Composite nanoarchitectonics with ionic clay nanofillers-embedded polypropylene for efficient flame retardance

• Published in: Applied clay science 2023-12, Vol.246, p.107181, Article 107181
• Main Authors: Ryu, Hyeon-Ju, Lee, Ji-Hee, Choi, J. Yoon, Choi, Goeun, Rejinold, N. Sanoj, Choy, Jin-Ho
• Format: Article
• Language: English
• Subjects: Flame retardant; Ionic clays; Mechanical strength; Organo-clays; PP (Polypropylene); Thermal stability
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2023.107181

The widely used flame-retardants (FRs) are of brominated ones with hazardous characteristics. Therefore, developing an eco-friendly FRs is important to maintain the safety upon large scale usage. Such a flame retardant was made using polypropylene (PP) by integrating ionic nanofillers ((layered double hydroxide, LDH; and cationic clay (Mica)) together. They were modified with stearate (SA) and cetyltrimethylammonium (CTA) respectively to be compatible with PP. For this, initially they were separately made by co-precipitation and ion-exchange reactions, then dispersed in xylene together and mixed with PP/xylene. The SA-LDH content was 1 wt% and CTA-Mica ∼3 wt%. TEM showed that exfoliated 2D organo-clays were uniformly dispersed in PP nanocomposites enhancing thermo-mechanical strength than pristine PP. The peak heat release rate (PHRR) of pristine PP was decreased by SA-LDH and CTA-Mica, corresponding to 58% reduction. Additionally, for PP nanocomposites, more char residues were remained; suggesting that PP nanocomposite as an efficient FRs. A poly propylene composite containing cationic and anionic clays were developed by incorporating sodium stearate-LDH (cationic clay) and citric acid-Mica (anionic clay) in to it, effectively reducing the thermo-oxidative process thereby enhancing the flame retardancy. [Display omitted] •Integration of ionic clay-nanofillers into poly propylene for enhanced thermo-mechanic properties.•For this, anionic LDH and cationic Mica were organo-modified to be compatible with polypropylene.•The PHRR of pristine polypropylene was decreased by LDH and Mica, corresponding to 58% reduction.•The integration of ionic clay nanofillers enhanced both mechanical and flame retardancy.