Melt free radical grafting of glycidyl methacrylate (GMA) onto fully biodegradable poly(lactic) acid films: effect of cellulose nanocrystals and a masterbatch process

Abstract

This article reports the preparation, by means of a masterbatch procedure, of poly (lactic acid) (PLA)/ cellulose nanocrystal (CNC) films via premixing 1% wt of CNC into PLA or glycidyl methacrylate (GMA) grafted PLA (g-PLA). These films were obtained by reactive extrusion and subsequent film processing. In this study, 10% wt of GMA with respect to neat PLA was used in the extrusion phase, after that a final grafting degree of 5.69% was obtained. The film obtained by using the masterbatch steps were compared with the system obtained by a direct extrusion of 1% wt of CNC in PLA/g-PLA. Thermogravimetric, crystallization and mechanical properties, as well as morphology of CNC reinforced PLA nanocomposites were characterized. Differential scanning calorimetry and thermogravimetric analysis showed enhanced crystallization ability and an improved heat resistance for the resulting nanocomposites obtained after the use of masterbatches, for example field emission scanning electron microscopy confirmed that the masterbatch preparation procedure was beneficial to the dispersion of CNC in the final nanocomposites. Furthermore, different mechanical performance was obtained when using different masterbatches, which were considered to contribute to extend the applications of PLA based composites as food packaging materials in different sectors.

Nanomaterials for products and application in agriculture, feed and food

“…Nanocor ® ) (Nanocor, 2016) which have been reported in the US, but so far not in the EU. Natural biopolymer-based nanocomposite packaging materials with bio-functional properties include chitosan, cellulose and carrageenan (Rhim, Park, & Ha, 2013;SanchezGarcia, Lopez-Rubio, & Lagaron, 2010;Shatkin & Kim, 2015;Yang, Dominici, Fortunati, Kenny, & Puglia, 2015). Carbon nanotubes can be used in food packaging to improve mechanical properties and introduce antimicrobial effects (Rungraeng, Cho, Yoon, & Jun, 2012).…”

Influence of nanoclay and graft copolymer on the thermal and flammability properties of poly(lactic acid)/banana fiber biocomposites

“…where V and N are volume (ml) and normality of the standard HCl used for titration, C is the concentration of KOH, 142.2 is the molecular weight of GMA, and m is the weight of sample in g [18].…”

“…Many studies have been made to use maleic anhydridegrafted polymer as a compatibilizer for polymer composites [9][10][11][12]. Amongst all types of graft copolymers, the most suitable candidates in research which have emerged as a new class of materials in recent years is glycidyl methacrylate (GMA)-grafted-copolymer [13][14][15][16][17][18].…”

Surface Alkylation of Cellulose Nanocrystals to Enhance Their Compatibility with Polylactide

“…However, several properties of PLA such as its gas permeability and thermal stability are somewhat insufficient. These properties should be further improved for specific applications [29]. Such improvements could be achieved by incorporating CNCs, homogeneously dispersed in a PLA matrix, for the reason of its chain immobilization effects as well as its excellent physical properties [30].…”