排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
Polypropylenes of differing morphologies were examined by differential thermal analysis. The problems of reordering during
the programmed heating are discussed. Four potential procedures by which the reordering could be inhibited are considered,
and three of these are experimentally assessed. Their advantages and deficiencies are identified. Two pretreatments, an etching
and a crosslinking, are recognised as able to qualitatively characterise the initial morphology, with a preference for the
former. A test to identify the occurrence of reordering is identified.
In celebration of the 60th birthday of Dr. Andrew K. Galwey 相似文献
2.
Four polyphenylacetylene samples, synthesized using different C6H5OH/Mo molar ratios, were investigated thermoanalytically by modulated temperature differential scanning calorimetry (MTDSC) in order to clarify a non-reversible exothermic event observed between 473 and 523 K on normal DSC. A stepwise, non-reversible change in heat capacity suggests the presence of internal reactions within the sample, that are followed by decomposition with loss of volatile products. 相似文献
3.
A novel Schiff base type polyester containing 2,2’-diamino-4,4’-bithiazole(DABT) was prepared by low-temperature interface polycondensation of 1,4-benzenedicarbonyl dichloride with 4,4’-(4,4’-bithiazole-2,2’-diylbis(imine-2,1-diyl)diphenol(BDDP), which is derived from a 2,2’-diamino-4,4’-bithiazole(DABT) Schiff base reacted with a 4-hydroxybenzaldehyde monomer.The newly generated polyester was evaluated based on characterization of its solubility,FTIR spectroscopy,elemental analysis,X-ray diffraction measurements and thermogravimetric analysis(TGA) studies. 相似文献
4.
A study of the effects of changing sample mass and purge gas on the phase lag and calculation of the out of phase (kinetic)
component for polystyrene in MTDSC was undertaken. The results confirm those from an earlier study that suggested the kinetic
signal is unchanged by altering these parameters thus it is probably a correct quantitative measure of this signal. The effects
of long annealing times were also studied and it was shown that all the signals of MTDSC are affected in contrast to a previous
study showing that for moderate annealing the reversing and kinetic signals are substantially invariant. Nevertheless the
non-reversing signal remains useful for characterising relative enthalpy losses.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
P. Sreekumari Nair T. Radhakrishnan N. Revaprasadu A.S. Luyt 《Journal of Physics and Chemistry of Solids》2005,66(7):1302-1306
Composites of CdS nanoparticles confined in a polystyrene-co-maleic acid (PS-co-MAc) matrix have been prepared and characterized. It was shown that the acid groups of the co-polymer could be successfully used to control the aggregation of the nanoparticles, because they act as coordinate sites for Cd ions. UV-VIS measurements showed a blue shift of the absorption threshold, proving the presence of nanoparticles. An average size of the nanoparticles of about 4 nm is estimated from the change in band gap energy. Although the FTIR spectrum of the nanocomposite showed the presence of C-S bonds, a broad emission originating from surface recombination sites are noticed. DSC and TGA measurements revealed changes in thermal properties upon incorporation of nanoparticles. No thermal transition was observed in the nanocomposite, while the pure co-polymer exhibits a glass transition at 190 °C. In the presence of nanoparticles the onset of the thermal decomposition of the matrix is also shifted by 50 °C towards a higher temperature. 相似文献
6.
Amanda L. Martin Jennifer L. Hickey Amber L. Ablack John D. Lewis Leonard G. Luyt Elizabeth R. Gillies 《Journal of nanoparticle research》2010,12(5):1599-1608
The imaging of molecular markers associated with disease offers the possibility for earlier detection and improved treatment
monitoring. Receptors for gastrin-releasing peptide are overexpressed on prostate cancer cells offering a promising imaging
target, and analogs of bombesin, an amphibian tetradecapeptide have been previously demonstrated to target these receptors.
Therefore, the pan-bombesin analog [β-Ala11, Phe13, Nle14]bombesin-(7–14) was conjugated through a linker to dye-functionalized
superparamagnetic iron oxide nanoparticles for the development of a new potential magnetic resonance imaging probe. The peptide
was conjugated via click chemistry, demonstrating a complementary alternative methodology to conventional peptide-nanoparticle
conjugation strategies. The peptide-functionalized nanoparticles were then demonstrated to be selectively taken up by PC-3
prostate cancer cells relative to unfunctionalized nanoparticles and this uptake was inhibited by the presence of free peptide,
confirming the specificity of the interaction. This study suggests that these nanoparticles have the potential to serve as
magnetic resonance imaging probes for the detection of prostate cancer. 相似文献
7.
8.
Martin AL Hickey JL Ablack AL Lewis JD Luyt LG Gillies ER 《Journal of nanoparticle research》2009,12(5):1599-1608
The imaging of molecular markers associated with disease offers the possibility for earlier detection and improved treatment monitoring. Receptors for gastrin-releasing peptide are overexpressed on prostate cancer cells offering a promising imaging target, and analogs of bombesin, an amphibian tetradecapeptide have been previously demonstrated to target these receptors. Therefore, the pan-bombesin analog [β-Ala11, Phe13, Nle14]bombesin-(7-14) was conjugated through a linker to dye-functionalized superparamagnetic iron oxide nanoparticles for the development of a new potential magnetic resonance imaging probe. The peptide was conjugated via click chemistry, demonstrating a complementary alternative methodology to conventional peptide-nanoparticle conjugation strategies. The peptide-functionalized nanoparticles were then demonstrated to be selectively taken up by PC-3 prostate cancer cells relative to unfunctionalized nanoparticles and this uptake was inhibited by the presence of free peptide, confirming the specificity of the interaction. This study suggests that these nanoparticles have the potential to serve as magnetic resonance imaging probes for the detection of prostate cancer. 相似文献
9.
Nanostructured wollastonite was synthesized by a sol–gel method and then used as a filler for polypropylene (PP). The obtained wollastonite particles were investigated using XRD, TEM and FTIR techniques. Non-isothermal crystallization measurements revealed that the wollastonite filler reduced the crystallization temperature of the matrix. TGA analyses showed improved thermal stability of the nanocomposite with respect to that of the pure polypropylene. From the DMA tan δ curves, it was concluded that the introduction of the filler into the PP matrix induced a slight shift of the β-transition (glass transition) towards higher temperature. The measurements of storage moduli showed that the nanocomposites have higher stiffness than the pure PP over the whole range of test temperature. An increase in stiffness was also confirmed by tensile measurements. 相似文献
10.
Simpson EJ Hickey JL Breadner D Luyt LG 《Dalton transactions (Cambridge, England : 2003)》2012,41(10):2950-2958
Histidine is a convenient tridentate chelator used in the synthesis of technetium-99m radiopharmaceuticals, as it can be pendantly attached to a biomolecule for molecular imaging applications. Once coordinated, it forms a neutral complex that is capable of forming diastereomers at the alpha amine of the histidine. This is demonstrated through the synthesis and characterization of four different histidine chelators; three small molecule chelators, which consist of a benzylated histidine at the alpha amine, and one modified dipeptide, containing a phenylalanine derivative at the C-terminus and a histidine at the N-terminus. Upon rhenium coordination, two products are observed, each having the desired exact mass of the metal-containing species. The two products have been characterized through LC-MS, (1)H, gCOSY, NOESY and ROESY NMR experiments, and the relative stereochemistry determined. The implications of diastereomer formation when using this chelation system for creating molecular imaging agents is also discussed. 相似文献