Non‐isothermal crystallization of poly(ethylene oxide)/silver nanoplate composites

The non‐isothermal crystallization of poly(ethylene oxide) (PEO)/silver nanoplate composites was studied using differential scanning calorimetry. The non‐isothermal crystallization was analyzed by combining the Avrami and Ozawa equations. It was found that the Avrami exponent for neat PEO ranges from 2.51 to 2.53, whereas it ranges from 2.54 to 3.16 for its composites, indicating that the spherical crystal morphology does not change with the addition of nanoplates. However, the rate determination of crystal growth transfers from diffusion to nucleation. The crystallization half‐time showed an increase with the addition of silver nanoplates in PEO, indicating that the overall crystallization rate of PEO decreases with the addition of nanoplates. However, the nucleation activity is larger than unity in the composites and the value increases with an increase in the nanoplate content. This behavior implies that the nanoplates act as anti‐nucleating agents to hinder nucleation. Copyright © 2011 Society of Chemical Industry     

Isothermal crystallization of polyethylene oxide/silver nanoplate composites

This research was accomplished to investigate the kinetics of isothermal crystallization of polyethylene oxide (PEO)/silver nanoplate composites. It was obtained that the spherulites increased in size and numbers with time for the composites with various particle loadings. Additionally, the spherulite growth rate of composites decreased with an increase in the crystallization temperature and increased with the addition of nanoplates. The spherulite growth rate was further analyzed by the theory developed by Lauritzen and Hoffman. The product of the lateral surface free energy (σ) and the end surface free energy (σ_e) decreased with an increase in the content of nanoplates. We proposed the possible crystallization mechanisms of these PEO/nanoplate composites according to the change of σ and σ_e with the presence of nanoplates. A controlled experiment showed a minor change in PEO crystallization with the presence of a surfactant C₁₆TAB. This implied that the unique size and shape of nanoplates plays a key role on hindering the primary nucleation of PEO and increasing the spherulite growth rate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011