Preparation of some starch ethers using the semi-dry state process

Khalil, M. I.; Beliakova, M. K.; Aly, Amal

doi:10.1016/s0144-8617(00)00304-0

Cited by 32 publications

(21 citation statements)

References 25 publications

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“…This phenomenon was in accordance with several observations in the etherification and esterification of starch. 38,44 Dissolution of CCs. It is well-known that the introduction of carbamate groups on the cellulose backbones leads to the increase of its solubility.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Wang

et al. 2015

ACS Sustainable Chem. Eng.

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Cellulose carbamates (CCs) were successfully prepared from cellulose/urea (CU) mixtures based on an easy scale-up method and minimum urea. Urea content and the reaction conditions on the nitrogen content of the reacted CU (RCU) mixtures and CCs were systematically investigated. RCU mixtures and CCs were characterized with elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, NMR spectrometry and solubility testing. The result indicated that almost all of urea was involved in the derivatization reaction and cellulose was converted into CC with absence of byproducts. The nitrogen content of CCs increased with an increase of the urea content and the reaction temperature, as well as the reaction time. CCs retained the cellulose I crystalline, and the degree of polymerization hardly changed with the reaction conditions. CCs prepared from CU mixtures with the urea content of 3.4−4.6 wt % displayed good solubility in NaOH/ZnO aqueous solutions. Especially, RCU mixtures without washing could be also well dissolved in NaOH/ZnO solutions and its solubility could reach 97%. This work provided a simple, pollution-free and economic pathway for preparing CCs, which is expected to be useful for the CarbaCell process.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Wang

et al. 2015

ACS Sustainable Chem. Eng.

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“…The mixture was then transferred into a stoppered bottle and kept for 120 min in a thermostated water bath at 40°C. At the end of the reaction time, the reaction product was neutralized with an acetic acid/ethanol mixture (1:20, v/v) and then Soxhlet extracted with an ethanol/water mixture (70:30, v/v) for 12 h and finally dried at 60°C [5].…”

Section: Preparation Of Carbamoylethyl Starchmentioning

confidence: 99%

Evaluation of Some Starch Derivatives Containing Amide Groups as Flocculants

Khalil¹,

Aly²

2001

Starch/Stärke

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Three types of starch derivatives namely poly(acrylamide)-starch graft copolymer, carbamoylethylated starch, and starch carbamate were prepared and evaluated as flocculants. Native and hydrolyzed maize starches were used as parent materials for these derivatives. The flocculation was followed by monitoring transmission % and weight removal %. The different factors affecting flocculation were studied. These factors include: (a) flocculant dose, (b) pH of the flocculation medium and (c) starch derivatives type, molar mass and nitrogen content. The flocculation efficiency of the three starch derivatives follows the order: poIy(acryIamide)-starch graft copoIymer > carbamoylethylated starch > starch carbamate. The flocculation efficiency increases on increasing the nitrogen content and/or decreasing the molar mass of the flocculant. The flocculation efficiency of various flocculants at pH 6 is higher than at pH 8. The poIy(acryIamide)-starch graft copoIymer based on H 3 -starch has a higher flocculation efficiency than polyacryIamide. I = Poly(acrylamide)-starch graft copolymer; II = Carbamoylethylated starch; III = Starch carbamate. D = optimal dose (ppm); W = weight removal %; T = transmission %. Nitrogen content given in matom/100 g sample.

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“…The graft copolymerization of starch with vinyl monomers has been extensively studied and recognized as one of the most effective methods for improving starch properties . This technique imparts desirable and useful properties to starch without sacrificing its biodegradable nature, thereby expanding the range of starch application .…”

Section: Introductionmentioning

confidence: 99%

Desizability of the Grafted Starches Used as Warp Sizing agents

Liu

Zhu

et al. 2017

Starch Stärke

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An attempt is made to examine the effect of the consitituent units in the branches grafted onto the backbones of starch on the desizability of grafted starches for warp sizing. The starches investigated include starch‐g‐polyacrylamide, starch‐g‐poly(acrylic acid), starch‐g‐polyacrylate, and starch‐g‐polymethacrylate, which are synthesized via graft copolymerization in water using Fe2+‐H2O2 initiators. The desizability is evaluated by enzyme, alkali, and oxidant desizings in terms of desizing efficiency, water swellability of starch film, and the time for breaking the starch film in water. It is found that the constituent units play an important role in desizability. Hydrophilic units are superior to hydrophobic ones in improving desizability. For the (meth)acrylate units, the increase in the number of carbon atoms in alkyl esters and the presence of α‐methyl show adverse impact on desizability. An increase in the grafting ratio of starch‐g‐polyacrylamide favors improvement of the desizabity whereas the increase in the ratio of starch‐g‐poly(methyl acrylate) reduces the desizabity. Of the three desizing methods considered here, oxidant and enzyme desizings have superior desizability to alkali one.

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Preparation of some starch ethers using the semi-dry state process

Cited by 32 publications

References 25 publications

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Evaluation of Some Starch Derivatives Containing Amide Groups as Flocculants

Desizability of the Grafted Starches Used as Warp Sizing agents

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