Development of Novel Blown Shrink Films from Poly(Lactide)/Poly(Butylene-Adipate-co-Terephthalate) Blends for Sustainable Food Packaging Applications

Abstract

Heat-shrinkable films, largely made of polyolefins and widely employed in the packaging sector as collation or barrier films, due to their short service life, are held responsible for high environmental impact. One possible strategy for reduction in their carbon footprint can be the use of biodegradable polymers. Thus, this work aimed to develop novel, heat-shrinkable, fully biodegradable films for green packaging applications and to analyze their functional performance. Films were obtained from blends of amorphous polylactic acid (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT) at different mass ratios and compatibilized with a chain extender. They were produced by means of a lab-scale film blowing extrusion apparatus and characterized in terms of physical–mechanical properties and shrinkability. The influence of the processing parameters during the extrusion blowing process on the films’ behavior was investigated, highlighting the effects of blend composition and stretching drawing conditions. Shrinkage tests demonstrated that the produced films have shrinkability values in the typical range of mono-oriented films (ca. 60–80% in machine direction and ca. 10–20% in transverse direction). Moreover, the shrinkage in machine direction increases both with the mass flow rate, the take-up ratio to blow-up ratio and the bubble cooling of the film blowing process, and with the PLA content into the blend. In particular, films at higher PLA content also exhibit higher transparency and stiffness.

Biodegradable Blown Film Composites from Bioplastic and Talc: Effect of Uniaxial Stretching on Mechanical and Barrier Properties

“…BUR is the measure of the TD orientation, which is accomplished by air inflation, which enlarges the bubble diameter and primarily elongates the polymer along the transverse axis. [ 21 ] The bubble diameter can be calculated using lay flat width, D 1 = 2*(lay flat width/π); D 0 = 60 mm $$$$\begin{equation}{\mathrm{BUR}}\ = \ \frac{{{D_1}}}{{{D_0}}}\end{equation}$$$$…”

Reusable, Recyclable, and Biodegradable Heat-Shrinkable Melt Cross-Linked Poly(butylene adipate-co-terephthalate)/Pulp Biocomposites for Polyvinyl Chloride Replacement

“…Thanks to the UV cross-linking, the blends displayed heat-driven shape-memory and heat-shrinkage. Pietrosanto et al, have reported heat-shrinkable blends of PBAT and poly­(lactide) melt compounded with a chain extender . The blends were shaped by film-blowing, and the heat-shrinking was achieved mainly in the machine direction, as the films were unidirectionally oriented.…”

“…Pietrosanto et al, have reported heat-shrinkable blends of PBAT and poly(lactide) melt compounded with a chain extender. 9 The blends were shaped by film-blowing, and the heat-shrinking was achieved mainly in the machine direction, as the films were unidirectionally oriented. Yu et al, have shown that pure PBAT can heat shrink and it displays shape-memory.…”

Development of PBS/Nano Composite PHB-Based Multilayer Blown Films with Enhanced Properties for Food Packaging Applications

“…In such cases, blending different polymers through melt processing can be an easily affordable solution. Many works focus on this strategy with the aim of obtaining blends with enhanced properties, taking advantage of the complementary characteristics of the neat materials [ 15 , 16 , 17 , 18 , 19 ]. Another approach that has been studied and is currently performed in the flexible packaging industry is the designing and production of multilayer structures [ 20 , 21 , 22 , 23 , 24 ].…”