Cross-Linking Modification of Ammonium Polyphosphate via Ionic Exchange and Self-Assembly for Enhancing the Fire Safety Properties of Polypropylene.

Yingtong Pan,Zhonglin Luo,Biaobing Wang

doi:10.3390/polym12112761

Abstract

Modified ammonium polyphosphate (MAPP) was prepared as a novel mono-component intumescent flame retardant (IFR) via the ionic exchange between ammonium polyphosphate (APP) and piperazine sulfonate, which is synthesized by self-assembly using 1-(2-aminoethyl) piperazine (AEP) and p-aminobenzene sulfonic acid (ASC) as raw materials. This all-in-one IFR integrating three functional elements (carbon, acid, and gas source) showed more efficient flame retardancy and excellent smoke suppression as well as better mechanical properties than the conventional APP. The incorporation of 22.5 wt.% MAPP into polypropylene (PP) eliminated the melt dripping phenomenon and passed the UL-94 V-0 rating. The results of the cone calorimetry test (CCT) revealed that the release of heat, smoke, and CO is significantly decreased, demonstrating that this novel IFR endows PP with excellent fire safety more effectively. For PP/MAPP composites, a possible IFR mechanism was proposed based on the analysis of the pyrolysis gas and char residues.

Highlights

With the wide application of polymers in construction, electronics, and other fields, the possibility of polymeric materials being exposed to flames has increased significantly [1]
Most polymeric materials are liable to combust, possessing the characteristics of a high heat release rate [2], improving the fire resistance of polymeric materials is of great significance for diminishing fire hazards and protecting the safety of people’s lives
The intumescent flame retardant (IFR), which is made of an acid source

Summary

Introduction

With the wide application of polymers in construction, electronics, and other fields, the possibility of polymeric materials being exposed to flames has increased significantly [1]. Most polymeric materials are liable to combust, possessing the characteristics of a high heat release rate [2], improving the fire resistance of polymeric materials is of great significance for diminishing fire hazards and protecting the safety of people’s lives. Its further application and development are restricted by its disadvantages, including the inherent flammability, severe dripping behavior, and the release of smoke and toxic gases during combustion [5]. It is significant to improve both its flame retardancy and smoke suppression performance simultaneously. Phosphorus-based (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, APP), nitrogen-based (melamine phosphate, melamine salt of pentaerythritol phosphate kaolinite), mineral-based (aluminum trihydroxide), and carbon-based (graphene) flame retardants have gradually replaced the halogen-containing flame retardants due to their high efficiency, low smoke, and low toxicity [6,7]. The intumescent flame retardant (IFR), which is made of an acid source

Methods

Results

Conclusion