Thermoplastic starch polymers products

During the same period, commercialization of thermoplastic starch polymer blends was pursued by Novamont, a division of the Ferruzzi Group of Italy.162-172 Their products, marketed under the trade name Mater-Bi, are typically comprised of at least 60% starch or natural additive and hydrophilic, biodegradable synthetic polymers.64,165 It is stated that these blends form interpenetrated or semi-interpenetrated structures at the molecular level. Properties of typical commercial formulations have properties similar to those in the range of low- and high-density PE. Blends of Mater-Bi products with biodegradable polyesters have been claimed for use as water impervious films.173... 

Thermoplastic starch polymers are generally used as films in shopping bags, bread bags, bait bags, over wrap, flushable sanitary product backing material, and mulch films. 

It is clear that research into modifications to thermoplastic starch based polymers is burgeoning and that property and processing improvements derived from this research will help thermoplastic starch polymers widen their application products and markets. 

Commercial Applications and Products for Thermoplastic Starch Polymers... 

Novamont www.novamont.com/ Materbi Thermoplastic starch polymer blends biodegradable mulch films and bags, thermoformed products, injection molded items, and packaging foam... 

Table 1. Energy requirements for the production of pure thermoplastic starch polymers (without petrochemical copolymers) ...

Commercial applications and products for thermoplastic starch polymers... 

Some commercial thermoplastic starch polymer based products were highlighted in Table 6.1, and some of them can be examined in more detail in this section. Probably one of the first starch based products developed was the National Starch expanded starch foam packaging material ECO-FOAM . ECO-FOAM materials are derived from maize or tapioca starch and include modified starches. This relatively short-term, protected-environment packaging use is ideal for thermoplastic starch polymers. National starch now has additional thermoplastic starch materials, blends and speciality hydrophobic thermoplastic starches for a range of apphcations including injection moulded toys, extruded sheet and blown film apphcations. [http //www.eco-foam.com/ loosefill.asp]. 

The blends of starch and a synthetic polymer (usually polyethylene) are products of commercial importance. Two families of blends are obtained those using dehydrated starch pellets and those using gelatinised or thermoplastic starch. In both cases, the mixture with the synthetic polymer is done by extrusion. Further processing by moulding or blowing is still possible, depending on the kind of starch used. 

Biotec s product portfolio includes thermoplastic starch, which can be substituted for petrochemical based plastic packaging. Stanelco s radio frequency sealing technology can be used to process starch polymers without the degradation caused by other methods such as thermal processing. The purchase of Biotec will help the company develop alternatives to petroleum-based packaging. 

Starch is the major carbohydrate reserve in higher plants and has been a material of choice since the early days of human technology. Recently starch gained new importance as a raw material in the production of plastics, in particular, for the synthesis of monomers to produce polymers such as polydactic acid) and, after chemical modification (e.g. esterification) and thermomechanical processing, to produce thermoplastic starch. This chapter gives a general overview of the most recent research on the development of materials from starch, focusing on thermoplastic starch and the perspectives for future development in this field. A brief review on reactive extrusion of thermoplastic starch is also provided. 

Currently, great efforts are being made to produce thermoplastic starch with improved mechanical properties, low water sensitivity and better compatibility with other polymers, which is of fundamental importance to the production of TPS-based blends. Studies have also been carried out on multilayered systems, as an interesting way to overcome some TPS drawbacks [58]. These... 

The characteristics of the developed material demonstrate that pure potato starch can be used for the production of foams without the need of modified starches or blends with other additives or polymers. This will make new applications for thermoplastic starch based foams possible. 

Particularly suitable polyesters considered in the past have been poly-e-caprolactone (PCL) and its copolymers. Nevertheless, films made of thermoplastic starch and PCL are tacky as extruded, rigid, and have low melt strength at temperatures over 130 °C. Moreover, due to the slow crystallization rate of such polymers, the complete cooling process needs a long time after production of the finished articles, giving an undesirable change of properties with time. 

TTie ability of textile fibers to be set is not characteristic of manufactured fibers alone. Aided in many cases by the presence of starch or other polymers, products made of natural fibers can be set in a wrinkle-free or a sharply creased form. In manufactured, particularly synthetic, fibers, a durable kind of setting can be produced with heat. When yarns or fabrics made from these fibers are shaped and then exposed to elevated temperatures either in dry condition or, in the case of nylon in particular, in the presence of water vapor, thermoplastic relaxation of induced stresses in the fiber takes place and configurations at the molecular level adjust to a new and lower energy level. This depends not only on the temperature used but also on the duration of the exposure. The permanency of the setting, that is, the ability of the product to return to its original configuration after temporary distortion even while exposed to moisture and raised temperatures, is a function of the heat setting. To achieve true permanence, it is essential that the internal crystalline structure should be annealed. 

Starches are insoluble in water. They can be digested by hydrolysis, catalyzed by enzymes (called amylases), which can break the a/p/za-linkages. Humans and other animals have amylases, so they can digest starches. Potato, rice, wheat, and maize are major sources of starch in the human diet. Thermoplastic starch is used for niche products, because of the water solubility often in combination with other polymers, e.g. as blends with PVAL, polyesters, polyesteramids, sometimes as fillers of synthetic polymers. 

Starch (Figure 2), a mixture of atttylose arrd arrtylopectin, is also one of the most abundant natural polymers artd is considered as a promising raw material for the development of novel materials, including biocomposites. It can be converted into a thermoplastic material, known as thermoplastic starch (TPS), through the dismption of the molecular chain irrteractions under specific conditions, in the presence of a plasticizer (Carvalho, 2008). Water and glycerol are the most widely used plasticizers in the production of TPS. 

---