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There is a growing drive in replacing conventional non-renewable fibres such as glass and carbon reinforced composites with more sustainable and renewable reinforcements such as flax, hemp, jute in biobased composites in key industry sectors such as automotive, marine, building and construction motivated by lower carbon footprint and sustainability. Despite this drive, flammability characteristics of these sustainable biobased composites are not fully understood. Through an up-to-date review, this article meticulously discusses the theme of bio-based and eco-friendly flame retardants (FRs), delving into their intricate mechanisms, flammability testing methodologies, and emerging research trends. It underscores the pivotal necessity of developing tailor-made eco-friendly FRs customised for a diverse range of materials to bolster fire safety in sustainable material applications. Furthermore, it illuminates the limitations associated with prevalent methods for assessing flammability and advocates for advancements in dynamic testing and multi-scale analyses to more accurately simulate real-world fire scenarios. This review also highlights the key characteristics of natural plant fibres and their composites critical for the development of sustainable and fire safe materials for key applications areas. Additionally, it highlights the diverse spectrum of strategies employed in the realm of flame-retardant materials research, emphasizing a pronounced shift towards eco-friendly alternatives, innovative coatings, and the ongoing exploration of synthetic biopolymers, nanocomposites, and fibres in the pursuit of heightened fire safety. Amidst the inherent challenges, this comprehensive review unequivocally underscores the pivotal role of interdisciplinary research collaboration in driving forward fire safety within the domain of sustainable materials. [ABSTRACT FROM AUTHOR]

This article investigates the effect of multiphase fiber system based on plain weave woven fabrics and chopped short fibers in glass/epoxy composite laminates on low‐velocity drop weight impact and quasi‐static tensile after impact (TAI) behaviors. In this regard, glass/epoxy composites with two stacking sequences (intercalated and sandwich‐like lay‐ups) were tested and compared with homogeneous standard composites fabricated with either only woven or only chopped fibers. In all the samples with multiphase fiber system, the amount of woven and chopped glass fibers were equal (4 layers and 3 layers, respectively), while stacking sequences were different. This enabled us to investigate the associated influences of fiber architecture and stacking sequence on low‐velocity drop weight impact and TAI behavior of the glass/epoxy composite laminates. All the glass/epoxy samples were impacted at four various impact energy levels, particularly 2, 4, 6, and 8 J. Results depicted that fiber architecture and stacking sequence played a vital role in low‐velocity drop weight impact and TAI behavior (i.e., damage degree, absorbed energy, peak contact force, residual deformation, residual tensile strength, displacement to ultimate failure, and failure profile) of the glass/epoxy samples. The results depicted that the sandwich‐like lay‐up configuration presented superior impact properties and damage tolerance capabilities at low impact energies (up to 4 J). On the contrary, intercalated lay‐up arrangement suited better to withstand widespread damage generated by higher impact energy levels (6 and 8 J), because they enabled a more efficient redistribution of low‐velocity impact damage in the composite. POLYM. COMPOS., 40:1450–1462, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

This article investigates the compressive response of damaged glass/epoxy composite laminates repaired using hybrid external patches. Hybrid external patches based on glass and Kevlar woven fabrics bonded on both faces of the damaged parent laminate were considered. Five different kinds of plain weave woven fabrics with a different ratio between glass and Kevlar fibers (100/0, 75/25, 50/50, 25/75, and 0/100) were used as the external patches. The intention of using these hybrid patches is to build up a patch of optimum stiffness that facilitate to restrict the critical adhesive or cohesive failure on the joints unlike high stiff glass fibers or extensive fiber micro‐buckling of the external patches unlike low stiff Kevlar fibers under compression loading and consequently to produce repaired laminates with a strain to failure and residual strength nearly close or similar as that of virgin or normal components. The virgin and damaged specimens were taken as the reference specimens for comparison of residual mechanical properties and damage mechanisms. Damage evolution and the failure progression of the repaired glass/epoxy specimens were monitored using real‐time Acoustic Emission (AE) monitoring technique. Specimens repaired with the equal volume fraction of glass and Kevlar fibers in the external patches presented the most favorable residual compressive response by effectively releasing the stress concentration in the damaged area. POLYM. COMPOS., 39:1922–1935, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]