A solution blow spinning technique was developed using elements of both electrospinning and melt blowing technologies as an alternative method for making non-woven webs of micro-and nanofibers with diameters comparable with those made by the electrospinning process with the advantage of having a fiber production rate (measured by the polymer injection rate) several times higher. The diameters of fibers produced ranged from 40 nm for poly(lactic acid) to several micrometers for poly(methyl methacrylate). This solution blow spinning method uses a syringe pump to deliver a polymer solution to an apparatus consisting of concentric nozzles whereby the polymer solution is pumped through the inner nozzle while a constant, high velocity gas flow is sustained through the outer nozzle. Analysis of the process showed that pressure difference and shearing at the gas/solution interface jettisoned multiple strands of polymer solution towards a collector. During flight, the solvent component of the strands rapidly evaporates forming a web of micro and nanofibers. The effect of injection rate, gas flow pressure, polymer concentration, working distance, and protrusion distance of the inner nozzle was investigated. Polymer type and concentration had a greater effect on fiber diameter than the other parameters tested. Injection rate, gas flow pressure, and working distance affected fiber production rate and/or fiber morphology. Fibers were easily formed into yarns of micro-and nanofibers or non-woven films that could be applied directly onto biological tissue or collected in sheets on a rotating drum. Indeed, virtually any type of target could be used for fiber collection.

Abstract. Although starch foams are well known as biodegradable alternatives to foamed polystyrene, starch-lignin foams have not previously been reported. Lignin is an abundant byproduct of paper manufacture usually burned as fuel for lack of higher-value uses. We have prepared novel starch-kraft lignin foams with a known technique similar to compression molding. Replacing 20% of the starch with lignin has no deleterious effect on density or morphology as indicated by scanning electron microscopy: a thin outer layer of approximately 100 μm encloses a region of cellular structure containing 100-200 μm voids, with the major internal region of the foam consisting of large voids of up to 1 mm in size. Powder X-ray diffraction shows residual structure in both starch and starch-lignin foams. Differential scanning calorimetry displays endothermic transitions in the starch foam but not in the starch-lignin foam, indicating that lignin stabilizes the residual starch structure. Lignin decreases water absorption; diffusion constants for the starch and starch-lignin foams are 2.68·10 -6 and 0.80·10 -6 cm 2 /sec, respectively. The flexural strength of the starch-lignin foam is similar to that of foamed polystyrene, the strain at maximum stress is smaller, and the modulus of elasticity is larger.

Amylose contents of prime starches from nonwaxy and high‐amylose barley, determined by colorimetric method, were 24.6 and 48.7%, respectively, whereas waxy starch contained only a trace (0.04%) of amylose. There was little difference in isoamylase‐debranched amylopectin between nonwaxy and high‐amylose barley, whereas amylopectin from waxy barley had a significantly higher percentage of fraction with degree of polymerization < 15 (45%). The X‐ray diffraction pattern of waxy starch differed from nonwaxy and high‐amylose starches. Waxy starch had sharper peaks at 0.58, 0.51, 0.49, and 0.38 nm than nonwaxy and high‐amylose starches. The d‐spacing at 0.44 nm, characterizing the amylose‐lipids complex, was most evident for high‐amylose starch and was not observed in waxy starch. Differential scanning calorimetry (DSC) thermograms of prime starch from nonwaxy and high‐amylose barley exhibited two prominent transition peaks: the first was >60°C and corresponded to starch gelatinization; the second was >100°C and corresponded to the amylose‐lipid complex. Starch from waxy barley had only one endothermic gelatinization peak of amylopectin with an enthalpy value of 16.0 J/g. The retrogradation of gelatinized starch of three types of barley stored at 4°C showed that amylopectin recrystallization rates of nonwaxy and high‐amylose barley were comparable when recrystallization enthalpy was calculated based on the percentage of amylopectin. No amylopectin recrystallization peak was observed in waxy barley. Storage time had a strong influence on recrystallization of amylopectin. The enthalpy value for nonwaxy barley increased from 1.93 J/g after 24 hr of storage to 3.74 J/g after 120 hr. When gel was rescanned every 24 hr, a significant decrease in enthalpy was recorded. A highly statistically significant correlation (r = 0.991) between DSC values of retrograded starch of nonwaxy barley and gel hardness was obtained. The correlation between starch enthalpy value and gel hardness of starch concentrate indicates that gel texture is due mainly to its starch structure and functionality. The relationship between the properties of starch and starch concentrate may favor the application of barley starch concentrate without the necessity of using the wet fractionation process.