Thermal stability of poly(diallyldimethylammonium chloride) with different molecular weight

Abstract

The thermal stability of poly(diallyldimethylammonium chloride) (PDMDAAC) with serial molecular weights M_w ranged from 0.2850 × 10⁶ to 1.144 × 10⁶ was determined by TG-DSC. The decomposition activation energy of PDMDAAC, with different molecular weight was from 83.42 to 98.53 kJ/mol in Step I and from 163.63 to 223.68 kJ/mol in Step II, was obtained from TG with different heating rates, using the methods of Coats-Redfern and Ozawa. The evaluated decomposition activation energy E_a of PDMDAAC with M_w of 1.144 × 10⁶ calculated by Ozawa method was 124.1 and 211.1 kJ/mol for each decomposition step, respectively. The results indicated that there were two decomposition steps for polymer PDMDAAC, while there was only one for its monomer DMDAAC. The calculation results by using the Coats-Redfern method indicated that the reaction order for two decomposition steps of PDMDAAC was both one. The E_a increased with the molecular weight of linear PDMDAAC. The thermal characteristic of crosslink products was more stable than the linear product.

Keywords:

• Poly(diallyldimethylammonium chloride)
• molecular weight
• thermal stability
• TG-DSC
• activation energy

Acknowledgments

The authors are thankful for the financial support from the National Natural Science Foundation of China (51503100 and 21377054).

Conflict of interest

The authors declare that they have no competing interests.