Crystallization and Properties of Poly(lactide)/Poly(δ-valerolactone) Alternating Supramolecular Copolymers Adjusted by Stereocomplexation

The crystallization behavior of a series of synthesized polylactide (PLA)/poly(δ-valerolactone) (PVL) supramolecular copolymers with 2-ureido-4[1H]-pyrimidinone (UPy) groups is investigated by differential scanning calorimetry and X-ray diffraction. The stereocomplexation of PLA-based supramolecular polymers (SMPs) is strongly related to the block length, L/D ratios, and the UPy groups. Both the increase of the PLA block length and the self-complementary hydrogen bonding of the UPy end groups restrain the crystallization of the PVL blocks. The stereocomplexation of PLA-SMPs is greatly promoted by UPy groups, while the homocrystallization of PLA is constrained. The dynamic mechanical analysis indicated that the enhanced stereocomplexation would lead to higher thermal resistance and mechanical properties of PLA-based SMPs.