MUMBAI, India, Sept. 22 -- Intellectual Property India has published a patent application (202641107165 A) filed by Hindustan Institute Of Technology And Science on September 07, 2026, for Sisal-Kenaf Hybrid Natural Fibre Reinforced Glass Fibre Polymer Composite Laminate With Enhanced Impact Resistance And A Method Of Fabrication Thereof.
Inventors include Nyved Menon; Naresh J; Nikkil Ratheesh; Ravikumar Solomon; Sandhya Jayakumar; and Rajesh Munusamy.
The application for the patent was published on September 18, 2026, under issue no. 38/2026.
Abstract: The present invention discloses a hybrid natural fibre reinforced glass fibre polymer composite laminate and a method of fabrication thereof, wherein alkali-treated sisal (Agave sisalana) and kenaf (Hibiscus cannabinus) fibres are incorporated as interior filler-reinforcement layers within a five-ply General Purpose polyester resin matrix. Natural fibres are surface-treated through sequential washing, sodium hydroxide alkali treatment, acetic acid neutralization, and ambient drying to improve fibre–matrix interfacial adhesion. Treated fibres are formed into standardized pre-compressed mats of 9.15 g each prior to layup. Fabrication is accomplished by hand layup with compression curing in a plug mould assembly comprising interlocking male and female mould halves, which provide uniform consolidation pressure and controlled excess resin drainage, resulting in laminates of consistent thickness and reduced void content. Five laminate configurations were fabricated and comparatively evaluated: pure GFRP control (GGGGG), all-sisal core (GSSSG), all-kenaf core (GKKKG), sisal-kenaf-sisal hybrid core (GSKSG), and kenaf-sisal-kenaf hybrid core (GKSKG). Mechanical testing of cut specimens (100 mm × 25 mm × 8 mm) was conducted for ultimate tensile strength, flexural strength, elongation at break, and Charpy impact energy. All hybrid configurations demonstrated improved impact resistance over pure GFRP, with impact energies ranging from 19.5% to 41.5% higher than the control, accompanied by moderate reductions in tensile strength of 17.6% to 24.3%. The GSKSG configuration — placing a kenaf fibre core flanked by sisal interlayers between glass outer plies — produced the optimal mechanical profile, achieving a Charpy impact energy of 116 kJ/m², an ultimate tensile strength of 122 MPa, and a flexural strength of 162 MPa. The kenaf core contributes ductile energy absorption through elastic deformation and fibre pull-out, while the sisal interlayers serve as transitional load-transfer media that reduce interfacial stress concentrations and delay delamination. The invention provides a mechanically viable, partially sustainable alternative to conventional GFRP in applications requiring resistance to dynamic or shock loading.
Disclaimer: Curated by HT Syndication.
