Plastic based products are used worldwide for packing and other consumer goods. Their wider use and non-biodegradable nature make them a serious threat to the environment. In order to circumvent the problem, incineration and dumping them in soil are the common practices. However, these practices are now unacceptable in terms of recent legislation in the matter. Incineration leads to hazardous smoke, whereas frequent land filling contaminates the soil and underground water. Hence, recycling is the ultimate choice and this has two benefits. On one hand the plastics are disposed of and on the other hand some valuable products are also obtained which have substantial benefits for domestic and 22 commercial use. In the present research work thermal decomposition kinetics of polypropylene was investigated in the absence and presence of catalyst (molecular sieve LZ Y52, Zeolite mordenite ammonium, cobalt doped molecular sieve LZ-Y 52, Cu-Co/MS) in a thermobalance system, at isothermal and non isothermal heating conditions with heating rate of 5 oC/min, 10 oC/min, 15 oC/min and 20 oC/min in the temperature range of 30–600 oC under nitrogen atmosphere. The apparent activation energy (Ea) and Pre-exponential factor (A) were determined using Ozawa Flynn Wall, Tang Wanjun and Coats-Redfern (modified) methods. In the absence of catalyst, the apparent activation energy and pre-exponential factor were found in the range 61.3– 110.9 kJmol-1 and 2.1×107 - 3.3×1013 min-1 respectively. The activation energies and pre-exponential factor determined in the presence of molecular sieve LZ-Y52, Co/MS, Cu-Co/MS and zeolite mordenite ammonium catalysts were in the range of 58.38 – 74.50,47.59 – 54.75, 48.36 – 73.81 and 72.77 - 84.12 kJmol-1 and 2.4×107 - 9.05×108, 1.86×106 - 1.9×107, 3.2×106 - 9.9×108 and 2.7×108 - 3.6×109 min-1 respectively. Increasing the heating rate shifted the Tmax to a higher level. The lower activation energies observed indicates breakage of the bonds at weak links. Moreover, the values of kinetic parameters are significantly controlled by the heating rate, level of conversion and calculation technique. A comparison among the different techniques has been made on the basis of the apparent activation energy from the TG data. The activation energies determined by all the three methods are in good agreement with each other. Furthermore, the pyrolysis of model polypropylene was carried out over the temperature range 350-415°C in an indigenously manufactured furnace using Pyrex reaction vessel. The liquid and gaseous fractions produced were collected and monitored using gas chromatography/mass spectrometry. The conditions for thermal and catalytic degradation were optimized for maximum liquid oil production. 10% catalyst amount, temperature 395 oC, nitrogen flow rate 16 mL/min and reaction time 60 minutes were the optimum conditions used during experimental work.It was found that, in case of thermal degradation no condensable 23 products were observed while in case of catalytic degradation more than 70% condensable products were obtained at 395oC for 1 hour. In commercial catalysts molecular sieve LZ-Y52 while in modified catalysts the cobalt doped was found to be preeminent catalysts for the conversion of model polypropylene in to valuable products. The physical parameters of the oil obtained from the pyrolysis of PP in the presence of catalysts were determined so as to evaluate its potential application for fuel oil and compared with standard values of gasoline, diesel and kerosene oil. The values of physical parameters were found out to be in close agreements with the standard values of diesel and kerosene oil. Moreover, the study conducted on pure polypropylene on laboratory scale could successfully be applied to waste polypropylene on commercial scale.