Preparation And Characterization Of Polymer Nanocomposites Based On Layered Double Hydroxides

With the development of society, it becomes an important issue to improve the properties of polymer. PBAT is a biodegradable polymer with great potential application. However, the water vapor barrier properties still should be enhanced. LLDPE is a raw material to produce agricultural film. Nevertheless, the heat retention still should be improved. In this work, we prepared LLDPE/LDH nanocomposite films and PBAT/LDH nanocomposit films to improve the performance of PBAT and LLDPE.1. Bio-nanocomposite films based on PBAT/LDH were prepared with solution casting method. The morphology and structural characterizations on the LDH and PBAT/LDH bio-nanocomposite films were performed by FT-IR, XRD, TEM and SEM. The physical properties of the films were determined by thermal, mechanical and optical analysis, and contact angle testing and WVT measurement. The XRD results show that the basal spacing of the LDH was increased from 0.88 nm to 4.45 nm after the modification by long-chain MAPK.The exfoliated LDH were well dispersed in the PBAT matrix. The crystallization temperature of the PBAT/LDH bio-nanocomposite films was significantly higher than the base matrix.The hydrophilic, optical, tensile and water vapor barrier properties of the films were obviously improved by the addition of LDH with low content(1%). The results of this study would be useful for investigating the potential to develop the eco-friendly packaging films.2. Biodegradable nanocomposite films based on PBAT and LDH were prepared via melt-blowing method by co-rotating twin screw extruder and blown film unit. The LDH was large-scale synthesized by the high-energy ball milling method at the first time. The XRD,SEM results show that exfoliated LDH nanosheets have a uniform dispersion in the PBAT matrix. The thermal, optical, mechanical and water vapor barrier properties of PBAT/LDH films with low LDH content are obviously enhanced compared to pure PBAT film.Furthermore, the haze reduced by 37%, while the nominal tensile strain at break in machine direction improved by 41.9% upon the incorporation of 1% LDH. Therefore, this study shows great potential in developing eco-friendly films for industrial application.3. A LLDPE/LDH nanocomposite films with enhanced heat retention were prepared via melt-blowing method by co-rotating twin screw extruder and blown film unit. The LDH was large-scale synthesized by the high-energy ball milling method. The structural and morphological characterizations of LLDPE/LDH films were characterized using FT-IR, XRD and SEM. The thermal, mechanical, water vapor barrier, optical properties and heat retention were also investigated. The structural and morphological characterizations show that exfoliated LDH nanosheets have a homogeneous dispersion in the LLDPE matrix. Thethermal properties and mechanical performances were enhanced upon 1% LDH loading. The improved water vapor barrier, better optical properties of LLDPE/LDH films also can be observed compared to the pure LLDPE film, which is vital to the application as agricultural films. Furthermore, the IR absorbance(1,180-914 cm-1) of LLDPE/LDH films improved obviously, revealing the significant enhancement of heat retention. Therefore, this study shows great potential in developing agricultural plastic films with superior heat retention.