SciELO - Scientific Electronic Library Online

vol.21 número6Effect of Solid Solution + Double Ageing on Microstructure and Properties in the Layer by Layer of the Z-Y Interface of Inconel 718 alloys Fabricated by SLMThermal Behavior of Pyrite in the CO2 and N2 Atmosphere for Obtaining Pyrrhotite: A Magnetic Material índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados




Links relacionados


Materials Research

versão impressa ISSN 1516-1439versão On-line ISSN 1980-5373


RAMOS, Renata Brandão Brito; SOUZA, Patrícia Moraes Sinohara  e  MORALES, Ana Rita. Influence of clay surfactants polarity on the crystallization and rheological behavior of nanocomposites of PDLLA. Mat. Res. [online]. 2018, vol.21, n.6, e20180059.  Epub 11-Out-2018. ISSN 1980-5373.

The effect of clay hydrophobicity on the cold crystallization and rheological properties of nanocomposites of poly(D,L-lactic acid) (PDLLA) was investigated. Crystallization was evaluated by DSC for isothermal and non-isothermal conditions. The clay modified with a hydrophilic surfactant acts as a nucleating agent, while the clay modified with a hydrophobic surfactant acts in an opposite way. The Avrami and Ozawa parameters showed a three-dimensional spherulitic growth for all samples and the activation energy increased for the hydrophobic clay and decrease for the hydrophilic one. The equilibrium melting point for the PDLLA was found at 161ºC, being slightly altered as function of the surfactant polarity. The rheological behavior was investigated in terms of Isothermal Flow-Induced Crystallization and Structural Recovery. The hydrophobic clay showed to reduce the mobility of chains and retard the chain relaxation, which is attributed to the formation of a network, while the hydrophilic clay increased the chain mobility.

Palavras-chave : PDLLA; nanocomposites; organoclays; crystallization.

        · texto em Inglês     · Inglês ( pdf )