Optimum loading level of nanoclay in PLA nanocomposites

Abstract

Biodegradable polymer nanocomposites of poly(lactic acid) and nanoclay (Cloisite 30B) samples were prepared with compositions of 0%, 1%, 2%, 3%, 4%, and 5% (by mass) nanoclay using extrusion followed by injection molding. An exfoliated morphology was observed using x-ray diffraction. The nanocomposites were investigated for their mechanical properties using dynamic mechanical analysis (DMA) and tensile testing. The combination with 3% nanoclay was found to be optimum as a result of having the greatest mechanical strength. The fracture surfaces of the samples were also observed with the help of a scanning electron microscopy, and the images obtained complied with the experimental values attained for the samples, indicating more ductile fractures for those samples with greater mechanical strength. The thermal properties of the composites were studied with the help of differential scanning calorimetry and DMA data, and it was found that the trend followed by the glass transition temperature values obtained by both the methods was the same.

Single and hybrid organoclay‐filled PLA nanocomposites: Mechanical properties, viscoelastic behavior and fracture toughening mechanism

“…PLA nanocomposites prepared with MTDP and HMPETA caused nearly no change in E ', which can be associated to the reduction of molecular mass by thermal degradation during extrusion, as suggested by TGA and GPC discussion in previous work 19 . Furthermore, it was reported that at high OMt content the chain confinement effect can be reduced and there is a reduction of the fillers/matrix contact area due to an increase in the number of OMt agglomerates 11,12,15 . Indeed, the increase of C30B content from 2 to 6 wt% caused a significant increase in E ' for PNC30B nanocomposites, but the same was not observed for 8 wt%.…”

“…PLA has processing characteristics, such as extrusion and injection molding, comparable to conventional thermoplastics, 2 and optical, thermal and mechanical properties similar to polypropylene (PP), poly(ethylene terephthalate) (PET), and polystyrene (PS) 4 ; nevertheless, it presents high brittleness, a rather low heat deflection temperature and high gas permeability, limiting its use for packaging purposes 2,5 . Many of PLA's limitations, especially mechanical ones such as excessive brittleness, low toughness and low impact resistance, have been minimized by the addition of plasticizers or flexible polymers, 6–8 organic compounds, such as ionic liquids, 9 and nanofillers, as calcium carbonate, 10 silica, 11,12 zinc oxide, 13 graphene, 14 and organoclays 12,15–17 …”

“…2,5 Many of PLA's limitations, especially mechanical ones such as excessive brittleness, low toughness and low impact resistance, have been minimized by the addition of plasticizers or flexible polymers, [6][7][8] organic compounds, such as ionic liquids, 9 and nanofillers, as calcium carbonate, 10 silica, 11,12 zinc oxide, 13 graphene, 14 and organoclays. 12,[15][16][17] We have previously published the study of the chemical composition effect of different Brazilian organic-modified montmorillonites (OMt) in PLA clay polymer nanocomposites (CPN), as well as the morphology and thermal properties, 18 and thermal stability and fire performance as a function of the type of organoclay modifier. 19 It was concluded that the morphology, structure and properties of the PLA nanocomposites depended on chemical composition of the organoclays.…”

Thermally stable low‐density polyethylene/polyhydroxybutyrate pairs: Synergy between organomodified nanoclay and LDPE‐g‐MAH

“…Above this critical point, the thermal stability is reduced . Elsewhere, the effect of Cloisite 30B on thermal stability of PLA was investigated, and it was observed that 3 wt % is the critical point above which the thermal stability starts to drop . According to these studies, nanoclay incorporation can improve barrier properties by acting as an insulator to volatile compounds and limiting gas transportation during degradation which improves thermal stability .…”

The effect of organobentonites from spent bleaching earth (SBE) and commercial bentonite on nanocomposite properties

“…PLA is promising polymer produced from renewable sources. Pirani [5] conducted the addition of 1-3% Cloisite 30B content to PLA matrix result in tougher nanocomposite than the neat PLA. This improvement was not shown for the addition of 4% and 5% Cloisite 30B.…”