The objective of this research was to characterize the cotton stalk resource. This paper also focused on the manufacturing of formaldehyde-free particleboards using whole cotton stalk. The effects of opening particle sizes and cotton ball residue ratios on performance properties of manufactured particleboard was assessed. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), and thickness swelling (TS) were characterized. Particleboards manufactured from four different opening particle sizes (6, 8, 10, and 20 mm) using an emulsifiable polymeric isocyanate adhesive (eMDI) were investigated. Similarly, the same performance properties were evaluated using four different cotton ball residue ratios (0, 5, 10, and 15 wt%). Results showed that the stem length and diameter of cotton stalks cultivated in Queensland (Australia) vary greatly and range from 160 to 890 mm and 5.03 to 10.88 mm, respectively. The highest weight proportion of the resource is the cotton stem making up 46 wt% of the available resource. The highest average values of MOR, MOE, IB, and the lowest TS were observed for boards with an opening particle size of 8 mm. The cotton ball residues had detrimental effects on the mechanical properties with a decrease in properties observed with increasing cotton ball residue load.