In this investigation, biodegradable composites were fabricated with polycaprolactone (PCL) matrix reinforced with pine cone powder (15%, 30%, and 45% by weight) and compatibilized with graphite powder (0%, 5%, 10%, and 15% by weight) in polycaprolactone matrix by compression molding technique. The samples were prepared as per ASTM standard and tested for dimensional stability, biodegradability, and fracture energy with scanning electron micrographs. Water-absorption and thickness-swelling were performed to examine the dimensional stability and tests were performed at 23 °C and 50% humidity. Results revealed that the composites with 15 wt % of pine cone powder (PCP) have shown higher dimensional stability as compared to other composites. Bio-composites containing 15–45 wt % of PCP with low graphite content have shown higher disintegration rate than neat PCL. Fracture energy for crack initiation in bio-composites was increased by 68% with 30% PCP. Scanning electron microscopy (SEM) of the composites have shown evenly-distributed PCP particles throughout PCL-matrix at significantly high-degrees or quantities of reinforcing.

Composites are being used in the place of metals in many industries as they have a lower density and are cheaper than metals. In aerospace industries there is requirement for light weight together with strength, and reinforced fibre composites are superior in some critical properties compared with metals. In this study, laminated composites were fabricated with woven E-glass and jute fibres in an epoxy matrix by a hand layup method. The samples were prepared as per the relevant the America Society for Testing ad Materials (ASTM) standard and tested for mode II interlaminar fracture toughness to investigate delamination resistance. Mode II interlaminar fracture toughness was evaluated by an end-notched flexure test using three-point bending. The fracture toughness G IIC was calculated for a curing temperature range from 40 °C to 70 °C at intervals of 5 °C for different sets of laminated composites. The investigations revealed that when the curing temperature of laminated composites was increased from 40 °C to 70 °C, the interlaminar fracture toughness G IIC was increased in neat woven E-glass laminated composites, decreased in neat jute laminated composites, significantly increased in laminated composites with woven E-glass fibres in compression and jute fibres in tension and slightly increased when woven E-glass fibres were kept in tension and jute fibres in compression.

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The need of developing Radar absorbing materials which meet the structural requirement of Defense applications is growing swiftly due to extensive use of electromagnetic (EM) waves in Radars. With major development and extensive use of Radar in military applications, the role of Radar absorbing structures with light weight and high strength has become prime objective for researcher working on development of Radar absorbing materials. Various composites are developed by using reinforcements which are dielectric such as CNT, Magnetic materials like Ferrites, have been extensively used as reinforcement in developing Radar absorbing materials. The ferromagnetic materials have high density and can achieve only narrow bandwidth absorption, CNT have very good electrical, mechanical and thermal properties and can achieve high dielectric losses but its complex synthesis process is a barrier in commercial applications. The research of reinforcing MWCNT with ferrites and metal oxides can also be extend to study thermoplastic polymers like PEEK and PAEK which is gaining prominence in aeronautical applications owing to its superior mechanical and low moisture absorbing properties. Further research can be done on the reinforcing metal oxides as metal oxides when reinforced with MWCNT proved to enhance the dielectric properties which improved the reflection losses as reported in a few studies.