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The performance of incompatible blends is strongly depended on their morphology and interfacial properties that can be controlled by proper compatibilizers. This research systematically investigates the interfacial properties of the binary and the ternary blends based on low-density polyethylene (LDPE), poly(lactic acid) (PLA) and maleic anhydride-grafted polyethylene (PE-g-MAH) through the melt linear viscoelastic rheological behavior of the blends and neat components analyzed by proper rheological models. Moreover, the relationship between rheology, phase morphology and mechanical properties of LDPE/PLA ternary blends with different amounts of PE-g-MAH was studied. In the rheological analyses via the additive rule indicated in the molten state, no consistent interfacial interaction between LDPE and PLA phases is made due to the presence of PE-g-MAH at the interface of the blend. However, the analyses based on the Palierne's model implied that the interfacial tension of compatibilized blends decreases. This not only resulted in improving PLA dispersed phase morphology in the compatibilized blends, but also forming in situ fibrillar composites where the compatibilizer amount was relatively high (5 and 7.5 wt.%). Unlike the molten state, because of the strong interactions between PE and PLA phases of compatibilized blends in the solid state, the tensile mechanical properties, including Young's modulus, strength and elongation-at break, could be reinforced up to 24%, 25% and 90%, respectively. Overall, findings make a profound realization of the amount depended performance of PE-g-MAH as the most common compatibilizer for PE/PLA blends, very helpful not only from scientific viewpoints but also in terms of the blend industry applications. [ABSTRACT FROM AUTHOR]

Plastic products are used in large quantities. However, the fact that plastics do not degrade in nature for many years causes environmental pollution. Addressing this issue, the study focuses on recycling the widespread high-density polyethylene (HDPE) plastic waste. In this study, HDPE waste was collected randomly from the environment, mirroring real-world scenarios. Then, the waste was transformed into granules. Afterward, washing and drying processes were carried out. HDPE filaments of different linear densities were successfully produced from the waste plastic granules. Tensile tests revealed that the breaking strength of the filaments from waste plastic was lower than that of virgin HDPE filaments, highlighting the challenges of recycling. Hybrid yarns were formed by twisting the filaments with cotton yarn to improve the mechanical properties of the filaments from waste plastic. Remarkably, statistical analysis demonstrated that the breaking load values of the hybrid yarns from waste plastic were statistically equivalent to those made from virgin polymer. This outcome indicated that the hybrid yarns made from waste HDPE plastic were as strong as those made from virgin HDPE polymer. In addition, both hybrid yarns exhibited a breaking load 36% higher than the reference extra-twisted cotton yarn. The hybrid yarn formation made filaments produced from waste plastic a valuable component of the high-strength hybrid yarn. Overall, this study shows that recycling HDPE plastics can lead to the production of high-strength hybrid yarns, which can contribute to reducing plastic waste pollution. [ABSTRACT FROM AUTHOR]

The kinetics of polymerization of epoxy resin ED-20 cured with a polyethylene polyamine hardener modified with silicone rubber, tris(trimethylsiloxy) phenylsilane, octamethyl cyclotetrasiloxane is studied. A more rapid decrease in the amount of epoxy groups in systems modified with silicon-contained additives during polymerization is observed. A differential equation describing the change in changes in the concentration of epoxy groups with the polymerization time is proposed. The found exact solution to the proposed equation describes adequately the experimental data. The modification of epoxy binder reduces the time and temperature of the maximum heat release during the curing. The modification with the addition of tris(trimethylsiloxy) phenylsilane leads to the maximum increase in heat release. A differential equation describing the change in the heat release temperature with the curing time is formulated. The exact solution to the equation formulated is found, which is applied to estimate the curing end time of the compositions. [ABSTRACT FROM AUTHOR]

High voltage AC/DC cables require thicker insulation to ensure excellent insulation performance. Selecting the appropriate crosslinker to design the crosslink and crystalline structure of XLPE is key to the insulating properties. Although the crystallinity of XLPE has been extensively studied by using X-ray diffraction and differential scanning calorimeters, few researchers have designed in situ experiments to observe its structure. In this paper, we have created an in situ observational experiment to monitor the structural changes of XLPE insulation. XLPE formed by DTAP crosslinker produces lower gas byproducts, which can effectively reduce the degassing time and energy consumption. The test results and COMSOL simulations indicate that the XLPE formed by straight-chain alkane crosslinkers has better mechanical, thermal and electrical insulating properties than cyclic alkane crosslinkers. Our work is of great significance for selecting suitable crosslinker to control the structure of XLPE and determining the production conditions for high-voltage cables. [ABSTRACT FROM AUTHOR]

This study evaluates the effect of calcium carbonate (NCC), montmorillonite Cloisite 15A (MMT), and graphene nanoplatelets (GNP) nanofillers on the morphological, rheological, thermal, mechanical, and dynamic compression of polymeric films. Samples of pure high-density polyethylene (HDPE) and HDPE reinforced with 1% of each nanofiller, as well as hybrid samples containing 0.5% of each nanofiller, were prepared using a co-rotating twin-screw extruder and subsequently processed through a single-screw extruder equipped with a tubular plastic film extrusion. The films (~ 50 µm thickness) display a homogeneous surface, except for the GNP-containing sample and a single thermal loss event at around 475 °C. The results of mechanical strength analysis indicate that NCC and MMT reinforce the film, while GNP, which has the highest degree of crystallinity (62%), shows inferior values to pure PE. In the dynamic compression test using the Hopkinson bar, the highest stress and toughness are observed for samples containing 1% NCC with maleic anhydride, 1% MMT, and 1% GNP, and the hybrid samples do not yield satisfactory results. The choice of nanofiller to be added to HDPE films depends on the desired application and properties. [ABSTRACT FROM AUTHOR]

A new approach for compatibilizing polyamide-66 (PA-66)/high density polyethylene blends using polyamide-grafted ethylene vinyl alcohol copolymer (EVOH-g-PA) is presented in this study. EVOH-g-PA was prepared through sequential reactions of adipoyl chloride and hexamethylenediamine with hydroxyl groups of EVOH chains. Two different EVOHs having 44 and 88 mol% ethylene monomer were modified to obtain EVOH44-g-PA and EVOH88-g-PA, respectively. The efficiency of modified EVOHs in compatibilization of PA/PE blends were evaluated by morphological observations as well as rheological and crystallization measurements. The PE droplets in the PA matrix became finer when EVOH44-g-PA or EVOH88-g-PA were incorporated in the blends. However, the compatibilizing effects of EVOH88-g-PA were more pronounced due to higher ethylene content in the primitive EVOH chain promoting its diffusion into the PE droplets. The complex viscosity of compatibilized blends were also enhanced showing the improved adhesion between PA and PE phases. A reduction in the crystallization temperatures (Tc) of PA matrix was noticed upon inclusion of modified EVOHs which was associated with the lowered nucleating activity of the interface due to decreased interfacial tension in the compatibilized blends. Eventually, the results revealed the opportunity of using EVOH-g-PA as a compatibilizing agent in the PA/PE blends. [ABSTRACT FROM AUTHOR]

The recovery stress of shape-memory polymers is often low; therefore their field of application is limited. In this study, we compared the effects of different fiber reinforcements on the shape memory characteristics of cross-linked polyethylene (X-PE) matrix. We used fiber reinforcement to increase the recovery stress of the shape memory polymer and compared the results of different fiber reinforcements to find the ones that confer the best shape memory properties. We investigated glass, carbon, Kevlar®, and Dyneema® fibers to find the fibers that increase the recovery stress of the composites most. The deformed shape was created by three-point bending, and then heat-activated shape recovery was examined. All reinforcements increased the recovery stress and decreased the shape fixity ratio and the shape recovery ratio. The samples had similar characteristics, except for the low recovery stress Kevlar® fibers and the low recovery ratio of the composite reinforced with glass fibers. With the polyethylene Dyneema® fibers, the composite was self-reinforced and did very well by all metrics. They increased the maximum recovery stress from 0.3 to 2.4 MPa, through having excellent adhesion to the matrix and high strength in their own right. Our research proved that self-reinforced composites could measure up to conventional composites in shape memory applications. Aside from the Dyneema® fibers carbon fibers work best in the X-PE matrix, and should be the preferred conventional reinforcement materials. [ABSTRACT FROM AUTHOR]

In the present study, it has been synthesized a new polymer, OXPESH (oxidized polyethylene functionalized with thiol groups), based on commercially used OXPE (oxidized polyethylene) for possible uses in the removal of heavy metals. Thiol-based oxidized polyethylene was successfully obtained by the esterification process. The synthesized polymeric material was employed as a possible adsorbent for the removal of heavy metal ions from aqueous solutions. Different techniques (1H-NMR, FTIR, ICP-MS, (Elemental Analysis), XPS, SEM–EDX, TGA/DTG) were used to characterize the physical and chemical properties of the obtained adsorbent. it was observed that the optimum pH values for the adsorption capacity and removal efficiency of heavy metal ions were 6–8. It was observed that the adsorbent removed the best Ag+ > Cr3 + > Pb2+ > Al3+ > Cd2+ > Ni2+ > Cu2+ from the aqueous solution. As a result, thiol–based oxidized polyethylene has been demonstrated to be an effective sorbent for the removal of heavy metal ions from aqueous solution, indicating its potential relation with water improvement. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE), nano-calcium carbonate (NCC) and polyethylene-g-maleic anhydride (PE-g-MA) nanocomposites were blended utilizing the infusion shaping strategy. Three frameworks of different NCC and PE-g-MA loadings were planned and fused into the lattice of HDPE. The qualities of each planned framework with various rates of NCC and PE-g-MA were checked. The hardening impact of these various loadings on the grid of HDPE was assessed. Mechanical, warm and physical examinations were performed on such nanocomposites tests to explore and think about their properties. The pliable highlights were estimated utilizing the automated mechanical general testing machine recording an expansion of 22% in the endure break contrasted with the flawless HDPE with keeping up the elastic worth demonstrating the hardening impact event. PE-g-MA affected the de-holding impact and raised the strength at yield point. TGA warm examination decided the warm decay of unadulterated HDPE and its nanocomposites. The NCC particles contributed in limiting the warmth saturation into the HDPE lattice by going about as a warmth hindrance during the warm deterioration measure and helping the development of carbide which forestalled the volatilization of the disintegrated materials. The joining of PE-g-MA improved the scattering of the NCC particles, the probabilities of agglomeration expanding the interfacial attachment between the nanoparticles and the HDPE grid. Dissolve stream list is a significant boundary which can anticipate the processability of polymeric materials. The expansion of PE-g-MA as a compatibilizer to the HDPE/NCC grid caused an expansion in the consistency which prompts a lessening in the dissolve stream list. This lessening is a mechanical preferred position that sparing the creation energy and may be ascribed to the physical snares that created among added substance and compatibilizer in the HDPE network. [ABSTRACT FROM AUTHOR]

Bicomponent nanofibers of cellulose acetate (CA) and polyethylene imine were successfully fabricated by electrospinning technique to capture CO2 gas. The concentration of polyethylene imine was fixed to 25, 50, and 75% compared to the CA concentration. The nanofibers were characterized using FT-IR, X-ray diffraction (XRD) and thermogravimetric analyzer (TGA). The effect of PEI on the morphology of CA nanofibers was studied using scanning electron microscope (SEM). The diameter of electrospun CA/PEI nanofibers becomes larger with the increase of PEI content due to repulsion of electrical force from side polar groups. In addition, PEI diffused on the nanofiber surface was observed at high concentrations of PEI. The CO2 adsorption capacity of electrospun CA/PEI nanofiber membranes was investigated at different temperatures using a BET. The increase of PEI content in nanofibers increased the CO2 adsorption capacity, and the adsorption capacity was larger at lower temperature. The decrease in CO2 adsorption capacity with increasing temperature indicates that CO2 adsorption is more responsible for physisorption. Moreover, the CA/PEI electrospun membrane retains 99% of its initial CO2 adsorption capacity after 5 cycles of the adsorption and desorption process. [ABSTRACT FROM AUTHOR]

The mechanical α-relaxation of polyethylene was studied under different testing conditions and distinct polyethylene sheets. The condition of 2.5 mm thickness and 3 ℃/min was in favor of observing and analyzing the α-relaxation. The α2-relaxation peak in tan δ curves disappears under the high-frequency condition of 10 Hz since the α2-relaxation temperature is higher than melting temperature, which provide the support for the explanation on the disappearance of the α2-relaxation caused by crystalline properties. The influences of thermal history for the sheets of linear and branched polyethylene, as well as melting index for linear polyethylene on α-relaxation can be attributed to both lamella thickness and crystallinity. The higher lamella thickness and crystallinity, the more obviousness and higher temperature of α1-relaxation, as well as the higher temperature of α2-relaxation or cause the disappearance of α2-relaxation peak. The variation of multiple α-relaxations was interpreted using a microcrystalline structure and macro-crystallinity. The chain motion in amorphous being more restricted and the chain motion in crystal lattices requiring more energy contribute to the temperature increasing of α1- and α2-relaxation, respectively. The higher remaining crystallinity during the premelting process causes the increase in the α2-relaxation temperature. [ABSTRACT FROM AUTHOR]

In this work, the surface of single-wall carbon nanotubes (SWCNTs) was functionalized with amide group to improve the interfacial adhesion and dispersion of the SWCNT within an ultrahigh molecular weight polyethylene (UHMWPE) polymer matrix. The UHMWPE/SWCNTs nanocomposites were prepared by ultra-sonication mixing and hot press molding methods. Fourier transform infrared spectroscopy results confirm the amide functionalization. The prepared nanocomposites were characterized based on morphology, structure, and mechanical properties by scanning electron microscopy, X-ray diffraction, and a Universal Testing Machine, respectively. The crystallinity, crystal size, space between atomic lattice and lattice constant were calculated from XRD spectra. The results show an increase in the UHMWPE crystallinity when adding pristine SWCNTs and Amide-SWCNTs (1–5 wt %) due to changing the nucleation type of the UHMWPE from homogeneous to heterogeneous nucleation, which led to accelerating the nucleation process and the formation of more crystalline grains. The tensile test results show an increase in toughness of ~ 95% when adding 4 wt % Amide-SWCNTs. This indicates that the amide group achieved good interfacial adhesion and dispersion compared to pristine SWCNTs. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) modification to have flame retardant and anti-dripping capabilities is indispensable for public safety and environmental protection. To the end, PE modification with flame retardant resorcinol bis(diphenyl phosphate) (RDP) is suggested but a poor compatibility of PE with RDP is problematic. In this work, a microencapsulation of RDP using melamine-urea-formalin resin as shell material was proposed to resolve the compatibility problem, making PE composites with microencapsulated RDP (MCRDP), red phosphorus (MCRP) and magnesium hydroxide (MH). Through the material characterization, it was found that the spherical MCRDP particles were fabricated in homogeneous distribution of particle sizes. The flame retardance of the PE composite samples with different compositions was tested according to the UL-94 method, finding that the PE/20%MCRDP/5%MCRP/5%MH composite has the best performance. Moreover, the thermogravimetric analysis showed that this composite exhibited higher decomposition temperature than pure PE and PE/30%MCRDP composite, revealing the P-N synergy effect on improving the flame retardance of PE composites. [ABSTRACT FROM AUTHOR]

An intermediate stage in the net casting that can potentially limit the features of the final metallic product, called dewaxing, is highly dependent on features of pattern wax. The general process of dewaxing, involved in investment casting for the reuse of the wax, requires a high amount of energy and entails high processing time through conventional heating methods thus resulting in a lower rate of processing at a bulk scale production. In this research, the pattern wax blends, containing polyethylene, ethylene–vinyl acetate, bitumen, and paraffin wax, were investigated for their microwave processing time in the presence of susceptor material (polyaniline). Polyaniline in wax blends was incorporated as a microwave susceptor in concentrations of 0.15, 0.45, 0.75, 1.5, 3, 5, and 10 wt%. Advancements in processing properties of pattern wax blends, using microwave dewaxing technology, were observed along with the improvement in melting behavior of pattern wax blends owing to the creation of heat-sensitive sites due to the addition of a susceptor. The decrease in complete flow time was observed from 202 to 55 s by the addition of 10 wt% of polyaniline in wax. A ceramic die and stand to hold the die at a hotspot in microwaves were designed for experiments. FTIR-ATR, rheological, TGA, DSC, mechanical (UTM), and morphological analysis (SEM and OM) were performed to investigate the behavior of pattern wax blends under the application of microwave heating. An inverse trend was observed in processing time with susceptor loading in microwaves. [ABSTRACT FROM AUTHOR]

Cement kiln dust (CKD) is a residue produced during the manufacture of cement that contains hazardous solid waste of high toxicity that affects the environment and public health. In this study, the possibility of using CKD as a filler in the plastic and rubber industry was studied. The effect of CKD concentration and gamma irradiation dose on the mechanical and physico-chemical properties of the composite containing waste polyethylene/devulcanized rubber/EPDM rubber (named blank) was investigated. Different concentrations of CKD, namely 10, 15, 20, and 30 phr (part per hundred part of composite), were used. The results indicated that this composite (blended with CKD) properties were improved. The most significant improvement was achieved by using CKD concentration of 20 phr at the dose of 100 kGy of gamma irradiation. These findings were demonstrated by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. [ABSTRACT FROM AUTHOR]

In view of the intense interest in applications of silver nanoparticles in products for the medical field and in food preservation packaging due to their antimicrobial properties, the ecotoxicology of silver nanocomposites was evaluated in films. Test with the sea urchin Echinometra lucunter, to evaluate embryonic development and contamination by the action of silver and titanium nanoparticles in polyethylene nanocomposite films presents new results. The silver nanoparticle's stability in polymeric materials can be enhanced by adding carriers, such as titanium dioxide and montmorillonite clay (MMT) without to producing one unfriendly material. For this research, low-density polyethylene (LDPE)/linear low-density polyethylene (LLDPE) were used processed in a twin-screw extruder, followed by gamma irradiation with 25 kGy and characterized by ecotoxicology assays, field emission scanning electron microscopy (FESEM), scanning electron microscopy and energy dispersive spectroscopy (SEM–EDX), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Raman spectroscopy (SERS) and mechanical properties. The antibacterial properties of the LDPE films were investigated against Escherichia coli and Staphylococcus aureus. The gamma irradiation had an important effect in the synthesis of silver nanoparticles resulting in bactericidal activity and the death of 100% of the tested bacteria. The evaluation of the environment was considered with the ecotoxicological investigation carried out. The results indicated that the polymeric films with silver nanoparticles and TiO2 do not contaminate the environment and neither interfere with the larval development of Echinometra lucunter. The obtained materials can be used in various applications with antimicrobial properties. [ABSTRACT FROM AUTHOR]

In the current study, nano-silanized silica-filled crosslinked polyethylene (XLPE) nanocomposites were prepared by a novel two-step melt blending technique. Nano-silanized silica was used as a filler and dicumyl peroxide was used as a crosslinker. Crosslinking was introduced in the base polymer by adding 0.2% dicumyl peroxide in second step in order to avoid premature crosslinking. The effect of nano-silanized silica on XLPE nanocomposites was investigated. FTIR analysis was carried out to detect the degree of crosslinking in the composite. The effect of nano-silanized silica on the UV degradation behavior was also assessed. The extent of crosslinking was also estimated by density measurement and solvent swelling method. Thermal behavior was studied by thermogravimetric analysis and differential scanning calorimetry. Dielectric breakdown strength was studied in the frame of Weibull distribution method. The flammability of nano-silanized silica-filled crosslinked nanocomposites was studied by both vertical and horizontal flame test methods to quantify flammability rating and rate of burning, respectively. SEM analysis was carried out to explain the morphology of polyethylene after crosslinking and dispersion and distribution of filler within the polymer matrix. It was shown that 2 phr addition of nano-silanized silica improved the performance of XLPE composites. [ABSTRACT FROM AUTHOR]

Branched polyesters based on the polyethylene terephthalate were synthesized by incorporating isophthalic acid (IPA) and trimellitic anhydride (TMA). TMA has the branching agent role. During the esterification step, only terephthalic acid, IPA, and ethylene glycol were reacted and TMA was added at the beginning of the polycondensation step. Reaction progress was studied using water production and mixing torque increase during esterification and polycondensation steps, respectively. Polycondensation time increases with IPA and decreases with TMA. Fourier transform infrared spectroscopy spectrum shows the production of polyester. Randomness and sequence length were studied using 13CNMR. Results reveal that randomness increases with TMA. Crystallinity and morphology of samples were studied using differential scanning microscopy (DSC). DSC thermograms show that samples turn to an amorphous structure by adding IPA and TMA with decreasing glass transition temperature, Tg. X-ray diffraction spectra approve changing nature similar to DSC results. Dynamic light scattering results present that with an increase in TMA, some size-increasing particles were detected. The rheological behavior of samples was studied using RMS. By adding TMA, the elastic behavior of samples changes to viscous behaviors. [ABSTRACT FROM AUTHOR]

The dynamic rheological behavior of polypropylene (PP)/low-density polyethylene (LDPE) blending melts at 210 °C and 230 °C was measured by small-amplitude oscillatory shear mode on a rotational rheometer. The complex viscosity and dynamic modulus of pure PP are higher than those of pure LDPE at low frequency. For the blends with dispersion morphologies, Palierne model is applied to fit the storage modulus data and the model almost underestimates the data since most of the experimental dynamic modulus of the blends lay between that of pure PP and pure LDPE. While Lee and Park model predicts the dynamic storage data well for the PP/LDPE blends 90/10, 10/90 and 70/30 blends. For the 30/70 blend, this model describes the data much closer than Palierne model and a little deviation occurs at low frequency. The comparison between the two models' fitting results indicates interaction among dispersed droplets should be considered. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) is one of the polymers with the best abrasive wear performance that exists, being used in engineering applications where this property is required. Despite its excellent property, UHMWPE still performs poorly in many applications. Therefore, the development of new materials with better properties is always very desirable. In this study, it is presented for the first time that it is possible to obtain polyethylene blends with better wear performance than UHMWPE. Linear polyethylenes, high-density polyethylene (HDPE), high molecular weight polyethylene (HMWPE) and UHMWPE, and blends, HMWPE-UHMWPE (10, 20 and 40 wt%), and HDPE-UHMWPE (20 and 40 wt%), have been studied here. The study was developed based on the correlation between the tensile test and the wear test of these materials. In 1968, Lancaster suggested that the abrasive wear resistance of polymers is strongly related to the product between the stress and strain at breaking obtained from the tensile test. This correlation is known as the Ratner–Lancaster correlation. Although this correlation is suitable for many polymers, it is not suitable for all. HDPE, HMWPE, and UHMWPE are examples of polymers where this correlation is not suitable. With the knowledge that the amorphous phase of polymers is responsible for wear resistance and ultimate tensile properties, a new and more suitable correlation for linear polyethylenes is suggested in this study. This correlation shows that the hardening modulus must be included as a factor to predict the abrasive wear resistance. The blends of HMWPE containing 10 and 20 wt% of UHMWPE showed volumetric loss after the wear test of 47.0 and 45.2 mm3, respectively, while UHMWPE presented a higher volumetric loss, of 55.7 mm3. The excellent performance of the blends was possibly due to a better understanding of the correlation between the tensile and abrasive tests proposed in this study. [ABSTRACT FROM AUTHOR]

The objective of this research was to apply a novel approach viz. Alkali treated hemp fiber (HF) was used as a process variable for optimization of the properties of polyethylene (PE)/polypropylene (PP)-based bio-composite packaging film using central composite design-response surface methodology (CCD-RSM). The optimum conditions for three process variables, i.e., PE, PP, and alkali-treated hemp fiber, were predicted using RSM and then confirmed experimentally. The optimum results were PE (1.8 g), PP (1.118 g), and treated HF (1.2 g) provided the highest mechanical stability and lowest water vapor transmission rate (WVTR) as compared to native-hemp fiber (NHF)-based composite film. The ANOVA analysis confirmed the packaging film properties were highly dependent on treated HF followed by PE and PP, respectively, in desired composites. Thus, WVTR and mechanical strength are one of the reliable indexes to evaluate packaging properties. The film prepared using optimum independent factors were also characterized by different analytical techniques such as Thermogravimetric Analysis (TGA), contact angle, optical characteristics test, impact test, and water vapor permeability (WVP). Those findings showed Contact angle, impact strength, and transparency were increased by 30%, 24%, and 66%, respectively, whereas WVP was decreased by 57%, respectively as compared to NHF-based film. Thus, Alkali-treated hemp fiber-based bio-composite film properties were comparable with pure polymeric or real polyethylene packaging films, declaring its suitability for green applications. [ABSTRACT FROM AUTHOR]

The solid–liquid (S–L) phase separation occurs in the polyethylene (PE)/liquid paraffin (LP) blend, which exhibits different characteristics for the molecular weight of PE. Herein, we have studied the S–L phase separation process of PE-500 (molecular weight of 5,000,000)/PE-60 (molecular weight of 600,000)/LP melts by the hot-stage-optical device. It is found that the clarification temperature and cloud temperature of PE-500/PE-60/LP blend decreased with the addition of PE-60. The isothermal crystallization behavior of these ternary blends is explored further using differential scanning calorimetry (DSC). According to the analysis results of Avrami equation and Arrhenius equation, the exponent n increases from 1.23 to 2.42 at higher temperature, indicating that the melt with high PE-60 content have a growth pattern between two and three dimensions, which could lead to larger pore. The activation energy at high temperature increases from 738.568 to 1321.259 kJ / mol with enhancing PE-60 content, while the activation energy decreases from 209.689 to 36.608 kJ / mol at lower temperature. It demonstrates that PE-60 content is not conducive to nucleation at high temperatures, but in favor of growth at low temperature. We believe the pore structure of PE microporous membrane may be controlled by different ratios of PE-500/PE-60 and crystallization temperature. [ABSTRACT FROM AUTHOR]

The mechanical (flexural, tensile and impact) properties and water kinetic parameters of water-absorbed hard wood (mangrove) reinforced high-density polyethylene composites were evaluated as untreated and treated mangrove dust (MD). Samples were prepared by mixing high-density polyethylene (HDPE) with MD at 10, 20 and 30% by weight in a twin-screw laboratory compounder and injection moulded into dumb-bell and rectangular-shaped test specimens for flexural, tensile and impact tests. Samples were soaked in distilled water for 1440 h at room temperature and a relative humidity of ~ 65%. The flexural strength and modulus indicated that treated composites exhibited lower decrease in values than their untreated counterparts at water equilibrium points. The dry composites maintained higher values of tensile properties, notwithstanding the treatment. Scanning electron microscopy of impact fractured surfaces showed evidence of improved MD-HDPE interfacial adhesion of treated composites in both dry and water-absorbed conditions. The water kinetics parameters such as the diffusion, sorption and permeability coefficients further show that dry composites are more water-resistant than the wet composites. Overall, the treated composites at dry and moisture-saturated conditions indicated better mechanical and moisture stability than the untreated MD/HDPE composites. [ABSTRACT FROM AUTHOR]

In this study, to improve the thermo-mechanical properties of glycidyl azide polymer (GAP)-based elastomers, polyethylene adipate (PEA) with different molecular weights was successfully synthesized using a solvent-free method. GAP was synthesized by cationic ring-opening polymerization of epichlorohydrin and then azidation. The structure of PEA and GAP was characterized by FTIR, 1HNMR, and GPC. The compatibility of GAP/PEA at various weight ratio blends was investigated by differential scanning calorimetry. The result indicated GAP/PEA is compatible, and addition of PEA to GAP leads to the decrease in glass transition temperature. The copolyurethane elastomers were prepared by cross-linking GAP and PEA at various weight ratios using isophorone diisocyanate and N100 as curing agent. The thermo-mechanical properties were evaluated by dynamic mechanical analysis and tensile test. Based on the results, with increasing weight ratios of PEA, the copolyurethane elastomers displayed an increase in tensile strength (6.97 MPa) and elongation (792%) in comparison with GAP. [ABSTRACT FROM AUTHOR]

Due to the importance of rheology and morphology of microfibrillar reinforced composites (MFCs), a study has been conducted on MFCs based on high-density polyethylene (HDPE) and polyamide-6 (PA-6) using scanning electron microscope and dynamic rheometer. In the absence of an interfacial modifier and at 10 wt% concentration of the dispersed phase (PA-6), two principal factors, elongational deformation and coalescence, were found to be controlled by viscosity and elasticity ratios of the pure constituents accounting for the observed morphology of MFCs. The developed microfibrillar morphology remarkably influenced the viscoelastic properties of MFCs. It was observed that when the viscosity ratio approached unity and the elasticity ratio was minimal, the extent of coalescence in composite was significant. The rheological assessment showed enhanced storage modulus and complex viscosity upon microfibrils formation. This was more pronounced for samples with thinner microfibrils due to more strongly entangled network, compared to the composites with thicker microfibrils. The length-to-diameter ratio of the microfibrils could not be estimated due to their highly asymmetric length scale. [ABSTRACT FROM AUTHOR]

Recently, injection molding process has generated growing interest, exhibiting great potential to easily fabricate unique polymeric materials for industrial applications. To increase the sustainability of the process, determinative parameters and their effects should be examined. This study focuses on the effect of melt temperature on as-injection molded product, thereby high-density polyethylene samples were fabricated by performing three different melt temperatures (180, 190, and 200 °C), and subsequently, their mechanical, thermal, and morphological and surface quality properties were examined. The results showed that higher melting temperature lowered crystallization rate and decreased the strength of tensile and bending; however, it increased crystal lamellar thickness and impact strength. Moreover, the type of fibrillation changed with the temperature. Moreover, defects formation increased with the temperature. For further application, the effect of the temperature on surface quality was discussed. This work will provide a guide for manufacturing injection-molded products at desired properties by arranging melt temperature. [ABSTRACT FROM AUTHOR]

Effect of gamma radiation on the mechanical and structural properties of polylactic acid (PLA) and high-density polyethylene (HDPE) is analyzed. Samples were irradiated in ambient conditions with doses in the range of (0–175 kGy) using 60Co gamma irradiation facility. Experimental results showed a clear effect of gamma radiation on polymer properties through the action of crosslinking, chain scission and oxidative degradation. Tensile testing results for both polymers showed a decrease in the tensile strength and ductility at high irradiation doses, suggesting that the effect of both chain scission and oxidative degradation is dominant over crosslinking for higher doses. Results from Fourier transform infrared (FTIR) spectroscopy show that signature peaks of both PLA and HDPE were present after irradiation indicating that exposure to gamma radiation does not lead to diminishing their corresponding structural modes. Nevertheless, new peaks were observed upon irradiation of HDPE samples. These new peaks are attributed to modes of different oxygen bonds in oxidation products such as carbonyl groups and alcohol groups. Finally, X-ray diffraction (XRD) results show that both polymers exhibit increased crystallinity with increased radiation exposure due to chain splitting that is stimulated by oxidative reactions. [ABSTRACT FROM AUTHOR]

This work presents a lightweight electrically insulating composite material for high thermal conductivity: all polymer composites created by mixing ultra-high molecular weight polyethylene flakes into a matrix of low-density polyethylene or ethylene vinyl acetate. The ultra-high molecular weight polyethylene flakes have a reported thermal conductivity of 40 W m−1 K−1, and when 30 volume percent is compounded in an ethylene vinyl acetate matrix, the thermal conductivity is measured to be 2.5 W m−1 K−1 at 52 °C and the notched impact strength is 350 J/m. The temperature stability of the polyethylene flakes is investigated using polarized Raman spectrometry and thermal conductivity measurements, and it is discovered that flakes compounded at temperatures of 115 °C and above show a dramatic drop in thermal conductivity due to melting and reduced polymer chain alignment. This study highlights the possibility of using high-thermal-conductivity polymer fillers in bulk composites for near-room-temperature applications. [ABSTRACT FROM AUTHOR]

The present study investigates the physical, thermo-mechanical and tribological properties of coir–coconut husk particulate-reinforced polymer composites subjected to a corrosive environment. The composites were prepared by the conventional facile hot compression molding method. The composite was immersed in a strongly acidic environment of pH 2.2 for a period of 3, 6, and 9 days. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used to elucidate the structure and morphology of the composites. The thermal analysis using differential scanning calorimetry, water absorption, hardness, coefficient of friction and wear rate was performed as per the ASTM standards to characterize the as-prepared and aged composites. The experimental test results revealed that with an increase in acid aging time, the acid aged samples lost surface matrix such that the fiber was seen on the surface. The effects of corrosion seemingly reduced the crystallinity of the acid aged samples allowing amorphous regions to be trapped within the crystals. Water absorption of the samples increased with aging time due to inherent voids in the specimens as weight gain values were 5.27, 16.80, 19.33 and 19.91%, respectively for control and acid aged samples. Hardness values initially decreased with immersion time and increased which was attributed to the crystallinity of the specimens and to some extent the elemental carbon present in the specimens before and after aging. The measured hardness values of the control and acid aged composites were 2.98, 7.27, 14.40 and 9.07 HV, respectively. From the thermal analysis, it was noticed that the glass transition temperature (Tg) of the polymer shifts to higher temperatures as the aging time in the acidic medium increased, which can be attributed to cross-linking of the polymer chains. The control specimen shows higher coefficient of friction (CoF) because they are more rigid than the acid aged samples, and hence under dry sliding can cause more friction leading to increased heat and CoF. [ABSTRACT FROM AUTHOR]

Mold surface temperature is one of the most critical process parameters in injection molding. This study aimed to determine the effect of mold surface temperature on plastic parts in injection molding of high-density polyethylene materials. Other process parameters were kept constant, and samples were prepared by changing mold surface temperatures by the injection molding method. The samples' mechanical tests, thermal tests, and gloss measurements by a gloss meter were performed, and the amount of warpage and collapses was measured by a video measuring system. Microstructures were examined under a scanning electron microscope. It was observed that the mold surface temperature increased the crystallization rate, tensile and bending strength of the materials, decreased the thicknesses of the crystal lamella and impact strength, and had an effect on the melting temperature of the crystal. The microstructure investigations demonstrated that as the mold surface temperature increased, the cavity formation in the structure increased, and fibrillation decreased due to expansion and cooling time. It was determined that the amount of collapse and warpage was affected by the mold surface temperature and that the increase in the mold surface temperature decreased the amount of collapse and increased the amount of warpage and surface gloss. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE) and nanoparticles of calcium carbonate (NCC) have been mixed via melt blending technique using different ratios of NCC as nanofiller and high-density polyethylene-g-maleic anhydride (HDPE-g-MA) as a compatibilizer. The combined effect of NCC as well as HDPE-g-MA concentrations on the breakdown strength and dielectric spectroscopy performance of HDPE was investigated. According to the American Society for Testing and Materials (ASTM) standard, the ac breakdown voltage of such nanocomposites was measured at constant 500 V/s ramp. The ac breakdown voltage was enhanced by 8.2% for HDPE/ 2wt% NCC and reached 21% in the presence of 1 wt% HDPE-g-MA which increases the efficiency of NCC dispersion. The surface morphology of synthesized HDPE/NCC and HDPE/NCC/HDPE-g-MA nanocomposites was characterized by field-emission scanning electron microscopy (FE-SEM). FE-SEM images showed an enhanced dispersion of NCC that may be due to good adhesion between NCC and HDPE under the compatibilization effect of HDPE-g-MA. Fourier-transform infrared (FTIR) analysis showed chemical interaction between HDPE-g-MA and stearic acid on the surface of NCC and physical entanglement among HDPE and HDPE-g-MA. Dielectric constant (ε′) and tangent loss (tan δ) were measured under different applied frequency values from 1 kHz to 1 MHz. [ABSTRACT FROM AUTHOR]

The present work is mainly focused on the synthesis and comprehensive rheological investigation of uniform and large macroporous polyethylene glycol-modified polyacrylamide hydrogels [PEG-m-P(AAm)] through free radical polymerization using different accelerators (ascorbic acid (AsA), thermal activation (60 °C) and N,N′,N″,N‴-tetramethyl ethylenediamine (TEMED)). The synthesis and surface morphology of the hydrogels were confirmed by FTIR and SEM techniques. Rheological investigation was carried out to determine the effect of accelerator nature on the rheological parameters and pseudo-plastic behavior of polymer hydrogels. A decline in viscosity with the increase in shear rate confirms the non-Newtonian pseudo-plastic behavior of hydrogels. From the creep-recovery study, the least strain (0.2) and creep compliance (2 × 10−2 Pa−1) for the thermally activated synthesized polymer hydrogel show more elastic property than the hydrogels synthesized by AsA and TEMED having strain values of 0.6 and 2.2, respectively. The thixotropic character of the hydrogels was found by the hysteresis loop test. The hydrogels prepared via AsA (998.825 Pa s−1) showed greater thixotropic behavior, followed by thermal activation (652.857 Pa s−1), and TEMED (531.9 Pa s−1) respectively. The hydrogels synthesized by different routes attained a completely different morphology, which can be applicable for specific applications. The obtained results verify that these materials may be used for the removal of potentially toxic materials, as a carrier for bioactive compounds and in cosmetic industry. [ABSTRACT FROM AUTHOR]

A novel hyperbranched mono-component intumescent flame retardant poly(piperazine methylphosphonic acid pentaerythritol ester) defined as PPMPPE was synthesized, and its chemical structure was characterized. The individual PPMPPE was incorporated into polyethylene (PE), and the fire resistance, thermal properties and flame retardant mechanism of PE composites were investigated in detail. The 1.6-mm PE/PPMPPE sheets fulfilled UL-94 V-0 level during vertical burning tests, and the limiting oxygen index was 25.3% when the loading amount of PPMPPE was 22 wt%. PPMPPE was completely melted, and the expanded char layer was generated on heating. The addition of PPMPPE stimulated the degradation and charring of PE composites in advance and improved the residual mass and thermal stability of FR-PE at high temperature. The cone calorimeter tests verified that the heat release rate and total heat release of PE/PPMPPE composites were obviously declined. PPMPPE exerted shielding effect in condensed phased and quenching active free radicals in the gas phase. The flame was constrained and even extinguished. Thus, PE composites fulfilled superior flame retardant properties. [ABSTRACT FROM AUTHOR]

This work deals with the study of the degradation of films made of low-density polyethylene (LDPE) by the incorporation of commercial titanium dioxide nanoparticles (TiO2 Nps). These nanoparticles were functionalized with three types of dicarboxylic acid, which have different length chain (glutaric, pimelic and azelaic acids), to improve their compatibility with LDPE. Besides, the effect of the functionalized TiO2 Nps concentration on the photodegradation, roughness, mechanical and thermal stability of the nanocomposites was evaluated. The obtained results show that the organic coating helps to passivate the photodegradation of LDPE; the longer carbon chain of the dicarboxylic acid, the higher active sites on filler/polymer interface, which inhibits photodegradation. Also, it was elucidated that calcium, from the functionalization, increased the thermal stability of the polymer nanocomposites when exposed to UV radiation. The thermal, physical (surface wear) and aesthetic (color) properties of polyethylene, with the functionalized nanoparticles, were less affected when exposed to the weather, where it is attributed to the UV photo-stabilization of the polymer. The resultant materials (LDPE with functionalized TiO2 Nps) can be used in diverse applications such as films for greenhouse and other agricultural applications, outdoor appliances (furniture and decks, for example), among others. [ABSTRACT FROM AUTHOR]

A synthesis by plasma of polymers with structure of oxidized ethylene (PPEO) obtained from ethanol is presented in this work with the objective to obtain hydrophilic and potentially biodegradable PPEO films. The synthesis was carried with rf glow discharges in the 20–120 W interval obtaining films with a 0.38 μm/W growing rate thickness. Morphology, chemical structure, hydrophilicity and absorption of electromagnetic energy in the UV–visible interval were analyzed. The results indicated that PPEO has smooth surfaces with particles and/or folded areas with water contact angles between 72° and 97°, in the limit between hydrophilicity and hydrophobicity. The structural chemical analysis showed the presence of C–H and O–H bonds characteristic of the monomer, and C=O and ≈C≈ groups characteristics of plasma polymers with dehydrogenation and formation of multiple bonds. The absorption of electromagnetic energy of PPEO was more intense in the UV than in the visible wavelength interval. These characteristics indicate that PPEO can be biodegradable under the sunlight and/or under wet environments. [ABSTRACT FROM AUTHOR]

Commercially, polyethylene is a highly produced commodity polymer. But due to its hydrophobic nature, it limits its applications, where utility is based on surface properties, such as adhesion, printability, wettability, and miscibility with other polar polymers. Therefore, the presence of a hydrophilic polar functionality is desired to overcome such difficulties. With its high exigency, synthesis of functionalized polyethylene with unique surface properties is now a very challenging task to be accomplished. In this perspective, developments on palladium and nickel (mainly based on ligands containing neutral α-diimine and anionic phosphine–sulfonate derivative)-mediated coordination/insertion copolymerization of ethylene with polar functionalized co-monomers are discussed herein. [ABSTRACT FROM AUTHOR]

The effect of ultrasonic (US) irradiation on solutions of low-density polyethylene (LDPE) was studied. Different irradiation times and intensities were examined. It was found that gel content increased very little as a result of US irradiation. However, this increase showed no variation with either the US irradiation time or intensity. The IR spectra of irradiated LDPE showed new absorption bands, indicating the presence of C–O groups, assumed to be the result of the US irradiation. GPC showed that the LDPE average molecular weight (Mw) decreases with an increase in either the US irradiation time or intensity. But these MWD curves, however, do not say if the "observed" modifications in Mw are due to chain scission or chain branching, which was inferred from the chain scission distribution function (CSDF) curves. From the GPC curves, it appears that chain scission is the dominant reaction at all US irradiation times and intensities. On the contrary, using the CSDF methodology, it appears that chain scission is the dominant reaction up to the intermediate irradiation times and intensities, but chain branching becomes dominant at the US higher times and intensities. On the contrary, using the proposed methodology, it appears that chain scission is the dominant reaction up to the intermediate irradiation times and power intensities, but chain branching becomes dominant at higher times and power intensities. [ABSTRACT FROM AUTHOR]

Mangrove wood particle (MP) of size range 500–1000 microns was thermally modified under inert condition to avoid oxidation at 120 °C. The untreated and treated mangrove were compounded with high-density polyethylene (HDPE) at 10 wt%, 20 wt% and 30 wt% in an extruder with twin screw and injection-moulded into rectangular bar shapes for impact tests; fractured surfaces of impact specimens were examined. Also, the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were evaluated. The results of the impact tests showed that increase in fibre loadings gave rise to an increase in peak load and critical stress intensity factor while energy to failure and critical strain energy release rate decreased which signifies improvements in the toughness of the composites. Scanning electron microscopy images revealed that there is stronger adhesion between the HDPE matrix of treated MP than their untreated counterparts. A decrease in the degree of crystallinity (Xc) was noted in the DSC of all composites with treated composites showing higher values of Xc. TGA showed a slight increment in the degradation peak temperature (Tp) of treated MP and MP/HDPE composites. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) is a polymer largely applied in the packing industry; however, it has limitations like high water absorption, notch-sensitive impact and high electrical resistance. Some strategies have been developed aiming to improve these drawbacks, as blending PA6 with other polymers, like linear low-density polyethylene (LLDPE) which is also an electrical insulator. In this work, antistatic packages for the transportation and storage of electronic devices were prepared by mixing PA6 and LLDPE with the addition of carbon black as an antistatic agent to reduce the electrical resistivity of polymers. PA6/LLDPE (50/50) blend-based carbon black composites with different contents of carbon black (5, 10 and 15 wt%) were prepared in a twin screw extruder, and their mechanical, rheological, electrical and permeation properties were studied. Thereby, the effects of the addition of maleic anhydride-grafted LLDPE (LLDPE-g-MA) in the composites were also studied. The addition of LLDPE-g-MA and 5 wt% and 10 wt% of carbon black in the PA6/LLDPE blend resulted in a 130 and 150% increase in impact strength, respectively. Adding 10 wt% of carbon black in the PA6/LLDPE/LLDPE-g-MA blend increased the elastic modulus, reduced the electrical resistivity by 14 decades and also reduced the water vapor permeability, allowing this material to be eligible for use as antistatic packaging. [ABSTRACT FROM AUTHOR]

The approach of upgrading barrier properties of polymer with nanofillers is effectual and well established now-a-days to manufacture films and quality packaging. This research deals with enhancement of barrier attributes of clay-based high density polyethylene nanocomposites against oxygen and water permeability. Na-Montmorillonite and two grades of kaolin clays were used for HDPE/clay nanocomposites preparation in twin-screw extruder with temperature profile of 160, 170, 180, 190 and 200 °C along the extruder at 110 rpm with clay loading up to 10 wt%. The extent of maximum reduction in water and oxygen vapors permeation was more prominent at 5 wt% sample of each clay. XRD analysis revealed no exfoliation in kaolin clay samples but indicated presence of exfoliation in Na-MMT samples. SEM and TEM micrographs revealed nano-level dispersion for both kaolin clays and Na-MMT and agglomerate formation at high wt% of clays. Experimental data for oxygen and water vapors permeation through nanocomposites were fitted on Nielsen, Cussler and Gusev–Lutsi models. Modelling of barrier performance was utilized for acquiring aspect ratio of filler for nanocomposites. Maximum and average aspect ratio of fillers and third-degree polynomial equation for nanocomposite, through curve fitting, were determined to predict improved barrier properties of nanocomposites. [ABSTRACT FROM AUTHOR]

Investigating the compatibility mechanism of hybrid composites based on two polymers and one mineral nanofiller is a challenge that needs to be better understood. This study evaluates the effect of calcium carbonate (nCaCO3) nanoparticles as co-compatibilizers in a blend based on poly(lactic acid) (PLA), polyethylene from renewable sources (HDPE) and maleic anhydride grafting polyethylene (HDPE-g-MA or MA) using rheological and morphological analyses. Morphological assessment by scanning electron microscopy showed the formation of co-continuous-like phase morphology when nCaCO3 was added to the PLA/MA/HDPE blend, indicating that nCaCO3 affected the dispersion of PLA domains in the HDPE matrix. Rheological characterization carried out by stress relaxation and sweep frequency response analysis demonstrated that the addition of nCaCO3 improved the solid-like behavior of the blend, corroborating the morphological results. Additionally, an interaction mechanism of nCaCO3 as a co-compatibilizer was also proposed. [ABSTRACT FROM AUTHOR]

The reaction of one equivalent of 1,2,4,5-tetrakis(pyrazolyl-methyl)benzene ligand (L) with two equivalents of Cr(THF)3Cl3 in tetrahydrofuran has produced a binuclear neutral complex of general formula [Cr2L(THF)2Cl6] (1). It was characterized by mass spectrometry, Fourier-transformed infrared, X-ray photoelectron spectroscopy, and magnetic susceptibility. Theoretical calculations supported the formation of binuclear complex (1) with each hexacoordinate metal center. This complex was active in ethylene polymerization employing methylaluminoxane as cocatalyst, with moderate activities (5.7–20.8 kg polymer/(mol precat.) (bar) (h)). The reaction parameters such as temperature, monomer pressure, and Al/Cr ratio were studied. An increase of reaction temperature produced a decreasing of catalytic activity. However, an increase in the monomer pressure did not produce a significant increase in catalytic activity. The Al/Cr ratios used to activate this complex are smaller than those reported for the tris(pyrazolyl)borate chromium complex. This system produced high-density polyethylenes with wide molecular weight, Mw, distributions between 42,280 and 74,346 and polydispersity index from 2.3 to 6.6. [ABSTRACT FROM AUTHOR]

In the current research, physical and morphological properties of high-density polyethylene (HDPE) were investigated after equal-channel angular pressing (ECAP) for up to three passes via route A, in which the sample is pressed without any rotation between individual passes, at the temperature of 80 °C. The results of density, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) represent a decrease in the polymer's crystallinity after deformation, which is more evident after three passes of ECAP. Moreover, a phenomenological mechanism is proposed to explain the variations of crystallinity after ECAP processing. The occurrence of an additional crystalline peak in the XRD pattern, as well as melting doublet in the DSC curve of three-pass ECAP-deformed sample, demonstrate that some part of the initial orthorhombic crystalline phase of HDPE has been transformed to monoclinic crystal structure after ECAP deformation. Furthermore, a reduction in melting temperature and broadening of crystalline peaks show that the thickness of crystalline lamella may decline in one-pass ECAP-deformed sample, which could significantly affect dynamic mechanical behavior of HDPE. In addition, dilatometry results and observation of the impact-fractured surfaces of deformed samples reveal that oriented structures formed in amorphous and crystalline regions of the workpiece. [ABSTRACT FROM AUTHOR]

Nano-TiO2 particles were used as photo-catalysts and ferric stearate (FeSt3) powders were used as the thermo-oxidant promoters for degradable low-density polyethylene films in order to increase the rate of abiotic degradation of waste PE in the natural environment. The TiO2–FeSt3–polyethylene (TFPE) composite film was synthesized through two stages: a melt-granulating process and a film-blowing process. The final TiO2 and FeSt3 in composite film were controlled at around 1 wt%. The film thickness was about 25 μm. The photo-degradation and thermo-degradation of the composite film were investigated by exposing to UV irradiation for 240 h and/or in an air oven maintained at 70 °C for 30 days. Their residues were assembled in a aquatic test systems, and the effective biodegradation was assessed by monitoring the amount of CO2 developed over time according to the international standards ISO 14852 (1999). After 30 days of thermo-oxidative degradation, TFPE film containing both TiO2 and FeSt3 exhibited the strong characteristic absorptions of the carbonyl group (> C=O) and the amorphous region in ATR-FTIR spectroscopy. The loss rate for tensile strength and elongation at break of TFPE film reached 60% and 97.7%. After 240-h UV irradiation, the weight loss of TFPE film was 14%, and also, the absorption peaks appeared for carbonyl (> C=O) group and hydroxyl group in FTIR spectroscopy. The results showed that the addition of TiO2 and FeSt3 into the PE film could promote the photo-degradation and thermo-oxidative degradation of PE film. A lot of oxygenated groups were inserted into PE matrix during photo- or thermo-aging treatments, which was helpful for further biodegradation of films. Residues of TFPE films could be degraded completely by microorganism after incubation in aqueous medium. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of cobalt hydroxide nitrate (CoHN) and cobalt hydroxide p-aminobenzoate (CoHAB), which were dispersed in polyethylene with the objective of protecting the polymer from ultraviolet (UV) radiation degradation. First, CoHN was synthesized by urea hydrolysis in the presence of Co(II) nitrate and the intercalation of p-aminobenzoate into CoHAB was performed under hydrothermal alkaline conditions. The structure and thermal stability of the CoHN and CoHAB were characterized by several instrumental techniques. Results indicated that both fillers were dispersed in polyethylene and absorb radiation in the whole UV range, modifying the behavior of the polymer degradation under artificial weathering conditions. [ABSTRACT FROM AUTHOR]

Breast cancer is a chronic disease that is characterized by an uncontrolled growth of abnormal cells from the breast tissue. It is one of the leading causes of mortality among women worldwide because of its early metastasis, aggressive behavior and resistance to the currently used anticancer drugs. Most of these drugs suffer from poor absorption and toxicity, and lack long-term efficaciousness because of drug resistance. Recently, polymeric thermosensitive hydrogels have emerged as excellent drug delivery systems for anticancer drugs with the potential to improve the overall therapeutic effect of the incorporated drug. In this current research, doxorubicin and curcumin were loaded into biodegradable PEG–gum acacia-based hydrogels. These hydrogels were pH-sensitive, biodegradable and non-toxic. The release mechanism of the drugs from the hydrogels was pH-dependent. In vitro cytotoxicity studies on MCF-7 cancer cell lines further confirmed that the incorporation of doxorubicin and curcumin into the hydrogels resulted in significant cytotoxic effect when compared to the free drugs, suggesting that these hydrogels are potential dual-drug delivery systems. The cytotoxic effect was dose- and time-dependent. [ABSTRACT FROM AUTHOR]

A temperature-controlled dispersion technique was used to develop ornidazole-loaded micron-level particles. To overcome the problem of generating the reservoir-type particles from polyethylene glycol, the influence of camphor and menthol (1:1 ratio)-based eutectic liquid on reservoir-type particle formation, drug entrapment efficiency and drug release behavior was examined. A distinct wall formation was observed for the particles on contact with water. Higher drug entrapment efficiency (~ 15–20%) was noted for the particles prepared with eutectic liquid. Significantly, (one-way ANOVA) higher t50% values (35.16 ± 1.44 min for HCl and 43.6 ± 0.76 min for pH 6.8 phosphate buffer) were noticed for the eutectic liquid-based particles in comparison with the t50% values (30.66 ± 0.76 min for HCl and 35.5 ± 0.86 min for pH 6.8 phosphate buffer) observed for the particles made without the same. The potential of eutectic liquid to generate the microcapsule structure should be explored further. [ABSTRACT FROM AUTHOR]

Efficient photocatalytic degradation of a commercial low-density polyethylene (LDPE) was developed via incorporation of polystyrene grafted ZnO nanoparticles. The free radical reaction was used for grafting process of the styrene monomer on the ZnO nanoparticle. Neat LDPE and composite LDPE films, containing pristine and grafted ZnO nanoparticles, were prepared via film blowing techniques. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were employed for investigation of successful grafting process and amount of grafting determinations. Tensile tests and weight loss assessments were used for evaluation of the photocatalytic degradation. The FTIR and TGA results confirmed the successful grafting, whereas the TGA results determined 16 and 39 wt% of polystyrene grafting on the ZnO nanoparticles. The mechanical tests showed that both incorporation of the nanoparticles and grafting increased the tensile strength of the prepared LDPE films. Photocatalytic degradation evaluations revealed that incorporation of ZnO nanoparticles improved the degradation in the composites films after 200-h UV irradiation. The polystyrene grafting increased the ZnO nanoparticle's dispersion, whereas the increase in grafting from 15 to 39 wt% mitigated the efficiency of the ZnO photocatalytic performance. It was possibly due to the surrounding polystyrene that reduced the nanoparticle UV absorption. [ABSTRACT FROM AUTHOR]

Blends based on recycled high-density polyethylene (rHDPE) and jackfruit seed starch were prepared using a melt blending method. A total of three blend systems was studied: rHDPE/native starch blends, rHDPE/thermoplastic starch (TPS) blends and rHDPE/citric acid-treated thermoplastic starch (TPSCA) blends at ratios of 90/10, 80/20, 70/30 and 60/40. Modifications were made to overcome the problems of dealing with starch based blends, due to the blends' compatibility with hydrophobic rHDPE and the hydrophilic nature of starch. For the rHDPE/starch blends, the tensile properties were poorer than those of neat rHDPE, with lower ultimate tensile strength and elongation at break, but higher Young's modulus. Upon the conversion of starch into thermoplastic starch, the ultimate tensile strength (UTS), dispersion and thermal stability slightly improved. A blend ratio of 90/10 exhibited the highest tensile strength, while the 60/40 ratio exhibited the highest Young's modulus and better thermal stability. Similar trends were observed in rHDPE blended with citric acid-treated thermoplastic starch, with much better interfacial bonding between the rHDPE matrix and the TPSCA phase, as observed by SEM, thus improving the thermal stability as well as the tensile properties. [ABSTRACT FROM AUTHOR]

This study focuses on the effects of fiber treatment on the mechanical, morphological, physical and thermal properties of kenaf/jute/polyethylene composites, by using alkaline-treated and raw fibers. The core of jute and kenaf fibers was chopped into shorter lengths and used for composite fabrication. The composites were then subjected to tensile, water absorption, SEM, FTIR, DSC and TGA tests. According to the FTIR spectroscopy results, the alkaline treatment removed a significant amount of lignin and other impurities, especially at lower infrared band. This reduced fibers' hydrophilicity, making it more compatible with the polymer. This is evident from the SEM results, as it shows improved interfacial bonding. Therefore, the treated fiber composites, especially for 15 wt% composites, have higher tensile strengths, more thermal stability and higher activation energy. [ABSTRACT FROM AUTHOR]