Nuclear magnetic resonance (NMR) spectroscopy has been used to study the morphology and dynamics in semicrystalline polymers.
Dynamics may be observed through NMR relaxation rates that are sensitive to motions in the 1–108 Hz range, or through modulation of anisotropic magnetic interactions, such as the chemical shift and dipole-dipole interactions.
Morphological structure may be inferred through NMR measurements of polymer dynamics or investigated directly through studies
of the magnetic interactions. Here, we discuss the study of morphological structure in semicrystalline polymers using NMR,
and review results on poly(ethylene terephthalate) that address the question of the number of phases in this semicrystalline
Authors:J. Kontschán, R. Albert, K. Almási, V. Kerezsi, and I. Tóbiás
(Acarina: Prostigmata) associated with South African plants . S. Afr. J. Sci. , 3 , 481 – 496 .
Murray , A. ( 1877 ): Economic Entomology, Aptera. Chapman and Hall, Piccadilly, UK, 433 p.
Narayan , D. S. ( 1962 ): Morphological, biological and
Authors:Marta Sánchez-Cabezudo, Margarita Prolongo, Catalina Salom, and Rosa Masegosa
The cure kinetics
and morphology of diglycidyl ether of bisphenol A (DGEBA) modified with polyvinyl
acetate (PVAc) using diaminodiphenylmethane (DDM) as hardener were investigated
through differential scanning calorimetry (DSC) and environmental scanning
electron microscopy (ESEM). Isothermal curing measurements were carried out
at 150, 120 and 80C. The kinetic parameters were obtained using the general
autocatalytic chemically controlled model. The comparison of the kinetic data
indicates that the presence of PVAc does not change the autocatalytic nature
of the cure reaction. Two Tg’s
were observed in the fully cured samples of the modified systems. ESEM micrographies
confirm the biphasic morphology.
Authors:Krzysztof Marycz, Agnieszka Śmieszek, Jakub Grzesiak, and Jakub Nicpoń
., Czogala, J., Wrzeszcz, K. and Nicpoń, J. (2011 a ): Comparison of behavior, morphology and morphometry of equine and canine adipose derived mesenchymal stem cells in culture. Int. J. Morphol. 29 , 1012
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.
Investigated materials were produced from polyethylene
of low density (PE-LD) and a filler: carbon black or chalk. A part of the
samples was kept in ambient temperature over several months in order to study
the effect of material ageing. The qualitative conclusions were drawn based
on a precise analysis of shape of DSC curves and the basic investigations
of PE morphologies known from literature. The influence of the thermal history
and the filler contents on the amount and kind of crystal phase was established.
Additionally, the effect of the measurement technique, in our case it was
positron annihilation lifetime spectroscopy (PALS), on the morphological feature
changes was found. The paper serves selected examples of problems solved by
DSC. However, from the other hand, the authors discuss critically the opportunity
given by this method.
Authors:J. Zhou, Z. Yang, J. Feng, X. Zhang, G. Li, and Z. Ren
plays an important role in wheat improvement. Here we report a new triticale, named Fenzhi-1, derived from the wide cross MY11
after the in vitro rye pollen has been irradiated by He-Ne laser. Morphologically, Fenzhi-1 is characterized by branched-spikes. Genetically, Fenzhi-1 displays stable fertility and immunity to wheat powdery mildew and stripe rust. In situ hybridization (FISH) and seed storage protein electrophoresis revealed that Fenzhi-1 is a new primary hexaploid triticale (AABBRR). The present study not only provides a new method to synthesize an artificial species, but also shows that Fenzhi-1 could be a valuable source for wheat improvement.
Authors:T. Shakhtshneider, E. Ivanov, and V. Boldyrev
The thermal solid-state isomerizations of Copy2Cl2 (py=pyridine), Nien2(NO2)2 and Nien2(NCS)2 (en=ethylenediamine) were studied by thermal analysis, thermomicroscopy, X-ray diffraction and IR-spectroscopy. It was shown that the reactions proceed by nuclear formation and growth. The kinetic-morphological peculiarities of the processes suggest that the process-determining stage is a phase stage, i. e. structural transformation. The topography and kinetics of processes are therefore determined by the crystal structures of the initial material and the reaction product, and by the contact conditions at the interface. The stress relaxation processes affect the morphology of the products and the kinetics of the transformation.