Ethylene Bis-stearamide Research Articles

Decarburization and Gas Formation During Sintering of Alloyed PM Steel Components

This study investigates the delubrication, reduction, and decarburization processes of powder metallurgical steel alloys (CrM, CrL, AHC, Mo85, SintD 35) and an unalloyed steel during sintering in a pure hydrogen atmosphere. Utilizing in-situ FTIR gas phase analysis, components with ethylenebisstearamide (EBS) as a lubricant are analyzed. EBS decomposition in steel components yields CO, CO2, H2O, and CH4, with dominant CH groups observed in the 230 °C to 480 °C range. In the temperature range between 750 °C and 850 °C, where CO formation is expected due to the reduction of surface iron oxides, CH4 is present instead, indicating that an “internal getter effect” also occurs in pre-alloyed powders. In addition, with high carbon activity, the reduction of internal iron oxides and the reduction of chromium oxides also trigger an internal getter effect. Depending on the carbon potential, these processes cause a considerable reduction in the carbon content of the powder metallurgical components. The study therefore shows that the decarburization of powder metallurgical components during the heat treatment phases prior to sintering in a 100 pct hydrogen atmosphere is less due to the mechanism of delubrication, but rather to mechanisms of carbothermal reduction.

Trap-induced hydro-charging polylactic acid nonwovens with high charge storage capability for stable and efficient air filtration

Under the background of carbon neutrality, eco-friendly biodegradable polylactic acid (PLA) melt-blown nonwovens have been developed in air filtration. Nevertheless, the filtration performance of existing PLA melt-blown nonwovens is in an embarrassing situation and fails to meet the requirement of high efficiency air filters. Here, with controllable doping of N, N′-ethylene bis-stearamide (EBS), and barium titanate (BaTiO3) into PLA, through the melt-blown process, the charge-storage capacity of PLA nonwovens enhanced significantly. By utilizing the hydro-charging technology thereafter, we have prepared hydro-charged PLA/EBS/BaTiO3 nonwovens (HCP-EB) with excellent filtration performances. The doped EBS and BaTiO3 could improve the crystallization and charge storage capacity of PLA during the melt-blown process, thus constructing a large number of interfacial traps between crystalline and amorphous regions, leading to more electric charges captured during the hydro-charging process. The HCP-EB exhibited a high filtration efficiency (99.69 %) for PM0.3, a low pressure drop (27.44 Pa), and superior charge storage stability. Furthermore, the HCP-EB, remained at 99.18 % filtration efficiency after 48 h of treatment at 90 % relative humidity. After 3 months of storage, it still possessed an excellent filtration efficiency (99.02 %). Our work will contribute to the practical application of PLA melt-blown nonwovens in air filters and masks, and inspire the research of next-generation biodegradable electret air filtration materials.

Fabrication of large cross-section Ti–6Al–4V alloy using EBS-modified POM-based feedstock

Plastic shaping offers a viable method for the formation of complex structures. However, current research primarily focuses on small and medium-sized components, with limited exploration on the forming, debinding, and sintering of complex components with large cross-section. In this study, by mixing spherical Ti–6Al–4V powder with polyformaldehyde (POM)-based binder, three different feedstocks were prepared, varying in powder loadings and modified with ethylene bis-stearamide (EBS) modification. The feedstock properties were studied, and cylindrical samples with a cross-section thickness of 30 mm were fabricated via rheological press molding (RPM) to investigate their debinding and sintering behavior. The results showed that the increase in powder loading increased the feedstock viscosity but reduced the impurity content (C, O). EBS reduced the contact angle between the powder and POM, and increased the viscosity and sensitivity to shear rate changes. Catalytic debinding of the samples was completed in 2 h. After sintering, EBS-modified Ti–6Al–4V h showed uniform sintering shrinkage, microstructure, the highest relative density of 97.10%, a yield strength of 701 ± 5 MPa, and an ultimate tensile strength of 746 ± 13 MPa.

Viscosity Reduction Mechanism and Rheological Properties of Ethylene-Bis-Stearamide and Crumb Rubber Modified Asphalt

This study investigates the effect of ethylene-bis-stearamide (EBS) on viscosity reducing of crumb rubber modified asphalt (CRMA) and explores the interaction mechanism via molecular dynamics simulation (MD), microscope method and rheological experiment. It is confirmed that the EBS play an important role in reducing the viscosity of ethylene-bis-stearamide and crumb rubber modified asphalt (EBS-CRMA), especially when the content is within 3%. The micro morphology and MD results showed that the EBS is coating on rubber and asphaltenes and then forming lubrication film, which is the main reason leading to the viscosity decrease of EBS-CRMA. Additionally, other factors also have significant effect in reducing the viscosity of EBS-CRMA, including the more uniform distribution of asphaltenes, the enhanced diffusion ability of saturates and resins, the reduction of hydrogen bonds and soluble substances within asphalt phase. When EBS content exceeds 3%, the influence on viscosity of EBS-CRMA is not obvious with the EBS content continuously increasing. It can be concluded from Fourier Transform Infrared (FTIR) Spectrometer and MD results that the molecular aggregation, the concentration increase of intermolecular hydrogen bonds and the diffusion ability decrease of EBS-CRMA molecular system are main reasons. Meanwhile, the coating effect of EBS and soluble substances concentration within asphalt phase are limited as the EBS content over 3%.

Blown film extrusion of poly(lactic)acid/poly(3‐hydroxybutyrate‐4‐hydroxybutyrate) blends for improved toughness and processability

AbstractPoly(lactic acid) is one of the most commonly used bioplastics thanks to its mechanical performance and low environmental impact. Strategies to overcome excessive rigidity of PLA are constantly investigated. Poor viscoelastic behavior and brittleness of PLA seriously limit its potential application as a common film material. Herein highly amorphous Poly(3‐hydroxybutyrate‐4‐hydroxybutyrate) (P(3HB)(4HB)) was introduced to improve toughness and reduce brittleness of PLA. Anti‐blocking (silica) and anti‐slipping agent (Ethylene bis‐stearamide (EBS)) were added to improve the processability of the blends, specifically to solve winding issues of the blown film and unfolding of the layflat. In this study three formulations containing PLA and different ratios of P(3HB)(4HB), specifically 10–20–30% were extruded. The mechanical, thermal and surface characterization of the films was performed. The tensile and the tear strength test results show that P(3HB)(4HB) increased the ductility of PLA based films. Increasing amounts of P(3HB)(4HB) provide a toughening effect on PLA/P(3HB)(4HB) blown films without altering transparency of PLA. Moreover, the processing additives proved to be efficient in improving film blowing stability and avoiding tackiness during the winding phase of the film.

Aging of Industrial Polypropylene Surfaces in Detergent Solution and Its Consequences for Biofilm Formation

The performance of plastic components in water-bearing parts of industrial and household appliances, often in the presence of harsh environments and elevated temperatures, critically relies on the mechanical and thermal polymer stability. In this light, the precise knowledge of aging properties of polymers formulated with dedicated antiaging additive packages as well as various fillers is crucial for long-time device warranty. We investigated and analysed the time-dependent, polymer-liquid interface aging of different industrial performance polypropylene samples in aqueous detergent solution at high temperatures (95 °C). Special emphasis was put on the disadvantageous process of consecutive biofilm formation that often follows surface transformation and degradation. Atomic force microscopy, scanning electron microscopy, and infrared spectroscopy were used to monitor and analyse the surface aging process. Additionally, bacterial adhesion and biofilm formation was characterised by colony forming unit assays. One of the key findings is the observation of crystalline, fibre-like growth of ethylene bis stearamide (EBS) on the surface during the aging process. EBS is a widely used process aid and lubricant enabling the proper demoulding of injection moulding plastic parts. The aging-induced surface-covering EBS layers changed the surface morphology and promoted bacterial adhesion as well as biofilm formation of Pseudomonas aeruginosa.

Study on UV resistance of high density polyethylene composite using waste gypsum

Every year, a large amount of waste gypsum, a by-product of fertilizer production, was produced and landfilled that increasing the harm to the environment. In this study, for the purpose of utilizing waste gypsum, it was studied as the filler in blend of high density polyethylene (HDPE) and ethyelene vinyl acetated (EVA) with anti UV additives in order to improve the mechanical strength and lifespan of this composite. After using ethylene bis stearamide (EBS) to modify waste gypsum, modified waste gypsum (mGyp) and anti-UV additives at various contents were dispersed into HDPE/EVA blend by melt-mixing method to obtain HDPE/EVA/mGyp composites. As the results, the color difference and tensile strength of composite using additives did not changed much after 20 cycles of accelerated weathering test. In the presence of anti-UV additives, the photodegradation process was inhibited by showing the low carbonyl index of composite compared with samples without additives. Beside, the structure of composite using anti-UV additives is smooth and without cracks after accelerated weathering test as observed in SEM images. That led to the tensile strength of sample did not change much.

Effects of solid lubricants on properties of Al-Si-SiC composite powder produced by gas atomization technique

Al-Si-SiC composites powder was analyzed in this research. The powder was made by gas atomizing process. Powder characterization was done to observe its morphology, particle size distribution and thermal properties. Effects of lubricants were intensively investigated in this research with compositions and pressure variables. It is assumed that higher amount of solid lubricant put into the powder, the lower ejection force needed to take out compacted powder. Finding appropriate solid lubricant is necessary to improve green and sintering properties. EBS (ethylene bis stearamide), aluminum stearate, zinc stearate and paraffin wax were used for investigation. Sintering under ultra high purity nitrogen gas 99.9999% was carried out to produce high density material. SEM-EDS and XRD were carried to characterize this powder. SiC particles in this powder prohibit to achieve optimum sintering properties of Al-Si-SiC due to their resistance during compaction which leads to form pores and lower sintering density. And ethylene bis stearamide (EBS) seems to be suitable solid lubricant for this powder by giving lower ejection force, flowability and higher sintering density for 93.5%.

Optimisation of liquid rubber modified bitumen for road pavements and roofing applications

Polymer Modified Bitumens (PMBs) are largely used for pavement and roofing membranes applications with Styrene-Butadiene-Styrene Block copolymer (SBS) playing a major role in both markets despite its constantly increasing price due to the rising demand for quality bitumen modifiers. On the other hand, there is an increasing trend of recycling end of life tyres generating Recycled Tyre Rubber (RTR) at affordable price. This investigation aims at engineering a modified bitumen with a combination of Liquid Rubber (LR), a homogeneous blend of 50–70% RTR pre-processed in combination with heavy oils, and a wax denominated Ethylene Bis Stearamide (EBS). In the first phase, the effect of LR and EBS was independently characterised and compared to PMBs. Next, the Response Surface Methodology (RSM) was used to predict the response of different combinations of LR and EBS in terms of low and high temperature properties and cost, to then be optimised targeting conventional and rheological properties of PMBs currently used in asphalt mixtures and roofing membranes in UK. As a result, an optimum combination of LR and EBS was found leading to a cost-effective modified bitumen comparable to PMBs. The work provided also analytical functions that could be of use in further design exercises.

The melting rheology, mechanical properties, thermal stability and morphology of polylactic acid/ethylene bis stearamide modified gypsum composite

AbstractIn this research, gypsum (calcium sulfate) was surface modified by ethylene bis stearamide (EBS) before dispersing into PLA in melting state at various contents to obtain PLA/gypsum composites. The FTIR analysis revealed the presence of EBS on gypsum. The mechanical properties of the composite, such as tensile strength, impact strength, flexural strength…, showed that composite using EBS treated gypsum owns mechanical properties higher than composite using untreated gypsum. In thermal analysis, the maximum decomposition temperature of composite using EBS treated gypsum was higher than that of neat PLA and composite using untreated gypsum. SEM images on fracture surface of the composites also showed the difference between these samples.

Advance on processing of compostable and thermally stable biodegradable polyester blends

ABSTRACTFlexible and semiflexible packagings can be manufactured by cast extrusion of plastic sheet and thermoforming of containers. Thermal stability is often required as packaging items after being thermoformed can come in contact with hot food/beverage, especially during hot filling operations. In this framework, the present study deals with the design and manufacturing by thermoforming of plastic containers that are, at the same time, compostable and suitable for high‐temperature applications (~100 °C). First, extrusion compounding of Poly(l‐lactic acid) (PLLA)‐based biodegradable polyester blends was performed. In particular, the effect on the material properties of different types of nucleating agents was investigated. Combinations of micro‐lamellar talc, poly(d‐lactic acid) (PDLA), ethylene bisstearamide (EBS), and titanium dioxide (TiO2) were studied. The formulations involving EBS boast the highest crystallinity and the fastest onset of the crystalline phase on sheets produced by cast extrusion. Conversely, the formulations involving TiO2 feature the lowest degree of crystallinity and the slowest onset of the crystalline phase. Combinations of talc and PDLA exhibit an intermediate behavior. Second, thermoforming of the plastic foils was performed. A very different trend of the crystallization after thermoforming is shown. Indeed, crystallinity is the highest for the formulations involving talc and PDLA, the lowest for the ones containing EBS. In conclusion, the biodegradable polyester blends are found to be suitable for the manufacturing of compostable and thermostable packaging items by cast extrusion and thermoforming. Final crystallization of the material and the resulting thermal stability can be fine‐tuned by modulating type and amount of nucleating agents. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48722.

Influence of the combination of nucleating agent and plasticizer on the non-isothermal crystallization kinetics and activation energies of poly(lactic acid)

The influence of the combination of the nucleating agent (talc, N, N′-ethylene bis-stearamide (EBS) and a commercial nucleating agent NT-20) and the plasticizer (poly(ethylene glycol), PEG) on the melting and crystallization behaviors of poly(lactic acid) (PLA) was investigated by means of differential scanning calorimetry (DSC). The Jeziorny’s, Ozawa’s and Mo’s models were used to describe the non-isothermal cold and melt crystallization kinetics of the modified PLA samples. The non-isothermal cold and melt crystallization activation energies were evaluated by Kissinger’s method and Friedman’s method, respectively. The results show that the non-isothermal cold and melt crystallization kinetics of the samples are successfully analyzed by Jeziorny’s and Mo’s models, whereas Ozawa’s model is only suitable for the non-isothermal melt crystallization kinetics of PLA/talc sample. It is shown that the combination of one nucleating agent and PEG results in the synergistic effect on the cold and melting crystallization rates of PLA. Moreover, the combination of dual nucleating agents and PEG improves the cold crystallization rate but hinders the melt crystallization rate. It is indicated that dual nucleating agents act as physical hindrance to the molecular chain movement of PLA which results in the increases in the cold and melt crystallization activation energies.

Tribological behavior of polymer composites functionalized with various microcapsule core materials

Severe abrasion wear of water-lubricated bearings usually occurs during low-speed and heavy-duty working conditions. It is vital to improve the anti-friction and tribological properties of the composites used in the water-lubricated bearings. In this reported work, polymer microcapsules were added to matrix material as compositional modifications, to improve the tribological properties of the bearing as it was worn against a cast copper bushing. These microcapsules appeared to reduce the phase splitting between the low-melting-point lubricant and the matrix. In this particular study, urea formaldehyde (UF) microcapsules loaded with two lubricants included N, N′-ethylene Bis-stearamide and Erucic Amide as core materials were synthesized by double emulsion method (w/o/w) and then blended with high-density polyethylene (HDPE) to form the composites. The tribological properties of the microcapsule-modified composites were investigated using a CBZ-1 tribometer under different running conditions. After testing, the microcapsules were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and the surface morphologies of composites were analyzed by using Scanning Electron Microscopy (SEM). The analytical results revealed that the tribological properties of the composites were improved as the quantity of microcapsules in the composite was increased. The composites containing the microcapsules produced lower sliding friction and exhibited a smoother surface morphology, which was due to the lubrication provided by the Erucic Amide in the microcapsules. As shell of microcapsules was worn away during the test, the encapsulated Erucic Amide was released into the friction pairs, which established a dense lubrication film. When the mass fraction of the Erucic Amide containing microcapsules is 10 wt%, the frictional coefficient of composites is reduced by 66.9% under low sliding velocity and middling applied load conditions. This study also provided an experimental basis for the structural design and performance enhancement of water-lubricated bearings.

Preparation and characterization of coffee hull fiber for reinforcing application in thermoplastic composites

ABSTRACT Nowadays, there is an increasing concern toward substituting the scarce wood fibers with alternative lignocellulosic fibers that originate from crop residue to reinforce biocomposites. In this paper, the potential application of coffee hull (CH) of the reinforced polyethylene (PE) matrix composites was studied for the first time. Experiments of composite that enhanced with CH on mechanical properties, hydroscopicity, thermogravimetric analysis, fiber treatment, and microstructures were tested in this study. The PE matrix was reinforced with varying volume fractions of CH and was studied. The results show that incorporation of coffee hull markedly improved the mechanical properties of the reinforced high-density polyethylene (HDPE) matrix composites. Micrographs show a strong interfacial adhesion between the CH fiber particles. This property may be the main reason for the stability between composites. At the same time this work investigated the effect of different treatments on the mechanical properties and water absorption behavior of composites. The fiber surface treatments were done using active chemicals such as calcium hydroxide (Ca(OH)2), silane coupling agent (SCA), maleic anhydride grafted polypropylene (MA-g-PP), stearic acid (SA), ethylene bis stearamide (EBS) and the combination (MA-g-PP, SA, EBS). The results show that (Ca(OH)2)treatment is the best way to improve its properties. Probably because attributed to removal of surface active functional groups (-OH) from the CH fiber and induction of hydrophobicity that in turn improved the compatibility with the polymer matrix. As a result, the use of coffee hull in composites could have great significance for the industry.

Moisture resistance study on PE-wax and EBS-wax modified warm mix asphalt using chemical and mechanical procedures

Global warming, environmental concerns, and energy prices have led to increased use of wax additives to produce warm mix asphalt (WMA) as an alternative to hot mix asphalt (HMA). Despite many advantages, moisture susceptibility of WMAs is a legitimate concern. Although there have been many studies about moisture susceptibility of warm mix additives, mixtures containing ethylene-bis-stearamide (EBS) and polyethylene (PE) waxes have been less studied. In this research, moisture susceptibility of asphalt mixtures containing PE and EBS were evaluated. Furthermore, rheological and chemical evaluations of EBS and PE-wax modified binders were evaluated using dynamic shear rheometry and Fourier infrared spectroscopy, respectively. Moisture susceptibility was assessed using the modified Lottman test and the effects of aggregate type and production temperature were also evaluated. Results indicate improved moisture resistance for mixtures containing EBS. Additionally, the effect of PE-wax on moisture susceptibility was observed to be temperature dependent showing adverse effects at higher compaction temperatures.

PROPERTIES OF COMPOSITE BASED ON HIGH DENSITY POLYETHYLENE/ETHYLENE VINYL ACETATE BLEND AND A NOVEL ORGANIC MODIFIED WASTE GYPSUM

In this study, waste gypsum (WGS) was used as the filler in blend of high density polyethylene (HDPE) and ethylene vinyl acetate copolymer (EVA) in order to improve the flame resistance of this composite. After modification by ethylene bis stearamide (EBS), modified gypsum (EGS) at various contents was dispersed into HDPE/EVA blend by melt-mixing method to obtain EGS/HDPE/EVA composites. The IR analysis of the EGS showed the interaction between EBS and gypsum. The difference in morphology of HDPE/EVA/EGS and HDPE/EVA/OGS composites was also observed in SEM images. By adding EGS and small amounts of flame retardant additives such as ammonia polyphosphate and zinc borate, the thermal stability and the flame resistance of HDPE/EVA/EGS composites have improved and classified at V2 grade of UL94 standard. Moreover, the second self extinguishing time (t2) of EGS composite is shorter than that of unmodified gypsum (OGS) composite because of the quality char forming after the fist burning and it plays a role as thermal barriers to protect material from heat of the second ignition. About mechanical properties, both tensile strength and elongation at break of the composite decreased with increasing the gypsum content and flame retardant additives because of filler aggregation.

Effects of lubricant and part geometry on the ejection characteristics during die compaction

ABSTRACTThe ejection of a part following die compaction is a critical step in manufacturing powder metal and ceramic parts as well as pharmaceutical tablets. In this paper, the ejection of die-compacted hollow cylinders of heights 0.5 and 1.2 cm from Fe–2%Cu–0.5%C powders mixed with various amounts of (0.2–0.8 wt-%) of ethylene-bis-stearamide (EBS) was studied to understand the effect of lubricant amount and part geometry on the ejection process. Additionally, the ejection data of gears of 0.5 and 1.2 cm die compacted from Fe–2%Cu–0.5%C powders with 0.8 wt-% EBS was analysed to understand the effect of geometry on the ejection process. Several ejection parameters were found to be sensitive to the amount of EBS as well as the size and shape of the parts. The results from the present study indicated that the major portion of the ejection cycle involved the movement of the part within the die.

Design, Processing and Characterization of Materials with Controlled Radial Porosity for Biomedical and Nuclear Applications

The manufacture of graded materials has gained an enormous interest during the last decade due to the diversity of industrial and biological materials systems that require or are actually designed to implement that criterion; those natural or artificial materials offer multiple possibilities of applications. In this work, a novel uniaxial and sequential compaction device has been successfully designed and fabricated, in order to obtain samples with three different layers; this new device is suitable for both conventional and non-conventional powder metallurgy (PM) techniques. In addition, this device allowed us to use different combinations of powders and space-holder particles, irrespective of their nature, sizes, morphologies and proportions. It has no restriction about applying different compaction pressures for every layer, which may result in increasing or decreasing porosity. This compaction device is especially powerful if the aim is obtaining samples with radial graded porosity for biomedical applications (replacement of cortical bone involved in different joints and dental restorations) and nuclear applications (mimicking burnt used nuclear fuel). Specifically in this work, different samples with radial graded porosity were fabricated and then microstructurally and mechanically characterized: i) Commercially pure titanium (CP Ti) samples, starting from blends CP Ti with 20 vol.%, 40 vol.% and 60 vol.% of Sodium Chloride (NaCl) as space holder, which were placed in core, intermediate and external layers, respectively; processing conditions were 800 MPa of compaction pressure and 1250 °C for 2h in high vacuum of sintering; and ii) CeO2 samples, starting from blends CeO2 with 0.5 vol.%, 3.0 vol.% and 7.5 vol.% of Ethylene Bis Stearamide (EBS) as space holder, which were placed in core, intermediate and external layers, respectively; processing conditions were 460 MPa in external layer and 700 MPa in core and intermediate layers of compaction pressure, and 1700 °C during 4h in static air of sintering. This new device has proved to have unique advantages for solving problems of structural integrity in conventional PM manufacturing in a simple, economic and reproducible way.

Characterization of rutting resistance of EBS-modified asphalt mixtures

ABSTRACTDriven by Kyoto protocol to reduce the gas emission, warm mix asphalt (WMA) as an alternative of hot mix asphalt has gained huge interest among researchers. Despite many advantages, rutting resistance of WMAs is always questionable. In this study, ethylene bis(stearamide) (EBS) was used as a wax-based additive to produce WMAs. Samples were produced at three different compaction temperatures. To evaluate rutting resistance of mixtures, all cylindrical specimens were tested by dynamic creep and dynamic modulus tests at various compaction temperatures. Results indicate that rutting resistance of EBS-modified samples are remarkable, especially when compaction temperature is low.

Improvement of flow of an iron-copper-graphite powder mix through additions of nanoparticles

Nanoparticles of carbon black, silica and ferrous oxide were added to FC-0208 powder metallurgy blends prepared using ethylene bis stearamide as lubricant to investigate their influence on improving flowability of this formulation that tends to be cohesive. This study consisted in preparing multiple premixes having different quantities of nanoparticles of different types and evaluating their impact on flowability and apparent density according to MPIF standards. The important variables for the distribution of nanoparticles on the surface of the host particles were the sequence of addition of all of the constituents, the quantity of nanoparticles and the mixing time. It was possible to identify a condition presenting good flowability with a flow time of 34.9s/50g and an apparent density of 2.78g/cm3.