Preparation of methacrylic acid modified microcrystalline cellulose and their applications in polylactic acid: flame retardancy, mechanical properties, thermal stability and crystallization behavior

Tao Zhu, Jia Guo, Bin Fei, Zhengyu Feng, Xiaoyu Gu, Hongfei Li, Jun Sun, Sheng Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)

Abstract

Microcrystalline cellulose (MCC) extracted from bamboo powder was used as bio-based carbon source in intumescent system. Before using, MCC was modified with methacrylic acid (MA) by grafting polymerization to prepare MA-MCC, which may improve both the dispersibility and compatibility of in/with polylactic acid (PLA). MA-MCC, together with ammonium polyphosphate, was blended into PLA by melt compounding. The flame retardant properties of the composites were characterized by the limiting oxygen index (LOI), UL-94 vertical burning test and cone calorimeter test. The results showed that the LOI of PLA composite sample containing 3% MA-MCC and 7% APP could reach up to 26.8% and pass V-0 rating in UL-94 test. The addition of APP and MA-MCC could also decrease the peak heat release rate from 556 kW/m2 of neat PLA to 456 kW/m2 and form a continuous, dense, homogeneous residue char to prevent PLA from further burning. Thermogravimetric analysis showed that the presence of APP and MA-MCC could enhance the thermal stability of the composites, which is also essential for the improvement of fire performance. The mechanical properties of PLA composites were also improved with the unnotched impact strength increased to 8.16 kJ/m2 and Young’s modulus increased to 1612.8 MPa. The possible mechanisms for the improvement of flame retardancy and mechanical properties had also been proposed.

Original languageEnglish
Pages (from-to)2309-2323
Number of pages15
JournalCellulose
Volume27
Issue number4
DOIs
Publication statusPublished - 1 Mar 2020

Keywords

  • Flame retardancy
  • Microcrystalline cellulose
  • Polylactic acid
  • Toughness

ASJC Scopus subject areas

  • Polymers and Plastics

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