Effect of Ionomeric Compatibilizer on Clay Dispersion in Polyethylene/Clay Nanocomposites

Abstract

Summary: Linear low‐density polyethylene (LLDPE)/clay nanocomposites are obtained and studied by using a zinc‐neutralized carboxylate ionomer as a compatibilizer. LLDPE‐g‐MA is used as a reference compatibilizer. Two different clays, natural montmorillonite (Closite Na+) and a chemically modified clay Closite 20A have been used. Nanocomposites are prepared by melt blending in a twin‐screw extruder using two mixing methods: two‐step mixing and one‐step mixing. The relative influence of each compatibilizer is determined by wide‐angle X‐ray diffraction structural analysis and mechanical properties. The results are analyzed in terms of the effect of the compatibilizing agent and incorporation method in the clay dispersion, and the mechanical properties of the nanocomposites. Experimental results confirm that the film samples with ionomer show a good mechanical performance only slightly below that of the samples with maleic anhydride (MA). The two‐step mixing conditions result in better dispersion and intercalation for the nanofillers than one‐step mixing. The exfoliation of clay platelets leads to an improved thermal stability of the composite. The oxygen permeability of the clay nanocomposites, using ionomer as a compatibilizer, is decreased by the addition of the clay.TEM image of a PE/4 wt.‐% Closite 20A nanocomposite formed using ionomer.imageTEM image of a PE/4 wt.‐% Closite 20A nanocomposite formed using ionomer.

Effect of different dispersing additives on the morphology and the properties of polyethylene-based nanocomposite films

“…The obtained results suggest that the presence of OMMT nano-particles in the composite leads to an increase of the elastic modulus with no changes, or in some systems a slight decrease, in the ultimate properties, in keeping with what already reported in the literature [5][6][7][8][9]. In general, in order to obtain a better dispersion of the OMMT nano-particles and achieve good performances, use of dispersing additives and/or adhesion promoters is required [10][11][12]14]. It is interesting to note that the values of all the mechanical properties of films containing 5 wt% of PEgMA or 5 wt% of EAA are practically the same of films containing only 0.5 wt% of TEG.…”

“…When polymer melt and filler are not well adherent, e.g. in the case of a non-polar matrix such as polyolefins containing polar particles such as nanoclays, use of an adhesion promoter or compatibilizer, having polar groups is necessary [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In order to modify the clay morphology and consequently the final macroscopic properties in clay filled polyethylene, different commercial compatibilizers have been used.…”

“…In order to modify the clay morphology and consequently the final macroscopic properties in clay filled polyethylene, different commercial compatibilizers have been used. Sánchez-Valdes et al [11] have used Zn-neutralized carboxylate ionomer, while, Shah et al [12] used Na-neutralized poly(ethylene co-methacrylic acid), both Surlyn ® by DuPont, in LDPE/clay nanocomposite formulation. Filippi and coworkers [13][14] have used as a compatibilizer, the ethylene-acrylic acids copolymers (Et-g-AA), namely Escor ® by Exxon-Mobil.…”

Linear low‐density polyethylene colored with a nanoclay‐based pigment: Morphology and mechanical, thermal, and colorimetric properties

“…On the other hand, samples prepared with NP(20) and NP(100) (a high load of MB) had lower values of E and E abs than PE, and they showed an uncertain trend as the concentration of the nanopigment in the samples increased. It is generally accepted that there will be an increase in E with the load of organoclay and compatibilizer,1, 26 whereas the ductility (related to E abs ) in general decreases when the concentration of organoclay increases 21, 27, 28. However, increases in E and the ductility have also been described for LDPE/LLDPE/NC systems 16.…”

Melt processed polyethylene/fullerene nanocomposites with highly improved thermo-oxidative stability

“…PE suffers from a relatively low thermal and thermo-oxidative stability and, therefore, with the purpose of improving this particular property, it has been previously compounded with a large number of different micro-and nanoparticles. Amongst the particle fillers considered are: clays (montmorillonite, silica, etc) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], layered double hydroxides (LDHs) [10,19,20], calcium carbonate (CaCO 3 ) [21], carbon nanotubes (CNTs) [13,[22][23][24][25][26] and the fullerene C 60 [27][28][29][30].…”