Bottles and other packaging account for approximately 70% of the global market of biopolymers, which include both biodegradable and durable materials. Durable materials account for the vast majority of the market, especially the bottles. Degradable polymers are instead refrained by the often-insufficient mechanical and thermal properties, which limit their usage to single-use packaging items at ambient temperature and in dry conditions. In this respect, the present work deals with the development and manufacturing of innovative and custom-built Poly Lactic Acids (PLAs) for injection and compression molding, which are designed to be compostable, suitable for food contact and characterized by a good compromise of mechanical properties and thermal stability. A commercial grade PLA was, therefore, compounded in a twin-screw co-rotating extruder by the addition of maleated and glycidyl methacrylate PLAs as chain extenders and micro-lamellar talc as mineral filler and nucleation promoter. Compatibilization between PLA, chain extenders and mineral filler was, therefore, investigated. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to evaluate the material structure and thermal response of the pellets after reactive compounding extrusion. The experimental findings show that material structure and, especially, crystallization of the PLA can be controlled by fine-tuning the compound formulation as well as by setting of the operational parameters. In addition, achievement of the appropriate crystallization degree in the polymer is found to lead to composite materials, which can boast very good thermal stability. Accordingly, the custom-built PLA formulations feature the potential to expand significantly the fields of application of non-durable polymers, thus posing a valid alternative to both durable biopolymers and conventional plastics in injection and compression molding process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44504. © 2016 Wiley Periodicals, Inc

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Reinforced biocomposites were compounded by the reactive extrusion of poly(lactic acid) (PLA) and chemically modified microlamellar talcs. Talc was functionalized by the hydrolysis and condensation reaction of its surface hydroxyl groups with different kinds of organosilanes, namely, 3‐aminopropyl triethoxysilane and (3‐glycidoxypropyl)trimethoxysilane, and commercially available tri‐isocyanates, namely, Bayhydur 3100 and Desmodur 3900, which feature hydrophilic and hydrophobic behaviors, respectively. PLA–talc biocomposites were also compounded by the addition of two types of reactive biodegradable compatibilizing agents, namely, maleic anhydride and glycidyl methacrylate modified PLA. The resulting compounds were melt‐processed by injection molding to get flat substrates with different formulations. The thermal responses of the extruded compounds and injection‐molded items, specifically the first and second thermal transitions, were analyzed by differential scanning calorimetry. In particular, the influence of the different material formulations, their thermal history, and/or shear stress in single‐ or multiple‐stage heating and/or melt processing on the glass transition, crystallinity, and melting behavior of the biocomposites was investigated. The experimental findings revealed that the macroscopic thermal response of the compounds (i.e., extruded pellets) and substrates (i.e., injection‐molded flat slabs) manufactured by the melt processing of the available formulations was controlled and significantly improved by the fine‐tuning of the chemical (i.e., reaction mechanisms, chemical bonds) and physical interactions (i.e., steric hindrances, physical bonds) among the modified talc, PLA, and compatibilizing agents. These results are of great practical importance and open up broader scenarios for the industrial application of biopolymers and biocomposites, specifically in all of those consumer goods where thermal stability and the preservation of mechanical performance at moderate and high temperatures of the materials are pivotal. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45179.

Degradable polymers are limited by their often-insufficient mechanical and thermal properties, which limit their usage to single-use packaging items at room temperature and in dry conditions. In this respect, the present work deals with the manufacture of custom-built Poly Lactic Acids (PLAs), which are designed to be compostable, suitable for food contact and are characterized by a good compromise between mechanical properties and thermal stability. A commercial grade PLA was, therefore, compounded in a twin-screw co-rotating extruder by the use of specific additives: maleated and glycidyl methacrylate PLAs as compatibilizers/chain extenders and microlamellar talc as mineral filler/nucleation promoter. After pelletizing, the resulting compounds were melt-processed by injection and compression molding.Differential scanning calorimetry, flexural tests in static machine and top-hat cylindrical flat indentations were performed to evaluate the thermal and mechanical response of the molded components. The experimental findings show that crystallization of the PLA can be controlled by fine-tuning the compound formulation as well as by properly setting the processing parameters. In addition, achievement of the appropriate crystallization degree in the polymer can lead to molded components, which exhibit improved mechanical strength and high thermal stability. K E Y W O R D Scompostable polymer, mechanical response, melt processing, molding, thermal stability

Flexible and semiflexible packagings can be manufactured by cast extrusion of plastic sheet and thermoforming of containers. Thermal stability is often required as packaging items after being thermoformed can come in contact with hot food/beverage, especially during hot filling operations. In this framework, the present study deals with the design and manufacturing by thermoforming of plastic containers that are, at the same time, compostable and suitable for high‐temperature applications (~100 °C). First, extrusion compounding of Poly(l‐lactic acid) (PLLA)‐based biodegradable polyester blends was performed. In particular, the effect on the material properties of different types of nucleating agents was investigated. Combinations of micro‐lamellar talc, poly(d‐lactic acid) (PDLA), ethylene bisstearamide (EBS), and titanium dioxide (TiO2) were studied. The formulations involving EBS boast the highest crystallinity and the fastest onset of the crystalline phase on sheets produced by cast extrusion. Conversely, the formulations involving TiO2 feature the lowest degree of crystallinity and the slowest onset of the crystalline phase. Combinations of talc and PDLA exhibit an intermediate behavior. Second, thermoforming of the plastic foils was performed. A very different trend of the crystallization after thermoforming is shown. Indeed, crystallinity is the highest for the formulations involving talc and PDLA, the lowest for the ones containing EBS. In conclusion, the biodegradable polyester blends are found to be suitable for the manufacturing of compostable and thermostable packaging items by cast extrusion and thermoforming. Final crystallization of the material and the resulting thermal stability can be fine‐tuned by modulating type and amount of nucleating agents. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48722.

In recent time, the quest for renewable materials for the development of packaging items is constantly increasing. The class of polylactic acids (PLAs) is the most promising one, although a broader scale commercial expansion of these polymers cannot leave unceasing enhancement of their functional properties aside, especially toughness and thermal stability. Similarly, continuous innovation in prototyping competitive easy-route solutions for material processing is another key to successful industrial applications of PLAs. In this respect, this study deals with the design and formulation of innovative custom-built PLAs for injection and compression molding, which are compostable, suitable for food contact, and characterized by a good compromise of mechanical properties and thermal resistance. Therefore, a commercial grade PLA was modified by reactive compounding extrusion with maleic anhydride (MAH)-grafted PLA (PLA-MA) and glycidyl methacrylate (GMA)-grafted PLA (PLA-GMA) and micro-lamellar talc. Material structure and thermal response of the compounds were evaluated by differential scanning calorimetry (DSC) and Fourier transform-infrared spectroscopy (FTIR). The experimental findings show that material structure and, especially, crystallization of the PLA can be controlled by fine-tuning the compound formulation. In addition, achievement of the appropriate crystallization degree in the polymer can lead to compostable composite materials with good thermal stability. Accordingly, the custom-built PLA formulations feature the potential to expand significantly the fields of application of compostable biopolymers, thus posing a valid alternative to both durable not compostable bioplastics and conventional plastics in injection and compression molding process

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