Preparation and Investigation on Morphology, Thermal Stability and Crystallization Behavior of HDPE/EVA/Organo-Modified Layered Double Hydroxide Nanocomposites

Organo-modified MgAl layered double hydroxide (OLDH) was synthesized by anion exchange reaction and potassium monolauryl phosphate was used as organic anion modifier. High-density polyethylene (HDPE)/ethylene vinyl acetate (EVA)/OLDH nanocomposites were prepared by melt blending from HDPE as polymer matrix with OLDH as filler and EVA as compatibilizer. The morphological structures, thermal stability and crystallization behaviors of the nanocomposites were investigated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry. OLDH is synthesized from the appearance of P = 0 stretching vibration peak at 1,216 cm(-1) of phosphate and P-O-C stretching vibration peak at 1,083 cm(-1) in FTIR and the basal space is increased from 0.74 to 1.64 nm in XRD. When OLDH content is lower (<6 wt%), the exfoliated structure is formed. The dispersibility and compatibility between the fillers and matrix are improved. The results from TGA indicate that the thermal stability of HDPE/EVA/OLDH nanocomposites is better than HDPE/EVA and HDPE/EVA/LDH at high temperature. HDPE/EVA/OLDH nanocomposites with 4 wt% OLDH form exfoliated structure and acquire the most optimum thermal stability. In addition, the degree of crystallinity of HDPE in the nanocomposites is affected by OLDH. (C) 2018 Society of Plastics Engineers