Cellulose esters from waste cotton fabric via conventional and microwave heating

Ratanakamnuan, Usarat; Atong, Duangduen; Aht‐Ong, Duangdao

doi:10.1016/j.carbpol.2011.07.016

Cited by 70 publications

(60 citation statements)

References 40 publications

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“…2a, c, the DS values of xylan esters with anhydrides (Aa, Pa and Ba) and the corresponding acyl chlorides (Ac, Pc and Bc) were nearly equal, indicating the similar reactivity of anhydrides (Aa, Pa and Ba) and the corresponding acyl chlorides (Ac, Pc and Bc) under the selected conditions. Similar results were found in cellulose esters (Ratanakamnuan et al 2012). In Fig.…”

Section: Resultssupporting

confidence: 86%

“…The solubility of xylan esters in DMF and CHCl 3 increased with an increase of DS. Similar results can also be observed in acylated cellulose (Fundador et al 2012a;Ratanakamnuan et al 2012). In general, the introduction of hydrophobic acyl groups into the molecular structure of xylan results in the destruction of hydrogen bonds, which was expected to improve its solubility.…”

Section: Solubilitysupporting

confidence: 72%

“…In Fig. 2b, d, the noticeable differences of WPG increment of each xylan ester were observed with the increase of chain length of anhydrides and acyl chlorides, probably due to the attachment of acyl substituents (Ratanakamnuan et al 2012). The longer acyl substituents represented the higher molecular weight of acyl group which can result in higher WPG of xylan derivatives [WPG XyBa (C4) …”

Section: Resultsmentioning

confidence: 98%

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Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Zhang

Liu

et al. 2016

Cellulose

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The per-O-acylation of xylan-type hemicellulose was firstly carried out in dimethylsulfoxide/ N-methylimidazole (DMSO/NMI) at room temperature without additional catalyst. The optimum conditions for esterification of xylan was investigated in terms of the molar ratio of reagents to anhydroxylose units (AXU) in xylan and the kinds of esterification reagents to obtain a high degree of substitution (DS, 1.98) and weight percent gain (WPG, 86.88 %) of xylan esters. In this solvent system, NMI acted as a solvent, a base and an excellent catalyst, therefore, the per-O-acylation of xylan (DS of 1.98) was readily accomplished in DMSO/NMI system at room temperature. Structure elucidation of xylan esters was characterized by FT-IR and NMR ( 1 H-NMR, 13 C-NMR and HSQC). FT-IR and NMR analyses provided the direct evidence of per-O-acylation of xylan under the given conditions. Furthermore, HSQC revealed the higher reactivity of hydroxyls at C-2 position than those at C-3 position of xylan. The solubility of xylan in DMSO, DMF and CHCl 3 improved after esterification. TGA/DTG indicated that the thermal stability of xylan increased after the esterification with anhydrides, while decreased with acyl chlorides, probably due to degradation and hydrolysis of the acylated xylan at the presence of by-product hydrochloric acid.

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Section: Resultssupporting

confidence: 86%

Section: Solubilitysupporting

confidence: 72%

Section: Resultsmentioning

confidence: 98%

See 1 more Smart Citation

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Zhang

Liu

et al. 2016

Cellulose

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“…This technique is well known for the modification of starch and cellulose, for example for increasing the hydrophobicity [18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Water Repellence and Oxygen and Water Vapor Barrier of PVOH-Coated Substrates before and after Surface Esterification

et al. 2014

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This study investigates chemical grafting with fatty acid chlorides as a method for the surface modification of hydrophilic web materials. The resulting changes in the water repellence and barrier properties were studied. For this purpose, different grades of polyvinyl alcohol (PVOH) were coated on regenerated cellulose films ("cellophane") and paper and then grafted with fatty acid chlorides. The PVOH grades varied in their degree of hydrolysis and average molecular weight. The surface was esterified with two fatty acid chlorides, palmitoyl (C16) and stearoyl chloride (C18), by chemical grafting. The chemical grafting resulted in water-repellent surfaces and reduced water vapor transmission rates by a factor OPEN ACCESSPolymers 2014, 6 2765 of almost 19. The impact of the surface modification was greater for a higher degree of hydrolysis of the polyvinyl alcohol and for shorter fatty acid chains. Although the water vapor barrier for palmitoyl-grafted PVOH was higher than for stearoyl-grafted PVOH, the contact angle with water was lower. Additionally, it was shown that a higher degree of hydrolysis led to higher water vapor barrier improvement factors after grafting. Furthermore, the oxygen permeability decreased after grafting significantly, due to the fact that the grafting protects the PVOH against humidity when the humidity is applied on the grafted side. It can be concluded that the carbon chain length of the fatty acid chlorides is the limiting factor for water vapor adsorption, but the grafting density is the bottleneck for water diffusing in the polymer.

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“…However, both chemical processes follow the same route as halogenations, through reaction on carbon 6, with greatest advantage being the occurrence of only one step 19 . The molecule chosen to be immobilized has a chlorine atom that will react with the hydroxyl group, releasing hydrochloric acid to form the ether or ester bonds 20 . Besides, acylation has also been widely investigated as a cellulose surface modification reaction, starting from a cyclic organic in which all three structural hydroxyl groups are involved.…”

Section: Introductionmentioning

confidence: 99%

Surface cellulose modification with 2-aminomethylpyridine for copper, cobalt, nickel and zinc removal from aqueous solution

et al. 2012

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Cellulose was first modified with thionyl chloride, followed by reaction with 2-aminomethylpyridine to yield 6-(2'-aminomethylpyridine)-6-deoxycellulose. The resulting chemically-immobilized surface was characterized by elemental analysis, FTIR, 13 C NMR and thermogravimetry. From 0.28% of nitrogen incorporated in the polysaccharide backbone, the amount of 0.10 ± 0.01 mmol of the proposed molecule was anchored per gram of the chemically modified cellulose. The available basic nitrogen centers attached to the covalent pendant chain bonded to the biopolymer skeleton were investigated for copper, cobalt, nickel and zinc adsorption from aqueous solution at room temperature. The newly synthesized biopolymer gave maximum sorption capacities of 0.100 ± 0.012, 0.093 ± 0.021, 0.074 ± 0.011 and 0.071 ± 0.019 mmol.g -1 for copper, cobalt, nickel and zinc cations, respectively, using the batchwise method, whose data was fitted to different sorption models, the best fit being obtained with the Langmuir model. The results suggested the use of this anchored biopolymer for cation removal from the environment.

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Cellulose esters from waste cotton fabric via conventional and microwave heating

Cited by 70 publications

References 40 publications

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Per-O-acylation of xylan at room temperature in dimethylsulfoxide/N-methylimidazole

Water Repellence and Oxygen and Water Vapor Barrier of PVOH-Coated Substrates before and after Surface Esterification

Surface cellulose modification with 2-aminomethylpyridine for copper, cobalt, nickel and zinc removal from aqueous solution

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