Water resistance, thermal stability, and flame retardation of polypropylene composites containing a novel ammonium polyphosphate microencapsulated by UV-curable epoxy acrylate resin: WATER RESISTANCE AND FLAME RETARDATION OF PP COMPOSITES

Microplastic label in microencapsulation field - Consequence of shell material selection

Plastics make our lives easier in many ways; however, if they are not appropriately disposed of or recycled, they may end up in the environment where they stay for centuries and degrade into smaller and smaller pieces, called microplastics. Each year, approximately 42000 tonnes of microplastics end up in the environment when products containing them are used. According to the European Chemicals Agency (ECHA) one of the significant sources of microplastics are microcapsules formulated in home care and consumer care products. As part of the EU's plastics strategy, ECHA has proposed new regulations to ban intentionally added microplastics starting from 2022. It means that the current cross-linked microcapsules widely applied in consumer goods must be transformed into biodegradable shell capsules. The aim of this review is to provide the readers with a comprehensive and in-depth understanding of recent developments in the art of microencapsulation. Thus, considering the chemical structure of the capsule shell's materials, we discuss whether microcapsules should also be categorized as microplastic and therefore, feared and avoided or whether they should be used despite the persisting concern.

Flame Retardant Polypropylenes: A Review

Polypropylene (PP) is a commodity plastic known for high rigidity and crystallinity, which is suitable for a wide range of applications. However, high flammability of PP has always been noticed by users as a constraint; therefore, a variety of additives has been examined to make PP flame-retardant. In this work, research papers on the flame retardancy of PP have been comprehensively reviewed, classified in terms of flame retardancy, and evaluated based on the universal dimensionless criterion of Flame Retardancy Index (FRI). The classification of additives of well-known families, i.e., phosphorus-based, nitrogen-based, mineral, carbon-based, bio-based, and hybrid flame retardants composed of two or more additives, was reflected in FRI mirror calculated from cone calorimetry data, whatever heat flux and sample thickness in a given series of samples. PP composites were categorized in terms of flame retardancy performance as Poor, Good, or Excellent cases. It also attempted to correlate other criteria like UL-94 and limiting oxygen index (LOI) with FRI values, giving a broad view of flame retardancy performance of PP composites. The collected data and the conclusions presented in this survey should help researchers working in the field to select the best additives among possibilities for making the PP sufficiently flame-retardant for advanced applications.

Synergistic Effects of Two-Dimensional MXene and Ammonium Polyphosphate on Enhancing the Fire Safety of Polyvinyl Alcohol Composite Aerogels

Fire and smoke suppressions of polyvinyl alcohol (PVA) aerogels are urgently required due to the serious fire hazard they present. MXene, a 2D transition-metal carbide with many excellent properties, is considered a promising synergist for providing excellent flame retardant performance. PVA/ammonium polyphosphate (APP)/transition metal carbide (MXene) composite aerogels were prepared via the freeze-drying method to enhance the flame retardancy. Thermogravimetric analysis, limiting oxygen index, vertical burning, and cone calorimeter tests were executed to investigate the thermal stability and flame retardancy of PVA/APP/MXene (PAM) composite aerogels. The results demonstrated that MXene boosted the flame retardancy of PVA-APP, and that PAM-2 (with 2.0 wt% MXene loading) passed the V-0 rating, and reached a maximum LOI value of 42%; Moreover, MXene endowed the PVA-APP system with excellent fire and smoke suppression performance, as the the peak heat release rate and peak smoke production rate were significantly reduced by 55% and 74% at 1.0 wt% MXene loading. The flame retardant mechanism was systematically studied, MXene facilitated the generation of compact intumescent residues via ita catalyst effects, thus further restraining the release of heat and smoke. This work provides a simple route to improve the flame retardancy of PVA aerogels via the synergistic effect of MXene and APP.

An efficient method to improve simultaneously the water resistance, flame retardancy and mechanical properties of POE intumescent flame-retardant systems

The water resistance, flame retardancy and mechanical properties of POE intumescent flame-retardant systems were improved simultaneously.