Differential thermal analysis cellulose

Thermal Properties. The thermal stabiUty of cellulose esters is deterrnined by heating a known amount of ester in a test tube at a specific temperature a specified length of time, after which the sample is dissolved in a given amount of solvent and its intrinsic viscosity and solution color are deterrnined. Solution color is deterrnined spectroscopically and is compared to platinum—cobalt standards. Differential thermal analysis (dta) has also been reported as a method for determining the relative heat stabiUty of cellulose esters (127). 

Tang, W. K., H. W. Eickner. Effect of Inorganic Salts on Pyrolysis of Wood, Cellulose, and Lignin Determined by Differential Thermal Analysis FPL Research Paper 82, U.S.D.A., 1967. 

Ramiah, M.V. (1970). Thermogravimetric and differential thermal analysis of cellulose, hemicellulose, undLligmn. Journal of Applied Polymer Science, 14(5), 1323-1337. 

The acrylonitrile cellulose grafts were examined by differential thermal analysis, solvent extraction and solubility studies. They conclude from their data that the unextractable portion is present mainly in grafted form. 

Fig. 10 shows the thermograms of cellulose in atmospheres of helium and of oxygen, obtained by Tang and Neill. In the helium atmosphere, there is an endothermic dip in the differential thermal analysis curve and a sharp loss of weight in the thermogravimetric analysis curve beginning at about 300°, which denote the pyrolytic reactions. In the oxygen atmosphere, instead of the endothermic dip, there is an exotherm due to oxidation of the pyrolysis products. 

Fig. 10. —Thermograms of Cellulose. [(A) Thermogravimetric analysis in helium (B) differential thermal analysis in oxygen (C) difiFerential thermal analysis in nitrogen.]...

For the treated cellulose, the differential thermal analysis curve starts to rise rapidly at about 220°, with no indication of an endotherm, and the thermogravimetric analysis curve shows a continuous weight-loss, which is accelerated at this temperature, and a relatively large residue is left. 

Figure 3. Differential thermal analysis of untreated wood, cellulose, and lignin run in an oxygen atmosphere.

Figure 14, Differential thermal analysis of wood (top), cellulose (middle), and lignin (bottom) treated with 8% sodium tetraborate decahyarate run in oxygen atmosphere (47).

Previous articles in this Series dealt with etherifications of cellulose, and an atlas on infrared analysis includes spectral data for various cellulose ethers. The preparation and industrial importance of starch ethers have been reviewed. The degree of substitution of cellulose ethers may be determined by differential thermal analysis. Where an endothermic or exothermic peak that is characteristic of the cellulose derivative occurs in the analysis curve, the peak height and area have been shown to correlate with the degree of substitution. 

Figure 8.12 Comparison of torsional braid analysis, differential thermal analysis, and ther-mogravimetric analysis data for cellulose triacetate. The bottom figure shows the twisting of the sample In the absence of oscillations as a result of expansion or contraction of the sample at Tg and T, (35).

H Hatakeyama, K Kubota, J Nakano. Thermal analysis of lignin by differential scanning calorimetry. Cellulose Chem Technol 6 521-526, 1972. 

Figure 21. Differential scanning calorimetry and thermogravimetry of oxygen chemisorption on cellulose char at 118 C. The analysis was carried out on 2.5-mg samples in aluminum pans using a Cohn R-lOO electrobalance and a DuPont calorimeter cell attached to a DuPont model 990 thermal analyzer, and nitrogen and oxygen gas flows (60 mL/min, dried by passing through H2SO4) were rapidly interchangeable for DSC and TG.

Although water is known as a natural plasticizer for many polar polymers such as nylon, polyester resins, and cellulosic polymers, similar behavior for polyacrylamide and poly(acrylamide-co-acrylic acid) has not been investigated. In this study, the effect of water content (and/or thermal history) on the Tg s of acrylamide-based pol3 TOers was studied by Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Thermomechanical Analysis (TMA), and Simultaneous Thermogravimetry - Mass Spectrometry (TG/MS). 

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