TY - JOUR A1 - Sunder, S. A1 - Jauregui Rozo, Maria A1 - Inasu, S. A1 - Schartel, Bernhard A1 - Ruckdäschel, H. T1 - Investigating the changing dynamics of processing, temperature-based mechanics, and flame retardancy in the transfer of ammonium polyphosphate/inorganic silicate flame retardants from epoxy resins to glass fiber composites N2 - Although numerous investigations study the improvement of flame retardancy of epoxy resins using additives, maintaining the flame retardant (FRs) modes of action present in the resins upon transfer to composites is challenging. In this study, ammonium polyphosphate (APP) and inorganic silicate (InSi) are loaded at 10%, 30%, and 50% by weight, in a diglycidyl ether of bisphenol A (DGEBA) resin cured with dicyandiamide and transferred to bidirectional (BD) glass fiber (GF) composites. Although a 50% loading of the FRs impacts the curing kinetics of the resin system, the effect on the glass transition temperature of the resin system remains negligible compared to reactive FRs in the state of the art integrated into the resin's chemical structure. Increasing the FR content improved the heat release characteristics in both the resins and composites. However, the charring mode of action is completely suppressed in the formulation with 10% APP + InSi. A 30% concentration of the FRs restored the charring action in the composite and the GFs provide increased protective layer action upon transfer to the composites. This study highlights the importance of accounting for the changing dynamics related to processing and flame retardancy upon transferring FRs from resins to composites. KW - Composites KW - Flame retardance KW - Resins KW - Synthesis and processing techniques PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610484 DO - https://doi.org/10.1002/app.55988 SN - 1097-4628 VL - 141 IS - 39 SP - 1 EP - 18 PB - Wiley CY - New York, NY AN - OPUS4-61048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sanchez-Olivares, Guadalupe A1 - Brehme, Sven A1 - Calderas, F. A1 - Schartel, Bernhard T1 - Flame Retardant Polyolefins Using Fibers From Leather Waste: Adjusting Extrusion Variables to Balance the Property Profile N2 - The extrusion processing variables represent a key to the optimal use of additives and thus the development of flame-retardant polymer composites. Adjusting the property profile, for example, finding a balance between flame retardancy and mechanical properties is the main challenge. In this work, the effect of blending temperature and rotational speed on physico-mechanical properties and fire behavior of polyolefin composites was investigated. High-density polyethylene or polypropylene was used as polymer matrices; the polymers were compounded by the extrusion process using industrial-waste leather fibers as flame retardant adjuvant and commercial flame-retardant additives. A detailed rheological analysis highlighted different viscoelastic behavior, that is, a predominant elastic or viscous one. The effect of the extrusion processing variables was also investigated on the morphology, mechanical properties, thermal decomposition, fire behavior under forced flaming combustion and flammability. Important improvements were revealed with respect to using only high loading of flame retardants. For high-density polyethylene-based composites, impact resistance and elongation at break increased 8 and 7.5 times, respectively. The total heat evolved (87MJ/m2), effective heat of combustion (31.6MJ/kg), flame retardancy (UL 94 rating) results were comparable with the reference sample. Meanwhile for polypropylene composites, the impact resistance increased 2.2 times and the flame retardancy was improved from no rating in the UL 94 vertical test to V-0 rating. Tailored processing was highlighted as an autonomous and powerful approach to achieve balanced and demanding properties. KW - Biomaterials KW - Composites KW - Extrusion KW - Flame retardance KW - Leather waste KW - Polyolefins PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656732 DO - https://doi.org/10.1002/vnl.70048 SN - 1548-0585 SN - 1083-5601 VL - 32 IS - 2 SP - 410 EP - 430 PB - Wiley Periodicals LLC. AN - OPUS4-65673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -