Preparation And Properties Ofpolyvinyl Alcohol/Layered Double Hydroxide Nanocomposites

As a widely used water-soluble polymer, polyvinyl alcohol (PVA)’s performance is between ones of plastic and rubber. With a unique film-forming property, biological compatibility, gas barrier property and biodegradability, PVA materials are widely applied in the fields of membrane technology, drug delivery systems, flame retardant materials and artificial medical equipment, etc. But in the mechanical properties PVA materials have some deficiencies, which limit their wider application. For this reason, looking for a new type of PVA material with a sharp rise in mechanical performance is particularly important for the application of PVA and PVA industrial. Our work was conducted under this background above.In recent years, polymer/inorganic nanocomposites have become a hot area in the field of materials science. However, based on the preparation and properties researches of PVA/LDH’s were still rare, the present paper took layered double hydroxides (LDHs) as an inorganic filler to prepare a new style of PVA/LDH nanocomposites with a structure like "brick-wall". Meanwhile, we prepared another kind of PVA/LDH by the traditional method as a comparison to research its mechanical performance, rigidity and crystallization behavior. The mechanism was also investigated.The main contents and results of this paper are listed in the following:First, pure LDH-NO3samples were successfully prepared by both urea-ion exchange method and co-precipitation method respectively. Then, in formamide the obtained LDH-NO3was completely exfoliated into single layers, which are used to preapare orentied LDHs films. After that, respectively, the solution cast method and the intercalation method were used to prepare PVA/LDH nanocomposite material. XRD, FTIR and SEM results show that, comparing with the PVA/LDH prepared by solution casting method, PVA successfully intercalated in layers of LDH by intercalation method and they formed a kind of nanocomposite materials consisted of PVA and single layers of LDHs. Tensile experiment and nano indentation test showed that LDHs effectively changed the mechanical properties and hardness of PVA materials. At last, we preliminary studyed the crystallization behavior of PVA/LDH by DSC.