Preparation of nucleotide-based microsphere and its application in intumescent flame retardant polypropylene

- Nucleotide based microsphere (MFA) was prepared by embedding AMP into MF.
- MFA promotes formation of microporous char and improves flame retardant efficiency of PP/IFR.
- PP composites containing 18 wt% IFR/MFA(17:1) achieve LOI 27.0 vol% and the UL-94 V-0 rating.

The toxicity, environmental persistence and bio-accumulation of flame retardant additives have attracted a lot of attentions for several years. People try to develop perfect strategy to achieve green flame retardant materials. Bio-based flame retardants are one of the most environmentally friendly alternatives, but lots of natural resources are thermal unstable. Therefore, it is important and necessary to modify the performance of biological raw materials by using physical or chemical methods to meet the requirements of flame retardant materials. In this paper, biological element-nucleotide was embedded in the backbone of melamine fomaldehyde resin to form a functional microsphere (MFA). The MFA was employed in polypropylene (PP)/intumescent flame retardant (IFR) system to modify its flame retardant performance. The flammability of PP composites was evaluated by using the limiting oxygen index (LOI) and UL-94 vertical burning tests etc. The results showed that PP composites containing 17 wt% IFR and 1 wt% MFA achieves a LOI value of 27.0 and passes the UL-94 V-0 rating, while no less than 25 wt% single IFR is needed to obtain the same UL-94 rating. Furthermore, the MFA delays the time to the peak heat release rate (PHRR) and decreases 65% for PHRR. This paper provides a novel approach for constructing a bio-based IFR system and opens another door for the applications of bio-resources in flame retardant materials meanwhile.

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