The study examined the influence of processing parameters, mechanical characteristics, fire resistance, and the morphology of mixtures using both fractional geometry technology (FGT) and conventional screw designs.

This is the main cause of thermal degradation in LLDPE/EVA/ATH/MDH systems. The results showed that the use of halogen-free flame retardants improved the relative elongation at break and the ultimate oxygen index (LOI) when processed using an Omega 70 mm extruder that supports fractional geometry technology. In addition, the fractional geometry processing showed lower specific mechanical energy (SME) and
lower melt temperature compared to standard screw configurations, indicating increased process efficiency and improved material stability.

Since then, however, their role as functional additives, especially
as flame retardants, has been widely accepted. Halogen-free flame retardant (HFFR) formulations require large amounts of micronized metal hydroxide fillers – typically more than 50 wt% – to achieve adequate fire-extinguishing performance.

Polyethylene (PE) and polyvinyl chloride (PVC) are widely used as insulating materials in electrical cables. Polyethylene medium-density (MDPE) and polyethylene high-density (HDPE) have excellent environmental cracking resistance, high mechanical strength, low abrasion levels, good barrier properties, and high UV resistance. However, halogen-free polyolefin systems require the inclusion of inorganic flame retardant, such as aluminum hydroxide (ATH) and magnesium hydroxide (MDH), to meet regulatory fire safety standards. PVC, although easy to process, poses significant environmental and health concerns as it releases
corrosive and toxic gases when burned. On the contrary, halogen-free non-combustible polyolefin flame retardant produce minimal smoke and do not release hazardous gases during combustion, making them more suitable for use in cables that meet environmental requirements.

The installation of cables, often arranged in bundles or vertical stacks, poses a significant risk of fire spread. In high-rise buildings, more than 80% of fire-related fatalities are caused by smoke inhalation and exposure to toxic gases, rather than direct contact with flames. Therefore, the development of fire-resistant cable insulation materials with improved fire-fighting capabilities is crucial for enhancing fire safety and reducing life-threatening hazards.
Metal hydroxides are currently the most widely used non-halogenated fire retardant fillers. Among them, aluminium trihydrate (ATH, Al(OH)₃) and magnesium hydroxide (MDH, Mg(OH)₂) account for the largest global consumption due to their availability, cost-effectiveness, and proven fire-extinguishing capabilities.