Accumulation of industrial waste is a serious environmental problem, which lead to air and water pollution. Addition of industrial waste in polymer composites as reinforcement can enhance the various properties. To overcome this issue, an attempt has been made to investigate mechanical, tribological and water absorption behaviour of industrial waste (red mud) based sisal/glass fiber reinforced hybrid composites and also no research has been done on this. In this work, prepared the composite specimens using sisal fiber (35, 30, 25 and 20 wt%), red mud (0, 5, 10 and 15 wt%) through hand layup technique. In addition to this, glass fiber (5 wt%) and polyester matrix (60 wt%) are kept as constant. From the results, it is observed that, enhanced mechanical properties, minimum wear behaviour and good water resistance were observed on 30 wt% of sisal fiber and 5 wt% of red mud filled composite and recommending this material for marine applications due to good water resistance in sea water. Morphological analysis shows fiber breakages, voids, wear debris, minor cracks, voids and delamination.

The mechanical, thermal, and morphological analysis of red mud filled sisal/glass fiber–reinforced polyester composites have been investigated. In this study, four composite specimens were prepared through hand layup technique by changing the weight percentage of sisal fiber and red mud. Weight percentage of glass fiber and polyester resin are kept constant. The fabricated composite specimens were subjected to mechanical properties such as hardness, impact and tensile behavior, thermal, and morphological analysis. From the results, it is observed that, maximum tensile strength of 45.6 MPa was obtained for C1 specimen. Maximum hardness and impact strength of 85.67 and 391.5 J m⁻¹ was achieved for C2 specimen. In TGA study, C1 and C2 specimen exhibited 85 % of weight loss with the temperature ranges from 300 °C to 400 °C. From SEM analysis, good bonding between fiber and matrix, voids, fiber breakages, fiber pullout, delamination, rich matrix area, poor adhesion between fiber and matrix, poor arrangement of fibers, interlinked fibers, and crack propagation were observed. Based on the results, C2 specimen which contains 30 wt% of sisal fiber and 5 wt% of red mud is performed well than other composites and it is suitable for various applications such as marine, automobile, and aeronautical.

Composite materials with high compressive, flexural, and shear strength are essential for constructing various structural elements in automotive, aerospace, marine, and construction sectors. The present research aims to create bauxite residue filled sisal/glass fiber reinforced polyester composites. The different weight percentages of sisal fiber (35 %, 30 %, 25 %, and 20 %), red mud (0 %, 5 %, 10 %, and 15 %), glass fiber (5 %), and polyester matrix (60 %) were used to fabricate composites. The combined use of compression molding and hand layup technique was employed in the creation of composite materials due to its frequent utilization in the manufacturing of large-scale components found in various sectors, including automotive, aerospace, marine, and construction. In this work, investigated the physical, compressive, flexural and v notch rail shear strength of the fabricated composites. Results revealed that the composites with 30 % of sisal fiber and 5 % of red mud has the highest compressive, flexural, and v notch rail shear strength of 83.45 MPa, 182.74 MPa, and 10 MPa, respectively. Further, this composite showed high density, less void content, and less thickness swelling than other composites. According to the outcomes, this composite material demonstrates suitability for various structural applications across automotive, aerospace, marine, and construction sectors.

In response to the rising demand for sustainable engineering materials and waste valorisation strategies, this study investigates the multi-objective optimisation of eco-friendly hybrid composites reinforced with natural fibres and industrial waste. Sixteen composite specimens were fabricated using compression moulding by varying sisal fibre from 0 to 45 wt.%, banana fibre from 0 to 45 wt.%, NaOH alkali treatment from 0 to 6%, and red mud filler from 1 to 4 wt.%. Mechanical properties were evaluated following ASTM standards D256 for impact strength, D790 for flexural strength, D638 for tensile strength, D5379 for shear strength, and E18 for hardness. The Taguchi method combined with grey relational analysis was employed to identify optimal processing conditions. The best mechanical performance, with an impact strength of 6.57 J, flexural strength of 72.58 MPa, and tensile strength of 65.52 MPa, was achieved with 30 to 45 wt.% sisal fibre, 15 wt.% banana fibre, 6% NaOH, and 3 to 4 wt.% red mud. ANOVA revealed that NaOH treatment had the most significant influence on mechanical properties, with high F values and p values close to 0.05. Grey relational analysis proved more effective for multi-objective optimisation, with the highest grey grade of 0.894 observed in the specimen containing 45 wt.% sisal fibre, 6% NaOH, and 2 wt.% red mud. These findings highlight the critical role of fibre treatment and hybrid reinforcement in enhancing performance. The optimised composites demonstrate strong potential for use in automotive interior panel applications, offering a sustainable alternative with balanced strength and reduced environmental impact.

The aim of this work is to study the effect of chitosan on mechanical and thermal properties of aloe vera fiber reinforced composites. In this work, we have fabricated the five different composites namely pure polyester composite (SP), pure aloe vera fiber composite (S0), 1 wt.% of chitosan filled aloe vera fiber composite (S1), 3 wt.% of chitosan filled aloe vera fiber composite (S3), and 5 wt.% of chitosan filled aloe vera fiber composite (S5) through simple hand layup method and investigated the mechanical and thermal properties. From the results, it is concluded that, 3 wt.% of chitosan filled aloe vera fiber reinforced composite was performed well in all the testing and it is suitable for various engineering applications such as automobile, aeronautical and marine. SEM analysis shows good adhesion behavior between fiber and matrix with the addition of chitosan. Further, 3 wt.% of chitosan can be added in natural fiber based polymer composites to enhance mechanical properties of the composites.