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1) Cross-Linking of PVOH with Maleic Acid and Succinic Acid Solution. 2) Using Differential Scanning Calorimeter (DSC) to study Thermal Changes.
1) Two masses, 0.5 g and 1.0g of 22,000 MW PVOH solutions were cross-linked with 10 weight percent (0.500 g) maleic acid solution. In 0.5 g of 22,000 MW PVOH solution, 5 ml of water and of 1 drop maleic acid solution was added in addition to 1 drop of phosphoric acid. Also, in 1.0g of 22,000 MW PVOH solution, 8 ml of water, and 2 drops of maleic acid was added.
2) Two masses, 0.5 g and 1.0 g of 100,000 MW PVOH solutions were cross-linked with 5 weight % (succinic acid). 0.5 g was added into 5 ml of milliQ water in addition to 1 drop of succinic acid solution. The second mass, 1.0 g of PVOH was added into 8 ml of milliQ water in addition to 2 drops of succinic acid solution.
Differential Scanning Calorimeter (DSC):
Four chambers of DSC were used, and were labelled as A1, A2, A3 and A4.
In A1, 2.57 mg of (0.5 g 22,000 MW PVOH, with phosphoric acid) was placed. In A2, 2.8 mg of (100,000 MW PVOH, no acid) was placed In A3, 3.22 mg of (0.5 g, 22,000 MW PVOH, no acid)was placed In A4, 2.95 mg of (0.5 g 100,000 MW PVOH, no acid) was placed
DSC is used to study thermal properties. It measures thermal changes: glass transition temperature and Melting point of a sample analyzed.
Fully cross linked PVOH films should be thermally resistant to glass transition and the melting point temperatures, i.e., they do not show the consistent peaks in the DSC spectrum around the glass transition and the melting point temperatures.