To extend the practical application of poly(propylene carbonate) (PPC), the chemical methods were used to improve its mechanical properties. In this connection, random copolymer poly(propylene-cyclohexyl carbonate) (PPCHC) and di-block copolymers poly(propylene carbonate-cyclohexyl carbonate) (PPC-PCHC) were synthesized. Dynamic mechanical analysis (DMA), nanoindentation and nanoscratch test were applied to evaluate their mechanical properties. The storage's modulus, Young's modulus (E) and hardness (H) obtained from DMA and nanoindentation tests showed that the introduction of the third monomer cyclohexene oxide (CHO) can greatly improve the mechanical properties of PPC, and that the block copolymer PPC-PCHC hand better mechanical properties than the random copolymer PPCHC. The annealing treated PPC-PCHCs exhibited deteriorated mechanical properties as compared with untreated PPC-PCHC. From the results of scratch tests, the plastic deformation of PPC-PCHC was smaller than those of PPC and PPCHC. Meanwhile, the plastic deformations of the heat-treated PPC-PCHCs were smaller than the untreated PPC-PCHC because of the possible rearrangement of the molecular chains of PPC-PCHC. The scratch hardness (Hs) of the block copolymer PPC-PCHC is larger than random polymer PPCHC and PPC, but lower than the values of heat-treated samples indicating that the surfaces' hardness of block polymers increase after heat treatment. These different measurement methodologies provide a more precise assessment and understanding for the synthesized block polymers. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013