Starch plasticizers

Averous, L. and Halley, P.J., Biocomposites Based on Plasticized Starch, Biofuels, Bioprod. Biorefin., 3, 329 (2009)... 

Eilm products with good mechanical characteristics are only obtained if thermoplastic, plasticized starch has been used. If no plasticizer is used, biodegradable polymers with limited mechanical properties will be obtained. In this case, coextmsion with the base polyester or another polymer is the way to upgrade the mechanical and/or moisture barrier properties (for comparison see Table 6). 

Tarvainen et al. (2002) studied the film-forming ability of starch acetate (DS 2.8) and the effect of commotfly used plasticizers on the physical properties of starch acetate films. The properties were compared with ethylcellulose films. Mechanical studies, water vapor and drug permeability tests, and thermal analysis by differential scarming calorimetry (DSC) were used to characterize the film-forming ability of starch acetate and efficiency of tested plasticizers. Starch acetate films were foimd to be tougher and stronger than ethylcellulose films at the same plasticizer concentration. Also, in most cases, the water vapor permeability of starch acetate... 

The starch plasticization is obtained by gelatinization of the grains in low moisture conditions leading to the melting of the starch grains. This is the key phenomenon in the transformation of the whole corn plant. The plasticized starch forms a continuous matrix in which the defibrated fibers are embedded, as showed schematically in Figure 5.22. 

Surprisingly, the association between TPS and cellulose fibres (polysaccharide-based composites) has been little analysed. In the literature, cellulose fillers used in association with a plasticized starch matrix are commercial paper fibres,10 potato pulp microfibrils,11 12 tunicin whiskers and paper bleached pulp.13-14 The literature reports that these cellulose fillers improve the tensile strength. Besides, the composite water sorption seems to be decreased. This behaviour is related to the well known lower water uptake of cellulose compared to starch.10-14... 

The glass transitions of plasticized starches are sometimes difficult to determine by DSC analysis because the drop heat capacity change is quite low at the glass transition. Then, DMT A determination is preferably used to approach this transition which is clearly demonstrated by a broad tan <5 peak.6 The dynamic thermo-mechanical analyser is a TA instrument DMA-2980 (USA). The experimental protocol has been fully described in a previous publication.6... 

L. Averous, L. Moro and C. Fringant, Properties of plasticized starch acetates, 1CBT Conference, Coimbra (Portugal), 28-30 Sept. 1999. 

In its application in biodegradable plastics, starch is either physically mixed, with the native granules kept intact, or melted and blended on a molecular level with the appropriate polymer as described in Sects. 5.7 and 5.8. In either form, the fraction of starch in the mixture which is accessible to the enzymes can be degraded by either, or both, amylases and glucosidases. 

Destructurized and plasticized starch used as a thermoplasticlike material. 

Here we will briefly discuss two major topics related to thermoplastic starch physical chemistry the starch granule destructuration or gelatinization during TPS production and the macromolecular properties of the semicrystalline plasticized starch which include indistinctly thermoplastic starch, destructurized starch and plasticized starch. 

Miladinov et al. reported the preparation of starch-fatty acid esters by reactive extrusion of plasticized starch and acid anhydrides (acetic, propionic, heptanoic and palmitic anhydrides) in the presence of sodium hydroxide as a catalyst [87]. Starch esters have been prepared by REX using maleic anhydride (MA) as a cyclic dibasic acid anhydride in the presence of 20 wt% glycerol as plasticizer. This material was melt-blended with biodegradable polyester. 

L. Averous, Biodegradable Multiphase Systems Based on Plasticized Starch A Review. Journal of Macromolecular Science Part C-Polymer reviews 44 231-274,2004. 

If starch is modified by partially fermenting it, or esterifying or etherification, the resulting material can be extruded by adding plasticizers. Starch-based plastics are readily biodegraded. In most cases, the polymers are also water-soluble. Several suppliers now offer thermoplastic starch. Major markets include soluble films for industrial packaging, films for bags and sacks, and loose fill. 

Formulation and Development of Biodegradable and Bio-based Multiphase Materials Plasticized Starch-based Materials... 

To coimter the loss of water dining the process and a significant degradation of the material, to prevent, e.g., the formation of cellular stractures output from an extruder, and to obtain a material with controlled properties, we use a non-volatile plasticizer such as glycerol or other polyols (sorbitol, xylitol, fructose, polyethylene glycol, etc.) [AVE 04a, XIE 12]. Blends of these different polyols are also used [CHI 10b]. Other, notably nitrogenous plasticizers (urea, ammonium derivatives, amines, etc.) can also be used. Plasticized starches are thus created. They are... 

After this treatment, we obtain a homogeneous melted system. The plasticized starch thus created can be taken up, in pellet form or otherwise, and used in different techniques such as injection, blowing and so on. 

Effect of water and non-volatile plasticizing agent on the behavior of plasticized starch... 

Biodegradable multiphase systems based on plasticized starch 9.4.1. Structures of plasticized starch-based multiphase systems... 

With a view to preserving the biodegiadabihty of the final material, various compounds can be combined with plasticized starch ... 

Plasticized starch has widely been studied in a mixture with other polymers [AVE 04a, AVE 00a, AVE 00b, AVE 01a, MAR 01a, MAR 01b, SCH 04]. A large nrrmber of patents have been pubUshed on this subject [AVE 04a]. These research efforts have led to the commercialization of different biodegradable blends - some of them based on plasticized starch (Table 9.4). 

Biograde B-F Cardia Bioplastics (China) and Biograde Limited (Australia) Aliphatic copolyesters Plasticized starch-based... 

Terraloy Cerestech (Canada) and Technor Apex (USA) Biodegradable polyesters Plasticized starch-based... 

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