Novel Thermoplastic Materials Based on the Outer-Shell Oxypropylation of Corn Starch Granules

Abstract

The study of the plasticization of corn-starch granules through the bulk oxypropylation of their outer shell produced a novel biphasic material consisting of a low glass transition temperature component surrounding the granules' inner core, which could be hot pressed to form films of the granules dispersed into a thermoplastic matrix. The success and extent of these chemical modifications and the properties of the ensuing composites were assessed by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and contact angle measurements. This approach has the additional advantage of being simple and "green".

Self-reinforced composites obtained by the partial oxypropylation of cellulose fibers. 2. Effect of catalyst on the mechanical and dynamic mechanical properties

“…Apart from the expected absence of a Tg feature for the pristine filter paper, all the other samples gave values comprised between -55 and -45°C, compared with the Tg of the isolated PPO which was about -60°C. This behavior was already observed with different polysaccharides grafted with PPO chains (Schoenenberger et al 1995;VelazquezMorales et al 1998;Gandini et al 2005;de Menezes et al 2007de Menezes et al , 2008 and has been interpreted as reflecting the glass transition of the appended polyether chains (i.e., somewhat less mobile than free ones), without any substantial contribution from the polysaccharide trunk macromolecules.…”

“…A different and perhaps more original strategy to exploit these fibers has consisted in preparing composite materials entirely derived from them, whether through mixtures of cellulose fibers within a cellulose matrix Keckes 2005, 2007;Nishino et al 2004;Nishino and Arimoto 2007;Pommet et al 2008;Qin et al 2008;Soykeabkaew et al 2008), or through the generation of a thermoplastic cellulose shell which can be turned into a matrix by hot pressing, while the pristine inner core of the fibers is retained to function as the reinforcing element Lu et al 2003Lu et al , 2004aZhang et al 2005;Gandini et al 2005;Freire et al 2006Freire et al , 2008de Menezes et al 2007).…”

Thermoplastic starches: Properties, challenges, and prospects

“…However, the main disadvantages of TPS include their retrogradation and unsatisfactory mechanical properties, particularly in wet or dry environments 16, 17. One problem with the use of bioplastics in TPS is the fragile nature caused by its relatively low Tq ( T g ) and the lack of relaxation of sub‐ T g because of the molecular chain of starch 18–20. Moreover, the eventual migration of plasticizers into the environment increases the fragility of the material 21.…”

Starch-based nanocomposites reinforced with flax cellulose nanocrystals

“…However, it is becoming more evident that the ecosystem is considerably disturbed and damaged as a result of the non-degradable plastic materials used in disposable items. Therefore, the interest in polymers from renewable resources has recently gained exponential momentum and the use of biodegradable and renewable materials to replace conventional petroleum plastics for disposable applications is becoming popular [1,2]. Within the broad family of renewable polymers, starch is one of the most attractive and promising sources for biodegradable plastics because of the abundant supply, low cost, renewability, biodegradability, and ease of chemical modifications [3,4].…”