The use of a protein based coated layer was demonstrated to be successful for achieving a good separation of traditional plastic films or sheets in conventional multilayer packaging and thus improving its recyclability [1]. However, the possibility of developing a protein based film by conventional processing technique typical of thermoplastic polymers could open a large range of applications, but it is quite challenging. In fact, the processing of proteins is difficult because of their tendency to degrade and crosslink at high temperature [2]. The addition during extrusion of proper crosslinking inhibitors, the plasticization and the blending with bio-related polyester is necessary to achieve a material still compostable but also processable with conventional industrial equipment [3-4]. However, although biopolyesters represent the best available option, the high polarity usually shown by proteins is not compatible with them, and coarse phase morphology and poor mechanical properties were often observed in these blends [5]. Hence the selection of proper compatibilizers consisting in small molecules or in modified proteins is quite important for achieving a better phase morphology, in terms of phase dimensions and adhesion, and properties modulation. In the present paper tri-butyl Citrate (C), Glyceryl monostereate (G) and soy lecithin (L) were employed as small molecules having a behaviour of plasticizer or compatibilizer. Modified whey protein with oleic (+OL) or lauric (+LA) hydrophobic chains, synthesized by a Schotten-Baumann approach, were also employed.
PROCESSING AND PROPERTIES OF BIO-POLYESTER/PROTEIN BLENDS FOR HIGHLY RECYCLABLE MULTILAYER PACKAGING
COLTELLI, MARIA BEATRICE;CINELLI, PATRIZIA;LAZZERI, ANDREA
2015-01-01
Abstract
The use of a protein based coated layer was demonstrated to be successful for achieving a good separation of traditional plastic films or sheets in conventional multilayer packaging and thus improving its recyclability [1]. However, the possibility of developing a protein based film by conventional processing technique typical of thermoplastic polymers could open a large range of applications, but it is quite challenging. In fact, the processing of proteins is difficult because of their tendency to degrade and crosslink at high temperature [2]. The addition during extrusion of proper crosslinking inhibitors, the plasticization and the blending with bio-related polyester is necessary to achieve a material still compostable but also processable with conventional industrial equipment [3-4]. However, although biopolyesters represent the best available option, the high polarity usually shown by proteins is not compatible with them, and coarse phase morphology and poor mechanical properties were often observed in these blends [5]. Hence the selection of proper compatibilizers consisting in small molecules or in modified proteins is quite important for achieving a better phase morphology, in terms of phase dimensions and adhesion, and properties modulation. In the present paper tri-butyl Citrate (C), Glyceryl monostereate (G) and soy lecithin (L) were employed as small molecules having a behaviour of plasticizer or compatibilizer. Modified whey protein with oleic (+OL) or lauric (+LA) hydrophobic chains, synthesized by a Schotten-Baumann approach, were also employed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
