The market of non-woven fabrics presently in the world is 9.0 million tonnes ($ 37.4 billion), which is projected to rise 12.1 million tonnes ($50.8 billion) in 2020 as it can serve various purposes such as absorbent, bacterial barrier, cushioning, filtering, flame retardancy, liquid repellency, resilience, softness, sterility, strength, stretch and wash ability considering end use application. Along that, there is another pressing demand to reduce the basis weight of the fabrics in order to decrease the cost of raw material, shipping, and ware house. In situ generation of fibrils in the polymer matrix known as micro fibrillated composites (MFC) demonstrated higher flexural and tensile strengths due to the reinforcing effect of fibrillation of the dispersed phase (second phase). This technology has the potential to reduce the basis weight of non-woven fabric with an increase in the mechanical properties, if the fibril diameter reduces to nano scale level due to the size confinement effect. In this project polypropylene (PP as the matrix)/ polyethylene terephthalate (PET as the dispersed phase) was processed through a spun bond system, since majority of the non-woven fabric production is based on the spun-bond method. Morphology investigation through SEM shows that the PET has a nano-fibrillar structure and reached to a fiber diameter as low as 40 nm with an average diameter of 95 nm. The goal of this project is to understand the dependency of different processing parameters of spun bond on in situ generation of nanofibrils in polymer matrix.