Thermal degradation behavior of hypochlorite-oxidized starch nanocrystals under different oxidized levels. (25th June 2015)

• Record Type: Journal Article
• Authors: Wei, Benxi; Li, Hongyan; Tian, Yaoqi; Xu, Xueming; Jin, Zhengyu
• Is Part Of: Carbohydrate polymers. Volume 124(2015)
• Page Start: 124
• Page End: 130
• Publication Date: 2015-06-25
• Subjects: Starch nanocrystal -- Hypochlorite oxidation -- Thermal degradation; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2015.01.081
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Thermal properties of starch nanocrystal were mostly preserved after oxidation. There were adjacent two-step degradation processes for SNC and OSNC. Oxidation induced the increase of char content. Abstract: The thermal degradation behavior of hypochlorite-oxidized starch nanocrystals (OSNCs) was evaluated in this study. Carbonyl and carboxyl groups in OSNCs increased from 0.006 and 0.091 mmol/g to 0.033 and 0.129 mmol/g, respectively, as the active chlorine concentration increased from 1% to 4% (w/w). Compared with starch nanocrystals (SNCs), the initial degradation temperature of OSNCs with 4% oxidization decreased from 273 °C to 253 °C. Two degradation processes were detected using differential thermal analysis. The activation energy of the low-temperature process increased with increasing oxidization level because of removal of sulfate esters and reduction of the decomposition products of H2 O during oxidation. With increasing temperature, the H2 O generating from decarboxylation and decomposition of the carboxyl groups may catalyze SNCs depolymerization, leading to decrease in the activation energy of the high-temperature process. OSNCs (4% oxidized level) can be used in dry process below 253 °C to avoid degradation.