Intrinsic Viscosity Measurements Research Articles

Molybdenite Flotation in the Presence of a Polyacrylamide of Low Anionicity Subjected to Different Conditions of Mechanical Shearing

Polyacrylamides (PAM) are used as flocculants in the copper-molybdenum mining industry to improve the settling rate of flotation tailings. These types of reagents are recirculated to flotation in the water that is recovered from the thickeners, and as a result of this practice they can cause depression of flotation of some important minerals such as molybdenite. The objective of this work was to study the effect of a PAM of 11.9% of degree of anionicity on the flotation of molybdenite. The effect of the anionic PAM on molybdenite flotation was studied under different levels (three) of flocculant mechanical shearing. The flotation data was discussed along with intrinsic viscosity, adsorption, induction time, and electrophoretic mobility measurements. It was found that the non-sheared PAM (NS–PAM) had the strongest depressing effect on molybdenite flotation, followed by the moderately sheared PAM (MS–PAM). The depressing effect of the strongly sheared PAM (SS–PAM) was negligible. The flotation data correlated with the induction time measurements that showed that molybdenite became more hydrophilic in the presence of the NS–PAM. The SS–PAM has no effect on the induction times. Further work is ongoing to understand the effect of PAM on molybdenite flotation in the presence of clay minerals and different aqueous media.

Physicochemical and rheological properties of aqueous Tara gum solutions

Commercial Tara gum from three sources was purified by precipitation with isopropanol and evaluated on the structural, physicochemical and rheological properties. FT–IR and NMR techniques were used to determine the molecule structure and monosaccharide composition of Tara gum. The physicochemical properties were determined by intrinsic viscosity measurement using capillary viscosimetry and the rheological properties were determined by rotational viscosimetry. The monosaccharide composition of Tara gum galactomannans showed strong influence of their origin, with a mannose/galactose (Man/Gal) ratio varying between 1.54 and 1.85. Intrinsic viscosity of Tara gum in aqueous solution was influenced by its origin and temperature, and it was well correlated to the sigmoidal model. Hydrochloric acid was found to influence intrinsic viscosity below pH 2, however, combined with temperature treatment (80 ∘C), this limit was increased to pH 4. The rheological behavior at diluted concentrations resulted in shear thickening fluid, with an exponential increase of the consistency coefficient with concentration. Apparent viscosity of semi-diluted and concentrated Tara gum aqueous solutions were modeled by the Cross equation, where zero shear viscosity was influenced by gum concentration and temperature, with different activation energies.

Effect of organoclay modifier structure on the viscoelastic and thermal properties of poly(methyl methacrylate)/organoclay nanocomposites

Poly(methyl methacrylate) (PMMA)/clay nanocomposites (NCs) were prepared by suspension polymerization of methyl methacrylate in the presence of two different organoclays (Cloisite 30B, Cloisite 15A) with clay loading ranged from 0.5 to 5 wt%. Increase in molecular weight of the PMMA matrix with addition of the clay was revealed by gel permeation chromatography (GPC) and intrinsic viscosity measurements. As confirmed by X-ray diffraction (XRD), the NCs had an intercalated structure. The organoclays-MMA/PMMA compatibility was investigated by swelling tests and solubility parameter approach. Rheological behavior of PMMA NCs in molten state was analyzed through construction of master curves of complex viscosity, storage, and loss modulus by applying the time–temperature superposition procedure. Melt rheology, scanning electron microscopy (SEM), and UV/Vis spectroscopy results confirmed higher extent of clay dispersion in the NCs with Cloisite 30B. Compared to pure PMMA, all these NCs show increase of glass transition temperature as measured by DSC and improved thermal stability determined by thermogravimetric analysis (TGA). The results obtained by dynamic mechanical analysis showed that the storage modulus of the NCs was higher by incorporation of clay into the PMMA matrix, increasing as the amount of clay increased and that their mechanical performance was significantly enhanced.

The effect of thermal and irradiation treatments on structural and physicochemical properties of octenyl succinate maize starches.

The aim of this paper was to evaluate the effect of thermal treatment and UV irradiation on structural and physicochemical properties of octenyl succinate (OS) maize starches differing in content of OS groups (0.76%-2.38%). X-ray diffraction (XRD), gel permeation chromatography (GPC), and electron paramagnetic resonance (EPR) spectroscopy were used to estimate structural characteristics of octenyl succinate starches and their physically treated counterparts. Starch functional properties were also determined. XRD spectra and hydrodynamic volume distribution revealed that growth of octenyl succinate groups' content resulted in stabilization of starch structure, which was confirmed by processes of radical formation, stimulated by thermal and UV treatments. It was found, on the basis of measurements of water binding capacity, water solubility and intrinsic viscosity, that OSA addition changed physicochemical properties of starch and influenced the course of physical modifications. It was established that temperature affected starch properties to a greater extent than UV.

Experimental study on texturability of filament yarns produced from recycled PET

In the present work, the texturability of filament yarns produced from recycled bottle grade polyethylene terephthalate (R-PET) and new fiber grade PET (FG-PET) were investigated and compared experimentally. Yarn spun on a spin-draw spinning machine was draw-textured. Elongation at break in each fiber was set to reach 30 ± 5% in the texturing machine. The effect of the draw-texturing conditions on thermomechanical, structural, and crimp properties were examined. Draw-texturing behaviors of the fibers were analyzed using differential scanning calorimetry and measurements of intrinsic viscosity, mechanical and crimp properties, density, and X-ray diffraction. The results indicate that crystallinity of the textured yarn from R- PET and FG-PET has increased compared to the semi-drawn yarns. Further, the lateral dimensions of the R-PET crystals are relatively well developed. Crimp properties show nearly similar response for two polymer yarns for the texturing process. It was found that R-PET can be the premier feed supply for the draw-texturing process and that filaments with appropriate confidence could be obtained from the R-PET.

Investigation of the Influence of PLA Molecular and Supramolecular Structure on the Kinetics of Thermal-Supported Hydrolytic Degradation of Wet Spinning Fibres.

In this study, differences in the kinetics of the thermal-supported hydrolytic degradation of polylactide (PLA) wet spinning fibres due to material variance in the initial molecular and supramolecular structure were analysed. The investigation was carried out at the microstructural and molecular levels by using readily available methods such as scanning electron microscopy, mass erosion measurement and estimation of intrinsic viscosity. The results show a varying degree of influence of the initial structure on the degradation rate of the studied PLA fibres. The experiment shows that hydrolytic degradation at a temperature close to the cold crystallization temperature is, on a macroscopic level, definitely more rapid for the amorphous material, while on a molecular scale it is similar to a semi-crystalline material. Furthermore, for the adopted degradation temperature of 90 °C, a marginal influence of the pH of the degradation medium on the degradation kinetics was also demonstrated.

Corn zein undergoes conformational changes to higher β-sheet content during its self-assembly in an increasingly hydrophilic solvent

Viscoelasticity of corn zein is associated with the formation of β-sheet secondary structures; however, studies of the fundamentals of this conformational change are limited due to zein insolubility and poor analytical resolution. Here, changes in soluble zein conformation were evaluated as the protein self-assembles in increasingly hydrophilic solvents to the concentration just before aggregation and precipitation. Circular dichroism spectra of zein showed that α-helix structures decrease in favor of random coil and β-sheets with increases in water content in an ethanol-water system, similar to observations of zein when it becomes viscoelastic in dough systems. This was further supported by changes in Thioflavin T fluorescence emission spectra and intrinsic viscosity measurements. Two widely recognized molecular models for α-zein (hairpin and superhelical conformations) were tested at 75 and 45% ethanol concentration using molecular dynamics simulation for agreement with experimental results. Increase in solvent hydrophilicity increased β-sheets and reduced distance between backbone anomeric carbons only for hairpin model, suggesting it to be the more valid of the two. These findings emphasize the importance of transformation to β-sheets during zein self-assembly and provide further insight into the mechanisms by which the protein is functionalized into viscoelastic systems.

Protective action of lemongrass essential oil on mucilage from chia (Salvia hispanica) seeds

Mucilage extracted from chia seeds (Salvia hispanica) is reckoning an increasing interest for its mechanical and nutritional properties. Freeze-dried mucilage dispersed in solvent undergoes degradation, through autoxidation phenomena, that results in the loss of the initial rheological characteristics. In order to limit the extent of depolymerization, an essential oil (lemongrass essential oil, LEO) is here emulsified with chia mucilage (CM) suspensions, and the rheological behavior of samples containing LEO or not compared. Flow curves of CM suspensions and of CM emulsions dispersing LEO (O/W-CM) demonstrated that both the systems can be classified as plastic fluids, and that during storage a general decrease of the viscosity of CM suspensions is detected, while the viscosity of the O/W-CM systems remaining constant. The differences between the two systems were also confirmed by oscillatory tests and through measurements of intrinsic viscosity. By means of an accelerated oxidative test, it was unveiled that the short-term stability of CM suspensions is attributable to the reaction of oxidation, and that the presence of LEO, due to its anti-oxidative properties, allowed for preventing degradation phenomena on the chia mucilage.We conclude that the colloidal stability of chia-based mixtures can definitely be improved following to LEO treatment - hence forming an emulsion - thereby preventing short-term polymer degradation.

Ultraviolet‐induced chain extension of poly(ethylene terephthalate) based on radical reaction with the aid of trimethylolpropane triacrylate and glycidyl methacrylate during extrusion

AbstractIn order to improve the processing properties of poly(ethylene terephthalate) (PET), carbon–carbon double bonds were end‐capped onto the chain end of PET by reacting with glycidyl methacrylate (GMA) and then the product was reacted with trimethylolpropane triacrylate (TMPTA) based on a free radical reaction initiated by ultraviolet light to form long‐chain branching structures. The reaction was demonstrated by intrinsic viscosity measurements, carboxyl content analysis, Fourier transform infrared spectroscopy and size exclusion chromatography. Then the rheological and thermal properties of PET were investigated with various TMPTA and GMA contents. Chain extended PET displayed higher complex viscosity than pristine PET and pronounced shear‐thinning behavior. Moreover, the relaxation time spectrum revealed that the modified PET displayed a longer relaxation time during the relaxation process, which was attributed to the higher degree of entanglements resulting from long‐chain branching. Besides, its crystallization temperature and melt temperature shifted to lower temperatures, and the glass transition temperature shifted to higher temperature, indicating that the thermal properties of the modified PET had also been improved. Thus this method can be used to improve the overall properties of PET. © 2020 Society of Chemical Industry

Synthesis of ionic polymers by free radical polymerization using aprotic trimethylsilylmethyl‐substituted monomers

AbstractAprotic ionic polymers containing trimethylsilylmethyl‐substituted imidazolium structures are synthesized using free radical polymerization of monomers comprising a vinyl group either at the cation or at the anion. Bulk polymerization is used for the room temperature ionic liquid monomer 1‐trimethylsilylmethyl‐3‐vinylimidazolium bis(trifluoromethylsulfonyl)imide. In contrast to this, solution polymerization is applied for 1‐trimethylsilylmethyl‐3‐methylimidazolium p‐styrene sulfonate because this monomer undergoes self‐polymerization during melting at a higher temperature than selected for bulk polymerization. Glass transition temperature (T g) of the ionic polymers and intrinsic viscosity measurements indicate differences between these polymers, which are composed either of a polycation with a trimethylsilylmethyl substituent at each vinylimidazolium segment of the polymer chain and mobile bis(trifluoromethylsulfonyl)imide (NTf2−) anions or a polyanion containing p‐styrene sulfonate segments and mobile 1‐trimethylsilylmethyl‐3‐methylimidazolium cations. The new aprotic ionic polymers containing trimethylsilylmethyl substituents may be interesting for application in adhesive, interlayer and membrane manufacturing.

Preparation of magnetic nanocomposite with modified polyguanidine and its antibacterial properties

AbstractGuanidine‐based polymers are well‐known strong antimicrobial agents against a wide range of microorganisms. However, the high water solubility restricted their potential applications in the field of water treatment. In this study, polyguanidine (PG) has been modified with epichlorohydrin (Ep) and then used for synthesis of nanocomposite with Fe3O4 nanoparticles. The intrinsic viscosity measurements of modified product showed clearly that the viscosity increased with the increasing of Ep content. The characterization results indicated that magnetite Fe3O4/PG‐Ep nanocomposites were successfully synthesized, with 20‐30 nm particle size and high saturation magnetization, 62 emu.g‐1. The TGA results showed that PG‐Ep amount containing in the nanocomposite was about 10 % (wt.). As‐prepared nanocomposite Fe3O4/PG‐Ep demonstrated good antibacterial activity against Escherichia coli and had the potential to be used in disinfection applications.

Structure–property relationship of poly(cyclohexane 1,4‐dimethylene terephthalate) modified with high trans‐1,4‐cyclohexanedimethanol and 2,6‐naphthalene dicarboxylicacid

ABSTRACTA series of novel poly(1,4‐cyclohexanedimthylene terephthalate‐co‐1,4‐cyclohxylenedimethylene 2,6‐naphthalenedicarboxylate) (PCTN) copolyesters were successfully melt polymerized using different content of trans‐ or cis‐isomers. Before evaluations, the performance properties, their actual chemical composition, chemical structure, and molecular weight were determined using proton nuclear magnetic resonance (1H‐NMR), Fourier transform infrared spectroscopy (FTIR), and intrinsic viscosity (IV) measurements. Thermal studies of obtained copolyesters were carried out using differential scanning calorimetry (DSC). Thermal degradation behaviors were analyzed by thermogravimetric analysis (TGA). Randomly oriented film specimens were developed using a hot‐press and their thermal, barrier, dimensional stability, and optical properties were analyzed and compared with conventional poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN). The results revealed that glass transition temperature (Tg), melting temperature (Tm), and crystallinity (Xc) of the synthesized copolyesters are increased in a linear trend by increasing the trans‐1,4‐cyclohexanedimethanol (trans‐CHDM) isomers. It was also found that synthesized films had better thermal, barrier, optical, and dimensional stability properties than conventional PET and PEN films. Results clearly indicated that high trans‐CHDM isomers significantly improve the performance properties of the fabricated films. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48950.

Solubility parameters and solvent affinities for polycaprolactone: A comparison of methods

ABSTRACTIntrinsic viscosity measurements were used in combination with the functional solubility parameter (FSP) and Hansen solubility parameter (HSP) fitting methods to determine the solubility parameters (SPs) of polycaprolactone (PCL). Despite using only eight solvents, a simple similarity criteria approach showed that the HSPs and FSPs were good predictors of the relative solvent‐PCL affinity compared to HSPs available in the literature and SPs calculated using additive group contribution methods. Three complementary computational methodologies—Conductor‐like Screening MOdel for Real Solvents (COSMO‐RS), partial solvation parameters (PSPs), and a thermodynamic quantitative structure–property relationship (QSPR) approach—were used to substantiate the relative solvent–PCL affinities revealed by the intrinsic viscosity measurements. The solvent affinities predicted by all three techniques were in good agreement with the trend observed in the experimental intrinsic viscosity data, but the COSMO‐RS activity coefficients, ln(γPCL), were slightly superior to the PSP and thermodynamic QSPR methods, particularly when incorporating the Elbro free‐volume combinatorial correction in the COSMO‐RS calculations. As part of this study, the FSP fitting algorithm was modified to obtain the PSPs for PCL in terms of the intrinsic viscosity data, thereby, presenting a promising new way to calculate the PSPs of polymers from empirical solubility and solvent affinity data. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48908.

Dilute solution properties of poly(d,l-lactide) by static light scattering, SAXS, and intrinsic viscosity

The dilute solution properties of poly(d,l-lactide)s (PDL50) with a weight-averaged molar mass (Mw) ranging from 0.154 × 104 to 75.7 × 104 g mol−1 are thoroughly studied in tetrahydrofuran at 25 °C by static light and small-angle X-ray scattering and intrinsic viscosity ([η]) measurements. Fourteen PDL50 samples with a narrow molar mass distribution are synthesized at 150 °C by ring-opening copolymerization of a 1:1 mixture of d-lactide and l-lactide with benzyl alcohol as an initiator and tin(II) dichloride dihydrate as the catalyst, followed by fractionation using recycling preparative size exclusion chromatography. The Mw dependences of the z-averaged root-mean-square radius of gyration (〈S2〉z1/2) and [η] are rationalized and analyzed based on the cylindrical wormlike chain model. The experimental Mw dependence of 〈S2〉z1/2 is quantitatively described by the wormlike cylinder with stiffness parameter λ−1 = 2.9 nm, molar mass per unit contour length ML = 270 ± 20 g mol−1 nm−1, protruding effects at both ends δ = 0.4 nm, and excluded-volume strength B = 0.31 ± 0.07 nm. The experimental Mw dependence of [η] and the scattering form factor P(q) are also consistently expressed by the current theories with the same model parameters. The results indicate that the PDL50 chain behaves as a typical flexible polymer but is essentially 1.6−2.1 times stiffer than the representative vinyl polymers, polystyrene (λ−1 = 1.8 nm) and poly(methyl methacrylate) (λ−1 = 1.4 nm), most likely due to the planar feature of the ester linkage, which partially constrains the free rotation of the main chain. The dilute solution properties of poly(d,l-lactide)s (PDL50) with a weight-averaged molar mass (Mw) ranging from 0.154 × 104 to 75.7 × 104 g mol−1 are thoroughly studied in tetrahydrofuran at 25 °C by static light and small-angle X-ray scattering and intrinsic viscosity ([η]) measurements. The Mw dependences of 〈S2〉z1/2 and [η] are quantitatively described by the wormlike cylinder with stiffness parameter λ−1 = 2.9 nm, indicating that the PDL50 chain behaves as a typical flexible polymer but is essentially 1.6−2.1 times stiffer than polystyrene and poly(methyl methacrylate).

A Facile and Efficient Method for Preparing Chain Extended Poly(lactic acid) Foams with High Volume Expansion Ratio

In recent years, poly(lactic acid) (PLA) foams have drawn considerable attention worldwide due to their environmental friendliness and excellent biocompatibility. However, it was a big challenge to prepare PLA foams with high volume expansion ratio owing to their poor crystallization properties and melt strength. In this work, the random copolymer of ethylene and glycidyl methacrylate as an efficient chain extender (CE) was chosen and employed to improve the crystallization behaviors and foamability of PLA. The chain extension reaction between PLA and CE was proved by torque curves, Fourier transform infrared spectra, gel fraction, and intrinsic viscosity measurements. Differential scanning calorimetry results and polarized optical microscope images showed that the crystallinity and spherocrystal number of various PLA samples increased notably as well as their spherocrystal size decreased with the CE content increasing. The viscoelasticity of various PLA samples was improved by the increment in the CE content. Various PLA samples were foamed by a batch foaming method at different foaming temperature with supercritical CO2 to research the influence of crystallization behaviors and/or rheological properties on the foaming behaviors of PLA. At the high foaming temperature, the cell density and volume expansion ratio (VER) of various PLA foams were affected by rheological properties significantly and their highest VER could reach to 42.41 ± 0.01 times. At the low foaming temperature, the cellular morphology of various PLA foams was improved notably, due to the increased melt strength induced by the cooling and the generation of crystallization region.

Nanocellular Foaming Behaviors of Chain-Extended Poly(lactic acid) Induced by Isothermal Crystallization.

Recently, the fabrication of semicrystalline polymer foams with a nanocellular structure by supercritical fluids has been becoming a newly developing research hotspot, owing to their peculiar properties and prospective applications. In this work, a facile and effective isothermal crystallization-induced method was proposed to prepare nanocellular semicrystalline poly(lactic acid) (PLA) foams using CO2 as a physical blowing agent. Styrene–acrylonitrile–glycidyl methacrylate (SAG) as a chain extender (CE) was introduced into PLA through a melt-mixing method to improve the crystallization behavior and melt viscoelasticity of PLA. The chain extension reaction between PLA and SAG occurred successfully as well as the branching and micro cross-linking structures were generated in chain-extended PLA (CPLA) samples, which were confirmed by Fourier transform infrared spectra, gel fraction, and intrinsic viscosity measurements. Owing to the nucleation effect of branching points and the restricted movement of PLA molecular chains by the formation of branching and/or microcross-linking structures, a large number of small spherocrystals were generated in CPLA samples, which was beneficial to produce nanocells. Nanocellular CPLA foams were prepared successfully, when the foaming temperature was 125 °C. As the SAG content increased, the cell size of various PLA foams decreased from 364 ± 198 to 249 ± 100 nm and their volume expansion ratio increased from 1.15 ± 0.05 to 2.22 ± 0.01 times, gradually. When the foaming temperature increased from 125 to 127 °C, an interesting transition from nanocells to microcells could be observed in CPLA foam with the CE content of 2 wt %. Finally, the formation mechanism of nanocells in various PLA foams was proposed and clarified using a schematic diagram.

Ultrasonic Degradation of Konjac Glucomannan and the Effect of Freezing Combined with Alkali Treatment on Their Rheological Profiles.

The effect of freezing combined with alkali treatment on physicochemical property of konjac glucomannan (KGM) with different molecular weight was investigated in this work. The properties and structure of degraded KGM was characterized by means of intrinsic viscosity measurement, atomic force microscope (AFM) and Fourier transformation infrared (FT-IR). The results suggested that the intrinsic viscosity of KGM solution gradually decreased during the ultrasonic treatment. The AFM observation indicated that KGM with lower viscosity average molecular weight had smaller height and lateral diameter of molecules. The main repeating units of the KGM chain could not be destroyed no matter how long the KGM was sonicated. Rheometrical studies revealed that with increasing alkali concentration from 0% to 0.36%, both viscosities and shear stress of deacetylated konjac glucomannan (Da-KGM) system were increased and moduli G′ were substantially higher in either freezing or unfreezing samples. Da-KGM system performed a solid-like behavior (G′ > G′′) along the frequency range after freezing treatment. With increasing sonication time, both viscosity and shear stress of unfreezing samples were decreased while had an inverse effect for freezing treated samples. The modulus G′ and G′′ declined for unfreezing samples but rise significantly for freezing treated samples with increase of sonication time.

Hydrolysis and thermal stability of partially hydrolyzed polyacrylamide in high‐salinity environments

ABSTRACTPartially hydrolyzed polyacrylamide (HPAM) is the water‐soluble polymer most often used in flooding applications in the petroleum industry. However, in aqueous solutions at high temperatures, HPAM undergoes hydrolysis of the lateral amide groups, and the presence of salts in the solution can lead to precipitation of this polymer. Therefore, a method was developed to monitor the thermal stability of HPAM solutions in different saline environments and varying temperatures. The proposed test method involved measurements of intrinsic viscosity as a function of time and determination of the degree of hydrolysis of the HPAM by elemental analysis. The results obtained indicated that the presence of divalent cations (Ca+2 and Mg+2) negatively influenced the intrinsic viscosity of the solutions and in some systems led to precocious precipitation of the polymer in environments with higher concentrations of these cations. The hydrolysis reaction of the amide groups to the acrylate groups of the HPAM chain was significantly affected by rising temperature: at 50 °C, hydrolysis occurred, but not as significantly as at 70, 85, 90, and 95 °C. Hydrolysis up to 84% was observed for solutions processed at 90 °C. The results also indicated limits of hardness for the brine at some temperatures: 1353 ppm for 95 °C and 2867 ppm for 70 °C. For brine containing 13,610 ppm or more of divalent cations, hydrolysis and precipitation of the polymer were not observed at 50 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47793.

Preparation of ultra‐high‐molecular‐weight polyacrylamide by vertical solution polymerization technique

A straightforward and novel methodology has been developed for the synthesis of ultra‐high‐molecular weight polyacrylamide (PAM) by vertical solution polymerization technique. By varying the concentrations of acrylamide monomer, three different grades of polymers (PAM‐V1, PAM‐V2, and PAM‐V3) have been synthesized and compared with the series of different grades of PAM (PAM‐C1, PAM‐C2, and PAM‐C3) synthesized through conventional solution polymerization technique. The synthesized grades PAM‐V1, PAM‐V2, PAM‐V3, PAM‐C1, PAM‐C2, and PAM‐C3 have been characterized by 1H NMR, infrared spectroscopy, intrinsic viscosity measurement, molecular weight determination by gel permeation chromatography, and thermal analysis. Rheological analysis has been carried out on the aqueous solutions of various grades of PAMs. Swelling behavior of ultra‐high‐molecular weight PAMs has also been investigated. The flocculation performances of all grades have been investigated in kaolin suspension by settling and jar test methods. POLYM. ENG. SCI., 59:1175–1181 2019. © 2019 Society of Plastics Engineers

Radiation Degraded Chitosan: Efficiency and Investigation of Adsorption of Arsenic (V) from Aqueous Solution

High energy 60Co gamma radiation was used for degradation of chitosan under different radiation doses. Molecular weight of degraded chitosan was determined by intrinsic viscosity measurement. The intrinsic viscosity values were used to determine the viscosity-average molecular weight of degraded oligo-chitosan using Mark-Houwink equation. Degraded chitosan was investigated for its suitability as an adsorbent for removal of As (V) from aqueous solution. The adsorption capacity of degraded chitosan on As (V) was compared with pristine chitosan. The process of adsorption of As (V) ions was monitored and various adsorption parameters were evaluated. The experimental results indicate that adsorption of As (V) decreases with increasing rate of degradation of chitosan.