Nanocomposites based on polyolefins and functional thermoplastic materials

Abstract

Polyolefins are today the most used thermoplastic materials thanks to the high technology and sustainability of the polymerization process, their excellent thermomechanical properties and their good environmental compatibility, including easy recycling. In the last few decades much effort has been devoted worldwide to extend the applications of polyolefins by conferring on them new properties through mixing and blending with different materials. In this latter context, nanocomposites have recently offered new exciting possibilities. This has been made possible on the basis of the improvement of polyolefin functionalization processes with the availability of several olefin homo- and copolymers bearing a small (generally less than 1 mol%) amount of backbone grafted polar groups. These are indeed adequate to endow favourable interface interactions with polar macromolecules and inorganic compounds, leading first to compatible blends and then to microcomposites. The successful use of nanostructured dispersed materials has opened, on a similar basis, the way to nanocomposites as described in this review. This review provides a broad and updated description of the synthetic routes to nanostructured biphase materials having the typical structural properties of polyolefins (continuous matrix) but showing enhanced thermomechanical properties, thermostability, lower flammability, lower gas permeability and electrical and optical properties, thanks to the presence of an extended interphase interaction with very different nanodispersed species.\ud \ud  2008 Society of Chemical Industr

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

“…There are several methods reported in the literature for preparing organo-modified LDHs, i.e. anionexchange of a precursor LDH, regeneration, thermal reaction, direct synthesis by coprecipitation, and the more recent one-step synthesis method [15][16][17]. Among all of the methods described, anion exchange is one of the more commonly used and several anionic species, such as phosphates, carboxylates, sulfonates, and sulfates, have been used [18].…”

Fabrication, Structure and Properties of Epoxy/Metal Nanocomposites

“…Polymer/metal nanocomposites have attracted extensive interest in the past decades, [1] because of: (i) particle/ particle correlation arising at low concentrations (<0.1 vol.-%), (ii) ultra-low percolation thresholds (%1 vol.-%), (iii) large particle number densities of up to %10 20 cm À3 , (iv) extensive interfacial area per volume of particles (%10 7 cm 2 Á cm À3 ), (v) short particle/particle distances, and (vi) decrease in metal particle size leads to a broadening of the absorption band. [2] Two methods have been developed to-date for the fabrication of polymer/metal nanocomposites, including: (i) the in situ method involves mixing metal precursors with hydrophilic polymers, i.e., poly(ethylene glycol) and poly(vinyl alcohol), followed by thermal or photochemical reduction, [3][4][5][6][7][8] and (ii) the transfer method involves the preparation of nanoparticles and the subsequent solution mixing with polymers.…”

Organically modified hydrotalcite for compounding and spinning of polyethylene nanocomposites

“…On the contrary, much less work [6][7][8][9][10][11] has been focused on the effects of layered double hydroxides (LDH) in polyolefins. The structure of LDH, also referred as hydrotalcite, is derived from brucite or Mg(OH) 2 , where some Mg 2+ cations are replaced by trivalent cations yielding positively charged layer [6][7][8]. Organic modification is adopted to enlarge the interlayer distance of the pristine clay and to increase the hydrophobic nature, thus decreasing the interaction between platelets in order to facilitate its dispersion in hydrophobic polymers [6].…”

“…With proper processing conditions, organically modified nanofiller can be melt-dispersed into polyolefins and exfoliated, while it is not very good as that observed in polyamides, polyurethanes, and some other polar polymers [5]. However, significant improvement of thermo-mechanical, flame retardant, barrier, rheological properties and frequently better thermoforming properties were observed in nanofilled polyethylene [6][7][8]12], polypropylene [10] and polybutene [11]. Some polyolefin nanocomposites have been also processed by melt spinning, that is the most common textile process [13].…”