The blended pellets were processed by injection molding according to ASTM standards, and the molded samples were evaluated for their mechanical properties. The inclusion of fiberglass significantly improved the mechanical performance of the Nylon-6 composites. Additionally, the impact of process torque was investigated by comparing the high specific torque of the Mega 40 system with the lower specific torque of the Mega 50 system, while maintaining a constant production rate of 450 kg/h.

The fiber dispersion and the fiber-matrix interface morphology of the developed composites were analyzed using scanning electron microscopy (SEM), which further confirmed the results of the mechanical tests.

Polymer composites reinforced with glass fibers are widely used to improve mechanical properties such as tensile strength, bending strength, and impact resistance. The performance of these composites is heavily influenced by the degree of fiber dispersion, distribution, and orientation achieved during melt compounding. These parameters, in turn, are highly dependent on the screw mixing elements and the processing conditions used during extrusion.
Nylon-6 is a semi-crystalline engineering polymer known for its high chemical resistance, excellent mechanical properties, including high strength and abrasion resistance, and moderate processability. These characteristics make nylon-6 a suitable candidate for fiberglass reinforcement to
produce high-performance engineering thermoplastic composites.

Modern problems of the Nylon-6/glass fiber composite extrusion process
Processing of glass fiber reinforced Nylon-6 by extrusion is associated with a number of problems that can negatively affect the final characteristics of the composite.
The main problems that arise during conventional twin-screw extrusion include:

• Fiber abrasion due to high shear:
• Higher screw rotation rates and increased shear rates lead to excessive fiber breakage, reduced fiber aspect ratio, and consequently reduced mechanical strength.
• Increased melt viscosity at higher fiberglass loading: As the reinforcement percentage increases, the melt viscosity increases significantly, resulting in poor flow properties and additional processing energy.
• Insufficient wetting of the fiber matrix: Poor interfacial bonding between nylon-6 and fiberglass leads to fiber stretching, surface roughness, and void formation in the composite faces.

Nylon-6 composites reinforced with glass fiber with a content of 30 wt. %, were processed using Mega 40 and Mega 50 twin screw extruders under various torque conditions, and the resulting granules were subjected to injection molding and mechanical
properties were evaluated. The influence of the auger configuration — standard kneading elements, toothed mixing elements and fractional geometry technology (FGT) elements - was systematically studied.

The main conclusions are as follows:

• The composites processed using FGT elements in the Mega 40 extruder demonstrated the highest mechanical characteristics with a tensile strength of 179 MPa, a bending modulus of 9.49 GPa, and a toughness of 12.8 kJ/m2, surpassing the samples processed with standard kneading and gear mixing elements with a capacity of 400 kg/h.
• The Mega 40 extruder with higher specific torque demonstrated lower carbon dioxide emission and higher productivity compared to the Mega 50 extruder with lower specific torque, indicating improved process efficiency.
• The SEM analysis confirmed excellent interfacial adhesion, uniform fiber distribution, absence of voids, and minimal fiber stretching in the FGT-treated composites, indicating improved mechanical properties.