Insight into the influence of OA-Fe3O4 nanoparticles on the morphology and scCO2 batch-foaming behavior of cocontinuous LLDPE/PS immiscible blends at semi-solid state

Publication date: 27 October 2017
Source:Polymer, Volume 129
Author(s): Guangchun Zhang, Shaofeng Zhang, Jian Qiu, Zhiwei Jiang, Haiping Xing, Minggang Li, Tao Tang
The influence of oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles on the morphology and foaming behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of phase structure from cocontinuous structure to sea-island structure, when enough amounts of nanoparticles were added. Meanwhile the introduction of enough amounts of OA-Fe3O4 nanoparticles effectively enhanced the foaming ability of LLDPE/PS blend at semi-solid state during scCO2 batch foaming. The mechanism analysis for the change of foaming behavior showed that the improved foaming capacity resulted from the change of the phase structure of LLDPE/PS blends and heterogeneous nucleation of OA-Fe3O4 nanofillers. Sorption and desorption measurements showed that the addition of OA-Fe3O4 nanoparticles in the LLDPE/PS blend increased the solubility of CO2, and the presence of enough amount of OA-Fe3O4 decreased the desorption rate of CO2 in the initial period of depressurization process, which are beneficial to cell nucleation and growth. Furthermore, it was found that the melt behavior and crystalline properties of LLDPE/PS blends were not the key factors to improved foaming behavior of the blends in the presence of OA-Fe3O4 nanoparticles.

Graphical abstract

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