Studies concerning the accessibility of different allomorphic forms of cellulose

Ciolacu, Diana; Pitol-Filho, Luizildo; Ciolacu, Florin

doi:10.1007/s10570-011-9620-1

Cited by 51 publications

(29 citation statements)

References 36 publications

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“…41 Nevertheless, the number of network connections can be increased by the addition of a crosslinker, which is a small molecule carrying functional reactive end groups. Table I comprises different crosslinkers [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] used to obtain xanthan networks either in the absence or in the presence of a second polymer. One should note that if the final application is related to biomedical purposes, one must be very careful with unreacted residual crosslinkers.…”

Section: Xanthan Gum Networkmentioning

confidence: 99%

Xanthan gum: A versatile biopolymer for biomedical and technological applications

Petri

2015

J of Applied Polymer Sci

316

189

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Xanthan gum is an extracellular polymer produced mainly by the bacterium Xanthomonas campestris. Traditionally it plays an important role in industrial applications as thickener, emulsion stabilizer and it has been added to water-based drilling fluids due to its pseudoplastic behavior and thermal stability. The structural properties of xanthan in solution can be tuned by the temperature and ionic strength; under high ionic strength or low temperature, xanthan chains are arranged in helical conformation, whereas under low ionic strength or high temperature, xanthan chains are coiled. Xanthan high molecular weight favors the building up of physical and chemical networks, which have been used as carriers for drugs and proteins and as scaffolds for cells. In combination with other polymers xanthan has been applied as excipient in tablets or as supporting hydrogels for drug release applications, particularly due to its acid resistance. The large versatility of xanthan gum opens the possibility for the creation of new architectures and additional applications involving this fascinating polymer. AIMSThe purpose of this review is to report on the applications of xanthan gum in biomedical and technological products over the last ten years, but revisiting the background and the highlights of traditional applications as thickener. The in vivo biodegradability and biocompatibility of xanthan gum are fundamental characteristics that allow its use in biomedical applications. The ability to form networks and acid resistance make xanthan gum, as pure excipient or in combination with other polymers, very attractive as drug carriers. The recent combinations with inorganic particles open a range of new applications.

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Section: Xanthan Gum Networkmentioning

confidence: 99%

Xanthan gum: A versatile biopolymer for biomedical and technological applications

Petri

2015

J of Applied Polymer Sci

316

189

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“…Along with the lignin and hemicelluloses, it is a main component constituting 40-90% of a plant cell wall. Cellulose is a polysaccharide built with a linear chain counting from several hundred to several thousand repeating D-glucose units that are bound together covalently by (1-4) b glycosidic linkages (Ciolacu et al 2012). Transverse hydrogen bonds occurring between chains create a crystallinity structure, due to which cellulose is fermentable in a difficult manner (Yang et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Transformation of Miscanthus and Sorghum cellulose during methane fermentation

et al. 2018

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The purpose of the paper is designation of the changes in the structure of cellulose after the methane fermentation process of Miscanthus and Sorghum harvested during the growing season and afterwards. The percentage and structure of cellulose before and after fermentation were studied. Investigations into changes of the cellulose structure were conducted by the SEC, FT-IR and XRD methods. The average percentage of cellulose after the growing season for Miscanthus varieties was higher and for Sorghum varieties was lower. As a result of the fermentation, the percentage of cellulose for both investigated species harvested in two growth seasons was lower. The degree of polymerisation for the plants harvested after the growing season was lower for the most feedstock. As a result of the fermentation process, the degree of polymerization increased for each of the investigated feedstock. However, crystallinity of cellulose remained at the same level for Miscanthus and decreased for Sorghum. It was shown that changes were different in the cellulose structure of the compared species.

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“…The three stages of decomposition obtained in the 200-500 °C temperature range were associated by Fermoso and Mašek 10 with the decomposition of three biopolymers: hemicellulose (T m = 310 °C), cellulose (T m = 350 °C) and lignin (T m = 395 °C). [11][12][13] In our study, for the coffee grounds (P) containing 35% Arabica coffee and 65% Robusta coffee, we obtained very close values for the T m temperatures associated with the three steps.…”

Section: Experimental Materials Equipment and Measurementsmentioning

confidence: 61%

Thermal Behaviour of Different Types of Commercial Coffee and Resulting Coffee Grounds in Inert Atmosphere. The Influence of Composition (Arabica and Robusta)

Bejenari¹,

Lisă²

2019

Cellulose Chem. Technol.

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This paper aims at analysing the thermal behaviour of six types of commercial coffee and the coffee grounds resulting from their use in a professional DeLonghi coffee machine. The influence of composition (Arabica and Robusta) on the thermal behaviour was thus highlighted for the first time. The obtained results indicate that the degradation occurs in three or four stages, based on the composition. The first stage consists in water removal, which can be found in a percentage of 1 up to 5%. The thermal decomposition of the samples starts at temperatures higher than 230 °C, in the case of both, different coffee types and coffee grounds. By comparatively analysing the temperature values at which the degradation starts, it can be noticed that in all the cases there is an increase in the thermal stability of the coffee grounds with approximately 20 degrees, compared to the coffee types they come from. For coffee grounds originating from coffee that contains 35% Arabica and 65% Robusta, the degradation mechanisms change at temperatures higher than 320 °C, as confirmed by the occurrence of an additional degradation stage, compared to the case of other samples. The obtained DSC curves emphasized the presence of two melting peaks and one crystallization peak, which, according to the specialty literature, indicates the presence of coffee oil.

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Studies concerning the accessibility of different allomorphic forms of cellulose

Cited by 51 publications

References 36 publications

Xanthan gum: A versatile biopolymer for biomedical and technological applications

Xanthan gum: A versatile biopolymer for biomedical and technological applications

Transformation of Miscanthus and Sorghum cellulose during methane fermentation

Thermal Behaviour of Different Types of Commercial Coffee and Resulting Coffee Grounds in Inert Atmosphere. The Influence of Composition (Arabica and Robusta)

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