Phase transitionbehavior of NaCMC, PLys and CMC-PLyscomplex films in the presence of various amounts of water is measured by a DSC.Cooling and heating rates are 10 oC/min, sample weight of 3-5 mg in a sealed type aluminum vessel. For the measurement ofsamples containing sorbed water, a small amount of pure water is added using amicrosyringe. The water content (Wc, g/g) is calculated by the followingequation 1 20. Water content,Wc (g/g) = mass of sorbed water/ mass of dry sample (1) RachtanapunP et al. (2011) Synthesize and characterize carboxymethyl cellulose powder obtainedfrom Mimosa pigra. The effects of various NaOH concentrations on the degree of substitution, viscosity and thermalof carboxymethyl cellulose are also investigated.
Thermal properties are studied using DSC. The results obtainedrevealed that the melting point of the samples decreases as the percentage of NaOHis increased 21.Effect of various NaOH concentrations onthermal properties of CMC powderThe effectsof various NaOH concentrations on the thermal property of cellulose from Mimosapigra peel and CMCm powder are determined by differential scanning calorimetry.The melting temperature (Tm) of cellulose (Mimosa pigra pulp) is 107.
3 oC, and CMCm synthesized with 30, 40, 50, and 60% NaOH was 114.5, 106.7,98.3, and 98.1 oC, respectively. The melting temperature of carboxymethylcellulose obtained from mimosa (CMCm) slightly decreases as the level of NaOHincreased.
While the %NaOH in the alkalization reaction increases, thesubstitution of carboxymethyl group also increases.The change in melting temperature results from the interference withcrystallinity is caused by the presenceof random irregularities produce by the somewhat bulky side groups from carboxymethylgroup 21.Akram M.et al. (2016) identify the thermal behaviorof plain CMC and to characterize the resulting by-products resulting frompyrolysis processes.
The pyrolytic behaviorof the plain CMC at low temperature ranges between 260 and 300 oC.By preliminary experiments conducted using differential scanning calorimetry todefine the temperature range necessary for the process. Results of DSC undertemperature ramp-up conditions present inFigure 3 shows an endothermic peak indicating the loss of water content inthe range of 45-160 oC.
Further, two overlapping exothermic peaksare depicted at 284 and 304 oC revealing the splitting off of variousfunctional groups along with the decomposition of the cellulose chain and itssubsequent carbonization. The first exothermic peak coincides with thedecomposition process while the second is caused by the breaking down of thedecomposition products (acetic acid and various volatile organic matters) 22.