Advanced Fibres & Films

SMITA Research Lab is involved in creating composite fibres at micro and nanoscale. Various anisotropic rigid organic and inorganic nanostructures have been incorporated within different polymer systems to obtain specialty fibres like high-performance, high modulus, high tenacity, conducting, carbon fibres etc.

Challenges

• Stable dispersion of nanomaterials in the solvent/ polymer system

• Regulating the spinnability of fibres with the incorporated fillers

Achievements

• High initial modulus (4.26 GPa) and high tenacity (~1 GPa) fibre with highly oriented fibrillar structures out of commercial grade nylon 6.

• Energy efficient process for making carbon fibres with high graphitic content having ID/IG of 2.33.

Current Research

• Composite Fibres

The dispersion of nanomaterials in the solution/ melt is the crucial step in making of composite fibres. Investigation on incorporation of nanostructures within the fibre systems were carried out. Different solvent and polymer system like PVA/Water, PVA/Water/DMF and PAN/DMF were studied and Raman analysis confirm that the interaction with the solvent as well as the polymer system results in well dispersed and well aligned incorporation of the nanostructure. PAN nanofibers reinforced with ZnO nanorods up to 50 wt% on the weight of polymer could be readily electrospun in random and aligned configuration.

Reinforcement of nanofiller leads to better enhancement of properties as compared to microfillers because of their very high surface area to volume ratio. Small amount of nanofillers provide similar property as compared to those of microfiller which would require high concentration thus nanofillers doesn’t hamper in the spinnability of the fibres. Rigid anisotropic nanostructure (ZnO nanorods) was incorporated in the commercial grade Nylon 6 fibres. Nanorods incorporation improves the crystallinity of the fibres leading to highly oriented fibrillar morphology thus converts them into high performance fibres of tensile strength ~ 1 GPa and initial modulus of 4. 26 GPa.

In this study a slow process has been eliminated leading to more energy efficient way for the formation of  carbon fibres. Carbon fibres production involves two heat treatment steps, stabilization followed by carbonization. 

Stabilization is carried out at slow heating rate of 2 °C/min. ZnO nanorod incorporated PAN fibres were carbonized and the presence of nanorods eliminated the stabilization step.  Presence of nanorods in the precursor fibre helps in significantly faster carbonization with better graphitic content and the nanorods are reobtained after carbonization thus leaving pure carbon fibres

Natural fibre reinforced laminates have been prepared. Bhindi fibres were extracted as long strands from the stems of bhindi plant and they were laminated in the form of carded sliver between two sheets of packaging grade papers. The laminates show 400% increase in tearing strength and 1200% increase in the bending rigidity. It was found that they can easily replace the expensive paper corrugated composites