Structure and properties of clay nano‐biocomposites based on poly(lactic acid) plasticized with polyadipates

Abstract

The use of nano‐biocomposites based on plasticized poly(lactic acid) (PLA) has been proposed as a way to improve the polymer ductility and to expand PLA applications window. Novative nano‐biocomposites were elaborated with PLA plasticized by polyadipates (15 wt%) with different molar masses (from 1500 to 2500 Da), with 2.1 wt% of an organo‐modified montmorillonite (O‐MMT). These materials showed enhanced ductility and barrier properties. The clay was swelled in liquid polyadipates prior to their blending with PLA to facilitate chains intercalation and nanofiller exfoliation during melt‐blending. In certain processing conditions, quite homogenous and exfoliated structures were obtained, as shown by X‐ray diffraction (XRD) and transmission electronic microscopy (TEM) results. Irrespective of the average molar mass of the polyadipate, the clay addition induced a reduction in around 25% in oxygen transmission rate (OTR) without an important detriment in tensile properties. Nano‐biocomposites prepared with higher molar masses polyadipates showed the highest thermal stability as well as the lowest OTR, resulting in very promising and novative materials for different applications such as soft packaging. Copyright © 2010 John Wiley & Sons, Ltd.

MMT and LDH organo-modification with surfactants tailored for PLA nanocomposites

“…Accordingly, the OIt measurements did not show any benefit stemming from LDH (PLA_LDH) and its dispersion (PLA_(LDH-PLACOO)_1 and PLA_(LDH-PLA-COO)_2) (see Table 2). Instead, the addition of MMT-PLANH 3 , even if seemingly does not improve the thermal performance of the PLA matrix, as already reported in literature for PLA-based composites with MMT clays having similar morphologies [18,22,31], preserved the thermal stability of the PLA and showed a significant effect onto the OIT results. In particular, with reference to nanocomposites obtained by commercial organophilic MMT, Wu et al [32] reported even a decrease in the stability and Nieddu et al [33] fluctuating results depending on the content of inorganic clay and presumably on the morphology.…”

Infrared and Raman studies on polylactide acid and polyethylene glycol-400 blend

“…PLA has been used intensively in food and industrial packaging [4]. Surprisingly, PLA has the potential to replace conventional petroleum-based plastics such as polystyrene, polyethylene, polypropylene, polyethylene terephthalate in many disposable or short-term applications [5].Naturally, PLA has a good mechanical properties such as high strength, high Young modulus, and high biocompatibility [6].However, PLA has some drawbacks such as its ductility at ambient temperature. To improveits intrinsic properties, blending is applied using other polymer such as some plasticizers [7].…”

Characterization of PLA-limonene blends for food packaging applications

“…Polylactide (PLA) is one of the most promising bio-based polyester for food packaging [1,2] because of its good mechanical, superior transparency, ease of processing and availability in the market [3]. In this sense, poly(lactic acid) (PLA) is one of the most attractive biopolymers with many short-term or disposable applications, such as disposable cutlery (plates, cups, lids and drinking straws), bags and film packaging [4,5].…”

“…PLA is also widely used in rigid and flexible food packaging applications [6] since it has been approved by the US Food and Drug Administration (FDA) as a food contact substance [7,8].. However, the use of PLA for food packaging is somewhat limited because of its poor ductility, thermal and oxygen barrier properties [3].…”

“…Although the addition of plasticizer increases the PLA gas permeability, this could be detrimental for food packaging use [3] since polymer barrier properties are of fundamental importance for food packaging applications [20]. López-Rubio & Lagaron, (2009) reported that the addition of the β-carotene to PLA showed a significant plasticization of polymer matrix [21].…”