Cold Crystallization in Poly(lactic acid) (PLA) Induced by Various Forms of Pre-deformation*

To effectively transition to green polymers, it is essential that such polymers are able to meet or surpass mechanical properties of existing petroleum polymers such as PE, PP, and PET. In a prior publication ¹ we have shown how brittle PLA can be made ductile by uniaxial melt extension and resistant to heat well above its T_g of 60 ^oC. The present work further explores the molecular physics operative to create nano-confined crystallization (NCC) in PLA. For example, shear deformation is applied to show the emergence of NCC. On the other hand, NCC is insufficient to afford PLA ductility at room temperature in absence of the geometric condensation effect ².

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