The Enhanced Polymeric Blend Membranes (EPBM) have an exceptionally promising future in the gas separation industry due to improved physical and chemical properties compared to organic and inorganic membranes. In this research two reference membranes comprising PSU glassy and PVAc rubbery polymers were used as controls for comparative analysis. The research is focused on the preparation of flat sheet PSU/ PVAc polymeric blend membranes. The composition of PVAc contents varied between 5-20 wt in the PSU matrix. Differential scanning calorimetry (DSC) analysis showed the existence of single glass transition temperature (Tg) for different membrane blends which indicated miscibility among the PSU/PVAc polymer blends. The glass transition temperature (Tg) miscibility among the polymeric blends were further judged by using Fox equation (series model) or Wood's equation (parallel model) or Pochan's equation (logarithmic model). © 2016 The Authors. Published by Elsevier Ltd.