Evaluation of different amine-functionalized polyethylenes as compatibilizers for polyethylene film nanocomposites

The compatibilization effects provided by different amine-functionalized polyethylenes (PEs) versus those provided by a maleated polyethylene (PEgMA), for forming PE-based film nanocomposites, were studied. Amine-functionalized PEs were prepared by reaction of PEgMA with two primary amines, 2-aminoethanol (EA) and 1,12-aminododecane (D12), and a tertiary amine, 2-[2-(dimethylamino)ethoxy]ethanol (DMAE), in the melt to form the corresponding PEgEA, PEgD12 and PEgDMAE. Nanocomposites were prepared bymelt mixingin a twin-screwextruder PE andthese three functionalizedcompatibilizers with a modified montmorillonite clay. The purpose of the current work was to determine the effect of the various amine-functionalized PEs on the degree of exfoliation and optical properties of PE-clay nanocomposites in order to obtain nanocomposite films for greenhouse cover applications. Fourier transform infrared analysis confirmed the formation of the amine-modified PE compatibilizers. Structural, morphological, mechanical, rheological and optical properties of film samples were used to characterize the nanocomposites. All the amine-modified PE-compatibilized nanocomposites had better clay exfoliation compared to uncompatibilized PE composites. Results showed that PEgDMAE formed highly exfoliated morphology and a favorable balance between mechanical (stiffness and ductility), optical and thermal insulating film properties even at higher clay contents. It was determined that nanocomposites with greater exfoliated structure showed better optical and thermal insulating film properties. PEgEA and PEgD12 compatibilizers did not provide a better interaction for exfoliation of the organoclay than the PEgMA material. The PEgDMAE compatibilizer led to a highly exfoliated morphology and a favorable balance between mechanical, optical and thermal insulating film properties even at higher clay contents. The PEgDMAE film nanocomposites could be used ideally for greenhouse cover applications.