Oil–water separation capability of superhydrophobic fabrics fabricated via combining polydopamine adhesion with lotus‐leaf‐like structure

By the combination of dual bionic on the superhydrophobicity of lotus leaf and the bioadhesion of mussel adhesive protein, the nanoparticles were strongly immobilized onto the surface of cotton fabric to form superhydrophobic and superoleophilic coating. The as‐prepared fabric can be used as effective material for separating various oil/water mixtures. The separation efficiency can reach 99.0%, 97.6%, 98.1%, 96.0%, 94.2%, and 94.5% for toluene/water, n‐hexane/water, chloroform/water, paraffin oil/water, linseed oil/water, and crude oil/water mixtures with volume ratio of 1 : 4, respectively. In addition, the obtained fabric still kept stable superhydrophobicity and high separation efficiency for oil/water mixtures after using repeatedly for 90 cycles or ultrasonic treatment. They also exhibited excellent chemical durability in harsh conditions of strong acidic and alkaline solutions. Owning to high separation efficiency, stable recyclability, low cost, scalable fabrication, and excellent durability, the as‐prepared fabric can be considered as promising material for the separation of oil/water mixtures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42614.     

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

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

Preparation and characterization of linear low‐density polyethylene/low‐density polyethylene/TiO2 membranes

Because of their special functions, the application of nanoscale powders has recently attracted both industrial and theoretical interest. In this study, nanoscale TiO₂, which exhibited a special UV absorption and consequent antibacterial function, was added to a low‐density polyethylene/linear low‐density polyethylene hybrid by melt compounding to yield functional composite membranes. TiO₂ exhibited an apparent induced nucleation effect on the crystallization of polyethylene, and the size of the crystallites decreased while the number increaed with the introduction of TiO₂; however, the crystallinity of polyethylene changed little. Also, TiO₂ exhibited an ideal dispersion in the membrane with an average size less than 100 nm, and this excellent dispersion provided the membranes extra UV absorption; moreover, the transparency of the membranes was maintained to satisfy common requirements. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 216–221, 2005     

Melt strength of linear low‐density polyethylene/low‐density polyethylene blends

Linear low‐density polyethylenes and low‐density polyethylenes of various compositions were melt‐blended with a batch mixer. The blends were characterized by their melt strengths and other rheological properties. A simple method for measuring melt strength is presented. The melt strength of a blend may vary according to the additive rule or deviate from the additive rule by showing a synergistic or antagonistic effect. This article reports our investigation of the parameters controlling variations of the melt strength of a blend. The reciprocal of the melt strength of a blend correlates well with the reciprocal of the zero‐shear viscosity and the reciprocal of the relaxation time of the melt. An empirical equation relating the maximum increment (or decrement) of the melt strength to the melt indices of the blend components is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1408–1418, 2002     

Prediction of processability at extrusion coating for low‐density polyethylene

The neck‐in level and the maximum drawdown speed at extrusion coating for low‐density polyethylene are studied with the evaluation of the rheological properties in the molten state and the dilute solution properties. It is found that the viscous properties in the molten state and the dilute solution properties are not sensitive to the processability, whereas the elastic nature has a great impact. In particular, the elastic response in the nonlinear region, such as drawdown force and strain‐hardening behavior in elongational viscosity, can be employed for the prediction of the processability at extrusion coating. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Effect of perfluoroalkylmethacrylate ester‐grafted‐linear low‐density polyethylene on the tribological property of polyoxymethylene–linear low‐density polyethylene composites

In this work, perfluoroalkylmethacrylate ester (PFAMAE)‐grafted‐linear low‐density polyethylene (LLDPE) was synthesized by UV‐induced surface graft polymerization. The effect of PFAMAE‐grafted‐LLDPE on the tribological behavior of LLDPE‐filled polyoxymethylene (POM) composite was investigated using a friction and abrasion testing machine. The results showed that LLDPE‐g‐PFAMAE was a more effective modifier in improving tribological property of LLDPE‐filled POM composite than conventional maleic anhydride‐grafted‐polyethylene (PE‐g‐MAH). POM/LLDPE composite possessed much lower friction coefficient but higher wear rate than pristine POM. The incorporation of LLDPE‐g‐PFAMAE into POM/LLDPE further decreased the friction coefficient, which was 45% lower than that of POM. The wear rate of POM/LLDPE/LLDPE‐g‐PFAMAE composite was also reduced and was lower than that of pristine POM. The primary wear mechanisms of POM/LLDPE composite with and without LLDPE‐g‐PFAMAE were adhesive and abrasive wear. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Thermal analysis of high‐density polyethylene and low‐density polyethylene with enhanced biodegradability

The thermal properties of high‐density polyethylene (HDPE) and low‐density polyethylene (LDPE) filled with different biodegradable additives (Mater‐Bi AF05H, Cornplast, and Bioefect 72000) were investigated with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The DSC traces of the additives indicated that they did not undergo any significant phase change or transition in the temperature region typically encountered by a commercial composting system. The TGA results showed that the presence of the additive led to a thermally less stable matrix and higher residue percentages. The products obtained during the thermodegradation of these degradable polyolefins were similar to those from pure polyethylenes. The LDPE blends were thermally less stable than the HDPE blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 764–772, 2002     

Blend of high‐density polyethylene and a linear low‐density polyethylene with compositional‐invariant mechanical properties

This article presents the tensile properties and morphological characteristics of binary blends of the high‐density polyethylene (HDPE) and a linear low‐density polyethylene (LLDPE). Two constituents were melt blended in a single‐screw extruder. Injection‐molded specimens were evaluated for their mechanical properties by employing a Universal tensile tester and the morphological characteristics evaluated by using a differential scanning calorimeter and X‐ray diffractometer. It is interesting to observe that the mechanical properties remained invariant in the 10–90% LLDPE content. More specifically, the yield and breaking stresses of these blends are around 80% of the corresponding values of HDPE. The yield elongation and elongation‐at‐break are around 65% to corresponding values of HDPE and the modulus is 50% away. Furthermore, the melting endotherms and the crystallization exotherms of these blends are singlet in nature. They cluster around the corresponding thermal traces of HDPE. This singlet characteristic in thermal traces entails cocrystallization between these two constituting components. The clustering of thermal traces of blends near HDPE meant HDPE‐type of crystallites were formed. Being nearly similar crystallites of blends to that of HDPE indicates nearness in mechanical properties are observed. The X‐ray diffraction data also corroborate these observations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2604–2608, 2002     

Modification of recycled high‐density polyethylene by low‐density and linear‐low‐density polyethylenes

The present study investigated mixed polyolefin compositions with the major component being a post‐consumer, milk bottle grade high‐density polyethylene (HDPE) for use in large‐scale injection moldings. Both rheological and mechanical properties of the developed blends are benchmarked against those shown by a currently used HDPE injection molding grade, in order to find a potential composition for its replacement. Possibility of such replacement via modification of recycled high‐density polyethylene (reHDPE) by low‐density polyethylene (LDPE) and linear‐low‐density polyethylene (LLDPE) is discussed. Overall, mechanical and rheological data showed that LDPE is a better modifier for reHDPE than LLDPE. Mechanical properties of reHDPE/LLDPE blends were lower than additive, thus demonstrating the lack of compatibility between the blend components in the solid state. Mechanical properties of reHDPE/LDPE blends were either equal to or higher than calculated from linear additivity. Capillary rheological measurements showed that values of apparent viscosity for LLDPE blends were very similar to those of the more viscous parent in the blend, whereas apparent viscosities of reHDPE/LDPE blends depended neither on concentration nor on type (viscosity) of LDPE. Further rheological and thermal studies on reHDPE/LDPE blends indicated that the blend constituents were partially miscible in the melt and cocrystallized in the solid state.     

Preparation and characterization of linear low‐density polyethylene/dickite nanocomposites prepared by the direct melt blending of linear low‐density polyethylene with exfoliated dickite

Dickite particles were exfoliated by the thermal decomposition of molecular urea in the interlayer of dickite. The exfoliated dickite (ED) was composed with linear low‐density polyethylene (LLDPE) to prepare a novel LLDPE/dickite nanocomposite (LDN‐5). X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the exfoliation effect. FTIR spectra showed that the inner‐surface hydroxyls of dickite decreased because of the sufficient exfoliation of the dickite layers. The 001 diffraction of dickite in the XRD pattern almost disappeared after exfoliation; this indicated the random orientation of dickite platelets. SEM and TEM micrographs confirmed the effective thermal decomposition of the interlamellar molecular urea ED layers, which resulted in smaller particle sizes and better dispersions of dickite in the resulting LLDPE/dickite composite. The microstructure of LDN‐5 showed that most of the dickite platelets were exfoliated and homogeneously dispersed in the LLDPE; this led to increases in the anticorrosion properties and thermal stabilities of LDN‐5. The results of salt‐spray tests illustrated that the corrosion rate of the iron coupon decreased from 23% (LLDPE packing) to 0.4% (LDN‐5 packing). Moreover, the thermal degradation temperature corresponding to a mass loss of 10% increased from 330°C (pure LLDPE) to 379°C (LDN‐5). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Capillary flow of low‐density polyethylene

The capillary flow of a commercial low‐density polyethylene (LDPE) melt was studied both experimentally and numerically. The excess pressure drop due to entry (Bagley correction), the compressibility, the effect of pressure on viscosity, and the possible slip effects on the capillary data analysis have been examined. Using a series of capillary dies having different diameters, D, and length‐to‐diameter L/D ratios, a full rheological characterization has been carried out, and the experimental data have been fitted both with a viscous model (Carreau‐Yasuda) and a viscoelastic one (the Kaye—Bernstein, Kearsley, Zapas/Papanastasiou, Scriven, Macosko, or K‐BKZ/PSM model). Particular emphasis has been given on the pressure‐dependence of viscosity, with a pressure‐dependent coefficient β_p. For the viscous model, the viscosity is a function of both temperature and pressure. For the viscoelastic K‐BKZ model, the time‐temperature shifting concept has been used for the non‐isothermal calculations, while the time–pressure shifting concept has been used to shift the relaxation moduli for the pressure‐dependence effect. It was found that only the viscoelastic simulations were capable of reproducing the experimental data well, while any viscous modeling always underestimates the pressures, especially at the higher apparent shear rates and L/D ratios. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Melt electrospinning of low‐density polyethylene having a low‐melt flow index

Melt electrospinning is a cheaper, more environmentally friendly, and safer alternative to solution electrospinning. We have designed a novel melt spinning device which incorporates a reverse of the normal polarity, with the capillary grounded and the collector grid at positive potential. The apparatus is much simpler and more economical than conventional equipment because no syringe pump is required. Low‐density polyethylene (LDPE) with a low‐melt flow index of 2 g/10 min, which is not suitable for spinning using current commercial methods, was chosen to highlight the advantages of melt electrospinning in general, and our device in particular. The effects of varying the electrospinning parameters such as temperature, electrostatic field, spinning distance, and capillary inner diameter, have been studied. Although it was found that temperatures higher than normal processing temperatures had to be employed in our electrospinning system to reduce the viscosity of the polymer melt sufficiently, good quality fibers with smooth and even surfaces, most of which had diameters smaller than 15 μm, were electrospun successfully. It was observed that there was an optimum point for the spinning distance (14–15 cm) and the capillary inner diameter (0.4–0.6 mm) to get fine fiber. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Degradation of polyethylene during extrusion. II. Degradation of low‐density polyethylene,linear low‐density polyethylene,and high‐density polyethylene in film extrusion

The degradation of different polyethylenes—low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and high‐density polyethylene (HDPE)—with and without antioxidants and at different oxygen concentrations in the polymer granulates, have been studied in extrusion coating processing. The degradation was followed by online rheometry, size exclusion chromatography, surface oxidation index measurements, and gas chromatography–mass spectrometry. The degradations start in the extruder where primary radicals are formed, which are subject to the auto‐oxidation when oxygen is present. In the extruder, crosslinking or chain scissions reactions are dominating at low and high melt temperatures, respectively, for LDPE, and chain scission is overall dominating for the more linear LLDPE and HDPE resins. Additives such as antioxidants react with primary radicals formed in the melt. Degradation taking place in the film between the die orifice, and the quenching point is mainly related to the exposure time to air oxygen. Melt temperatures above 280°C give a dominating surface oxidation, which increases with the exposure time to air between die orifice and quenching too. A number of degradation products were identified—for example, aldehydes and organic acids—which were present in homologous series. The total amount of aldehydes and acids for each number of chain carbon atoms were appeared in the order of C5>C4>C6>C7?C2 for LDPE, C5>C6>C4>C7?C2 for LLDPE, and C5>C6>C7>C4?C2 for HDPE. The total amounts of oxidized compounds presented in the films were related to the processing conditions. Polymer melts exposed to oxygen at the highest temperatures and longest times showed the presence dialdehydes, in addition to the aldehydes and acids. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1525–1537, 2004     

Thermal and mechanical properties of linear low‐density polyethylene/low‐density polyethylene/wax ternary blends

The thermal and mechanical properties of uncrosslinked three‐component blends of linear low‐density polyethylene (LLDPE), low‐density polyethylene (LDPE), and a hard, paraffinic Fischer–Tropsch wax were investigated. A decrease in the total crystallinity with an increase in both LDPE and wax contents was observed. It was also observed that experimental enthalpy values of LLDPE in the blends were generally higher than the theoretically expected values, whereas in the case of LDPE the theoretically expected values were higher than the experimental values. In the presence of higher wax content there was a good correlation between experimental and theoretically expected enthalpy values. The DSC results showed changes in peak temperature of melting, as well as peak width, with changing blend composition. Most of these changes are explained in terms of the preferred cocrystallization of wax with LLDPE. Young's modulus, yield stress, and stress at break decreased with increasing LDPE content, whereas elongation at yield increased. This is in line with the decreasing crystallinity and increasing amorphous content expected with increasing LDPE content. Deviations from this behavior for samples containing 10% wax and relatively low LDPE contents are explained in terms of lower tie chain fractions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1748–1755, 2005     

Stable superhydrophobic surface based on low‐density polyethylene/ethylene‐propylene‐diene terpolymer thermoplastic vulcanizate

Stable superhydrophobic surface based on low‐density polyethylene (LDPE)/ethylene–propylene–diene terpolymer (EPDM) thermoplastic vulcanizate (TPV) was successfully fabricated by using etched aluminum foil as template. The etched aluminum template consisted of micropores and step‐like textures, was obtained by the metallographic sandpaper sanding and the subsequent acid etching. The surface morphology and hydrophobic properties of the series molded TPV surfaces were researched by varying the weight ratio of the LDPE/EPDM TPV. The superhydrophobic LDPE/EPDM TPV surfaces exhibited the microstructures consisting of step‐like textures obtained via molding with etched aluminum template and a large number of fiber‐like structures resulted from the plastic deformation of LDPE matrix. The obtained TPV (LDPE/EPDM weight ratio = 70/30) surface exhibited the remarkable superhydrophobicity, with a contact angle of 152.0° ± 0.7° and a sliding angle of 3.1° ± 0.8°. The molded TPV surface had excellent environmental stability when the pH of water solution was in the range of 1 to 14; moreover, the surface also showed the excellent resistance to various organic solvents. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46241.     

Effect of blending high‐pressure low‐density polyethylene on the crystallization kinetics of linear low‐density polyethylene

It is well known that the addition of a small amount of high‐pressure low‐density polyethylene (HP‐LDPE) to linear low‐density polyethylene (LLDPE) can improve the optical properties of LLDPE, and LLDPE/HP‐LDPE blend is widely applied to various uses in the field of film. The optical haziness of polyethylene blown films, as a result of surface irregularities, is thought to be as a consequence of the different crystallization mechanisms. However, not much effort has been directed toward understanding the effect of HP‐LDPE blending on the overall crystallization kinetics (k) of LLDPE including nucleation rate (n) and crystal lateral growth rate (v). In this study, we investigated the effect of blending 20% HP‐LDPE on the crystallization kinetics of LLDPE polymerized by Ziegler‐Natta catalyst with comonomer of 1‐butene. Furthermore, by combining depolarized light intensity measurement (DLIM) and small‐angle laser light scattering (SALLS), we have established a methodology to estimate the lateral growth rate at lower crystallization temperatures, in which direct measurement of lateral growth by polarized optical microscopy (POM) is impossible due to the formation of extremely small spherulites. This investigation revealed that HP‐LDPE blending leads to enhanced nucleation rate, reduced crystal lateral growth rate, and a slight increase in the overall crystallization kinetics of pure LLDPE. From the estimated crystal lateral growth rate, it was found that the suppression in v from HP‐LDPE blending is larger at lower temperatures than at higher temperatures. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface characterization of low‐temperature cascade arc plasma–treated low‐density polyethylene using contact angle measurements

Low‐density polyethylene (LDPE) was treated with a low‐temperature cascade arc plasma torch (LTCAT) of argon with or without adding a reactive gas of oxygen or water vapor. The static sessile droplet method and the dynamic Wilhelmy balance method were employed to perform surface contact angle measurement in order to investigate and characterize the effects of LTCAT treatment on LDPE surfaces. These treatment effects included changes in surface wettability and surface stability and possible surface damage that would create low‐molecular‐weight oligomers on the treated surface. Experimental results indicated that the combination of static and dynamic surface contact angle measurements enabled a comprehensive investigation of these effects of plasma treatment on a polymer surface. Without the addition of a reactive gas, a 2‐s argon LTCAT treatment of LDPE resulted in a stable hydrophilic surface (with a water contact angle of 40°) and little surface damage. The addition of oxygen into argon LTCAT produced a less stable LDPE surface and showed more surface damage. Adding H₂O vapor into argon LTCAT produced an extremely hydrophilic surface (with a water contact angle < 20°) of LDPE but with pronounced surface damage. When compared with conventional radio frequency (13.56 MHz) plasmas, LTCAT treatment provides a much more rapid, effective, and efficient method of surface modification of LDPE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2528–2541, 2006     

Recycled milk pouch and virgin low‐density polyethylene/linear low‐density polyethylene based coir fiber composites

The viability of the thermomechanical recycling of postconsumer milk pouches [a 50 : 50 low‐density polyethylene/linear low‐density polyethylene (LDPE–LLDPE) blend] and their use as polymeric matrices for coir‐fiber‐reinforced composites were investigated. The mechanical, thermal, morphological, and water absorption properties of recycled milk pouch polymer/coir fiber composites with different treated and untreated fiber contents were evaluated and compared with those of virgin LDPE–LLDPE/coir fiber composites. The water absorption of the composites measured at three different temperatures (25, 45, and 75°C) was found to follow Fickian diffusion. The mechanical properties of the composites significantly deteriorated after water absorption. The recycled polymer/coir fiber composites showed inferior mechanical performances and thermooxidative stability (oxidation induction time and oxidation temperature) in comparison with those observed for virgin polymer/fiber composites. However, a small quantity of a coupling agent (2 wt %) significantly improved all the mechanical, thermal, and moisture‐resistance properties of both types of composites. The overall mechanical performances of the composites containing recycled and virgin polymer matrices were correlated by the phase morphology, as observed with scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Morphology and rheological properties of compatibilized low‐density polyethylene/linear low‐density polyethylene/thermoplastic starch blends

Morphology and rheological properties of low‐density polyethylene/linear low‐density polyethylene/thermoplastic starch (LDPE/LLDPE/TPS) blends are experimentally investigated and theoretically analyzed using rheological models. Blending of LDPE/LLDPE (70/30 wt/wt) with 5–20 wt % of TPS and 3 wt % of PE‐grafted maleic anhydride (PE‐g‐MA) as a compatibilizer is performed in a twin‐screw extruder. Scanning electron micrographs show a fairly good dispersion of TPS in PE matrices in the presence of PE‐g‐MA. However, as the TPS content increases, the starch particle size increases. X‐ray diffraction patterns exhibit that with increase in TPS content, the intensity of the crystallization peaks slightly decreases and consequently crystal sizes of the blends decrease. The rheological analyses indicate that TPS can increase the elasticity and viscosity of the blends. With increasing the amount of TPS, starch particles interactions intensify and as a result the blend interface become weaker which are confirmed by relaxation time spectra and the prediction results of emulsion Palierne and Gramespacher‐Meissner models. It is demonstrated that there is a better agreement between experimental rheological data and Coran model than the emulsion models. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44719.