Hydroxyethyl Cellulose Polymer Research Articles

Emergent Self-Assembly of Sustainable Plastics Based on Amino Acid Nanocrystals.

Development of biodegradable plastic materials is of primary importance in view of acute environmental and health problems associated with the accumulation of plastic waste. We fabricated a biodegradable composite material based on hydroxyethyl cellulose polymer and tyrosine nanocrystals, which demonstrates enhanced strength and ductility (typically mutually excluding properties), superior to most biodegradable plastics. This emergent behavior results from an assembly pattern that leads to a uniform nanoscale morphology and strong interactions between the components. Water-resistant biodegradable composites encapsulated with hydrophobic polycaprolactone as a protection layer were also fabricated. Self-assembly of robust sustainable plastics with emergent properties by using readily available building blocks provides a valuable toolbox for creating sustainable materials.

Experimental investigation of drilling cutting transport using foam

This study investigates the stability of foam in drilling fluid, focusing on the impact of surfactant (sodium dodecyl sulfate) and hydroxyethyl cellulose polymer. The research analyzes various influential factors and examines three rock types (carbonate, limestone, and sandstone) commonly encountered in drilling operations. Additionally, the study explores the behavior of drilling cuttings from light, medium, and heavy reservoir oil types (Bangestan, Asmari, and Soroush) found in Iranian oil fields. The influence of salinity, specifically divalent (calcium) and monovalent salts (sodium), on foam performance is also investigated.Experimental findings reveal that higher concentrations of critical micelle concentration do not significantly affect foam stability, but are used in preparing the foaming solution. Furthermore, different polymer concentrations (ranging from 0% to 0.5%) enhance foam stability, except at a concentration of 0.5% where foam formation is impeded. Interestingly, the transfer of more stable foam and a greater volume of cuttings to the surface is facilitated in sandstone layers. The presence of heavy oil significantly impacts the rate of cuttings transfer compared to lighter oils.

Detailed physicochemical study and thermodynamic aspects of the interaction between nonionic cellulose derivative hydroxyethyl cellulose and anionic surfactant sodium N-dodecanoyl sarcosinate in aqueous media

BackgroundThe scheme of this work was to study the interaction between hydroxyethyl cellulose (HEC), a non-ionic, water soluble biopolymer and sodium N-dodecanoyl sarcosinate (SDDS), a novel, environmentally friendly amino acid-based anionic surfactant in aqueous medium. The study of this type of interaction is relatively less complicated compared to that between a polymer and a surfactant with opposite charges. MethodsThe critical micelle concentration (CMC) of HEC-induced SDDS has been determined by various physicochemical methods such as tensiometry, conductometry, fluorimetry and microcalorimetry. Several thermodynamic and surface parameters related to the binding of SDDS with HEC have been assessed. The aggregation number (Nagg) of SDDS micelles in the presence of non-ionic HEC polymer has been measured by the steady-state fluorescence method. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate have been measured by the dynamic light scattering method. The interaction study has further been amplified by detecting the change in the surface morphology of the polymer due to surfactant binding using Field Emission Scanning Electron Microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM) imaging in solvent-free state, as well as visualization of the HEC-SDDS micelle in the solution phase using fluorescence microscopy technique. Significant findingsFrom a physicochemical point of view, hydrophobic synergism seems to be important for understanding the interaction pattern of HEC-SDDS combination. In each scenario, the CMC of SDDS decreases with an increase in weight percentage of HEC. The aggregation number (Nagg) of SDDS micelles is also found to decrease with an increase in weight percentage of HEC in the medium. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate, these two parameters have been found to be strongly dependent on the amphiphile concentration. Finally, investigations of the surface morphologies by taking Field Emission Scanning Electron Microscopy (FESEM), high resolution transmission electron microscopy (HR-TEM) and fluorescence microscopy techniques assist the experimental data.

Analiza performansi polimera hidroksietil celuloze (HEC) kao sredstva za želiranje u tečnoj formulaciji nosača šljunka za kontrolu peska u bunarima za proizvodnju ugljovodonika

This study considers the performance of 40ppt and 60ppt hydroxyethyl cellulose (HEC) polymer used as a gelling agent in the formulation of carrier fluids for gravel pack transport in sand control operations in oil and gas wells. The gravel pack carrier fluid was prepared by adding adequate amounts of sodium persulfate (SP) used as gel breaker, Fe-2 used as an iron control agent, KCL brine as mixed fluid, K-35 used as pH buffer, BE-6, and BE-35 used as biocides, HEC used as a gelling agent, and distilled water. The effects of temperature, gel loading, and breaker fluid concentration on the rheology, gel break time, and sand settling of the formulated HEC carrier fluid were considered. The results showed that shear stress, plastic viscosity and yield point and consistency factor decreased with an increase in bottomhole temperature for both 40ppt and 60ppt HEC gels. Furthermore, flow behaviour index was observed to be within the range of 0.45±0.1 40ppt and 0.5±0.04 for 60ppt HEC of gel loading, respectively and showing shear-thinning characteristics. Good gravel settling was observed for the HEC gels when in contact with gravel, addition of breaker fluid greatly improved the sand/gravel suspension for 40ppt and 60ppt gel loadings. Gel break time of the HEC gel increased with increasing gel loading, and at higher breaker fluid concentrations, HEC gel degradation becomes more critical as temperature increases. The results highlight the adequate performance of HEC polymer as gravel pack fluid in sand control operation.

Effect of HEC (Hydroxyethyl Cellulose) Polymer on Nanoemulsion-Based Curcumin Transdermal Patch Release

Curcumin a hydrophobic polyphenolic compound and water-insoluble that creates low systemic bioavailability inside the body, has broad pharmacological activity, including anti-inflammation. This study aims to formulate, characterize and evaluate the nanoemulsion based on curcumin through an in vitro transdermal patch preparation. This study starts from formulating a curcumin nanoemulsion solution and characterizing the particle size of curcumin through PSA (Particle Size Analyzer). Further, it formulates the transdermal patch preparation with the smallest curcumin particles within three concentrations (HEC 0,625%, 1,25%, and 2,5%) combined with HPMC 2,5% as polymer. Those formulations are evaluated through organoleptic, thickness, weight uniformity, humidity, and folding resistance tests. In the next step, this study examines the penetration through an in vitro by using a franz diffusion cell within 72 hours. The result shows increasing penetration on each formula where the best penetrations occur in the 15th and 24th hours. It also discovers that the formula containing HEC 2,5% (2c) creates the highest cumulative drug penetration (15,83%). Therefore, it deduces that curcumin nanoemulsion in the transdermal patch has good characteristics and is compatible between drug and polymer.

Probing Selective Adsorption in Cationic-Polymer Induced Aggregation of Binary Anionic Particulate Dispersions Using Solvent Relaxation NMR.

NMR solvent relaxation has been used to characterize the surfaces present in binary anionic particle dispersions, before and after exposure to a cationic polymer. In the polymer-free case, it is shown that the measured specific relaxation rate of the solvent is a population-weighted average of all surfaces present, enabling preferential adsorption to be explored. The addition of the oppositely charged polymer led to phase separation, which was accelerated by gentle centrifugation. The measured relaxation rates and the equilibrium particle concentrations indicate that the cationic hydroxyethylcellulose polymer (HEC LR) exhibited no significant preference for either latex or laponite in binary blends with silica, but a strong preference for TiO2. This study illustrates the versatility of solvent relaxation to probe surface area, surface type and dispersion composition in complex formulations.

Experimental Evaluation of a Polymer Foam Agent on the Foam Stability, Concern to Surfactant, Nanoparticle, and Salinity

Summary In recent years, rising oil demand has led to a strong need to improve enhanced oil recovery (EOR) techniques. One of the most common methods for EOR in the oil industry is gas injection. When gas is injected into the reservoir, because of the low density of the gas relative to the oil and the undesirable gas mobility ratio, problems such as gas uptakes and the injected gas flow channeling arise, thus reducing the efficiency of oil production. Foam can improve mobility and increase EOR by reducing gas permeability. One of the most important properties of the foam is stability which affects the EOR. In recent years, many studies have been conducted on the use of nanoparticles (NPs) and polymers as stabilizers, but the use of stabilizers that have the ability to produce foam has been less studied. The main objective of this work is an experimental study of foam stability by the dynamic method of CO2 gas injection and static method of “Ross-Miles” in the presence of sodium dodecyl sulfate (SDS) and nanosilica in combination with a foaming polymer such as hydroxyethyl cellulose (HEC). The aim of this study was to compare the effect of a polymer that has the ability to produce foam relative to the stabilizer of NP on the foam stability. The zeta potential and the structure of the foam bubbles were measured to better understand the parameters affecting the foam stability. Experimental outcomes of this work show that the HEC polymer, despite being a foaming agent, has less effect on the foam stability than the nanosilica. That is, under similar conditions, SDS-NP based foams are more stable than SDS-HEC based foams. In addition, the composition of the SDS-NP-HEC foam system shows weaker foam performance compared to the case of SDS-NP and SDS-HEC dispersions. Also, salinity has an optimal concentration in which foam concentration has the best performance and stability; in this study, the optimal NaCl salt concentration is 2 wt% NaCl.

Nano-SiO2/hydroxyethyl cellulose nanocomposite used for 210 °C sedimentation control of petroleum drilling fluid

Abstract Cellulose derivatives are widely applied in the field of oil and gas exploration. However, this kind of natural polymers always shows poor temperature resistance due to their organic nature. To improve the temperature resistance of hydroxyethyl cellulose (HEC), inorganic nano-SiO2 was introduced onto HEC polymer chains through the silylation coupling technique. And Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectrum (XPS), and thermogravimetic analysis (TGA) were used to analyze the nanocomposite. As a result, nano-SiO2 particle is chemically coupled onto hydroxyethyl cellulose molecule, and nano-SiO2/hydroxyethyl cellulose nanocomposite (RJ-HEC) shows excellent thermal stability comparing with HEC polymer. In experiment, thermal aging tests were utilized, and test results suggest that nano-SiO2/hydroxyethyl cellulose (RJ-HEC) nanocomposite can be utilized as thickening agent of water-based drilling fluid, which shows improved rheology stability at 210 °C and excellent salt (NaCl) tolerance.

Ecotoxicity of cationic cellulose polymers to aquatic biota: The influence of charge density

Better performances of cellulose-based polymers can be achieved by adjust their architecture including the density of cationic modifications. In this study, the influence of cationic substitution on the ecotoxicity of four quaternized hydroxyethyl cellulose polymers (SK-H, SK-L, SK-M, SK-MH) was studied, using an aquatic biota acute ecotoxicity classification, and rheological and physicochemical characterization. The ecotoxicity characterization was achieved by performing standard ecotoxicity assays with seven key trophic level species: Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris, Daphnia magna, Brachionus calyciflorus, Heterocypris incongruens, and Danio rerio. Median effective concentrations were used to compute hazard concentrations, through the species sensitive distribution curves method. The microalga C. vulgaris and rotifer B. calyciflorus were the most sensitive species to the studied polymers. The SK-H variant was highly toxic to the rotifer. Overall, variants with intermediate levels of cationic charge (SK-M, SK-MH) presented the lowest toxicity. The SK-M variant showed the lowest value of maximum acceptable concentration (0.00354 mg/L), thus being indicated as the least toxic variant. Therefore, the obtained results suggest that industry could direct the development of this type of polymers by tailoring its cationic substitution to moderate levels, in such a way that both functionality and environmental toxicity could be maximized.

Performance of 4-Subsituted Pyridine Based Additive and Cobalt Redox in Poly(ethylene glycol)–Hydroxyethylcellulose Polymer Electrolytes with DTTCY Acid Sensitizer on Dye Sensitized Solar Cells

Performance of 4-Subsituted Pyridine Based Additive and Cobalt Redox in Poly(ethylene glycol)–Hydroxyethylcellulose Polymer Electrolytes with DTTCY Acid Sensitizer on Dye Sensitized Solar Cells

Charge Modification as a Mechanism for Tunable Properties in Polymer-Surfactant Complexes.

Oppositely charged polymer–surfactant complexes are frequently explored as a function of phase space defined by the charge ratio Z, (where Z = [), commonly accessed through the surfactant concentration. Tuning the phase behaviour and related properties of these complexes is an important tool for optimising commercial formulations; hence, understanding the relationship between Z and bulk properties is pertinent. Here, within a homologous series of cationic hydroxyethyl cellulose (cat-HEC) polymers with minor perturbations in the degree of side chain charge modification, phase space is instead explored through at fixed C. The nanostructures were characterised by small-angle neutron scattering (SANS) in DO solutions and in combination with the oppositely charged surfactant sodium dodecylsulfate (h- or d-SDS). Scattering consistent with thin rods with an average radius of ∼7.7 Å and length of ∼85 Å was observed for all cat-HEC polymers and no significant interactions were shown between the neutral HEC polymer and SDS (C < CMC). For the charge-modified polymers, interactions with SDS were evident and the radius of the formed complexes grew up to ∼15 Å with increasing Z. This study demonstrates a novel approach in which the Z phase space of oppositely charged polymer–surfactant complexes can be controlled at fixed concentrations.

Hydrophobic modifications of hydroxyethyl cellulose polymers: Their influence on the acute toxicity to aquatic biota

The hydrophobic substitution (HS) of cationic cellulose derivatives may be tuned, promoting their efficiency. This work studied the influence of HS on the acute ecotoxicity of quaternized hydroxyethyl cellulose polymers (SL) to aquatic biota. The ecotoxicity of four SL with different HS (SL-5, SL-30, SL-60, SL-100) was assessed for seven species: Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris, Daphnia magna, Brachionus calyciflorus, Heterocypris incongruens, and Danio rerio. The computed median effective concentrations were used to derive hazard concentrations, by using species sensitive distribution curves. All SL suspensions were characterized for particle size, zeta potential and rheological properties. Results indicated instability of the SL in suspension due to their relatively low zeta potential. Raphidocelis subcapitata, C. vulgaris and B. calyciflorus were the most sensitive to the four SL, suggesting that exposure to these compounds may imbalance the lowest trophic levels. Also, HS influenced the toxicity of SL, with the lowest HS (SL-5) revealing lower ecotoxicity. The maximum acceptable concentrations were 14.0, 2.9, 3.9 and 1.4 mg L−1 for SL-5, SL-30, SL-60, and SL-100, respectively. Accordingly, SL-5 is suggested as the eco-friendliest and is recommended to be used in the production of care products, in detriment of the other three tested variants.

Biocompatible thermosensitive nanostructures and hydrogels of an amino acid-derived surfactant and hydroxyethyl cellulose polymers

Aqueous surfactant/polymer mixtures form colloidal structures of great fundamental interest and practical relevance, such as nanostructured hydrogels for biomedical and pharmaceutical uses. In this work, we investigated the phase behavior, structure and cytotoxicity of mixtures of a double-tailed lysine-based surfactant, 16Lys12, and two hydroxyethyl cellulose (HEC) derivatives, JR400 and LM200. The surfactant, S−, is anionic and self-assembles into tubular structures at room temperature, undergoing a tubule-to-vesicle transition at ≈44 °C. JR400 is a cationic homopolymer, P+, longer and more densely charged than LM200, a closely related hydrophobically modified polymer, HMP+. Electrostatic and hydrophobic interactions play a crucial role in the observed phase behavior and resulting colloidal structures. Both the S−/P+ and S−/HMP+ mixtures show three main phase regions: at surfactant charge excess, bluish dispersions containing mixed polymer/tubular aggregates and, upon heating, polymer/vesicle clusters; a white precipitate near charge equimolarity, coexisting with either a solution or a gel; and highly viscous hydrogels, at polymer charge excess. In the bluish dispersions, the S−/P+ and S−/HMP+ systems show relevant differences in thermal behavior and type of aggregates present. Cryogenic scanning electron microscopy shows that the hydrogels consist of honeycomb-like structure of surfactant and polymer moieties. Cytotoxicity assays in the bluish dispersion region indicate good levels of cytocompatibility for both types of surfactant/polymer systems. Overall, these dispersions and hydrogels can be further explored for the encapsulation and temperature-triggered release of biomolecules.

The use of a shear-thinning polymer as a bubbly magma analogue for scaled laboratory experiments

Analogue materials are commonly used in volcanology to perform scaled laboratory experiments. Analogue experiments inform on fundamental fluid dynamic, structural and mechanical processes that are typically very difficult to observe and quantify directly in the natural volcanic system. Here we investigate the suitability of an aqueous solution of hydroxyethyl cellulose polymer (HEC) for use as a lava/magma analogue, with a particular focus on its rheological behaviour. We characterize a range of physical properties as functions of the concentration and temperature of the solution: density; specific heat capacity; thermal diffusivity; thermal conductivity; surface tension; as well as rheology. HEC has a non-Newtonian, shear-thinning rheology that depends on the concentration and temperature of the solution. We show that the rheology is well described by the Cross model, which was originally developed for polymer solutions, but has also been applied to bubbly magmas. Using this similarity, an approach for scaling analogue experiments that use shear-thinning polymers, like HEC, to bubbly magma is presented. A detailed workflow and a spreadsheet are provided to allow experimentalists to investigate the effects of non-Newtonian behaviour in their existing laboratory set-ups. This contribution will allow for the more complex, but often more realistic case of bubble-bearing magmas to be rigorously studied in experimental volcanology.

Application of cellulose-based polymers in oil well cementing

Cellulose-based polymers have been successfully used in many areas of petroleum engineering especially in enhanced oil recovery drilling fluid, fracturing and cementing. This paper presents the application of cellulose-based polymer in oil well cementing. These polymers work as multifunctional additive in cement slurry that reduce the quantity of additives and lessen the operational cost of cementing operation. The viscosity of cellulose polymers such as hydroxyethyl cellulose (HEC), carboxymethylcellulose (CMC) and hydroxypropyl methylcellulose (HPMC) has been determined at various temperatures to evaluate the thermal degradation. Moreover, polymers are incorporated in cement slurry to evaluate the properties and affect in cement slurry at 90 °C. The API properties like rheology, free water separation, fluid loss and compressive strength of slurries with and without polymer have been determined at 90 °C. The experimental results showed that the viscosity of HPMC polymer was enhanced at 90 °C than other cellulose-based polymers. The comparative and experimental analyses showed that the implementation of cellulose-based polymers improves the API properties of cement slurry at 90 °C. The increased viscosity of these polymers showed high rheology that was adjusted by adding dispersant which optimizes the rheology of slurry. Further, improved API properties, i.e., zero free water separation, none sedimentation, less than 50 ml/30 min fluid loss and high compressive strength, were obtained through HEC, CMC and HPMC polymer. It is concluded that cellulose-based polymers are efficient and effective in cement slurry that work as multifunctional additive and improve API properties and cement durability. The cellulose-based polymers work as multifunctional additive that reduces the quantity of other additives in cement slurry and ultimately reduces the operational cost of cementing operation. The comparative analysis of this study opens the window for petroleum industry for proper selection of cellulose-based polymer in designing of cement slurry.

Study on the Effect of the Oil-Water Ratio on the Rheological Properties of Hydroxyethyl Cellulose (HEC)

Hydroxyethyl cellulose (HEC) is widely used in water-base drilling fluid as tackifier because of its good fluidity, stability, prop-carrying capacity, and good reservoir protection, while it has insufficient rheological property under higher temperature. In order to make use of its advantages and improve thermal stability, an innovative method that HEC was dissolved in the emulsion was proposed. Research indicated that compared with traditional water solution, the oil-water emulsion as solution could effectively improve the rheological properties and thermal stability. The oil-water ratio has an obvious effect on rheological properties. Firstly, with the decrease in the oil-water ratio, the apparent viscosity and shear stress were decreased; secondly, under constant oil-water ratio or temperature, the larger the shear rate, the lower the apparent viscosity, and the greater the shear strength; lastly under extremely low shear rate, HEC emulsion’s viscosity peaked at more than 50000 mPa·s, which can effectively solve the problem of sand carrying difficulty and being easy to form sand bed in horizontal well and high angle hole. In addition, the emulsifying stability was degradative with the increase in the oil-water ratio. The degradation was not obvious when the oil-water ratio was less than 30 : 70. On the contrary, the performance deteriorated drastically when the oil-water ratio was greater than 30 : 70. The separator liquid was more than 2 cm and was even about 1/3 when the oil-water was 50 : 50. On the basis of analysis of the experimental results, we can see that oil-water emulsion could effectively improve the rheological stability and thermal stability of HEC and the optimal oil-water ratio was 30 : 70. This study provided a new thought for application of HEC or other polymers in drilling fluid.

Electrophoretic NMR Characterization of Charged Side Chain Cationic Polyelectrolytes and Their Interaction with the Anionic Surfactant, Sodium Dodecyl Sulfate.

Oppositely charged polymers and surfactants show a complex phase behavior with large regions of solubility and insolubility dependent on the concentrations of the species present. Here, a series of quaternized hydroxyethyl cellulose (cationic) polymers have been characterized by pulsed-gradient spin-echo NMR (PGSE-NMR) and electrophoretic NMR (eNMR) in simple aqueous (D2O) solutions and in combination with the oppositely charged (anionic) surfactant, sodium dodecyl sulfate (SDS). Analysis of the effective charge on the polymer derived from both the eNMR and PGSE-NMR results yields a readily interpretable insight into the polymer behavior; the effective charge on the polymer at infinite dilution shows a linear relationship with the degree of modification. On addition of low concentrations of SDS, typically Csurf < 5 mM, the surfactant interacts with the charged polymers, leading to substantial changes in the dynamics of the system (polymer diffusion, viscosity). At these levels of surfactant addition, there is no macroscopic phase separation. Further, with the absence of an interaction with the parent, the uncharged polymer strongly suggests that the SDS only interacts with the charged moieties present on the functionalized side groups and not the polymer backbone. Ultimately, the charge on the soluble polymer/surfactant complex was found to depend linearly on the level of surfactant binding across a series of polymers with differing levels of modification with the charge becoming effectively zero at the macroscopic phase separation boundary.

Study on the Mechanism of Micro-Defect Reduction during Si Final Polishing with Water-Soluble Polymers

The effect of water-soluble polymer in alkaline slurry on the micro-defect during Si final polishing was investigated. With the concentration of hydroxyethyl cellulose (polymer A) 0.15wt% and polyoxyethylene ether (polymer B) 0.05wt%, Haze value and the number of micro-defects (larger than 120nm) were reduced to 0.01 ppm and 7, respectively, on a 300mm silicon wafer surface. Also, the surface roughness was reduced from 17.2 to 0.153nm. Through the comprehensive analysis of slurry viscosity and Zeta Potential measurement, the mechanism of water-soluble polymers for micro-defect reduction during Si final polishing was discussed. Polymer B coated on the surface of SiO2 particle forming a “soft shell”, which functions as a “soft abrasive” and thus reduces friction between wafer surface and slurry abrasives. As for polymer A, the O atomic of -OH group in polymer A molecular could combine with Si-H bond on the surface of silicon wafer to form the hydrogen bond, like Si-H…O bond. As such, polymer A can be adsorbed on the surface of the silicon wafer to form a hydration film, which also can reduce friction between wafer surface and slurry abrasives/pad asperities. With the joint action of polymer A and polymer B, as experimental results showed, the number of micro-defects and Haze value in Si final polishing process can be significantly reduced.

Evaluating The Effect of Temperature and Polymer Concentration on Properties of Hydroxyethyl Cellulose Gravel Pack Fluid

The commercial success of petroleum wells depends greatly on the type of completion, especially the choice of gravel packing fluid system for wells with gravel pack completions. Currently several polymers are in use to viscosify gravel pack fluids. These polymers are expected to exhibit acceptable properties such as good solubility, viscosity yield, rheology, sand carrying capacity, thermal stability, break profile, low residue content and others, to match the job requirements, in order not to jeopardize the sand control process or cause hydrocarbon production impairment. Hydroxyethyl cellulose (HEC), one of the most commonly used polymers used in formulating gravel pack fluids has so many good qualities, such as very low solid residues and easy clean out. In this paper, gel break time was investigated for 40lbs/1000gal and 60lbs/1000gal HEC polymer concentrations at 140°F, 160°F and 180°F, using Sodium Persulfate as gel breaker at concentrations of 1.0lbs/1000gal, 5.0lbs/1000gal, 10.0lbs/1000gal and 20.0lbs/1000gal. The proppant carrying capacity at different temperatures was also investigated. Test results indicated that gel break is a function of temperature, breaker and polymer concentrations. At higher temperatures and higher breaker concentrations, gel break is faster, but slower for higher polymer concentration.

Synthesis and characterization of lignosulfonate-graft-poly (acrylic acid)/hydroxyethyl cellulose semi-interpenetrating hydrogels

Maximizing the use of waste is an important part of the strategy for sustainable development. Lignosulfonate, a waste product with sufficient reactive functional groups, can be used as reinforcing materials in polymer composites. In this work, composite hydrogels composed of lignosulfonate-graft-poly (acrylic acid) AA network and hydroxyethyl cellulose (HEC) polymer chains are synthesized through in situ polymerization and cross-linking reaction. The composite hydrogels have semi-interpenetrating network (semi-IPNs) structure, which is driven by the hydrogen bond interactions between proton-donating PAA and proton-accepting HEC. The mechanical properties of these composite hydrogels, including fracture stress, critical compression and elastic modulus and elongation are investigated by tensile measurements. These composite hydrogels exhibit higher toughness and extensibility compared to conventional PAA polymer hydrogels. Moreover, full recovery of their original shape after the removal of compression stress indicates their excellent shape-recovery property. Due to their porous structure, these hydrogels show stimuli responsive swelling properties in aqueous solution depending on the pH or ionic strength, which facilitate the repeating absorption and removal of dyes. Therefore, this work may open a new pathway to synthesize functional materials based on lignosulfonate.