Rapid homogeneous esterification of cellulose extracted from Posidonia induced by microwave irradiation

In this article, we report on the synthesis of cellulose esters by the reaction of cellulose and some cyclic anhydrides, such as succinic, maleic, and phthalic anhydrides. For this, an esterification method was finalized. Indeed, cellulose extracted from Posidonia biomass was first solubilized in the solvent system lithium chloride (LiCl)/N,N‐dimethylacetamide and then esterified by cyclic anhydride in the presence of catalysts such as N,N‐dimethyl‐4‐aminopyridine, tripropylamine, tributylamine, and calcium carbonate. This method was fast and reproducible with the LiCl system as a solvent and with an efficient activation by controlled microwave power. In this way, the reaction time was reduced from several hours to just a few minutes. The reaction products were characterized by IR and solid‐state cross‐polarization/magic angle spinning ¹³C‐NMR spectroscopy. The degree of substitution (DS) and the grafted ester group content of the different products were obtained by alkali saponification followed by titration of the excess alkali. Two activation methods were compared, and the results show that the application of classical heating gave less successful results than those obtained by microwave activation. Indeed, with microwave activation, a higher DS (2.25) was obtained after 10 min. However, with classical heating, a value of DS equal to 1.2 was obtained after 12 h. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of amidoximated bacterial cellulose and its adsorption mechanism for Cu2+ and Pb2+

Amidoximated bacterial cellulose (Am‐BC) was prepared through successive polymer analogous reactions of bacterial cellulose with acrylonitrile in an alkaline medium followed by reaction with aqueous hydroxylamine. It was used as an adsorbent to remove Cu²⁺ and Pb²⁺ from aqueous solutions. The adsorption behaviors of Cu²⁺ and Pb²⁺ onto Am‐BC were observed to be pH‐dependent. The maximum adsorption capacity of 84 and 67 mg g^–1 was observed, respectively, for Cu²⁺ and Pb²⁺ at pH 5. Scanning electronic microscopy (SEM) indicated that the microporous network structure of Am‐BC was maintained even after the modifacation. The adsorption mechanisms for Cu²⁺ and Pb²⁺ onto Am‐BC were investigated by fourier transform infrared spectroscopy (FTIR), ζ potential measurement and X‐ray photoelectron spectroscopy (XPS). The results revealed that the mechanism for the adsorption of Cu²⁺ onto Am‐BC could be mainly described as between metal ions and nitrogen atom in the amidoxime groups or oxygen atom in the hydroxyl groups. However, in the adsorption process for Pb²⁺, precipitation played the important role along with electrostatic interactions, although chelation action also existed in the process accounted for the adsorption process. The regeneration of Am‐BC was studied by treatment with a strong complexing agent, ethylenediaminetetracetic acid (EDTA). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of the new cellulose derivative films based on the hydroxyethyl cellulose prepared from esparto “stipa tenacissima” cellulose of Eastern Morocco. II. Esterification with acyl chlorides in a homogeneous medium

Esparto “Stipa tenacissima” cellulose esters derivatives: HECA‐COO? C₄H₈? COOC₂H₅, HECA‐COO? C₈H₁₆? COOC₂H₅, and HECA‐COO? C₆H₄? COOC₂H₅ were successfully prepared in Tetrahydrofuran (THF)/triethylamine system with a degree of substitution (DS), respectively, DS_AD‐Et=0.32, DS_SB‐Et=0.22, and DS_TRP‐Et=0.50 using hydroxyethyl cellulose acetate (HECA; DS_AC=0.50) as intermediate product, and we avoided the drawbacks of cellulose solubility. The structural modifications were investigated using Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (¹H‐NMR), Carbon‐13 nuclear magnetic resonance (¹³C‐NMR), and Distortionless Enhancement by Polarization Transfer 135° (DEPT‐135). The results from these analyses revealed the presence of the characteristic groups indicating that the grafting reaction was successful. The crystallinity and the structure order changes during the esterification reactions were recorded by X‐ray diffraction (XRD), it is found that the crystallinity degree decrease from 63.1% for Esparto “Stipa tenacissima” cellulose to 27.74% for HECA. The thermal stability of the esterified and unmodified cellulose samples was studied by thermogravimetric analysis (TGA)‐differential thermal analysis (DTA); the modified HECA exhibits a decrease in thermal stability relatively to the unmodified HECA, and this may be related to the groups grafted. The resulted cellulose esters HECA‐P_x (x = 1, 2, or 3) were soluble in THF and present an amorphous structure justified by XRD spectra. It was noted by TGA‐DTA analysis that the cellulose esters with low melting range were proved as thermoplastic polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Introduction of amidoxime groups into cellulose and its ability to adsorb metal ions

Introduction of amidoxime groups into cellulose substrate was investigated by reaction of cyano-group-containing celluloses such as cyanoethylcellulose (CE-Cell) and acrylonitrilegrafted cellulose (G-Cell) with hydroxylamine at 70°C in water medium (pH = 7.0). Dissolving pulp from softwood was used as the cellulose sample, and photografting was applied to the preparation of G-Cell, where hydrogen peroxide was used as a photoinitiator. Degree of substitution (DS) of CE-Cell and percent grafting of G-Cell employed were less than 1.5 and 40, respectively. The amidoximation of CE-Cell proceeded easily, and the amidoxime content increased with increasing the reaction time and increasing the concentration of hydroxylamine, but the amidoxime content of G-Cell decreased significantly at longer reaction time. The amidoximated samples prepared by CE-Cell exhibited an ability to adsorb metal ions such as Cu²⁺, Ni²⁺, and Co²⁺, and the adsorbed amount of Cu²⁺ was highest among the three metal ions. Moreover, the adsorption of Cu²⁺ varied depending on the DS of CE-Cell. That is, the absorption ability was reduced when the sample was prepared using CE-Cell with higher DS. The amidoximated samples prepared from G-Cell showed adsorption of Cu²⁺ similar to samples prepared by CE-Cell with lower DS, irrespective of percent grafting. © 1995 John Wiley & Sons, Inc.     

New methods for acylation of pure and sawdust‐extracted cellulose by fatty acid derivatives—Thermal and mechanical analyses of cellulose‐based plastic films

This work deals with the synthesis of cellulosic plastic films obtained in homogeneous conditions by microwave‐induced acylation of commercial or chestnut tree sawdust cellulose by fatty acids. The acylation reaction was studied according to N,N‐dimethyl‐4‐aminopyridine (DMAP) amount, DMAP simultaneously playing the role of catalyst and proton trapping base. This study clearly showed that DMAP does not influence degrees of substitution (DS), massic, and molar yields. Plastic films synthesized in the absence of DMAP showed a decrease in mechanical behavior. Organic (tributylamine) or inorganic bases (CaCO₃, Na₂CO₃) were then added to replace DMAP basic activity, and no changes were observed. Concerning thermal and mechanical properties of plastics obtained with various bases, glass transition temperatures (T_g) and degradation temperature (T_d) were found constant whatever the base, and the best mechanical properties were obtained for films synthesized in the presence of CaCO₃. The same remarks were made concerning the valorization of chestnut tree sawdust cellulose. Microbial biodegradation of plastic films with DS = 2.2 led to a loss of their mechanical behaviors. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1266–1278, 2005     

Experimental study on carboxymethylation of cellulose extracted from Posidonia oceanica

The production of carboxymethylcellulose (CMC) from bleached cellulose pulps obtained from Posidonia oceanica was explored. The optimal reaction conditions were studied for the carboxymethylation of cellulose in organic liquids. The carboxymethylation reaction was carried out with NaOH and monochloroacetic acid (MAC) as the reagent. Different alcohols were compared in terms of the degree of substitution (DS). The highest DS was obtained with n‐butanol. For this alcohol, the effects of the temperature, alkali concentration, and MAC concentration were studied. The reaction was also carried out in three consecutive steps. The resulting CMC had a DS of about 2.75. The functionalization of cellulose was checked using FTIR spectroscopy and ¹³C‐NMR. The X‐ray analysis showed that the crystalline structure of cellulose decreased when the DS increased and the structure was totally amorphous in high DS material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1808–1816, 2006     

H3PW12O40·4H2O as an efficient catalyst for the conversion of cellulose into partially substituted cellulose acetate

The preparation of partial acetylation of cellulose derived from rice straw was catalyzed by phosphotungstic acid with various numbers of crystal water, and H₃PW₁₂O₄₀·4H₂O was found to be as effective catalyst. The yield of the cellulose acetate was significantly enhanced by converting cellulose directly isolated from rice straw into microcrystalline cellulose before acetylation. The optimization of the acetylation was investigated by varying the amount of catalyst and acetic anhydride as well as reaction conditions including reaction time and medium, and a degree of substitution (DS) value of 2.29 and yield of 62.9% were obtained under the optimized conditions. The structure and the formation of the acetylated product were confirmed by Fourier transform infrared spectroscopy (FTIR) and powder X‐ray diffraction (XRD) technique, the thermal properties were determined by thermal analysis including thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC), and the morphology was observed by scanning electron microscope (SEM). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41212.     

N‐alkylation of chitosan by β‐halopropionic acids in the presence of various acceptors

N‐carboxyethylation of chitosan by β‐halopropionic acids in the presence of various proton and halogen ion acceptors was investigated. It has been observed that carboxyethylation of chitosan in aqueous medium is accompanied by the by‐processes of hydrolysis and dehydrohalogenation of the β‐halopropionic acids yielding β‐hydroxypropionic acid, bis(2‐carboxyethyl) ether, and acrylic acid. Degree of carboxyethyl substitution (DS) of chitosan and the relative rates of the by‐processes varied significantly depending on the conditions used and nature of the proton or halogen ion acceptor. At carboxyethylation of chitosan with the alkaline β‐bromopropionates, the DS increased in the order Cs⁺ < Rb⁺ < K⁺ ～ Na⁺ < Li⁺. For alkaline earth salts BrCH₂CH₂COOM_0.5 (M = Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺), the highest DS was obtained with strontium and barium salts, which could be subsequently removed from the reaction mixture by precipitation as sulfates. Among the organic bases applied (tetrabutylammonium hydroxide, triethylamine, trimethylamine, pyridine, 4‐N,N‐dimethylaminopyridine, 2,6‐lutidine, and 1,5‐diazabicyclo[4.3.0] non‐5‐ene), the highest DS was obtained using a moderately strong base triethylamine. For the halogen acceptors (Pb²⁺, Ag⁺, Tl⁺), the stoichiometrically highest DS was achieved in a system comprising iodopropionic acid plus Tl⁺ and a comparable conversion rate was obtained using also a combination of chloropropionic acid and Ag⁺. A novel alternative preparative approach—gel‐state synthesis—was suggested that provides for the highest DS at the optimum reaction conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and Photocrosslinking Reaction of N-Allylcarbamoylmethyl Cellulose Leading to Hydrogel

Summary The reaction of the carboxymethyl cellulose sodium salt (Na-CMC) (degrees of substitution (DS) = 1.2) with N-hydroxysuccinimide (Su-OH) in the presence of 1-hydroxybenzotriazole and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was carried out in water to obtain the Su-OH ester of carboxymethyl cellulose, Su-CMC, with the DS values of 0.19 – 1.04. N-Allylcarbamoylmethyl cellulose (Allyl-CMC), which was prepared from the reaction of Su-CMC with an excess amount of allylamine, was crosslinked by UV-irradiation. In addition, the photocrosslinked Allyl-CMC film was swollen with water to form a hydrogel having a relatively high water-swelling property, e.g., the degree of swelling (ds) was ca. 360% for Allyl-CMC with the DS of 0.93.     

Production of bacterial cellulose by a static cultivation using the waste from beer culture broth

Bacterial cellulose (BC) was produced by using the waste from beer culture fermentation instead of a chemically defined medium. Static cultivation was superior to the shaking cultivation on the basis of the BC production. The amount of BC produced during 120 hrs of cultivation using the waste from beer fermentation broth (WBFB) by a static cultivation was 4.52 g/L on the dry weight basis and much higher than 0.45 g/L produced from a Buffered Schramm and Hestrin (BSH) chemically-defined medium. The addition of 1% industrial-grade glucose to WBCB increased the production of bacterial cellulose from 8.46 to 13.95 g/L after 336 hrs of cultivation. Water soluble oligosaccharide (WSOS), the by-product obtained during BC cultivation increased to 5.05 g/L at 192 hrs of cultivation and then decreased to 2.18 g/L at 336 hrs. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

Synthesis and characterization of the new cellulose derivative films based on the hydroxyethyl cellulose prepared from “Stipa Tenacissima” cellulose of Eastern Morocco. I. Solubility study

Hydroxyethyl cellulose Acetate (HECA) was prepared starting from hydroxyethyl cellulose (HEC), acetic anhydride and perchloric acid which was used as catalyst. The synthesized product was characterized by FTIR, ¹³C NMR, and ¹H NMR. Substitution degree (DS) of HECA was determined using FTIR spectra taking a classical titration method as reference. The ¹H NMR spectroscopy was also used to confirm the results obtained by FTIR. The DS is substantially affected by the temperature, the time of reaction and especially the equivalent number (eq. nb.) of the acetic anhydride added. We have studied and discussed in the context of usage in modification reactions, the solubility of the HECA samples by varying their DS. This investigation was based on the determination of the Flory‐Huggins interaction parameters (χ_SP) using the partial Hansen solubility parameters (HSP). HSP of HEC and the HECA samples were calculated from the Van‐Krevlen‐Hoftyze (VKH) method and the T. Lindvig approximation. We have focused our work on predicting and controlling family solvents of HECA with various DS, to facilitate and to optimize the homogenous modification reaction conditions. From results on a range of HECA samples, it is conclude that their prediction solubility taking the value of DS into account is possible, and then the surface modification can relatively be easily realized. The thermal analysis study shows some differences in T_g and thermal degradation between HEC and HECA, moreover these thermal temperatures are influenced by DS values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Nucleophilic displacement reactions on tosyl cellulose by chiral amines

Summary New 6-deoxy-6-amino cellulose derivatives with a degree of substitution (DS) in the range from 0.4 to 0.6 were synthesized by nucleophilic displacement (S_N) reactions of cellulose tosylates (DS_Tos 0.74 and 1.29) with R(+)-, S(−)- and racemic 1-phenylethylamine under homogeneous conditions in N,N-dimethylformamide and water. The structure of the polymers was characterized by elemental analysis, FTIR and ¹³C NMR spectroscopy. The DS values obtained as well as the optical rotation and circular dichroism measurements in dimethyl sulfoxide reveal that the initial chirality of the cellulose backbone does not have any significant influence on its reactivity with either of the two enantiomeric amines. Received: 21 September 2000/Accepted: 5 January 2001     

Adsorption removal of Cu2+ and Ni2+ from waste water using nano‐cellulose hybrids containing reactive polyhedral oligomeric silsesquioxanes

Cellulose is an important biomass in natural material fields. Reactive polyhedral oligomeric silsesquioxane (R‐POSS) bearing multi‐N‐methylol groups is novel high reactive POSS monomer. The nano‐cellulose hybrids containing R‐POSS were synthesized by crosslinking reaction. It was interesting to investigate properties and applications of hybrids containing R‐POSS. In this work, nano‐cellulose hybrids as novel biosorbent were used for adsorpting copper and nickel ions in aqueous solution. Adsorption kinetics and equilibrium isotherm of Cu²⁺ and Ni²⁺ on the nano‐cellulose hybrids were investigated. The results showed that R‐POSS had been grafted to cellulose macromolecule. The nano‐cellulose hybrids could form new adsorptive position for heavy metal ions. The adsorption capacities of hybrid materials were obviously higher than that of control cellulose. The adsorption of heavy metal ions on nano‐cellulose hybrids followed the second‐order model. The equilibrium isotherms for adsorpting copper and nickel ions on the hybrids followed Langmuir isotherm model. Nano‐cellulose materials containing POSS as biosorbents or ultrafiltration membranes would be used in separation of toxic heavy metal ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Esterification of cellulose with acyl-1H-benzotriazole

For the first time, the acylation of cellulose was realized by activation of carboxylic acid with 1H-benzotriazole. The reaction could be carried out under mild conditions. The acyl-1H-benzotriazole reacts with cellulose leading to cellulose acetate, butyrate, caproate, benzoate, myristate, and stearate with DS values between 1.07 and 1.89. The reaction proceeds completely homogeneously in dimethyl sulfoxide (DMSO)/TBAF × 3H₂O (tetrabutylammonium fluoride trihydrate) using acyl-1H-benzotriazole as acylation agent. The cellulose esters were characterized by means of ¹H NMR, GPC measurements, and solubility tests.     

Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n‐octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity

The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n‐octyl)ammonium chloride (N₂₂₂₈Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal mol^?1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N₂₂₂₈Cl + MS) differ only by 0.8 kcal mol^?1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this “leveling‐off” of the dependence DS on the polarity of the parent MS employed. N₂₂₂₈Cl recovery and recycling is feasible.     

Aerobic biodegradation of cellulose acetate

Two separate assay systems were used to evaluate the biodegradation potential of cellulose acetate: an in vitro enrichment cultivation technique (closed batch system), and a system in which cellulose diacetate (CDA) films were suspended in a wastewater treatment system (open continuous feed system). The in vitro assay employed a stable enrichment culture, which was initiated by inoculating a basal salts medium containing cellulose acetate with 5% (v/v) activated sludge. Microscopic examination revealed extensive degradation of CDA (DS = 2.5) fibers after 2–3 weeks of incubation. Characterization of the CA fibers recovered from inoculated flasks demonstrated a lower average degree of substitution and a change in the mol wt profiles. In vitro enrichments with CDA (DS = 1.7) films were able to degrade > 80% of the films in 4–5 days. Cellulose acetate (DS = 2.5) films required 10–12 days for extensive degradation. Films prepared from cellulose triacetate remained essentially unchanged after 28 days in the in vitro assay. The wastewater treatment assay was less active than the in vitro enrichment system. For example, approximately 27 days were required for 70% degradation of CDA (DS = 1.7) films to occur while CDA (DS = 2.5) films required approximately 10 weeks before significant degradation was obtained. Supporting evidence for the biodegradation potential of cellulose acetate was obtained through the conversion of cellulose [1-¹⁴C]-acetate to ¹⁴CO₂ in the in vitro assay. The results of this work demonstrate that cellulose acetate fibers and films are potentially biodegradable and that the rate of biodegradation is highly dependent on the degree of substitution. © 1993 John Wiley & Sons, Inc.     

Cerium-doped calcium phosphates precipitated on bacterial cellulose platform by mineralization

Bacterial cellulose (BC) membranes biosynthesized by Komagataeibacter rhaeticus AF1 strain were used as a platform for precipitating cerium-doped calcium phosphates (Ce:CaP), which were synthetized by successive soaking of BC membranes in solutions containing Ca²⁺, PO₄³⁻ and Ce³⁺ precursor ions. After obtaining the as-prepared composites, BC-Ce:CaP was submitted to a thermal treatment at 600 °C for 3 h, and Ce:CaP was characterized by scanning electronic microscopy (SEM), energy dispersive X-ray spectrometry (EDX), thermogravimetric analysis (TG), derivative thermogravimetric analysis (DTG) and X-ray diffraction (XRD). Ce:CaP presented hydroxyapatite, chlorapatite and buchwaldite (sodium calcium phosphate) phases and revealed a trabecular structure composed per nanowires with interconnected pores. Furthermore, BC-Ce:CaP and Ce:CaP show cell viability and has been suggested for use as a mineral scaffold.     

Properties of bacterial cellulose produced in a pilot-scale spherical type bubble column bioreactor

The saccharogenic liquid obtained by the enzymatic saccharification of food wastes was used as a medium for production of bacterial cellulose (BC). The enzymatic saccharification of food wastes (SFW) was carried out by the cultivation supernatant of Trichoderma inhamatum KSJ1. 5.6 g/L of BC was produced in a new modified 50 L bubble column bioreactor by Acetobacter xylinum KJ1. The productivity was similar to that of a modified 10 L bubble column bioreactor (5.8 g/L). When pure oxygen was supplied into the scaled-up culture conditions, 6.8 g/L (12% enhancement) of BC was produced, indicating a very useful method for BC mass production. The oxygen uptake rate (OUR) and q _O2 (specific oxygen uptake rate) were 0.214 mg-DO/L·min and 0.257 mg-DO/g-cell·min, respectively. The physical properties, such as morphology, molecular weight, crystallinity, and tensile strength of BCs produced in static culture (A), 10 L (B) and 50 L (C) modified bubble column cultures were investigated. All BCs showed fibrils with highly networking structure. The number average molecular weight of BCs in A, B and C was 2,314,000, 1,878,000, and 1,765,000, respectively. All of the BCs had a form of cellulose I representing pure cellulose. The relative degree of crystallinity showed the range of 79.6–86.0%. Tensile strengths of BC sheet in A, B and C were 1.75, 1.21, and 1.19 kg/mm², respectively. In conclusion, BC production by the modified bubble column culture mode of 50 L brought more favorable results in terms of the physical properties and its ease of scale-up.     

Homogeneous synthesis and characterization of polyacrylamide‐grafted cationic cellulose flocculants

In this work, cationic cellulose (CC) with different degrees of substitution (DS) was successfully synthesized by the reaction between cellulose and 3‐chloro‐2‐hydroxypropyl‐trimethylammonium chloride (CHPTAC) in a 7 wt % NaOH and 12 wt % urea aqueous solution. The structure of the CC was characterized by using elemental analysis, ¹H‐NMR, and FTIR. The DS values of CC ranged between 0.18 and 0.50, which could be obtained by adjusting the reaction temperature, reaction time, and molar ratio of CHPTAC to anhydroglucose unit of cellulose. The cationic cellulose–graft–polyacrylamide flocculant (CC‐g‐PAM) based on CC and polyacrylamide (PAM) was also synthesized in a homogeneous aqueous solution. The flocculation characteristics of CC and CC‐g‐PAM were evaluated in a kaolin suspension. The results showed that CC‐g‐PAM was an effective flocculant for the kaolin suspension under acidic or neutral conditions, and the flocculation efficiency was over 90%, while the CC showed better flocculation performance under alkaline conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43106.     

Novel nanoporous membranes from regenerated bacterial cellulose

Bacterial cellulose (BC) in an NaOH/urea aqueous solution was used as a substrate material for thefabrication of a novel regenerated cellulose membrane. The dissolution of BC involved swelling BC in a 4 wt % NaOH/3 wt % urea solution followed by a freeze–thaw process. The BC solution was cast onto a Teflon plate, coagulated in a 5 wt % CaCl₂ aqueous solution, and then treated with a 1 wt % HCl solution. Supercritical carbon dioxide drying was then applied to the formation of a nanoporous structure. The physical properties and morphology of the regenerated bacterial cellulose (RBC) films were characterized. The tensile strength, elongation at break, and water absorption of the RBC membranes were 4.32 MPa, 35.20%, and 49.67%, respectively. The average pore size of the RBC membrane was 1.26 nm with a 17.57 m²/g surface area. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008