This work was aimed at understanding the influence of processing temperature on fibrillar morphology development. In this work, blend system of Polypropylene (PP)/ Polytrimethylene Terephthalate (PTT) with varying ratios of (PP/PTT: 99/1, 94/6, 90/10, and 80/20) was chosen. The melt blending process was conducted on co-rotating twin screw extruder and then the as-extruded blend systems were pelletized and fed into Laboratory Mixing Extruder (LME) to spin monofilaments. Fiber spinning was conducted at three different spinneret temperatures of 180 °C, 195 °C, and 240 °C to analyse the spinnability of the droplet phase. Scanning electron microscopy revealed a droplet morphology regarding the as-extruded samples and it was observed that upon using fiber spinning, the droplet is transferred into fibrillar state throughout the matrix. It was found that spinneret temperature of 240 °C efficiently increases the spinnability of the dispersed phase towards nano-fibrillar network formed throughout the fiber matrix. Rheologically speaking, it was seen that upon transformation from droplet state to fibrillar state, storage modulus in low frequency region represents a secondary plateau. According to storage modulus curves, it was found that fiber spun at 240 °C possessed thinner and longer fibrils which was mirrored by lower value and more broadened storage modulus curve. Startup of steady shear flow measurement, as a sensitive technique could not only confirm the more flexibility of the nano-fibrillar network formed in fibers spun at 240 °C, but also confirmed the fibril-fibril mechanism which has been previously reported for fibers microscopically. Stress relaxation analysis also showed that upon formation of fibrillar morphology, the fiber system obtains the ability to store the energy for longer times.