Kinds Of Polymers Research Articles

Valorisation of Posidonia oceanica Sea Balls (Egagropili) as a Potential Source of Reinforcement Agents in Protein-Based Biocomposites.

Nanocrystalline cellulose (NC) and a lignin-containing fraction (LF) were obtained from egagropili, the so called sea balls produced from rhizome and stem fragments of Posidonia oceanica that accumulate in large amounts along the coastal beaches in the form of tightly packed and dry materials of various dimensions. Both egagropili fractions have been shown to be able to improve the physicochemical properties of biodegradable films prepared from protein concentrates derived from hemp oilseed cakes. These materials, manufactured with a biodegradable industrial by-product and grafted with equally biodegradable waste-derived additives, exhibited an acceptable resistance with a still high flexibility, as well as they showed an effective barrier activity against water vapor and gases (O2 and CO2). Furthermore, both NC and LF decreased film moisture content, swelling ability and solubility, thus indicating that both additives were able to improve water resistance of the hydrocolloid films. The exploitation of egagropili, actually considered only an undesirable waste to be disposed, as a renewable source of reinforcing agents to blend with different kinds of polymers is suggested.

Reduction of asphaltenes adsorbed on kaolinite by polymers based on cardanol

Oilsands are suspended fine solids in bitumen in which asphaltenes become adsorbed on the surfaces of these particles, reducing the quality of the oil and hence generating higher costs for the oil industry. Since some polymers containing specific functional groups are able to interact with asphaltenes, it can be expected that these kinds of polymers are able to reduce the amount of asphaltene adsorbed. In this work, the performance of three (co)polymers, with different molar ratios of cardanol and styrene was evaluated in the adsorption process of a model system (pentane insoluble asphaltenes—C5I in kaolinite) monitored by ultraviolet–visible spectrometry. Kaolinite and asphaltene were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and the wettability of these samples was measured with a goniometer, before and after the adsorption process. The increase in polymer concentration (from 0.025 to 0.2%w/v) reduced the amount of adsorbed asphaltenes on kaolinite. Polycardanol homopolymer presented the best performance, indicating the important role of the hydroxyl group and pendent hydrocarbon chain on the adsorption of asphaltenes on kaolinite. The results evidence the potential of polycardanol, obtained from a renewable source, in the extraction process of bitumen from oil sand.

Fabrication of flexible SiO2 nanofibrous yarn via a conjugate electrospinning process

Abstract Nowadays, different kinds of polymers, including ceramics, are electrospun into fibrous materials with different structures by electrospinning. Generally, the as-spun ceramic fibers are randomly oriented membranes and brittle without flexibility. Here, we report the fabrication of flexible SiO2 electrospun yarns using poly(vinyl alcohol) (PVA) as a template through a conjugate electrospinning process and calcination. It was found that the calcined as-spun fibers and yarns are obviously thinned with PVA component removal. Fourier transform infrared spectroscopy and energy-dispersive spectroscopy examinations suggested that the obtained yarn after calcination was SiO2 yarn. The SiO2 yarn showed good flexibility without cracking after 180° bending. The flexible ceramic yarn may have potential application in functional textiles.

Soft computing method for predicting pressure drop reduction in crude oil pipelines based on machine learning methods

In the oil industry, the drag-reducing agent has been used to reduce turbulent friction of fluids. The main effort of this study is to examine the feasibility of four novel machine learning models, namely multilayer perceptron, M5Rules, decision table (DT), and trees M5P to estimate the percentage of drag reduction. Then, the mentioned methods are utilized to identify a relationship between the input and output parameters of the crude oil pipeline system. The parameter percentage of drag reduction was taken as the essential output. In contrast, the input parameters selected the flow rate of oil, polymer concentration, kind of polymer, temperature, as well as pipe diameter and roughness. The predicted results obtained by the tools mentioned above were evaluated according to several known statistical indices, namely coefficient of determination (R2), mean absolute error (MAE), root mean squared error (RMSE), relative absolute error (RAE), and root relative squared error (RRSE) as well as novel ranking systems of color intensity rating and total ranking method. The training and testing results of the DT learning method for the R2, MAE, RMSE, RAE, and RRSE were (0.9616, 3.9008, 5.8698, 24.5259%, and 27.4406%) and (0.8964, 6.937, 10.318, 43.3841%, and 45.6581%), respectively. The obtained results, in analyzing the training and testing datasets, proved that DT is the best predictive network to predict the percentage of drag reduction.

Ultra-Compact Optical Thermo-Hygrometer Based on Bilayer Micro-Cap on Fiber Facet

We demonstrate an ultra-compact optical fiber thermo-hygrometer on the base of a bilayer OA (Optical Adhesive, a kind of polymer) micro-cap covering the entire SMF (Single-Mode-Fiber) facet. In fabrication, two types of OA are dispensed to fiber facet successively and stratified distinctly forming the bilayer micro-cap, which contains a flat and 2 spherical interfaces reflecting emitted light. Hence, hybrid interference would occur. The experimental results show that the sensitivity for humidity and temperature reach −3.641deg/%RH and −4.527deg/°C when demodulating interference phase shift, and dual-parameter measurement could also be achieved. The proposed optical fiber thermo-hygrometer is integrated, robust and with high sensitivity, making it satisfy lab-on-tip measuring requirement.

Investigation into mobility control mechanisms by polymer flooding in offshore high-permeable heavy oil reservoir

ABSTRACT The systematic understanding of the mobility control of polymer solution in porous media is conducive to the engineering application and development of polymer flooding technology. In this paper, two kinds of polymers (partially hydrolyzed polyacrylamide (HPAM) and MJ-10 (a hydrophobically associating polyacrylamide, HAPAM)) with different adsorption characteristics were used to build a solution system with different performance characteristics. And run a series of viscosity measurement, residual resistance factor (RRF) measurement and oil displacement experiments on man-made sand packs. The results show that the viscosity and residual resistance coefficient of polymer solution can enhance its fluidity control. The higher the viscosity of solution, the higher the RRF, and the higher the displacement efficiency. The solution system HM3 can make full use of the solution characteristics of the two polymers to obtain a moderate solution viscosity and residual resistance coefficient. Compared with a single solution H2 and M2, it can increase the oil recovery by 5% in the low permeability layer. The compound application of polymer solution will be a development direction of polymer flooding in the future.

Polymeric nanocarriers in targeted drug delivery systems: A review

Today's medicine mainly relies on conventional means of therapeutics delivery to the human body, such as tablets, capsules, syrups, and injectable drugs. Utilizing such techniques are associated with a number of drawbacks including the need of high drug dosage, causing transient drug concentration changes in the patient's body, poor solubility, poor bioavailability, drug degradation, and interaction with the biological environment (enzymes and proteins). To address these issues, nanotechnology‐based novel drug delivery methods are proposed. Among the plethora of novel drug delivery techniques, the use of polymeric nanocarriers is shown to be promising. In fact, they focus on three main questions: first, where should a drug be released? Second, when should the drug be released? And finally, how should the drug be released? In this review, we are confined to explaining some concepts regarding to polymeric nanocarriers. First, different kinds of polymeric nanocarriers have been explained, in terms of their structures and properties. Second, different fabrication methods, for each one, have been elaborated. Finally, a handful of works carried out have been reviewed for their special structure, their kind of polymers which is used, and the drug which is encapsulated.

Insight into water lubrication performance of polyetheretherketone

AbstractPolyetheretherketone (PEEK) is a kind of polymer with excellent mechanical properties combined with good wear resistance and has been widely used in the engineering field. In order to explore the possibility for PEEK using as a water‐lubricated bearing material, an in‐depth study on the water lubrication performance of PEEK was conducted by using a series of experiments. The water lubrication performances combined with the lubricating mechanism were evaluated both by the friction coefficient and by the wear behavior of PEEK. The results indicated that PEEK was suitable for water‐lubricated bearing productions. The water film could form effectively between the friction pairs under high sliding velocity, while the transfer film could form under low sliding velocity. Both the water film and the transfer film could improve the water lubrication performance for the friction pairs. Moreover, sliding velocities and contact pressures highly influence the water lubrication performance of PEEK. The increase in contact pressure or the decrease in sliding velocity would exacerbate the wear of material. The stick–slip phenomena also occurred on the specimens under low sliding velocity. The main purpose of this study is to provide an experimental basis for PEEK using as a water‐lubricated bearing material.

Safe Coated Microneedles with Reduced Puncture Occurrence after Administration.

The goal of this study is the preparation of safer coated microneedles so that tips remaining after the initial use are less likely to be reinserted on a second use. Twelve groups of uncoated microneedles (u-MNs) were prepared from the combination of three different aspect ratios (height to base width) and four kinds of polymer (polyethylene (PE), polypropylene (PP), nylon and polylactic acid (PLA)). After coating the u-MNs with polyvinyl alcohol formulation to make coated MNs (c-MNs), the force displacement of the u-MNs and the c-MNs was measured. The aspect ratio was reduced from 2.2, 2.5 and 3.0 with u-MNs to 1.3, 1.4 and 1.6 with c-MNs, respectively, after the coating formulation was applied to the MNs. All PLA MNs had a puncture performance of more than 95%. However, the puncture performance of u-MNs made of PE and of PP with a 3.0 aspect ratio was only 8% and 53%, respectively, whereas the rates of c-MNs made of PE and of PP were 82% and 95%, respectively. In animal experiments with PP MNs with a 3.0 aspect ratio, the 59% rate of puncture performance with u-MNs increased to above 96% with c-MNs and fell to 13% for r-MNs. Safe c-MNs can overcome the disadvantages of standard c-MNs by reducing the probable contamination of remaining tips after use. Safe c-MNs have advantages over standard c-MNs in terms of humidity resistance, reasonable cost, sterilization process and short processing time through the separate process of u-MN preparation and simple dip-coating.

Experimental and analytical study on uniaxial tensile property of ionomer interlayer at different temperatures and strain rates

The ionomer material is widely used as interlayers in the laminated glass, and its tensile property plays a decisive role in the post-fracture response of the laminated glass. Since the ionomer material is a kind of polymer, its mechanical behaviour is highly affected by strain rate and temperature. In this work, two series of uniaxial tensile tests, low strain rate series (10−3s−1~10−1s−1) and medium to high strain rate series (1 s−1~800 s−1), were conducted over a wide temperature range (−40 °C~80 °C). Details of the test setup and corresponding true stress-true strain curves are presented. Characteristic mechanical parameters are then identified to evaluate the temperature and strain rate effects. It was found that higher strain rate and lower temperature result in higher strength and stiffness but lower ductility. The material shows apparent plasticity as more than 80% deformation is unrecoverable. Based on the observations, G’Sell model is adopted to build the temperature-dependent dynamic constitutive model, which is then validated through comparison between the predicted results and the published test data.

Baicalein Nanofiber Scaffold Containing Hyaluronic Acid and Polyvinyl Alcohol: Preparation and Evaluation

Background/aim Bone tumor is one of the major causes of tissue bone loss, particularly after performing surgical excision operation to bone lesion that needs to be replaced by biomaterials and ensure a complete filling of tissue-loss spaces. The purpose of our study was to produce a nanofiber-based bone graft scaffold to fill the gaps resulted from bone cancer treatment and also capable of carrying functional molecules that can play a major role in preventing further cancer growth at the targeted bone tissue.Materials and methods Electrospinning method was used in order to produce nanofibers from different kinds of polymers; Hyaluronic acid (HA), Polyethylene oxide (PEO) and Polyvinyl alcohol (PVA) blended with different concentrations of herbal antibiotic and anti cancer flavonoid molecules called Baicalein (BE). The morphological and chemical structures of scaffold samples were studied using Scanning Electron Microscope (SEM), Fourier Transform Infrared-spectroscopy (FT-IR) and Surface-enhanced Raman spectroscopy (SERS) Analysis.Results The results showed production of homogenous nanofibers-based scaffold (diameter between 80 nm and 470 nm) that contains the polymers used in the spinning process and the entrapped Baicalein molecules within the nanofiber structure.ConclusionIt was concluded that successful formation of bone tissue mimicking scaffold can be achieved by using Electrospinning method that produces nonwoven nanofibers and at the same time can hold functional anticancer agent such as Baicalein, which may allow using these types of scaffold in bone cancer treatment procedures.

An Infrared Chemical Sensor Based on Plasmonic-Enhanced Bulk Acoustic Wave Resonator Array

This letter reports a multi-spectral infrared chemical sensor based on a virtual array of bulk acoustic wave resonators with different frequencies. The plasmonic metasurfaces with different patterns on the top surface of resonators provide high IR absorption without degradation of resonating performance. The metasurfaces enhance the frequency responses of the resonant sensor to the specific infrared by about ten times. In a demonstration, four kinds of polymers and their mixtures were detected by the sensor to show its capability for distinguishing unknown compounds. The proposed chemical sensor shows great potential for fast, accurate and portable infrared spectrum microsystems for chemical composition analysis.

Enhanced polyethylene wetting properties by a simple dipping process

Functional surfaces with special wettability have drawn the researchers’ attention in recent years due to the numerous benefits they present in their various applications, especially in the field of polymeric materials. Several works were published concerning various kinds of polymers, but data on polyolefins, specifically polyethylene, are rather scarce, and all are involved and onerous processes. Herein we report a simple dipping method in a suspension of TiO2 nanoparticles combined with a silane coupling agent. The main result reported is the obtainment of superhydrophobicity in polyethylene with the addition of n-hexadecane to the suspension. A systematic study aiming at the increase in surface hydrophobicity was carried out on the most commercially used types of polyethylene. The surfaces were coated with titanium dioxide nanoparticles functionalized with an organosilane in order to obtain a superhydrophobic material. The main variation regarding the published data dwelled in the addition of an alkane to the treatment solution. The technique consisted of a single layer immersion (dip-coating) of the polymer in the treatment solution, at an optimally defined working temperature, and with variations in the parameters time of immersion and concentration of the alkane additive. The treated surfaces were analyzed and characterized by static contact angle measurement (WCA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and optical profilometry. A progressive increase in hydrophobicity was found with increasing alkane concentration, reaching WCA values higher than 150° for all types of polyethylene used, characterizing superhydrophobic behavior.

A new method to calculate the surface haze

Abstract Haze (H) is not an accumulative property based on the addition of internal haze (H i) and surface haze (H s) parameters, though the relation (H s = H − H i) is widely accepted and used nowadays in research and development of plastic films. To evaluate the correct relation, the analytical relation between the total haze (H) and the haze of a single film (h i) in the film superposition model was firstly concluded, which is 1 − H is equal to the product of 1 − h i of every single film. This relation was validated by the experimental results using thin films of different kinds of polymers with different hazes. Based on this relation, the expression of surface haze was concluded. When the two surfaces of a film were the same, the haze of the single surface H s ¯ = 1 − ( 1 − H ) / ( 1 − H i ) . $\overline {{H_{\rm{s}}}} = 1 - \sqrt {(1 - H)/(1 - {H_{\rm{i}}})} .$ The mathematical relation between haze and thickness was also obtained.

A study on thermal‐interrupting performance improvement of SF6 gas circuit breaker by promotion of nozzle ablation

In this paper, ablation polymer was studied to improve the thermal interrupting performance of an SF6 gas circuit breaker. One kind of polymer was used as the ablation polymer on the basis of the specific constraint conditions for SF6 gas circuit breakers, such as not including hydrogen, and its ablation characteristics were investigated. Furthermore, the dominant factor of that polymer ablation was discussed by comparing ablated mass characteristics between the ablation polymer and polytetrafluoroethylene, which is widely used as the nozzle material of an SF6 gas circuit breaker. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Modified walnut shell filter material for the enhanced removal of oil from oilfield wastewater

While polymer oil recovery greatly improves oil recovery, the polymer injected into the formation undergoes shearing, degradation, etc., and returns with the output liquid in the form of an anionic polyacrylamide of lower molecular weight, resulting in a production fluid. There is residual polymer, and this kind of polymer–containing wastewater is easy to contaminate the walnut shell filter in the sewage treatment process, resulting in failure of the walnut shell filter material, introduce hydrophilic sulfonic acid groups on the surface of the walnut shell filter material to lipophilic to hydrophilic of the surface. The dosage of NaHSO<sub>3</sub> is 10-20% of the mass fraction of walnut shell filter (mass ratio %). Reflux reaction, and the reaction time was 1-5 h; the surface wettability of the walnut shell reversed. The surface contact angle drops from 95° before modification to 36.75°-66.25°, Its surface hydrophilic oleophobic performance has been significantly improved, Treatment of 150-230 mg/L of oily sewage, filtration and oil removal rate increased from 38.05% to 89.51% by modification; Backwashing and degreasing effect is increased by 4 times.

A novel double‐doped polymer‐modified cement‐based sealant to enhance borehole seals and reduce methane emissions

AbstractThis study was conducted to develop a new type of sealing material: double‐doped polymer‐modified cement‐based sealant (DPCS) and to verify its sealing performance. The aim is to improve the sealing effect of borehole, improve the gas extraction efficiency, and reduce methane emissions. Two kinds of polymers are doped in DPCS, namely the water‐soluble polymer emulsion (A1) and the cationic polymer (A2). The fluidity, expansion, compactness, and mechanical properties of DPCS and the single‐doped polymer‐modified sealant were tested and compared. Additionally, the effects of the polymer–cement ratio and the dispersant dosage on the sealing performance of DPCS were analyzed. To evaluate these competing effects of multiple factors on sealing performance of DPCS comprehensively, an orthogonal test was designed with range and variance analyses. The results show that with a polymer–cement ratio of 6%, 0.10% expansion agent dosage, and 1.2% dispersant dosage, the DPCS performs best on mechanical and expansion properties. A field site test at the working face 15201 of the Baiyangling coal mine was conducted to verify DPCS's sealing performance. The test results indicate that the novel DPCS can improve the concentration of extracted gas, and is also a better choice than the common sealing materials used in the mine economically. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

TransPoly: A theoretical model to quantify the dynamics of water transfer through nanostructured polymer films

Mass transfer of penetrants is among the most important physical properties of polymer films to properly ensure function during service. In the case of interaction between penetrants and polymer, non-Fickian diffusion can be observed. This phenomenon is described by numerous reports and a few models have been proposed. Nevertheless, few of them quantify Fickian and non-Fickian behaviour using parameters with clear physical meaning. The present work develops a new non-Fickian mass transport model: TransPoly (Transfer through Polymers). Based on coupled heat and mass transfer, it accounts for simultaneous Fickian transport and molecular relaxation. This model is applied to data of water vapour mass transfer in nanocomposites of polylactide and cellulose nanocrystals. The contribution of the non-Fickian mass transfer on water vapour sorption is highlighted. TransPoly can be applied to several kinds of polymers and used for prediction purposes once the parameters are determined on a learning database.

A Benzo[1,2-b:4,5-c']Dithiophene-4,8-Dione-Based Polymer Donor Achieving an Efficiency Over 16.

It is of great significance to develop efficient donor polymers during the rapid development of acceptor materials for nonfullerene bulk-heterojunction (BHJ) polymer solar cells. Herein, a new donor polymer, named PBTT-F, based on a strongly electron-deficient core (5,7-dibromo-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c']dithiophene-4,8-dione, TTDO), is developed through the design of cyclohexane-1,4-dione embedded into a thieno[3,4-b]thiophene (TT) unit. When blended with the acceptor Y6, the PBTT-F-based photovoltaic device exhibits an outstanding power conversion efficiency (PCE) of 16.1% with a very high fill factor (FF) of 77.1%. This polymer also shows high efficiency for a thick-film device, with a PCE of ≈14.2% being realized for an active layer thickness of 190 nm. In addition, the PBTT-F-based polymer solar cells also show good stability after storage for ≈700 h in a glove box, with a high PCE of ≈14.8%, which obviously shows that this kind of polymer is very promising for future commercial applications. This work provides a unique strategy for the molecular synthesis of donor polymers, and these results demonstrate that PBTT-F is a very promising donor polymer for use in polymer solar cells, providing an alternative choice for a variety of fullerene-free acceptor materials for the research community.

Identification and photolytic characteristics of benzoquinone intermediates in photo Fenton system

ABSTRACT The predecessors believed that the rufous intermediates of benzene compounds degradation was quinhydrone. This article corrects this misperception. This paper takes benzene, phenol, chlorobenzene and nitrobenzene as the substrates, and p-benzoquinone as the reference; we studied the degradation law of benzene compounds in Fenton system. During the process of benzene, phenol, chlorobenzene and nitrobenzene degradation by Fenton method, it is found that the use of hydroxyl radical system for visible light would be enhanced as soon as the rufous substances were produced, which indicated that rufous substances have elevated photosensitivity. The analyses via high performance liquid chromatography, mass spectrometry, infrared spectroscopy and UV–visible spectroscopy indicate the common rufous substance is a kind of polymer formed by p-benzoquinone and oxygen. The yield of photoinduced electrons, singlet oxygen and superoxide anion radicals are carried to higher level by the rufous substance. The outstanding photosensitivity of the rufous substance provides a new idea for the treatment of wastewater containing benzene compounds by visible light.