Study On The Preparation And Thermal Properties Of LDHs/PS Nanocomposites

Polymer materials have been extensively used and palyed significant role in modern society. However, enhanced thermal stability and flame retardancy are expected in numbers of applications for polymer materials. Therefore, some inorganic additives can be introduced into the polymer composites. The different preparations will lead to the obtained composites with huge difference in properties. So, currently, in order to obtain composites with excellent performance, it is extensively investigated in the preparation method. By studying the enhancing mechanism of composites, it helps us to find appropriate additives with right ideas and theoretical foundation. So it is significant and meaningful in studying the enhancing mechanism of additives in composites. An inorganic nanolayer materials (layered double hydroxides:LDHs) was used as nanofillers. The polystyrene and various modified LDHs were used to prepare composites with emulsion seed growth technique. For futher explore composite additives with high efficiency, layer by layer assembly technique was carried out to prepare core-shell structural composites maed up of LDHs, montmorillonite (MMT) and polystyrene. It is attempt to reval the mechanism of LDHs function in LDHs/PS composites by analyzing the morphological structure and thermal properties of composites, and gives a promising thought in LDHs/PS composites design and preparation.The following works were done in this thesis:1. In order to investigate the effects of modification on LDHs interlayer spacing and thermal properties, LDHs was modified with intercalations with different chain lengths and functional groups. After analyzing the FTIR spectrum and XRD patterns, it was confirmed that modifications hava been successfully intercalated into the interlayer spacing. The influence of organic modifications on the degradation procedure of LDHs was studied by analyzing the TGA data of modified LDHs.2. LDHs/PS composites were prepared by seed growth emulsion technique. The obtained samples were cut into ultrathin slice, and the dispersion of different organic modified LDHs layers in polymer matrix was investigated using TEM. The mechanism of modified LDHs nanolayers in enhancing the thermal properties of polymer matrix was revealed by analyzing the pyrolysis procedure. The influence of anions between LDHs nanolayers on the dispersion of LDHs and thermal properties of composites was investigated.3. A novel core-shell structure composite was self-assembled layer by layer by depositing LDHs and MMT alternatively through electrostatic interaction. The synergistic effect of LDHs and MMT was investigated by studying the therrmal properties. This work provides a novel thought in designing the polymer composites preparation method.