Tga 701

Proximate and ultimate analysis was performed for each sample by measuring the water and ash content, combustion heat and elemental composition.
The moisture content was determined by Thermogravimetric analyzer LECO TGA701 where 1 g of each sample was dried at a temperature of 105 °C until the weight became constant.
The ash content was also determined by Thermogravimetric analyzer LECO TGA701 where 1 g of each sample was heated with increased oxygen concentrations up to temperature of 550 °C until the weight became constant.
Combustion heat was measured by an isoperibolic calorimeter LECO AC600 by controlled combustion in a bomb under high pressure of 3 MPa at a reference temperature of 28 °C. Stainless steel cups were used for the material placement and cotton thread for ignition. The device was calibrated with benzoic acid.
The element composition was measured with an elemental analyzer LECO CHN628 + S using the LECO instrumental combustion method for biomass. To determine the C, H and N values, a 0.1 g of each sample was burned in oxygen at the temperature of 950 °C. The analyzer was calibrated with ethylenediaminetetraacetic acid, rice and rye flour. Oxygen was determined as a difference in the dry sample.

The thermal stability of film samples was evaluated using a thermogravimetric analyzer (Leco TGA701; Leco, St Joseph, MI, USA). About 25 mg of film sample was taken in a standard aluminum cup and heated from 25 to 600 °C with a heating rate of 12 °C/min under a nitrogen flow (50 cm³/min). An empty cup was taken as a reference. The derivative form of TGA (DTG) was obtained by calculating the differentials of the TGA values using a central finite difference method as follows:
$\mathrm{DTG}=\frac{(W_{t+\Delta t}-W_{t+\Delta t})}{2\Delta t}$
where W_t+Δt − W_t−Δt are the residual weight of sample at time t + Δt and t − Δt, respectively, and Δt is the time interval for reading the residual sample weight [32 (link)].

Citric acid, (Tianjin Bodi Chemical Co., Ltd., Tianjin, China); corn starch, food grade, (Zhuhai Jindu Tide Food Co., Ltd., Zhuhai, China); glycerol, analytical pure, (Wuxi Yatai United Chemical Co., Ltd., Wuxi, China); polyvinyl alcohol (Shanghai Yingjia Industrial Chemical Co., Ltd., Shanghai, China); distilled water, (laboratory homemade).
DZKW-D-1 electric heating thermostatic water bath (Zhengzhou North and South Instrument Co., Ltd., Henan, China); FA2204B analytical balance (Guangzhou Ruiming Instrument Co., Ltd., Guangzhou, China); TWCL-T electronic thermostat (Shanghai Branch equipment Co., Ltd., Shanghai, China); JJ YZG/FZG vacuum dryer (Changzhou Nile Drying Equipment Co., Ltd., Changzhou, Jiangsu, China); WDW-20 computer controlled electronic universal testing machine (Beijing Dana Machinery Co., Ltd., Beijing, China); CH-1-B hand count (Shanghai music magnetic instrument company, Shanghai, China); Thermogravimetric analyzer (Leco TGA 701; Leco, St Joseph, MI, USA); FE-SEM (LINE No. 337, 338, S-4800) [Hitachi Co., Ltd., Matsuda, Japan]; ATR FT-IR, (Billerica, MA, USA).