LDPE Blends Research Articles

Features of extrusion of films from blends of LDPE and LLDPE of modern grades

The study of rheological and viscoelastic characteristics of modern grades of LLDPE and their mixtures with LDPE, intended for the production of fi lm products, as well as the evaluation of mechanical characteristics of films made of them have been carried out. As a result of studying the rheological properties of LLDPE and LDPE, it was found that polymer melts show behavior typical of pseudoplastic liquids. The flow index for all grades of LLDPE was 0.78–0.91, which indicates a narrow MWD of polymers; LDPE had a flow index of 0.56–0.57 and a higher activation energy for viscous flow than LLDPE.The viscoelastic properties of the polymers were assessed by the value of swelling coefficient (Ks) at two test temperatures. It is shown that the Ks of LDPE significantly exceeded that of all studied LLDPE grades at the same shear rates or shear stresses. The increase in temperature had an insignificant effect on the Ks value for both LDPE and LLDPE. It has been found that an increase in the content of LDPE in mixtures with LLDPE leads to an increase in Ks.The analysis of tensile properties of films obtained from the original polymers and their blends showed that the character of change in strength and elongation at break depends on the composition and type of LLDPE from different manufacturers. Films based on m-LLDPE of LUCENE brand had the maximum strength properties. The optimal content of LDPE in a mixture with LLDPE depends on the type of LLDPE and is no more than 10–20 wt.%.

Optimization and production of renewable fuels from waste cooking oil and low-density polyethylene: Evaluating fuel properties and techno-economic feasibility of diesel replacement

Pyrolysis of waste cooking oil (WCO) and plastics have caught the eye of contemporary researchers and industrialists, as valuable fuels can be produced from these wastes. However, process parameters such as feedstock blend ratio and temperature have to be optimized to obtain high-energy fuels at low-energy supply. Hence, this study aims to provide an insight into the optimization and techno-economic feasibility for the production of diesel-equivalent fuel from WCO and LDPE. A full-factorial design of experiments was delineated between six temperatures and seven feedstock blend ratios to compare oil yields. An optimum bio-oil yield of 65% was observed at 500 °C and 2:1 (WCO:LDPE) blend-ratio. Further, pyrolyzed WCO and equal blends of WCO and LDPE were tested for fuel properties, and these confirmed to Grade No. 2 and Grade No. 4 diesel–fuel as per ASTM standards respectively. A techno-economic analysis indicated a payback period of <14 months for both the fuels.

Interaction between the phase separation and flow-induced crystallization process in polyethylene/ethylene-methacrylic acid ionomers (surlyn) blends during the film blowing: An in-situ synchrotron radiation X-ray scattering study

A homemade blown film methodology simultaneously coupled with in-situ synchrotron radiation small and wide-angle X-ray scattering (SAXS and WAXS) measurement was assisted to investigate the immiscibility (phase separation) mingled with the flow-induced crystallization of the polyethylene (PE)/surlyn blends during the film blowing process. The whole process is studied within three different regions (I, II, and III) of the bubble along the take-up direction, where the microstructure and temperature evolutions exhibit significantly distinct behaviors. In the SAXS patterns, the equatorial streak signal in the vicinity of the die exit indicates the phase separation among the different polymer components, which is in particular strong in blends consisting of both PE (blends of LDPE, LLDPE, and co-ethylene) and surlyn. The equatorial streak signal attenuates progressively but remains obvious within Region I. The disappearance of phase separation induced by strong flow is an exothermic process, which suppresses the cross-linked crystal network formation prior to the frost line (Af) within Region II. After the frost line, the main structural evolution is the formation of the non-deformable scaffold during the completion of crystallization along the bubble. It is found that the initial phase separation shows a limited influence on the final structure of the cross-linked crystal network, the effect of phase separation on the crystallization in Region I is eliminated due to the flow field and sufficient crystallization time ultimately. This work should be supportive for extended study and understanding of the structural evolutions of polymer blends during the film blowing.

The influence in difference of compatibilizers on the mechanical and rheological properties of LDPE/PLST blends

In this present study, low density polyethylene/plasticizer starch (LDPE/PLST) blends were prepared as a product to be used in disposable packaging (film applications), reducing the negative polymeric environmental effect. Because of their different molecular structures, LDPE blends with starch are fully immiscible; therefore, a compatibility agent is required. Three different polymer and/or copolymer: poly (vinyl alcohol) hydrolyzed 75% (PVOH), styrene-allyl alcohol copolymer (SAA) and polyethylene glycol (PEG) were selected as compatibilizers containing –OH groups. The effects of compatibilizer on the mechanical and rheological properties of LDPE/PLST blends were investigated and compared to LDPE/PLST without compatibilzer. The blends are also characterized by FTIR, which strongly indicates the existence of compatibilizers that can enhance phase interaction and promote compatibility in the blends of LDPE/PLST. Comparing to the blend without a compatibilizer, the tensile strengths of the blends containing PVOH and SAA increased significantly. The elongation at break results shows similar observation. The rheological measurement results suggested that the addition of a compatibilizer exhibited an increase in the shear stress and apparent viscosity comparing to the uncompatibilized blend except the blend with PEG which exhibited phase separation.

Effect of LDPE-g-MA as a compatibilizer for LDPE/PA6 blend on the phase morphology and mechanical properties

The study covered the synthesis of low density polyethylene-graft-maleic anhydride (LDPE-g-MA) and investigated its influence as a compatibilizer for LDPE/polyamide 6 (PA6) blend. LDPE-g-MA characterized by FTIR spectroscopy. Melt blends of LDPE and PA6 which contain 0, 2, 4, 6, 8 and 10 phr of LDPE-g-MA were prepared using a Brabender Plasti-corder and characterized by scanning electron microscope (SEM). The static mechanical, water absorption and dynamic mechanical properties of the LDPE/PA6 blends were reported. The study deduced the optimum content of LDPE-g-MA in LDPE/PA6 blends is 8 phr for morphological properties, flexural strength, tensile strength, flexural modulus, E-modulus, impact strength, water absorption percentage and dynamic mechanical properties. The results demonstrated the possibility of using the LDPE/LDPE-g-MA/PA6 (80/8/20) blend in various industrial applications for LDPE such as the manufacture of products made of plastic and in packaging goods.

Physical and Mechanical Properties of Wood-Plastic Composites Made with Microfibrillar Blends of LDPE, HDPE and PET

The effect of microfibrillar blends of recycled plastics on selected physical and mechanical characteristics of wood-plastic composites (WPCs) was investigated in this study. The production of wood plastic composites was carried out through a two-step extrusion technique. The plastic blends were drawn after extrusion to obtain microfibrillar morphology. The addition of polyethylene-co-glycidyl methacrylate (E-GMA) enhanced compatibility between the two phases and a homogenous structure was seen in the fracture surfaces by scanning electron microscopy (SEM). The crystallinity of base polymers increased with the addition of polyethylene terephthalate (PET) microfibrils, E-GMA and wood flour. The X-ray diffraction (XRD) patterns were also used to determine the crystallinity of all samples. According to the XRD results, the crystallinity degree of recycled plastics was higher than that of virgin plastics. E-GMA improved the water resistance of wood-plastic composites. The mechanical properties of samples were improved with the addition of PET microfibrils. The microfibrillar blending technique was found to be an effective approach for the production of high quality WPCs from recycled plastic blends.

Study of natural weathering exposure on properties of ldpe incorporated with sago starch

In this study it was investigated the incorporation of sago starch in low-density polyethylene matrix (LDPE) to enhanced mechanical properties and to obtain partially biodegradable product with the aim to reduce the plastics wastes in the environment. The compounding of the LDPE with sago starch was prepared via a twin screw extruder followed by injection molding. Studies on their physical, mechanical properties and thermal properties of each formulation before and after natural weathering exposure were carried out by tensile, thermogravimetry analyzer (TGA-DTA) and scanning electron microscope (SEM). The biodegradability of sago starch–filled LDPE blend was studied by monitoring its weight loss. Tensile tests, TGA and SEM imaging were also carried out on the samples before and after degradation. Imaging showed that the increase in starch content from 5% to 20% in the formulations increases the biodegradability of the samples.

Tensile and Impact Behaviour of Thermoplastic BOPP/Milk Pouches Blends Reinforced with Sisal Fibers

Sisal (Agavae family) fiber reinforced BOPP/thermoplastic LLDPE: LDPE blend was prepared by melt mixing in a hydraulic compression press extruder. The composite were prepared with different fiber content: 5%, 10%, 15%, 20% (by weight). Mechanical properties (i.e. tensile strength and impact strength) were studied. Tensile strength showed an increasing trend with increase in fiber content up to 15% then decreases. Impact strength increases with the increase in fiber content. SEM shows the morphology and the melting point and material identification by DSC analysis.

Utilization of Waste Plastics in Stone Mastic Asphalt for Infrastructural Applications

This paper reports an experimental study on the use of waste plastics in stone mastic asphalt (SMA) for infrastructural applications (e.g. roads, carparks and underground construction). The binders investigated were conventional bitumen, target bitumen (polymer modified bitumen) and waste plastics (recycled low-density polyethylene LDPE of 5 wt% and 10 wt% blends). The properties of bitumen were assessed based on its penetration value and softening point; while the performance of asphalt premix (or asphalt mixture) was evaluated based on its Marshall stability, flow and quotient. The asphalt mixture incorporating waste plastics (10 wt% LDPE blend) as polymer modifier could be a promising material for use in SMA for infrastructural applications.

Thermogravimetric characteristic and kinetic of catalytic co-pyrolysis of biomass with low- and high-density polyethylenes

The pyrolysis of wood fuel (WF) and polyethylenes (low-density polyethylene; LDPE and high-density polyethylene; HDPE) in a non-catalytic and catalytic co-pyrolysis over zeolite catalyst (ZSM-5) were studied via a thermogravimetric analysis. The result obtained for the biomass with LDPE and HDPE blends shows that the peak temperature decreases significantly only at blends with catalyst as compared to the peak temperature of isolated LDPE and HDPE materials. The peak temperature of WF/LDPE/ZSM-5 (390 °C) was lower than that of WF/HDPE/ZSM-5 (480 °C). The weight loss differences between experimental and theoretical values were greater than 1% at temperature higher than 500 °C in the various admixtures which depicts the occurrence of chemical interactions between the blends. After catalysts were added to the blend, the fuels became more reactive to thermal degradation. The results of the non-catalytic pyrolysis kinetics revealed activation energy values of 54.09 and 95.90 KJ/mol for WF/LDPE and WF/HDPE, respectively. However, with the presence of ZSM-5 activation, energy falls to 24.13 and 50.45 for WF/LDPE/ZSM-5 and WF/HDPE/ZSM-5, respectively. The findings in this work show that the kinetic of catalytic co-pyrolysis of biomass with plastic can be viewed as a potential thermochemical conversion method that can be effectively utilized for a marked reduction in energy requirement of the process.

Rheological and mechanical properties of blends of LDPE with high contents of UHMWPE wastes

ABSTRACTThe mixing of UHMWPE wastes with other polymers aims to reduce the environmental impact of waste materials. The dynamic rheological behavior of the blends, tensile and abrasion properties, Shore D hardness and impact resistance, and morphology are important in characterizing polymer blends. In this work, we have sought to obtain blends containing different proportions of UHMWPE wastes and LDPE with properties suitable for the manufacture of useful products. The blends exhibit an increase in complex viscosities, storage modulus, and Young's modulus with increasing content of UHMWPE wastes and a decrease in both the maximal elongation and Charpy impact resistance. Summarizing, the addition of up to 60 wt % of industrial fragments of UHMWPE is possible using conventional methods of processing to prepare blends with values of tensile strength, abrasion, and Shore D hardness similar to those of LDPE. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44996.

THERMAL, MECHANICAL AND ANTIBACTERIAL PROPERTIES OF LDPE/STARCH BIO-BASED POLYMER BLENDS FOR FOOD PACKING APPLICATIONS

In this study, low density polyethylene, LDPE was melt blended with starch using twin screw extruder to form biodegradable polymer blends. The LDPE/starch blend films used in food packing were obtained by hot pressing of the granules produced by extrusion process. The starch content was varied from 0 to 40 wt% of LDPE. To provide fine starch dispersion, glycerol and zinc stearate were used as plasticizer and compatibilizer, respectively. The effect of starch content on the properties of LDPE film was investigated. A good dispersion was achieved for low starch contents, but agglomeration of the starch particles occurred in the presence of high amounts of starch. The addition of starch to LDPE reduced the tensile strength, elongation at break, crystallinity and water resistance of LDPE. This decline in the LDPE properties was dramatic when the starch content was increased to 30 wt% in the blend. In addition, silver nanoparticles as antibacterial agent were incorporated to the biodegradable LDPE blend where LDPE/starch weight ratio of 60/40. Antimicrobial activities of the nanocomposite films against gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus) were determined by measuring the inhibition zone around each film. The effects of these nanoparticles on morphological, mechanical, thermal and water resistance properties of the LDPE/starch biodegradable blend were also investigated. It was observed that the incorporation of nanoparticles to the LDPE/starch blend was completely changed the morphology of the film, and accordingly, the mechanical, thermal and water resistance properties were varied depending on the nanoparticle content in LDPE/starch blend film.

Interfacial self-adhesion of polyethylene blends: the role of long chain branching and extensional rheology

The interfacial self-adhesion strength of polyethylene (PE) binary blends in temperatures higher than the melting point was investigated in relation to their components’ structures and elongational rheological properties. Four binary blends were prepared from the combination of a conventional polyethylene; LDPE or Ziegler-Natta LLDPE, with a metallocene catalyzed ethylene α-olefin copolymer; linear (Linear-m) or long chain branched (LCB-m). Interfacial adhesion was carried out by bringing two films into intimate contact under slight pressure and heat for 0.5 s. Adhesion strength was then measured by peeling immediately after sealing while the adherents were still in the molten state. Blending metallocene in 20, 40, and 60 wt% compositions with conventional PEs enhanced the self-adhesion. However, the adhesion strength of the blends containing 60 wt% metallocene resins was significantly lower than the adhesion strength of neat metallocene resins. This was interpreted to be due to the formation of a segregated layer of highly branched short chains of LDPE or Zn-LLDPE at the surface of films. The increase in adhesion strength of LDPE/Linear-m and Zn-LLDPE/Linear-m blends was more than LDPE/LCB-m and Zn-LLDPE/LCB-m blends. This was attributed to the faster reptation of linear chains, hence superior diffusion across the interface compared to LCB containing resin. The higher increase of adhesion strength for all compositions of LDPE blends was observed compared to their Zn-LLDPE counterparts. The temperature range in which the film showed a plateau of its highest adhesion strength was determined for all blend compositions. The results indicated that the temperature window of plateau adhesion strength for LDPE blends were broader than their Zn-LLDPE counterparts. Therefore, this work suggests that the final plateau temperature (T pf ) can be correlated with the area under stress–strain curve of the extensional rheological measurements, which is called toughness. Then, the higher melt toughness can result in a broader adhesion strength plateau.

Anisotropic thermal conductive MWCNT/polymer composites prepared with an immiscible PS/LDPE blend.

This study focuses on MWCNT/polymer composites with flexible, anisotropic heat transporting properties. For this study, an immiscible polymer blend of MWCNT/PS and LDPE (13.5:86.5 v:v) were used as a template. MWCNT/PS composites were first prepared by a solution process, and then melt-blended with LDPE using a brabender mixer. For achieving an alignment of MWCNT/PS in LDPE matrix, the blends of MWCNT/PS and LDPE were continuously treated under a fixed shear rate of 10 s(-1) at 210 °C. With partial extraction of PS in the aligned blends, FE-SEM images of the aligned blends revealed morphology of MWCNT in the PS/LDPE matrix, indicating local distribution of MWCNT selectively inside PS, where PS was elongated parallel to shear direction in LDPE matrix. The prepared MWCNT/PS and LDPE blends showed an anisotropic heat transporting behavior with anisotropic ratio of thermal conductivity (AR = λx/λz) up to 1.330 at 10 wt% of MWCNT in PS (equivalent to 1.50 wt% of MWCNT in PS/LDPE).

Biofilm Green Packaging: Characterization and Biodegradation Studies

Normal 0 false false false EN-MY X-NONE X-NONE MicrosoftInternetExplorer4 The LDPE was blended with various contents of tapioca starch (10%, 20%, 30%, and 40%) with addition of compatibilizer, which is PE-g-MA and cooking oil as plasticizer. The blends were prepared by co-rotating twin screw extrusion process and characterized by melt flow index (MFI) analysis and tensile test. Tapioca starch based polyethylene biofilms were studied in term of biodegradability by fungi test. The increasing of starch content to LDPE blend was reduced the MFI values and tensile strength but in 30% and 40% of starch content in tensile strength is higher than control LDPE’s strength due to molecular orientation in sample. However, incorporation of PE-g-MA as compatibiliz increase the mechanical properties of starch based polyethylene blends due to the reaction between maleated PE and starch, thus improves adhesion and reduces slippage at matrix-filler interface.ers The increasing of TS also increase the water content in film sample, weight loss percentage in TGA, and percentage degradation of LDPE/TS blend film. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Features of the melt flow of polyethylene and boron oxide oligomer blends

The features of melt flow of LDPE and boron oxide oligomer blends during extrusion mixing are investigated. It is established that the extruder-wall pressure and the torque of the screw decrease monotonically with an increase in the boron oxide oligomer content up to 25 vol %. Exceeding this concentration threshold leads to a several-fold stepwise fall in of the mentioned characteristics. This result is explained within the concepts about spontaneous restructuring of the blend accompanied by an increase of the specific surface of phases and by slipping at the interface of the blend components that is caused by the planar structure of the boron oxide oligomer molecules.

Mechanical and morphological properties of LDPE/ PHB blends filled with castor oil pressed cake

Blends of PHB and LDPE were prepared by melt mixing in a twin screw extruder. Castor oil cake (CC) was used as filler for the blends. The design of experiments (DOE) technique was used to evaluate the effect of the components proportion on the materials properties. The mechanical properties and morphology of the materials were evaluated. The LDPE Young's modulus increases but the other tensile properties and impact resistance deteriorate with the addition of PHB or CC. The tensile strength values of binary mixtures of LDPE lie in the range from 8.9 to 10 MPa. As some commercial grades of LDPE have mechanical strength in this range, it may be inferred that the addition of a certain amount of PHB or CC to LDPE may be considered as a possibility for obtaining LDPE based materials with increased susceptibility to biodegradation. The poor interfacial adhesion between the phases became visible in all samples.

LDPE/PHB blends filled with castor oil pressed cake

Blends of PHB and LDPE were prepared by melt mixing in a twin screw extruder. Castor oil pressed cake (CC) was used as filler for the blends. The mixture design technique was used to evaluate the effect of the components proportion on the materials flexural properties. The results show that superior LDPE flexural properties may be obtained by the addition of PHB or castor oil cake to LDPE. Biodegradation was evaluated burying the samples in simulated soil for different periods of time. The ternary mixtures with higher content of PHB showed more pronounced degradation. Under the experimental conditions studied the LDPE/CC compositions presented no degradation. However, the loss of mass of the LDPE/PHB/CC ternary mixtures was higher than the loss of mass of the corresponding LDPE/PHB binary mixture. This result suggests that the castor oil cake accelerates the degradation of the LDPE/PHB mixtures.

Rheological and Thermal Properties of Blends of Recycled LDPE and Virgin LDPE

Blends of recycled LDPE and LDPE were prepared by the twin-screw extruder at different ratios. Recycled LDPE was used as matrix in this work, LDPE was used to improve the properties of RLDPE. Thermal and rheological properties of the blends were carefully evaluated and compared with pure LDPE. DSC measurements indicates that the RLDPE/LDPE blends are miscible in the crystalline phase and LDPE can increase the crystallization of the blends. Rheological analysis shows that virgin LDPE will promote the normal flow of RLDPE and improve the mobility of chain segments in flow. Consequently, the rheological and processing properties of the blends have improved compared to RLDPE. The blends show potential applications in high-value products.

Tailoring surface properties of polymeric blend material by ion beam bombardment

In this work, LDPE/SBR polymer blend samples were bombarded with 130keV He and 320keV Ar ions at different fluencies ranging from 1×1013 to 2×1016 ionscm−2. The changes in surface properties of the ion-bombarded polymers were investigated with ultraviolet–visible (UV–vis) spectroscopy, Photoluminescence (PL) and energy dispersive X-ray (EDX) techniques. The variations in the wettability, surface free energy and spreading coefficient of ion beam bombarded LDPE polymer blend samples have been studied. The UV–vis analysis revealed that the transmission spectra shifted towards lower energy region after bombardment with increasing ion fluence. This shift clearly reflects decrease in optical band gap. A remarkable decrease in the PL intensity with increasing ion beam fluence was observed. The EDX study indicates the oxygen uptake increases with increasing ion fluence. Contact angle measurements showed that wettability, surface free energy and spreading coefficient of LDPE blends samples have increased with increasing ion fluence. This increase in the wettability and surface free energy of the bombarded samples are attributed to formation of oxidized layer on the polymer surface, which apparently occurs after exposure of bombarded samples to the air.