Starch thermal stability

The polyester is stable in storage at RT. The thermal stability at 65.5° using a 1.3g sample and Kl-Starch indicator paper is failure after 100 mins (Ref NC, 10 min, no color) at 134,5 using a 2.5g sample and Methyl violet paper, failure is shown after SO mins (Ref NC, 30 mins, no color)... 

The polymer s Qc is 2996cal/g at 25° (Ref liq H20 at 25°). Impact sensy using the BM machine with a 2kg wt is 100cm at the 50% point (RDX, 28cm). Thermal stability at 65.5° using KI-Starch paper is 23 min (Ref NC, 10 mins, no color) thermal stability at 134.5° using Methyl violet paper shows no failure in 5 hrs (Ref NC, 30 mins, no color)... 

The polymer has an impact sensy of 40cm at the 50% point using a BM machine with a 2kg wt (RDX, 28cm), a thermal stability of 13 mins using a 1.3g sample with Kl-Starch indicator paper (Ref NC, 10 mins, no color), also, a rel vise of 1.50 centipoises at 25° using a 1% acet soln Ref PJ. Blatz et al, Research In Nitropoly-mers And Their Application To Solid Smokeless Propellants , Report No 907, Aerojet-General Corp, Azusa, Calif ONR Contract N7 onr-462, Task Order I and Contract NO as 54-399-C (15 Dec 1954), 16 17... 

In a current rheological study [296], the galactoxyloglucan from Hymenia courbaril was mixed with starch containing 66% amylose and with waxy corn starch (amylopectin). The gel mixtures showed, under static rheological conditions, an increase in paste viscosity compared to those of the polysaccharides alone. Dynamic rheometry indicated that the interactions resulted in increased thermal stability of the gel formed in comparison to that of the starch alone. 

In the matrix of PLA/ polycaprilactone (PCL)/OMMT nano-composites, the silicate layers of the organoclay were intercalated and randomly distributed (Zhenyang et at, 2007). The PLA/PCL blend significantly improved the tensile and other mechanical properties by addition of OMMT. Thermal stability of PLA/PCL blends was also explicitly improved when the OMMT content is less than 5%wt. Preparation of PLA/thermoplastic starch/MMT nano-composites have been investigated and the products have been characterized using X-Ray diffraction, transmission electron microscopy and tensile measurements. The results show improvement in the tensile and modulus, and reduction in fracture toughness (Arroyo et ah, 2010). 

Polydrill is a sulfonated polymer for filtration control in water-based drilling fluids [1775]. Tests demonstrated the product s thermal stability up to 200° C and its outstanding electrolyte tolerance. Polydrill can be used in NaCl-saturated drilling fluids as well as in muds containing 75,000 ppm of calcium or 100,000 ppm of magnesium. A combination of starch with Poly drill was used successfully in drilling several wells. The deepest hole was drilled with 11 to 22 kg/m of pregelatinized starch and 2.5 to 5.5 kg/m of Polydrill to a depth of 4800 m. Field experience with the calcium-tolerant starch/Polydrill system useful up to 145° C has been discussed in detail [1774]. 

Thomas, D.C. "Thermal Stability of Starch and Carboxymethyl Cellulose Polymers Used in Drilling Fluids," SPE Paper 8463, 1979 SPE Annual Technical Conference and Exhibition Las Vegas, September 23-26. 

Low melt temperatures, e.g., 140-170°C for Ecoflex and Ecoflex /starch compounds, 165-190°C for Ecovio need to be achieved, which are beneficial for blown film stability and thermal stability. 

Because of the limited thermal stability of, e.g., Ecoflex /starch compounds, dead spots in the feed block adapter or the film die have to be avoided. As a consequence, reduction of the film width by closing the die with metal bars (deckling) is not recommended for Ecoflex /starch compounds. 

By analogy with the works which dealt with cellulose micro crystal-reinforced nanocomposite materials, microcrystals of starch [95] or chitin [96, 97] were used as a reinforcing phase in a polymer matrix. Poly(styrene-co-butyl acrylate) [95,96], poly(e-caprolactone) [96], and natural rubber [97] were reinforced, and again the formation of aggregates or clustering of the fillers within the matrices was considered to account for the improvement in the mechanical properties and thermal stability of the respective composites processed from suspensions in water or suitable organic solvents. 

Immobilized cellulase and amylase are able to hydrolyze cellulose and starch. However, the immobilized enzymes possess only about 1-6% of the activity of the soluble forms. In addition, immobilization clearly enhanced the thermal stability of amylase. Immobilized amylase retained more than half of its activity, even after incubation at 125°C. By comparison, soluble amylase was almost completely inactivated under these conditions. Furthermore, kinetics modeling indicates that the susceptibility to product inhibition is dependent on the amylase source. Finally, immobilization can reduce the susceptibility to product inhibition fQ was less for each of the immobilized forms, compared with their soluble counterparts. 

Flory-Huggins approach, may be somewhat low even with highly crystalline preparations of A- or B-type starch lintners (DP —15). Despite its theoretical limitations, the Flory analysis (as illustrated in Figure 8.10 inset) can be used to simulate the melting behavior of starch in practical applications (e.g. extrusion cooking, baking) and to compare the thermal stability of different starch materials under dynamic heating at various moisture conditions.20,25 240 337... 

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