Blends Containing Starch

BiMaris D, Prinos J, Koutsopoulos K, Vouroutzis N, Pavlidou E, Frangis N et al (1998) LDPE/ plasticized starch blends containing PE-g-MA copolymer as compatibilizer. Polym Degrad Stab 59 287-291... 

LHM Blend containing nondried starch Blend containing dried starch... 

D. Bikiaris, J. Prinos, K. Koutsopoulos, N. Vouroutzis, E. Pavlidou, N. Frangis, and C. Panayiotou, LDPE/plasticized starch blends containing PE-g-MA copolymer as compatibi-lizer, Polym. Degrad. Stabil., 59, 287-291, 1998. 

Recycled LDPE/com starch blends containing 30, 40 and 50wt% starch were prepared by extrusion [19]. The addition of starch to LDPE reduced the melt flow index values, the tensile strengths, and the elongations at break, whereas the moduli increased. The decreases in the melt flow index and tensile properties were most evident when 40 and 50wt% starch was added. SEM showed that the inter-facial interaction was weak for blends containing virgin and recycled LDPE. 

ITie work described in this chapter was initiated to determine the kinetics of enzymatic and microbial attack on blends containing starch and LDPE or starch, LDPE, and EAA. From the initial studies came a more general goal of identifying structural and compositional characteristics of blends (in general) that facilitate or retard degradation of the polysaccharide component. 

Porosity characteristics also influence the degradation rate of blends containing intact starch grains. Amylase removal of starch from these films was not highly correlated with starch content, since films whose starch content was above possible "percolation thresholds" (6) were degraded at very different rates when starch content was not very different (Table I). 

Strengths of films made from a starch-poly(vinyl alcohol) blend containing glycerol and poly(ethylene-co-acrylic acid) have been examined.166 High-amylose starches produced films with the most consistent properties. In a process for extruded blown film, blending of high-amylose starch with starches with more typical amylose contents and plasticizers or gelatinization aids improved properties.167 Extruded... 

Flakes were blended with Parafilm (PF) as described for granular starch. Because of large volume of air-filled voids in the materials, blends containing more than 50% starch flakes (w/w) could not be made. 

Starch-Based Plastics. As can be seen in Table 8.7, a variety of starch-based plastics have been produced by several companies. Starch-based plastics are often water-soluble as well as biodegradable. Some contain almost entirely starch others contain blends of starch with other biodegradable components. 

The case of contradictory findings for the analysis of dietary fiber are due to differences among analytical methods employed. The AO AC total dietary fiber method measures all compounds not digested by amylase and protease and insoluble in 80% aqueous ethanol. While cellulose, pectin, hemicelluloses, gums and lignin do meet these criteria, extrusion-modified starches and proteins could also be measured as fiber. Sites formerly accessible to digestion by enzymes may be involved in new bonds or physically-hindered. Many materials used to add dietary fiber to foods contain far less than 100% fiber. Artz and co-workers (1990) found no difference in X-ray diffraction patterns of corn fiber-corn starch blends after extrusion, which was expected since very little crystalline cellulose was present. The com bran isolate used as a fiber source actually contained only 16.6% cellulose. Amorphous hemicelluloses comprised the remainder of the dietary fiber fraction. 

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