Preparation and characterization of chitosan derivatives and their application as flame retardants in thermoplastic polyurethane

Xiaodong Liu; Xiaoyu Gu; Jun Sun; Sheng Zhang

doi:10.1016/j.carbpol.2017.03.011

Preparation and characterization of chitosan derivatives and their application as flame retardants in thermoplastic polyurethane

Carbohydr Polym. 2017 Jul 1:167:356-363. doi: 10.1016/j.carbpol.2017.03.011. Epub 2017 Mar 7.

Authors

Xiaodong Liu¹, Xiaoyu Gu¹, Jun Sun², Sheng Zhang³

Affiliations

¹ State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
² State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: sunj@mail.buct.edu.cn.
³ State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: zhangsheng@mail.buct.edu.cn.

PMID: 28433172
DOI: 10.1016/j.carbpol.2017.03.011

Abstract

Our previous work has demonstrated that chitosan (CS) can be directly used as charring agents. In this paper, efforts were made to further improve the thermal stability and charring ability of CS by reacting with benzaldehyde, salicylaldehyde and hydroxybenzaldehyde respectively to obtain different CS derivatives. CS derivatives in association with ammonium polyphosphate (APP) was then introduced into thermoplastic polyurethane (TPU) to prepare flame retardant TPU composites. The sample containing 18.75% APP and 6.25% salicylaldehyde modified CS (SCS) achieved the maximal limiting oxygen index of 29.5%, passed the V-0 rating and significantly decreased the peak heat release rate from 840.8kW/m² of neat TPU to 206.2kW/m². Thermogravimetric analysis and char morphology observation demonstrated that SCS/APP could promote the char formation to form more intact intumescent char structure. It was proposed that the synergism between CS derivatives and APP might be responsible for the improvement of flame retardancy.

Keywords: Chitosan derivatives; Flame retardancy; Preparation; Thermoplastic polyurethane.