Compatibilizer interlayers composites

In ternary nanocomposites, compatibilizers have been mostly used to improve the adhesion at the polymer/filler interface rather than to modify the polymer/elastomer interface. Mishra et al. [80] compounded PP/EPDM/organoclay (75/25/5 wt%) and added PP-g-MA (1 wt% MA) as a compatibilizer with a clay/PP- -MA ratio of 1/3. They characterized the interlayer spacing of the clay platelets by XRD and observed that it increased from 3.4 to 4.3 nm for systems without and with compatibilizer. This was attributed to a better diffusion of the PP-g-MA chains inside the interlayer spacing thanks to their functional groups. Numerous other authors prepared and characterized ternary composites with a compatibilizer. Examples include Lim et al. [81] and Lee et al. [5] on PP/PP- -MA/POE/ organoclay systems, Mehta et al. [23] on PP/PP-g-MA/EPR/organoclay systems, and Liu and Kontopoulou [24,45] on PP/PP-g-MA/ethylene-octene copolymer/silica composites. It should be noted that the compatibilizer itself may affect the properties of the matrix... 

One of the keys to take full advantage of the reinforcement and/or tortuosity clay particles can provide to the nanocomposite is to obtain a satisfactory dispersion of the nanoclay in the polymer matrix and the insertion of polymer chains within the interlayer of the clay structure. In order to investigate the delamination of the MMT layers, XRD were performed on the composite film samples having different compatibilizer filler ratios. Depending on the exfoliation and distribution of MMT layers, three different types of composites are achievable tactoid or immiscible, intercalated or exfoliated. For a tactoid or immiscible composite structure, the filler dififaction peak should stay at the same position for an intercalated structure, it should be shifted to lower 20 value and for an exfoliated structure it should disappear. Figure 3.1 compares the position of diffraction peaks of MMT and RH/MMT filled LDPE nanocomposite films, with or without MAPE. 

---