Melting behavior of poly(trimethylene terephthalate)

In this study, the melting behavior of isothermally crystallized polytri‐ methylene terephthalate (PTT) was investigated. Multiple melting behaviors in DSC heating trace were found because two populations of lamellar stacks were formed during primary crystallization and the recrystallization at heating process, respectively. This fact could be also confirmed from the result of optical microscopy observation. The Hoffman–Weeks equation was applied to obtain equilibrium melting temperature (T). The T value of PTT is about 525 K, which is 10 K higher than that reported. Combining the enthalpy of fusion from the DSC result and the degree of crystallinity from WAXD result, the value of the equilibrium‐melting enthalpy ΔH was deduced to be approximately 28.8 kJ mol^?1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2426–2433, 2002     

Effect of dispersion method and process variables on the properties of supercritical CO2 foamed polystyrene/graphite nanocomposite foam

In this study, polystyrene/nanographite nanocomposite foams were made by different compounding methods, such as direct compounding, pulverized sonication compounding, and in situ polymerization, to understand the effect of the process variables on the morphology of the nanocomposites and their foam. The foam was made by batch foaming using CO₂ as the blowing agent. Various foaming pressures and temperatures were studied. The results indicated that the cell size decreased and the cell morphology was improved with the advanced dispersion of the nanoparticles. Among the three methods, the in situ polymerization method provided the best dispersion and the resulting nanocomposite foam had the finest cell size and the highest cell density. In addition, adding nanoparticles as a nucleating agent can make foams of similar cell size and cell density at a much lower foaming pressure. This result can be explained by the classical nucleation theory. This discovery could open up a newroute to produce microcellular foams at a low foaming pressure. POLYM. ENG. SCI., 53:2061–2072, 2013. © 2013 Society of Plastics Engineers     

Physical study of room‐temperature‐cured epoxy/thermally reduced graphene oxides with various contents of oxygen‐containing groups

In this study, the effects of different oxygen‐containing group contents in thermally reduced graphene oxides (TRGs) for enhancing the physical properties of epoxy nancomposites was examined. The epoxy/TRG nanocomposites (ETNs) were prepared by a room temperature curing method in the presence of TRGs containing different oxygen‐containing groups and were then characterized by Fourier transform infrared spectroscopy. TRG contents with higher oxygen‐containing group contents (ca 33%) were found to show better dispersion capability in the epoxy matrix than TRGs with lower oxygen‐containing group contents (ca 11%) based on morphological observations by transmission electron microscopy. The better dispersion capability of TRGs with higher oxygen‐containing group contents in ETN membranes was found to lead to significantly enhanced mechanical strength, thermal stability and thermal conductivity based on measurements of dynamic mechanical analysis, tensile tests, thermogravimetric analysis and by the transient plane source technique. © 2014 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry     

Effect of annealing on poly(urethane‐siloxane) copolymers

The N‐substituted polyaniline (PANi) was synthesized by incorporation of bromine‐terminated polystyrene (PS‐Br) onto the emeraldine form of polyaniline. End brominated polystyrene was synthesized by atom transfer radical polymerization (ATRP) technique and then deprotonated polyaniline was reacted with PS‐Br to prepare PS‐grafted PANi (PS‐g‐PANi) copolymer through N‐grafting reaction. The degree of N‐grafting can be controlled by adjusting the molar feed ratio of PS‐Br to the number of repeat units of PANi. The microstructure and compositions of the PS‐g‐PANi copolymers with different degrees of N‐substitution were characterized by FT‐IR, elemental analysis, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The cyclicvoltammetry shows that the electroactivity of N‐substituted PANi is strongly dependent on the degree of N‐grafting. The solubility of PS‐g‐PANi copolymers in common organic solvents such as tetrahydrofuran and chloroform was improved by increasing the degree of N‐grafting, and also the samples are partially soluble in xylene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Compatible and crystallization properties of poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) blends

Differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD) and dynamic mechanical analysis (DMA) properties of poly(lactic acid)/ poly(butylene adipate‐co‐terephthalate) (PLA/PBAT) specimens suggest that only small amounts of poor PLA and/or PBAT crystals are present in their corresponding melt crystallized specimens. In fact, the percentage crystallinity, peak melting temperature and onset re‐crystallization temperature values of PLA/PBAT specimens reduce gradually as their PBAT contents increase. However, the glass transition temperatures of PLA molecules found by DSC and DMA analysis reduce to the minimum value as the PBAT contents of PLA_xPBAT_y specimens reach 2.5 wt %. Further morphological and DMA analysis of PLA/PBAT specimens reveal that PBAT molecules are miscible with PLA molecules at PBAT contents equal to or less than 2.5 wt %, since no distinguished phase‐separated PBAT droplets and tan δ transitions were found on fracture surfaces and tan δ curves of PLA/PBAT specimens, respectively. In contrast to PLA, the PBAT specimen exhibits highly deformable properties. After blending proper amounts of PBAT in PLA, the inherent brittle deformation behavior of PLA was successfully improved. Possible reasons accounting for these interesting crystallization, compatible and tensile properties of PLA/PBAT specimens are proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Membrane electrode assemblies doped with H3PO4 for high temperature proton exchange membrane fuel cells

H₃PO₄ content plays a critical role in high temperature proton exchange membrane fuel cells (HT-PEMFC), as it is responsible for the majority of the conductivity of the key components under high temperature operation. The conductivities of commercial AB-PBI membranes doped by immersing in 85 wt.% H₃PO₄ for different times and temperatures are investigated. The effect of H₃PO₄ loading in electrodes, including the AB-PBI polymer and a Pt/C catalyst, is also studied. The as-prepared electrodes and membranes are combined to fabricate a membrane electrode assembly for HT-PEMFCs. The results reveal that AB-PBI membranes doped with 85 wt.% H₃PO₄ at 90 °C for 9 h display a maximum conductivity of 33 mS cm⁻¹. This membrane was selected and combined with electrodes including 15 wt.% AB-PBI and 0.75 mg cm⁻² Pt with different H₃PO₄ loadings. A maximum current density of 260 mA cm⁻² was achieved in the as-prepared MEA (with 5 mg cm⁻² H₃PO₄ in electrodes) operating at 0.6 V and 160 °C, using oxygen and hydrogen.     

Robust fault detection of turbofan engines subject to adaptive controllers via a Total Measurable Fault Information Residual (ToMFIR) technique

This paper provides a new design of robust fault detection for turbofan engines with adaptive controllers. The critical issue is that the adaptive controllers can depress the faulty effects such that the actual system outputs remain the pre-specified values, making it difficult to detect faults/failures. To solve this problem, a Total Measurable Fault Information Residual (ToMFIR) technique with the aid of system transformation is adopted to detect faults in turbofan engines with adaptive controllers. This design is a ToMFIR-redundancy-based robust fault detection. The ToMFIR is first introduced and existing results are also summarized. The Detailed design process of the ToMFIRs is presented and a turbofan engine model is simulated to verify the effectiveness of the proposed ToMFIR-based fault-detection strategy.     

An integrated remote sensing and GIS approach in the monitoring and evaluation of rapid urban growth for sustainable development in the Pearl River Delta,China

The publication of the Brundtland Report in 1987 has led to worldwide concern over sustainable development. Sustainable development is particularly important to regions that are undergoing rapid economic development, such as the Pearl River Delta and other rapidly developing regions in China, Malaysia, Thailand and Asia. Geographical information systems (GIS) and remote sensing are useful tools in the formulation, implementation and monitoring of urban development in the move towards a sustainable development strategy. Since the adoption of economic reform in China in 1978, cities in the Pearl River Delta are developing very rapidly. Economic growth is around 20% a year, making it one of the highest growth areas in the world. Accompanying economic development is rapid urban growth. This paper attempts to demonstrate the application of the integration of GIS and remote sensing in urban growth management in the Pearl River Delta by using them to monitor and evaluate land development. Remote sensing techniques are used to carry out land‐use change detection by using multi‐temporal remote sensing data. Land‐use change impact analysis is further carried out by the integration of GIS and remote sensing.     

Characterization of Starch from Maize Endosperm Mutants

Some maize endosperm mutants have branched-chain starch components with long exterior chains which make the blue-value procedure for estimating amylose content questionable. Gel filtration was used to estimate starch composition of normal, high-amylose, waxy and other maize endosperm mutants. Loosely-branched polymers appeared responsible for the apparent amylose content. In some mutants high and intermediate loosely branched polysaccharides were found in addition to amylose. The sweet corn background of some endosperm genotypes influenced the types of polymers produced compared to the dent backgrounds used by previous researchers.     

Pathogenesis and Treatment of Myeloma-Related Bone Disease

Multiple myeloma is a hematologic malignancy of plasma cells that causes bone-destructive lesions and associated skeletal-related events (SREs). The pathogenesis of myeloma-related bone disease (MBD) is the imbalance of the bone-remodeling process, which results from osteoclast activation, osteoblast suppression, and the immunosuppressed bone marrow microenvironment. Many important signaling cascades, including the RANKL/RANK/OPG axis, Notch signaling, the Wnt/β-Catenin signaling pathways, and signaling molecules, such as DKK-1, sclerostin, osteopontin, activin A, chemokines, and interleukins are involved and play critical roles in MBD. Currently, bisphosphonate and denosumab are the gold standard for MBD prevention and treatment. As the molecular mechanisms of MBD become increasingly well understood, novel agents are being thoroughly explored in both preclinical and clinical settings. Herein, we will provide an updated overview of the pathogenesis of MBD, summarize the clinical management and guidelines, and discuss novel bone-modifying therapies for further management of MBD.