An innovation will be recognized as successful only if it satisfies all phases of product development; i.e. from the specification to mass production. Therefore, a cost-effective production by keeping the best possible characteristics is vital in any Industry. Large scale production of polymer fibers with ultrafine morphology is such a challenge to in the field of nanotechnology. The idea proposed here utilizes the versatile electrospinning technology for the preparation of uniform, beadless and ultraviolet light absorbing polycarbonate (PC) nanofibers. The average diameter limits to 114 nm and that too by using most convenient and comparatively less toxic solvent mixture. This method is simple and so far, it is not reported elsewhere. For THF-DMF system a PC concentration of 17 w/v% and for DCM-DMF system a PC concentration of 15 w/v% was found to be the optimum polymer concentration. The average fiber diameter and bead density were very much influenced by the viscosity, conductivity and concentration of the solution used for electrospinning. The PC fibers (PC concentration of 15 w/v % in DCM-DMF system) with lowest average diameter of 114 nm shows excellent ultraviolet absorption, semicrystalline nature, enhanced glass transition temperature and thermal stability.

Natural fibers are promising bio-based materials to use as reinforcements in polymer composites as often more affordable and accessible alternatives to fossil-based fibers, especially because of their superior sustainability. Polyoxymethylene (POM) is a widely used engineering thermoplastic, which has a melting temperature suitable for processing with natural fibers. In this study, such composites consisting of POM and regenerated cellulose fibers have been developed and studied in terms of their mechanical, thermal, tribological and structural properties. Tensile and flexural moduli increased with incorporation of 30 wt% fibers up to 89% and 79% respectively, crystallinity increased as well by a maximum of approx. 11% at 30% fiber content. Furthermore, the specific wear rate was improved for the composite with 10 wt% fibers, showing a decrease of roughly 80%. This study investigates the processing parameters and tribo-mechanical performance of POM-based natural fiber composites as an important route towards future sustainable polymer composites in load bearing applications.

The use of 3D printing technology for manufacturing construction materials is gaining popularity, however, only a few studies have reported the fire behavior of such parts. In this research, the fire properties of 3D printed polylactide acid (PLA) parts with varying infill densities along with the tensile properties were analysed. The results from the fire tests showed that increasing the infill density increased the fuel load, which sustained combustion. Hence, the peak heat release rate and total heat release increased with an increment in infill density percentage. It was also observed that the increasing infill density had no effect on the flammability rating of the parts due to the constant shell thickness used for all the parts. In addition, the tensile strength and ductility of the parts increased with density as a porous part is more susceptible to failure than a solid homogeneous part.

The progressive transition from conventional structural designs to lightweight and more complex structures has led to the increase in the quantity of plastic materials in buildings. However, plastics have a major flaw: their low fire performance characterised by shorter ignition times and higher heat release rates. This has necessitated the incorporation of flame retardants (FRs) in plastics. Nevertheless, not all FRs are environmentally safe, hence, there is an urgent need for the development of sustainable biobased FRs that reduce environmental footprints while simultaneously improving the fire performance of plastics. This article addresses the negative connotation of FRs and reviews the most extensively used biobased FRs in plastics, their preparation (synthesis) and mode of application, performance evaluation as well as the leaching of FRs, and environmental fate. Some interesting observations in the review are the reduction of ignition times of plastics by the addition of FRs due to the rapid volatilisation of samples. In addition, the leaching rate of FRs is found to be higher in finer particles (micro and nanoparticles) compared to larger-sized ones and has the potential to dissolve in humic matter hence endangering the lives of humans and animals.

Thermal, thermo-mechanical and mechanical properties of four different commercially available polyetheretherketones (PEEK) based materials were investigated. PEEK matrix was either modified and/or reinforced with carbon fibres, graphite and/or PTFE. Impact strength was measured at three different temperatures: 25 °C, −100 °C, and −195 °C. At 25 °C, thermal stability and mechanical properties, including the elastic modulus, compression, and impact strength, were enhanced with the addition of carbon fibres. Matrix modification had a minor impact on thermal stability, while the mechanical properties decreased, except for impact strength. At −100 °C, the mechanical properties of the neat polymers were improved, including increased impact strength by 20% compared to values at 25 °C. Addition of fillers hindered the rise of impact strength due to complex mechanisms caused by different coefficients of thermal expansion of reinforcements and matrix. At −195 °C, the significant increase of impact strength was revealed for unmodified PEEK reaching 30 times higher values than at 25 °C, while matrix modification suppressed the rise of impact strength. The scratch test indicated the superior behaviour of unfilled PEEK during the tested load range (up to 15 N), while the effect of the fillers was observed at much lower load threshold of 7 N.

Although flame retardants are very effective in reducing the fire hazard of polymeric materials, their presence may be detrimental to mechanical strength. Hence, in order to have a holistic improvement of performance properties, a new approach has been developed wherein biochar is used to host a naturally-occurring flame retardant (lanosol). The issue of loss in mechanical strength of a polymer host is alleviated by the use of biochar. Three different doping procedures were investigated, namely, dry mixing, and chemical and thermal-based doping, to integrate lanosol into the biochar pores. The doped biochar was used to develop wheat gluten-based blends. The mechanical and flammability properties of the blends were assessed. It was found that thermal doping was the most effective in introducing significant amounts of lanosol particles inside the biochar pores. The bioplastic containing chemically, and thermally doped biochar had equal tensile strength (5.2 MPa), which was comparable to that of the unmodified material (5.4 MPa). The thermally doped biochar displayed the lowest cone calorimeter peak heat release rate (636 kW m−2) for combustion and the highest apparent activation energy (32.4 kJ mol−1) for decomposition. Thus, for flame retarding protein-based matrices, the use of additives thermally doped into biochar is recommended to both simultaneously improve fire-resistance and conserve mechanical strength.

The development of fibre composites in recent years has been remarkably strong, owing to their high performance and durability. Various advancements in fibre composites are emerging because of their increased use in a myriad of applications. One of the popular processing methods is additive manufacturing (AM), however, polymer-fibre composites manufactured through AM have a significantly lower strength compared to the conventional manufacturing processes, for instance, injection moulding. This article is a comprehensive review of the mechanical testing and performance analysis of polymer-fibre composites fabricated through AM, in particular fused deposition modelling (FDM). The review highlights the effect of the various processing parameters, involved in the FDM of polymer-fibre composites, on the observed mechanical properties. In addition, the thermal properties of FDM based fibre composites are also briefly reviewed. Overall, the review article has been structured to provide an impetus for researchers in the concerned engineering domain to gain an insight into the mechanical properties of fibre-reinforced polymeric composites manufactured through AM.

Ultra-high molecular-weight polyethylene (UHMWPE) composites reinforced with Graphene Oxide (GO), Nanodiamonds (ND), and Short Carbon Fibres (SCF) are characterised for their mechanical performance in tensile and short-term creep tests. A methodology to separate and analyse the materials’ viscoelastic (VE) and viscoplastic (VP) responses is applied and evaluated. The results show a clear dependence of the performance on size scale/morphology of the reinforcements. All composites show time-dependent VP responses that can be expressed by Zapas model and fit the experimental data with high accuracy. The analysed VE strains and creep compliance curves reveal the nonlinear stress-dependent VE behaviour of all composites at all tested creep stresses. Combining multiscale reinforcements results in an improvement that surpasses that of individual reinforcements. The results of this work offer valuable input for the design and selection of polymer-based materials in demanding applications where prolonged use under service conditions is critical to their performance.

Investigation was performed to evaluate the puncture resistance of multi-walled carbon nanotubes (MWCNTs)/glass fibre epoxy laminate composites using different indenters (conical, elliptical, flat, and hemispherical). For the puncture tests, MWCNT weight percentage and indenter type were varied. Furthermore, the impact of MWCNT on tensile, flexural, and interlaminar shear strength was evaluated. Ultrasonic C-scan provided insights into the damage evolution and failure mechanisms of the laminates under puncture. The results indicate that the flat indenter exhibits prolonged indentation time and enhanced energy absorption, resulting in a disc-shaped failure pattern. On the other hand, the conical indenter demonstrates rapid penetration due to its smaller contact surface area. The elliptical indenter generates higher frictional energy, leading to bulging damage. The hemispherical indenter showed an even distribution of force across the impacted surface, minimizing force concentration and reducing the extent of damage. These findings shed light on the puncture mechanisms of MWCNT/Glass fibre epoxy laminate composites, paving the way for more precise glass fibre laminate composite design and optimisation in practical applications such as aerospace, automotive, and sporting goods, where puncture loading is a critical consideration.