The evaluation of process stability was carried out by Mitrus. Temperature changes in each extruder section were recorded in the processing of all materials with different process parameters. The stability of temperature behavior of the final product immediately after it had left the extruder die was also studied. Temperatures in the cylinder were measured using […]
A pin extruder is a type of single-screw extruder that is commonly used in starch processing. There are two designs of this extruder: one has stationary pins and a rotating screw with interruptions of the flights, called the expander, while the other has a rotating and axially oscillating screw, also known as a co-kneader. The […]
Navigating the Basics of Single-Screw Extruders In the realm of industrial processes, single-screw extruders stand as stalwart players, especially when slip at the wall is a non-issue, and high shear is not a prime concern. Delving into their intricacies requires a grasp of their operational mechanisms and modeling intricacies, information readily available in literature sources […]
In the realm of extruders, a pivotal division emerges between the single-screw and twin-screw varieties, each wielding distinct transport mechanisms. Single-Screw Extruders: Friction at the Helm The single-screw extruder, a stalwart in the extrusion domain, operates with a lone rotating screw snugly fit into its barrel. The transport mechanism hinges on friction between the material […]
Wojtowicz conducted a study on the effects of plasticizers on starch, specifically the addition of water in amounts from 5 to 20%. Results showed that almost every recorded parameter during treatment in the Brabender Mixograph was affected by water addition. In mixtures of starch/glycerol/water, decreasing start melting temperatures were observed, ranging from 80°C for samples […]
The heating-shearing behavior of potato starch/glycerol mixtures with limited water addition (below 30%) was investigated by Wojtowicz and van der Goot and by Wojtowicz (paper in print). The goal of the treatment was to use Brabender Mixograph simulating mixing-kneading and a specially designed shearing device-shear cell to obtain a starchy molten phase under well-defined thermomechanical […]
Plastics can generally be considered to have a favorable environmental impact due to their lightweight nature, efficient use of resources and energy during production, transport and application, and their high energy potential for thermal recovery after use. Bioplastics have an added advantage of using renewable resources, which can be beneficial in terms of reducing consumption […]
A variety of international standards and test methods have been created for biodegradability, product safety, and compost-derived products. The primary difference among these standards is the percentage of biodegradation necessary for adherence. The main international organizations that have established standards or testing methods are: A family of ASTM standards addresses physical property deterioration under a […]
The use of additives that control the degradation behavior of conventional thermoplastics and inherently biodegradable plastics is becoming popular due to price competition. These additives, known as prodegradant concentrates, are typically based on catalytic transition metal compounds such as cobalt stearate or manganese stearate and are used at levels of 1-3%, resulting in additional costs […]
Photodegradable plastics are synthetic polymers with light-sensitive chemical additives or copolymers that weaken the bonds of the polymer in the presence of ultraviolet radiation. These plastics are designed to become weak and brittle upon prolonged exposure to sunlight. Biodegradation occurs only after an initial photodegradation stage in which UV light triggers degradation of the polymer. […]