quinoa starch on the mechanical properties of the LDPE films was evaluated. The torque for blending of starches and LDPE was in general lower than that for LDPE alone. Incorporation of all the three starches decreased the tensile strength. Maximum decrease was observed with corn starch, and minimum decrease with Chenopodium quinoa and Amaranthus paniculatas was in between.