The conformational and dynamic properties of polypropylene (PP) for both pure melts and blends with different chain tacticity were investigated by Monte Carlo simulation of isotactic (

i

PP)

atactic (

a

PP) and syndiotactic (

s

PP) polypropylenes. The simulation of coarse-grained PP models was performed on a high coordination lattice incorporating short- and long-range intramolecular interactions from the rotational isomeric state (RIS) model and Lennard-Jones (LJ) potential function of propane pairs

respectively. The dynamics of chains in binary PP/PP mixture were investigated with the composition of C

150

H

302

with different chain taciticity. The diffusion rates of PP with different stereochemistry are generally in the order as:

i

PP

>

a

PP

>

>

s

PP. For PP/PP blends with 50:50 wt% binary mixtures

immiscibility was observed when

s

PP was introduced into the mixtures. The diffusion rate of

i

PP and

a

PP became slower after mixing

while

s

PP diffuses significantly faster in the binary mixtures. The mobility of PP chains depends on both intramolecular (molecular size and chain stiffness) and intermolecular (chain packing) interactions. The effect of intramolecular contribution is greater than that of intermolecular contribution for

i

PP and

a

PP chains in binary mixtures. For

s

PP chain

intermolecular interaction has greater influence on the dynamics than intramolecular contribution.