Synthesis, thermal properties, and biodegradability of propyl-etherified starch

High amylose corn starch (HACS) was etherified with 1-bromopropane in dimethyl sulfoxide. The structure of the products was characterized by infra-red and ¹H-NMR spectroscopy. The degree of substitution (DS) on glucose unit calculated from ¹H-NMR spectrum was varied from 0.9 to 2.7 by changing feed ratio of 1-bromopropane to HACS. Thermogravimetric analysis reveals that the etherified HACS has a higher decomposition temperature than unmodified HACS. Differential scanning calorimetry analysis reveals that the etherified starch has a clear glass transition temperature which decreased with increasing DS, and that no melting point is observed. This result demonstrates that the etherified HACS mainly consists of amorphous region. The biodegradation rate decreases with increasing degree of etherification.     

Electrosprayed maize starch and its constituents (amylose and amylopectin) nanoparticles

Starch consists of amylose and amylopectin. Properties such as being natural and highly hygroscopic as well as biodegradability have opened a considerable range of applications for amylose, amylopectin and starch. The performance of particles is highly dependent on their size which in turn determines the specific surface area. This work studies the application of electrospraying to fabricate maize starch and its constituents: amylose and amylopectin nanoparticles. This study showed that electrospraying technique is capable of producing amylose, amylopectin and starch nanopowder with an average particle size around 100 nm. FTIR analysis showed no reaction or interaction occurring in amylose, amylopectin and starch nanoparticle compared with their natural form. Basically, lower concentration, lower viscosity and lower surface tension of the electrospraying solution as well as higher nozzle–collector distance, higher voltage and lower feed rate lead to smaller nanoparticle size. Copyright © 2015 John Wiley & Sons, Ltd.     

Entanglement properties of cellulose and amylose in an ionic liquid

Concentrated solutions of cellulose and amylose were prepared with an ionic liquid 1‐butyl‐3‐methylimidazolium chloride (BmimCl), which was chosen as a good solvent for these polysaccharides. Dynamic viscoelasticity of the concentrated solutions was examined to obtain the molecular weight between entanglements, M_e. The value of M_e in the molten state (M_e,melt), a material constant that reflecting the entanglement properties, was determined for cellulose and amylose by extrapolating M_e to the “melt.” A marked difference in M_e,melt was found: 3.2 × 10³ for cellulose and 2.5 × 10⁴ for amylose. The value of M_e,melt for cellulose, which is composed of β‐(1,4) bonding of D ‐glucose units, is very close to those for polysaccharides with a random‐coil conformation such as agarose and gellan in BmimCl. The much larger M_e,melt for amylose can be attributed to the helical nature of the amylose chain, α‐(1,4)‐linked D ‐glucose units. The effect of concentration on the zero‐shear viscosity for the solutions of cellulose and amylose was also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Mechanical properties and enzymic degradation of thermoplastic and granular sago starch filled poly(ε-caprolactone)

The mechanical, morphological and biodegradation properties of two types of poly(ε-caprolactone)/sago starch (PCL/sago) composites were investigated i.e. dried granulated sago starch and undried thermoplastic sago starch (TPSS). Thermoplastic starch was extruded with a twin screw extruder model Haake Rheomix (TW100 attached to a Haake Rheometer (Haake Rheodrive 5000). The composites were compounded with a Haake internal mixer (Haake Rheomix 3000) attached to the Haake Rheometer. Tensile properties were determined with the Monsanto Tensometer T10. A Shimadzu UV-160A visible UV spectrophotometer was used to monitor the liberation of carbohydrate as a consequence of starch hydrolysis by α-glucoamylase. Determining the weight loss of composites as well as the acid liberated from PCL also monitored biodegradation. The results indicate that dried granulated sago starch function better as fillers in terms of mechanical properties and the ease of biodegradation. However, TPSS imparted better yield strength to the composites. Poor wetting of starch accounts for the decreased mechanical properties at higher starch concentration as agglomeration occurs. While the rigid granular starch retained their shape in the composites, thermoplastic starch that is surrounded by microvoids is easily deformed due to plasticization.     

Flow front advancement of molten thermoplastic materials during filling stage of a mold cavity

In this study, an injection mold which allows images of the flow behavior in the mold cavity to be obtained was designed and manufactured. Under real processing conditions, HDPE and PP materials were forced into the mold cavity under five different injection pressures and six different injection velocities. Filling and flow behavior of molten HDPE and PP were recorded with a video camcorder capable of 25 frames/s. The records obtained were divided into frames and all of these frames were transformed to the *.jpg and *.bmp photo format with a photo capture program which was coded in Borland Delphi 6.0 by the authors. Under the same processing conditions, experimentally obtained melt front advancement results were compared with results from an independent injection molding analysis program, Moldflow 5.0, which employs a finite element method.     

Synthesis and properties of fluorinated thermoplastic polyurethane elastomer

A series of fluorinated thermoplastic polyurethane elastomers (FTPU) based on self-synthesized fluorinate polyether diol (PFGE) were prepared by two-step polymerization. For the purpose of improving the molecular weight and mechanical property of FTPU, polybutylene adipate (PBA) was used to be compounded with PFGE as the soft-segment of FTPU. Effects of the mass ratio of PFGE/PBA and the mass fraction of hard-segment on the mechanical property of FTPU were investigated. The structure and morphology of FTPU were characterized by FTIR, GPC, DMA, surface tension and AFM analysis.     

Synthesis and properties of a new SASRIN resin derivative: SASRIN-2-pyridylthiocarbonate (SASRIN-TOPCAT) resin

A new SASRIN resin derivative, SASRIN-TOPCAT resin, was synthesized by the reaction of SASRIN resin with 2-thiopyridyl chloroformate. The new resin can be used for the loading of alcohols and thiols under neutral conditions, and the release of alcohol from the resin is achieved by the treatment of 1% TFA in CH₂Cl₂ for 15-60 min. Compared to the other reported resins, SASRIN-TOPCAT resin is more suitable for the loading of alcohols in solid-phase organic synthesis.     

Two-dimensional1H and13C NMR spectroscopy and the structural aspects of amylose and amylopectin

Summary A complete assignment of the¹³C and¹H NMR signals of amylose dissolved in dimethylsulfoxide was achieved using two-dimensional H-H and C-H correlated spectroscopy and deuterium exchange. The same methods together with an INEPT experiment provided the assignments of the¹H and¹³C NMR signals of the amylose type glucan units, the branch end glucan fragments, and a few assignments of nuclei within the branching glucan units of amylopectin dissolved in dimethylsulfoxide. From these assignments and from the integration of pertinent proton signals the branching degrees of amylose and amylopectin were derived to amount to 3.9 and 8–9%.

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Zweidimensionale¹H und¹³C-NMR-Spektroskopie und die strukturellen Aspekte von Amylose und Amylopektin

Zusammenfassung Die vollständige Zuordnung der¹³C- und¹H-NMR-Signale von in Dimethylsulfoxid gelöster Amylose konnte mit Hilfe zweidimensionaler H-H- und C-H-Korrelationsspektroskopie und Deuteriumaustausch erzielt werden. Die gleichen Methoden sowie ein INEPT-Experiment ermöglichten auch die Zuordnung der¹³C- und¹H-NMR-Signale der amylosischen Glucaneinheiten, der Verzweigungsendfragmente und einzelner Kerne im Bereich der Verzweigungsstellen von in Dimethylsulfoxid gelöstem Amylopektin. Aus diesen Zuordnungen und der Integration entsprechender Protonensignale konnte ein Verzweigungsgrad von Amylose und Amylopektin von 3.9 und 8–9% abgeleitet werden.

     

Polypropylene ionic thermoplastic elastomers: Synthesis and properties

Polypropylene ionic thermoplastic elastomers have been prepared by melt radical grafting of maleic anhydride onto polypropylene in the presence of N-bromosuccinimide followed by neutralization of the resulting elastomeric grafted polypropylene using sodium salts. Sodium hydroxide and sodium acetate were compared in aqueous solution, as anhydrous or hydrated powders. The neutralization reaction was followed by Fourier transform infrared spectroscopy, allowing the development of a method to determine the effective neutralization degree. Important physical changes were recorded upon neutralization. Especially thermal stability, shear storage modulus and complex viscosity in the flow region were largely increased as a function of the neutralization degree.     

Structure and thermodynamic melting parameters of wheat starches with different amylose content

The hierarchical granule structure of starches with different amylose content extracted from winter wheat was investigated using light microscopy (LM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXS), high-sensitivity differential scanning calorimetry (HS DSC) and different thermodynamic approaches. Morphology (size, size distribution and shape), crystallinity of native granules with different amylose content (1.5-39.5%), as well as the cooperative melting unit, thickness of crystalline lamellae, heat capacity drop related to hydration during melting of native granules, and thermodynamic parameters related to the surface of crystalline lamellae were determined. The relationship between structure and thermodynamic properties of mutant wheat starches is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis of aliphatic amidediol and used as a novel mixed plasticizer for thermoplastic starch

In this paper,aliphatic amidediol was synthesized and mixed with glycerol used as a plasticizer for preparing thermoplastic starch（AGPTPS）.The yield of aliphatic amidediol was 91%.FF-IR expressed that the mixture of aliphatic amidediol and glycerol formed stronger and stable hydrogen bond with starch molecules compared to the native cornstarch.By scanning electron microscope（SEM）native cornstarch granules were proved to transfer to a homogeneous continuous system.After being stored for a period time at room temperature,the mechanical properties of AGPTPS were also studied.As a mixed plasticizer,aliphatic amidediol and glycerol would be practical to extend TPS application scopes.     

Underivatized amylose and cellulose as new stationary phases for hydrophilic interaction chromatography

Two polysaccharide stationary phases have been newly suggested for application in hydrophilic interaction chromatography (HILIC). Both columns (amylose‐silica, 250 × 4.6 mm, 5 μm and cellulose‐silica, 250 × 4.6 mm, 5 μm) demonstrated a satisfactory retention of polar compounds. The influence of the mobile‐phase composition (acetonitrile content, pH, salt concentration) on the retention was in agreement with the HILIC concept. The phases showed a very similar behavior, typical efficiency of about 50 000 plates/m, cellulose retained test compounds somewhat more strongly. Under the experimental conditions, electrostatic (non‐HILIC‐type) interactions due to the dissociation of silanol groups on the silica surface did not influence the retention, noticeably. The applicability of polysaccharide stationary phases for the chromatography of polar compounds was proven by the separation of mixtures of sugars (fructose, glucose, saccharose, maltose, trehalose) or vitamins (nicotinamide, pyridoxine, riboflavin, thiamine, nicotinic acid, ascorbic acid).     

‘Hierarchical self-assembly’ of helical amylose/SWNTs complex

Helical amylose/SWNTs complexes (A/S-C) of various sizes, a single nanotube wrapped by amylose in particular, were demonstrated. The formation process of the helical A/S-C was further explained by a novel hierarchical self-assembly model, including the wrapping of amylose chains around SWNT and the hierarchical self-assembly of wrapped-SWNTs into the superstructural A/S-C. Besides the hydrophobic interaction, the hydrogen bonding also plays a certain role in the self-assembly process. Supported by the National Natural Science Foundation of China (Grant No. 60577049) and Shanghai Municipal Science and Technology Commission (Grant Nos. 034319224 and 0652nm017)     

Synthesis and properties of modified aramids

The purpose of this study was to determine the influence of different kinds of main chain modification of aramids on their thermal properties and solubility. The properties of polyamides synthesized by direct polycondensation using phosphorylation reaction depend strongly on the chemical architecture of the macromolecules. Polymers thus obtained were characterized by viscosity measurements, differential scanning calorimetry, thermogravimetry and solubility tests. These polyamides were distinguished by inherent viscosities in the range of 0.12–1.67 dl/g. The thermal transitions decrease in all cases of modification and the solubility is improved. Furthermore, the liquid crystalline properties of the polyamides were investigated. Thermotropic liquid crystalline behavior can be stated for a polyamide composed of 4,4′-diaminodiphenylmethane (MDA) and sebacic acid (SEB) under shearing. Aromatic polyamides with kinks in their main chain exhibit lyotropic crystalline behavior whereas parallel displacement in the main chain prevent the formation of liquid crystals in solution.     

The processing of starch as a thermoplastic

The thermoplastics processing of native starch in the presence of water is a recent development with very wide possible applications. Eventually, oil-based polymer materials have to be replaced in many applications by sustainable, inexpensive, natural materials from renewable resources. As with conventional thermoplastics, starch-water melts may be processed by injection moulding and extrusion. The present contribution focuses on injection moulding. The bases of the processing and the thermal and molecular changes occurring are described. In addition, the rheological behaviour of the starch-water melts during processing is analysed quantitatively to give apparent melt viscosities. The dimensional, thermal and mechanical properties of moulded thermoplastic starch polymer (TSP) materials and the products presently being produced from them are discussed.     

Ultra-high concentration of amylose for chiral separations in capillary electrophoresis

In the present study, a capillary electrophoresis method using high concentration of amylose solutions as separation medium has been developed with the aid of dimethyl sulfoxide (DMSO) as co-solvent. The best buffer conditions for primaquine, trihexyphenidyl (THP), sulconazole and cetirizine enantiomers were optimized as 20 mM sodium phosphate buffer with DMSO/water (40/60, v/v) as solvent at a pH of 3.0, containing 10% (w/v) amylose. Partial-filling and semi-permanent coating techniques were used considering the influences of DMSO on UV detection. High chiral resolution for THP enantiomers was obtained showing good chiral separation capacity of this method. The method showed good linearity (R² > 0.998) over the concentration range of 0.50 and 2.00 mg L⁻¹ for all the enantiomers. The detection limits for the tested enantiomers were in the range from 0.05 to 0.12 mg L⁻¹. The linear calibration models were proven to be adequate for the experimental data by lack-of-fit test. The intra-assay precision, inter-day precision and accuracy were all evaluated to be acceptable. Separation and determination of THP enantiomers in rabbit blood were also carried out.     

Synthesis and properties of thermoplastic polyimides with ether and ketone moieties

A series of polyimides containing ether and ketone moieties were synthesized from 1,3‐bis(4‐fluorobenzoyl) benzene and several commercially available dianhydrides via a conventional two‐step polymerization. The inherent viscosities of Polyamide acids ranged from 0.46 to 0.73 dL/g. Thermal properties, mechanical properties, and thermalplasticity of the obtained polimide films were investigated by focusing on the chemical structures of their repeat units. These films were amorphous, flexible, and transparent. All films displayed low T_gs (184–225 °C) but also excellent thermal stability, the 5% weight loss temperature was up to 542 °C under nitrogen. The films showed outstanding mechanical properties with the modulus up to 3.0 GPa and the elongation at break in the range of 8–160%. The uniaxial stretching of PI‐a at high temperature was studied owing to its excellent flexibility. The PI‐a had an elongation at break up to 1600% at 245 °C and the uniaxially stretched film exhibited a much higher modulus (3.9 GPa) and strength (240 MPa) than undrawn film. The results indicated that PI‐a can potentially be used to prepare materials such as fiber, ultra‐thin film or ultra‐high modulus film. All the obtained films also demonstrated excellent thermoplasticity (drop of E′ at T_g > 10³) which made the polyimides more suitable for melt processing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2878–2884, 2010     

直链淀粉手性固定相法分离利阿唑对映体

建立了利阿唑对映体的高效液相色谱拆分方法。采用Chiralpak AD-H手性柱在正相条件下直接拆分利阿唑对映体,考察了流动相中有机极性调节剂的种类和浓度、酸碱的种类和含量、柱温及流速等对利阿唑对映体分离的影响。确定了最佳的拆分条件:流动相为正己烷-乙醇(含0.3%二乙胺和0.1%冰醋酸)(体积比为80∶20),流速0.6 mL/min;检测波长254 nm;柱温20 ℃。在此条件下利阿唑对映体的分离度为3.4。该法简单快速,重现性好。     

Synthesis and properties of thermoplastic and dissolvable polysiloxanes containing polyhedral oligomeric silsesquioxane

There are many benefits associated with thermoplastic silicones, but very few examples exist: silicone resins or rubbers are normally thermosets. In this article, a facile and efficient approach was reported to prepare thermoplastic silicone by introducing a bulky side siloxane group. Monofunctional polyhedral oligomeric silsesquioxane (POSS), as the bulky siloxane group, was grafted onto the linear polysiloxane backbone via thiol–ene click reaction, endowing the liquid polysiloxane with thermoplastic nature. The POSS-grafted polysiloxane could be remolded by a hot-melting or solution casting process. It was worth noting that the novel thermoplastic silicone was composed of both linear siloxane main chains and siloxane side groups, which was distinctly different from previous researches on thermoplastic silicones consisted of siloxane main chains and organic side groups. Thermal analysis, rheological characterization and molecular dynamics simulation results revealed the thermoplastic properties of POSS-grafted polysiloxane depended on the bulky POSS's hindrance to the movement of the polymer backbone rather than the interaction between the organic side groups.