Effect of low temperatures on polymorphic structures of cotton cellulose

Jung, H. Z.; Benerito, Ruth R.; Berni, Ralph J.; Mitcham, Donald

doi:10.1002/app.1977.070210724

Cited by 23 publications

(10 citation statements)

References 4 publications

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“…Regarding the crystalline structures of cellulose, they are classified into four crystallization types, viz. cellulose I, II, III, and IV, and their crystalline structures can be transformed from one type to another 19. Figure 4 shows the X‐ray diffraction pattern of the pure BC and BC/collagen composite.…”

Section: Resultsmentioning

confidence: 99%

Bacterial cellulose/collagen composite: Characterization and first evaluation of cytocompatibility

Cai

Yang

2011

J of Applied Polymer Sci

131

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The novel bacterial cellulose (BC)/collagen composites were prepared by immersing wet BC pellicle excreted by Acetobacter xylinum in collagen solution followed by freeze-drying process. The product looks like a foam structure. The morphology of BC/collagen composite was examined by scanning electron microscope (SEM) and compared with pristine BC. SEM images showed that collagen molecules was not only coated on the BC fibrils surface but also could penetrate inside BC and hydrogen bond interactions were formed between BC and collagen. The prepared BC/collagen composite was also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and mechanical test. With the incorporation of collagen in the BC, no changes happened in the crystal structure but the thermal stability was improved. Tensile test results indicate that the Young's Modulus and tensile strength have a big increase while the elongation at break has a slight decrease. The cytocompatibility of composite was preliminarily evaluated by cell adhesion studies. The tests were carried out using 3T3 fibroblast cells. The cells incubated with BC/collagen scaffolds for 48 h were capable of forming cell adhesion and proliferation. It showed much better cytocompatibility than pure BC. So, the prepared BC/collagen scaffolds are bioactive and may be suitable for cell adhesion/attachment suggesting that these scaffolds can be used for wound dressing or tissue-engineering scaffolds. Therefore, these results suggest that these novel BC/collagen scaffolds may have the potential to be sued for some biomedical applications.

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Section: Resultsmentioning

confidence: 99%

Bacterial cellulose/collagen composite: Characterization and first evaluation of cytocompatibility

Cai

Yang

2011

J of Applied Polymer Sci

131

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“…The crystalline structure of cellulose is classified into four types, namely cellulose I, II, III, and IV. Their crystalline structures are able to transform from one to another type. , Figure a shows the X-ray diffractograms of cellulose pulp and cellulose regenerated from DMAc/LiCl solvent system. Cellulose pulp exhibited typical cellulose I structure with X-ray diffraction peaks at 15, 16.8, and 23° assigned to (110), (1-10) and (200), respectively .…”

Section: Resultsmentioning

confidence: 99%

Electromechanical Behavior of Room Temperature Ionic Liquid Dispersed Cellulose

Mahadeva

Kim

2009

J. Phys. Chem. C

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The effect of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF 6 ) dispersion on the structure, thermal stability and electromechanical behavior of cellulose was investigated by infrared spectroscopy, X-ray diffraction, thermogravimetry and bending actuation test. Dispersion of BMIPF 6 in cellulose matrix was carried out by solution blending technique. Upon dispersion of 20 wt % BMIPF 6 , the bending displacement of the actuator was enhanced by four times as compared to that of pristine cellulose. However, BMIPF 6 dispersion resulted in increased amorphous region and reduced its thermal stability of cellulose. This might be due to interruption of cellulose crystallization by entrapment of BMIPF 6 molecules between cellulose layers and weakening of the intra-and intermolecular hydrogen bonds of cellulose. Humidity effect and the durability of the BMIPF 6 dispersed cellulose actuator are discussed.

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“…The degree of conversion to III increases as the temperature is lowered from ambient to as low as liquid nitrogen [ 10], but complete conversion does not occur at atmospheric pressure. At elevated pressures, the degree of conversion of I to III is increased.…”

Section: Resultsmentioning

confidence: 99%

“…These low degrees of conversion to III were obtained on several cotton varieties of various micronaires in the sliver form. Our initial investigations of the effects of temperature on the conversion of I to III by liquid ammonia at atmospheric pressure indicated that the degree of conversion to III increased as the temperature decreased [ 10]. The greatest conversion to III was obtained when liquid ammonia was removed with liquid nitrogen (-196°C).…”

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Conversion of Cellulose I to Stable Cellulose III

Yatsu

Calamari

Benerito

1986

Textile Research Journal

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Cotton cellulose in fiber, yarn, or fabric form was converted from cellulose I to the cellulose III polymorph. Excellent conversion to III was obtained by immersing cotton (cellulose I) in liquid ammonia at room temperature, subjecting it to pressures from 689.5 to 11,721.5 kPa (100 to 1700 psi) while saturated with ammonia, and de-gassing the ammonia at either room temperature or elevated (about 140°C) temperatures. De-gassing at either temperature was equally effective. Complete conversion to III was obtained when cotton fibers from a never-dried cotton boll were dried with dimethoxypropane, treated with liquid ammonia at 140°C and at 11,721.5 kPa, and dried at or above the critical temperature (132.5°C). Crystalline cellulose III obtained under high pressures was stable to boiling water. After several hours in boiling water, there was only a slight indication of its conversion to IV. Complete conversion of III to IV was obtained by first subjecting III to anhydrous ethylenediamine and then to the aprotic polar solvent, dimethylformamide.Formation of complexes between liquid ammonia and cellulose was reported as early as 1936, as were .changes in the crystal structures of cellulose resulting from decomposition of these complexes [2]. Changes in interplanar distances caused by interaction of cellulose I with liquid ammonia at atmospheric pressure and by interactions of cellulose with primary amines, as determined by x-ray diffraction, were reported [4,6,8]. Davis et al. [6] also noted that the interplanar distance, djol, of the product formed when cellulose was treated with ammonia in sealed tubes at 10 atmospheres of pressure differed from that obtained at atmospheric pressure. These findings were of academic interest until the advent of two British patents [9, 17] that described the use of liquid ammonia instead of aqueous NaOH to improve the smoothness of oellulosic fabrics and the strength and luster of cotton sewing threads. The report by Gogek [7] that pretreatment of cotton twill with liquid ammonia improved the washwear ratings and abrasion resistance of subsequently crosslinked fabric aroused the interest of the textile in-' dustry. Immediately, there was increased interest in the treatment of textiles with liquid ammonia [3,5].The degree of conversion of the crystalline lattice of native cotton (I) to cellulose III depends on the manner in which the liquid ammonia is removed [3,9, 17].Partial conversion to III occurs when ammonia is removed by evaporation or by extraction with solvents such as anhydrous acetone or tetrahydrofuran. Quenching of the ammonia-cellulose complex with either water or alcohols causes reversion to I. The literature reports that, at best, liquid ammonia pretreatments result in mixed I and III lattices, while conventional meroerizations result in mixed 1 and II lattices. Lewin and Roldan gave evidence that III is obtained by drying the cellulose-ammonia complex in the absence of water [ 12], but these investigators obtained decrystallization and poor conversion of ...

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Effect of low temperatures on polymorphic structures of cotton cellulose

Cited by 23 publications

References 4 publications

Bacterial cellulose/collagen composite: Characterization and first evaluation of cytocompatibility

Bacterial cellulose/collagen composite: Characterization and first evaluation of cytocompatibility

Electromechanical Behavior of Room Temperature Ionic Liquid Dispersed Cellulose

Conversion of Cellulose I to Stable Cellulose III

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