Bench-scale processing of amaranth seed for oil

Amaranth seed (Amaranthus hypochondriacus cv. K432) was processed to obtain oil, reported to be a promising source of squalene. The amaranth seed was ground using a stone mill, then separated into oil-rich embryonic tissue (or “bran”) and starchy perisperm. Amaranth bran was much more stable than rice bran when free fatty acid (FFA) content and peroxide value were monitored. Milling at a gap of 0.755 mm did not result in excessive damage to the starch in the perisperm fraction and yielded a bran fraction that contained more than three-fourths of the oil and a starchy fraction consisting of more than two-thirds of the seed weight. The bran particles were too fine for effective bench-scale extraction of the oil. Consequently the bran was extruded into collects prior to extraction. Two extrusion settings were evaluated regarding the rate of moisture injection, while the bran feed rates were constant. There was no significant difference in appearance or size between the two dried collets. Collets were extracted with hexane using an Armfield Extraction/Desolventizing Unit (Model FT 29, Armfield, Ltd., Hampshire, England). Oil recovery averaged 97.7 and 80.0%, respectively. Oil was extracted at high yield from the bran when the bran was extruded into collets. Oil can be obtained as a coproduct of amaranth starch by milling and separating the fractions of amaranth seed. Milling, extrusion, and extraction did not decrease significantly the squalene content in amaranth oil, but increased FFA content and peroxide value and changed tocopherol content of the oil.     

Recoverable shear strain of liquid crystal‐forming concentrated hydroxypropyl cellulose solutions

The recoverable shear strain (S_R) for the liquid crystal‐forming hydroxypropyl cellulose solutions was determined by means of a concentric cylinder rotational apparatus as functions of shear stress prior to recovery and concentration of the solutions at 30°C. S_R greatly depended on shear stress and concentration; the phase of the solution (the single phase or biphase) governed the dependences of S_R on stress and concentration. S_R increased with increasing stress for the single phase and decreased for the biphase. S_R seemed to be related to the die swell (B): S_R ∝ Bⁿ. S_R exhibited a maximum and a minimum with respect to concentration. S_R for the cellulosic cholesteric liquid crystalline solutions was greater than that for the isotropic solutions. A model was proposed for explaining the greater S_R. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 865–872, 2002     

马铃薯淀粉渣的羧甲基化研究

研究了马铃薯淀粉渣与氯乙酸进行羧甲基化反应的一般规律，考察了反应温度、反应时间、原料配比等因素对产物取代度的影响，通过正交试验，找到了最佳反应条件，并对产物性能进行了测试。     

Characterization and application of polypropylene films modified with stimuli‐sensitive copolymers with an Ar‐plasma postpolymerization technique

Surface‐modified polypropylene (PP) films with thermally and photochemically sensitive copolymers consisting of N‐(2‐hydroxypropyl)methacrylamide (HPMA) and 4‐(4‐methoxyphenylazo)phenyl methacrylate (MPAP), poly(HPMA‐co‐MPAP)‐g‐PP (abbreviated g‐PP) film, were prepared by graft copolymerization with an Ar‐plasma postpolymerization technique. The surfaces of the g‐PP films were characterized by means of X‐ray photoelectron spectroscopy; the percentage grafting of poly(HPMA‐co‐MPAP) with a number‐average molecular weight of 3.28 × 10⁴ was 7.12%, and the molar ratio of HPMA–MPAH in the copolymer was 0.75:0.25. The stimuli‐sensitive adsorption of albumin and polystyrene microspheres on the g‐PP film was also measured. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 143–148, 2003     

干法合成阳离子淀粉絮凝剂的初步研究

研究了干法合成阳离子淀粉絮凝剂的方法。结果表明,制备阳离子淀粉絮凝剂的最佳工艺条件为:在反应体系中水的质量分数为35％、阳离子醚化剂与NaOH混合温度低于110℃的条件下,阳离子醚化剂与淀粉物质的量比为0.35,NaOH与阳离子醚化剂物质的量比为1.4,反应温度90℃,反应时间4h。在此条件下合成的阳离子淀粉相对黏度为2.0。     

HPCS-AM-DAC共聚物的合成及絮凝性能研究

以羟丙基壳聚糖(HPCS)、丙烯酰胺(AM)、丙烯酰氧乙基三甲基氯化铵(DAC)为原料合成三元高分子共聚物(HPCS-AM-DAC)。采用FTIR、1HNMR、XRD、SEM对其结构和形貌进行了表征。考察了反应温度、引发剂硝酸铈铵用量、单体滴加时间及DAC用量对产物阳离子度及特性黏数的影响。结果表明,在水为25 mL、丙烯酰胺为2 g、HPCS为1 g、反应温度70℃、引发剂用量为1.7%(以HPCS质量为基准,下同)、单体滴加时间为35min、DAC为3.5g的条件下,产物的阳离子度和特性黏数均达到较佳值,分别为63.01%和468.81mL/g。采用壳聚糖(CTS)、HPCS、HPCS-AM-DAC及市售阳离子聚丙烯酰胺(CPAM)对高岭土模拟废水进行絮凝实验,考察了絮凝体系pH、不同絮凝产品投加量对浊度去除率的影响。结果表明,在浊度为200NTU的高岭土模拟废水中,HPCS-AM-DAC絮凝的适宜pH为2～6,适宜投加量为2～5 mg/L,在该条件下浊度去除率均在96%以上。     

Thermoplastic extrusion—the mechanism of the formation of extrudate structure and properties

Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water-plasticized biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow. The mixed-melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder die from a viscous state to a rubber-like state and then to a glassy state caused by cooling and drying. Incompatibility of proteins and polysaccharides in their water-plasticized melt mixtures impacts on structure formation and texturization during thermoplastic extrusion. Presented at the 20th ISF World Congress and 83rd AOCS Annual Meeting and Expo, May 10–14, 1992, Toronto, Ontario, Canada.     

Mechanical properties of poly(lactic acid) and wheat starch blends with methylenediphenyl diisocyanate

Poly(lactic acid) (PLA) and wheat starch are biodegradable polymers derived from renewable sources. A previous study showed that thermally blending starch and PLA in the presence of methylenediphenyl diisocyanate (MDI) enhanced the mechanical properties of the blends. In this work, blends of PLA with various levels of wheat starch and MDI were hot mixed at 180°C then hot‐pressure molded at 175°C to form test specimens. The blends were characterized for mechanical properties, fracture microstructure, and water absorption. Pure PLA had a tensile strength of 62.7 MPa and elongation of 6.5%. The blend with 45% wheat starch and 0.5 wt % MDI gave the highest tensile strength of about 68 MPa with about 5.1% elongation. The blend with 20% starch and 0.5 wt % MDI had the lowest tensile strength of about 58 MPa with about 5.6% elongation. Dynamic mechanical analysis showed that storage modulus increased and tan δ decreased as starch level increased, but almost leveled off when starch level reached 45% or higher. Water absorption of the blends increased significantly with starch content. Yet the blend, if water proofed on its surface, has potential for short‐term disposable applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1257–1262, 2002; DOI 10.1002/app.10457     

沙枣淀粉烷基多糖苷的制备与性能

以植酸和对甲苯磺酸二元体系为催化剂,以沙枣和脂肪醇作原料,采用转糖苷法合成了烷基多糖苷表面活性剂。确定较佳工艺条件为:m(乙二醇)∶m(十二醇)∶m(沙枣粉)=12∶1∶1;常压反应,温度90～100℃;沙枣糖转化率接近100%。测定其表面张力为25 9～28 9mN·m-1,25℃时临界胶束浓度为2×10-5mol/L,HLB值为18,并对其结构进行了红外测定。合成的烷基糖苷(APG)产品可应用于农药乳化,餐具洗涤剂等。     

Physical properties and morphology of polycaprolactone/starch/pine‐leaf composites

Polycaprolactone (PCL)/starch and PCL/starch/pine‐leaf composites, which can be possibly applied as biodegradable food packaging materials with natural pine flavor, were prepared and characterized in this study. The effect of incorporating a silane coupling agent at different content levels on the physical properties and morphology of the composites was studied. To investigate the melting behavior of the composites, a differential scanning calorimetry was employed. A universal testing machine was used to investigate the tensile properties of the composites and the water absorption properties of the composites were also investigated. Scanning electron microscope was used to investigate the morphology of the composites. The physical properties and morphology of the PCL/starch and PCL/starch/pine‐leaf composites were largely affected by the composition, especially the content of the silane coupling agent. The silane coupling agent led to a much better interfacial compatibility between the PCL matrix and the fillers and resulted in better physical properties of the composites. The PCL/starch/pine‐leaf composite with the silane coupling agent showed a morphology, indicating a good interfacial adhesion between the PCL matrix and the fillers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 928–934, 2007