Non-isothermal kinetics of cold crystallization in multicomponent PLA/thermoplastic polyurethane/nanofiller system

0480540 - ÚMCH 2018 RIV HU eng J - Journal Article
Kratochvíl, Jaroslav - Kelnar, Ivan
Non-isothermal kinetics of cold crystallization in multicomponent PLA/thermoplastic polyurethane/nanofiller system.
Journal of Thermal Analysis and Calorimetry. Roč. 130, č. 2 (2017), s. 1043-1052. ISSN 1388-6150. E-ISSN 1588-2926
R&D Projects: GA ČR(CZ) GA16-03194S
Institutional support: RVO:61389013
Keywords : poly(lactic acid) * cold crystallization * thermoplastic polyurethane
OECD category: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics
Impact factor: 2.209, year: 2017

The effect of platy and tubular nanofillers (NF) in combination with thermoplastic polyurethane (TPU) on cold non-isothermal crystallization (NIC) of poly(lactic acid) (PLA) was studied by differential scanning calorimetry. The data were processed using a recently proposed method of evaluating NIC kinetics. The results indicate that the NF/TPU combination leads to crystallization behaviour of the PLA matrix which is dissimilar from that of the NF-free blend and neat PLA. Addition of organophilized montmorillonite (C30) results in a dual effect on PLA crystallinity—stimulation at lower concentrations and suppression at higher loadings. In the case of halloysite nanotubes (HNT), this effect is practically absent. Crystallinity of injection-moulded samples is significantly increased by cold NIC. This indicates a synergy originating in a complex effect of NF/TPU, e.g. NF-induced changes in morphology and interphase parameters supporting the solid annealing process. TPU partially eliminates negative effect of high NF contents on cold crystallization rate. This effect is more marked in the remelted samples where the rate increases for all NF loadings. This is probably caused by absence of as-prepared crystallites in combination with higher mobility of PLA chains due to presence of TPU. The observed differences between C30 and HNT could be attributed to differences in size, shape, and specific surface. The results indicate that synergistic and antagonistic effects of NF/polymeric modifiers on mechanical and other material parameters are also significantly determined by the effects on crystallization of the matrix.
Permanent Link: http://hdl.handle.net/11104/0276444