Polyhedral Oligomeric Silsesquioxane (POSS)

Catalog NumberACMA00023495

CategorySilicon Flame Retardant

Purity	0.999
Density	1.26-1.38g/cm³
Application	POSS flame retardant is a silsesquioxane with excellent heat resistance, hydrolysis and weather resistance. Recommended for use in PC and PC alloys, dosage 0.08-0.3%.
Decomposition Temperature	≥450°C
Feature	Chemical and thermal properties are very stable, can withstand high temperatures above 400 °C very low dosage environmentally friendly, no bromine, chlorine, phosphorus can be used for ultra-thin products of 1.6mm or less.
Packaging	25kg/bag
pH	6.4-6.8

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Case Study

Development of Flame-Retardant Polylactic Acid Composites Through the Use of Phosphates Along with Polyhedral Oligomeric Silsesquioxane

Song, Lei, et al. Thermochimica Acta, 2012, 527, 1-7.

This study produced flame-retardant polylactide (PLA) by combining pentaerythritol phosphate (PEPA), melamine phosphate (MP), and polyhedral oligomeric silsesquioxanes (POSS). The IFRPLA/POSS composites underwent flame retardant evaluation through both the Limiting Oxygen Index (LOI) and UL-94 vertical test methods. This study also investigated how POSS affects the thermal breakdown patterns of composites when exposed to air and nitrogen environments.
Key Findings
· IFRPLA with 25 wt% IFR loading showed LOI values at 32.0% which increased from the 20.0% seen in pure PLA. The addition of trisilanolisbutyl-POSS (TPOSS) resulted in superior LOI values and exceptional anti-dripping performance. The material blend with 20 wt% IFR and 5 wt% TPOSS successfully reached UL-94 V0 ratings.
· Researchers employed TG-FTIR analysis to identify the degradation products of IFR and TPOSS and study their effects on PLA thermal degradation. The study revealed that acidic compounds generated by MP or PEPA accelerated PLA's thermal breakdown and substantially decreased flammable gas production. The RTFTIR analysis demonstrated that IFR and TPOSS enhanced PLA's thermal degradation in air by creating thermally stable poly(phosphoric acid) which formed a protective char layer and TPOSS provided additional thermo-oxidative resistance to this char layer.

Effect of Different POSS Particles on the Flame Retardancy of Intumescent Polypropylene Composites

Turgut, Gizem, et al. Polymer Degradation and Stability, 2018, 149, 96-111.

The research evaluated how four kinds of polyhedral oligomeric silsesquioxane (POSS) nanoparticles affected intumescent polypropylene (PP)'s flame retardancy. The four variants examined are aminopropyl isobutyl-POSS (A-POSS), octaphenyl-POSS (OP-POSS), octaammonium-POSS (OA-POSS), and trisulfonate propyl-POSS (TS-POSS). The ratio of ammonium polyphosphate (APP) to pentaerythritol (PER) was maintained consistently, with POSS contents set at 0.5%, 1%, and 3%.
Key Findings
· The PP/IFR system showed increased flame retardancy when POSS nanoparticles were added as demonstrated by mass-loss calorimetry (MLC), limiting oxygen index (LOI), and UL-94 test results. Notably, all POSS types, particularly A-POSS and OA-POSS, slowed the degradation of the protective char layer by promoting the formation of a ceramic coating on its surface. The optimum adjuvant effect of the POSS nanoparticles was observed at the lowest concentration of 0.5 wt%. The combination of OA-POSS and TS-POSS led to the highest UL-94 rating of V0 and LOI values of 29.9 and 32.4, respectively.
· In-line rheological analysis through vertical force measurement indicated that the POSS molecules functioned as plasticizers in the melt, thereby affecting the thermal and mechanical properties. SEM analysis of the fracture surfaces revealed inadequate interfacial interaction between APP and PP, but the dispersion of POSS nanoparticles within the PP matrix appeared consistent and uniform. The yield strengths of the composites were lower than that of pure PP; however, elongation at break and impact strength increased in composites containing A-POSS and TS-POSS.

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