Authors:B. Sauer, W. Kampert, R. McLean, and P. Carcia
The thermal and crystal morphological properties of poly[ethylene teraphthalate] (PET) and poly(ethylene-2,6-naphthalenedicarboxylate) (PEN) biaxially oriented films were compared to amorphous and other isotropic semi-crystalline samples. Crystal melting as a function of temperature was characterized by temperature modulated DSC (TMDSC) and found to begin just above the glass transition for both oriented films. About 75°C above the glass transitions, substantial exothermic recrystallization begins and continues through the final melting region in oriented films. The maximum in the non-reversing TMDSC signal for the oriented films signifies the maximum recrystallization exothermic activity with peaks at 248°C and 258°C for PET and PEN, respectively. The final melting endotherm detected was 260°C and 270°C for PET and PEN, and is shown by the TMDSC data and by independent rapid heating rate melting point determinations to be due to the melting of species recrystallized during the heating scan. The results are compared with TMDSC data for initially amorphous and melt crystallized samples. The volume fraction of rigid species (Frigid=total crystal fraction plus rigid amorphous or non-crystalline species) were measured by TMDSC glass transition data, and contrasted with the area fraction of rigid species at the oriented film surface characterized with very high resolution atomic force microscopy (AFM) phase data. The data suggest that the 11 nm wide hard domains in PET, and 21 nm wide domains in PEN film detected by AFM consist of both crystal and high stiffness interphase species.
Authors:R. Joshi, E. Lefevre, C. Patel, T. Provder, R. Crombez, W. Shen, and F. Jones
In the present report, thermal analysis (TMDSC, DMA, TG, stress-strain analysis), nano-indentation and AFM morphological characterization
of cross-linkable latexes, prepared with either a pre-coalescence cross-linker (1,3-butylene glycol dimethacrylate) or post-coalescence
cross-linker (adipic dihydrazide) at various levels of cross-linking, were done. The study assesses the effect of type and
level of cross-linking on the film formation process through the evolution of mechanical properties and latex morphology.
In addition, the final fundamental thermal and mechanical properties, specific end-use properties and latex morphology resulting
from the film formation process are reported.
Authors:C. Arribas, Rosa Masegosa, C. Salom, E. Arévalo, S. Prolongo, and Margarita Prolongo
Diglycidyl ether of bisfenol-A (DGEBA)/polybenzyl methacrylate (PBzMA)
blends cured with 4,4’-diaminodiphenylmethane (DDM) were studied. Miscibility,
phase separation, cure kinetics and morphology were investigated through differential
scanning calorimetry (DSC) and scanning electron microscopy (SEM). Non-reactive
DGEBA/PBzMA blends are miscible over the whole composition range. The addition
of PBzMA to the reactive (DGEBA+DDM) mixture slows down the curing rate, although
the reaction mechanism remains autocatalytic. On curing, initially miscible
(DGEBA+DDM)/PBzMA blends phase separate, arising two glass transition temperatures
that correspond to a PBzMA-rich phase and to epoxy network. Cured epoxy/PBzMA
blends present different morphologies as a function of the PBzMA content.
Authors:S. Mojumdar, J. Kozánková, J. Chocholoušek, J. Majling, and D. Fábryová
Fluoroapatite containing glass-ceramics were prepared from Li2O-CaO-CaF2-P2O5-SiO2 system. The glass was melted at 1480C for 1 h. The object of observation was the preparing crystal phase of fluoroapatite
in amorphous glass matrix. The morphology of lithium disilicate glass-ceramics was studied by SEM. The crystal growth and
thermal properties of fluoroapatite were studied by X-ray diffraction and DTA. The more the content of P2O5, the more the presence of fluoroapatite particles. SEM investigation clearly indicated the phase separation and formation
of a primary crystalline phase of fluoroapatite in the studied glass-ceramics. DTA curves of the fluoroapatite samples exhibit
exothermic effects in the temperature range 337-694C depending on the composition of the materials. The position of exothermic peak for lithium disilicate on DTA curves moves with increasing specific surfacetowards lower temperatures which points on its preferential surface crystallization. As far as physical qualities are concerned,
mainly color and gloss, the best qualities of all observed materials belong to glass-ceramics with 10% P2O5.
Authors:Margarita Prolongo, C. Arribas, Catalina Salom, and Rosa Masegosa
ether of bisfenol-A (DGEBA)/poly(vinyl acetate) (PVAc)/poly(4-vinyl phenol)
brominated (PVPhBr) ternary blends cured with 4,4’-diaminodiphenylmethane
(DDM) were investigated by differential scanning calorimetry (DSC), dynamic
mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM).
Homogeneous (DGEBA+DDM)/PVPhBr networks with a unique Tg
are generated. Ternary blends (DGEBA+DDM)/PVAc/PVPhBr are initially miscible
and phase separate upon curing arising two Tgs
that correspond to a PVAc-rich phase and to epoxy network phase. Increasing
the PVPhBr content the Tgof
the PVAc phase move to higher temperatures as a consequence of the PVAc-PVPhBr
interactions. Different morphologies are generated as a function of the blend
Kucharczyk, H. (2010): Comparative morphology of the second larval instar of the Thrips genus species (Thysanoptera: Thripidae) occurring in Poland. Mantis Publishing Company, Olsztyn, pp. 1–152.
Authors:H. Nagy-Déri, Zs. Orosz-Kovács, and Á. Farkas
The receptaculo-ovarial nectary of quince is located on the adaxial surface of the hypanthium. The glandular tissue is protruding out of the basal part of the receptacular tissue, but the apical part of the nectary is epimorphic. The glands can have various shapes if observed in the median longitudinal section of the flower and gland shapes are characteristic to the cultivars. The anisodiametrical cells of the nectarial epidermis are arranged in one or two rows. The surface of the nectary is covered by cuticle, the thickness of which depends on climatic conditions. Stomata of the nectary are mesoxeromorphic, the guard cells are sunken below the outer anticlinal wall of the epidermis cells. The investigated pear-shaped quince cultivars have more sunken stomata than the apple-shaped ones. Both the glandular tissue and the nectary parenchyma are the thickest on the basal part of the nectary, but taper on the apical part. The nectary parenchyma cells differ from the receptacular ones in shape and size. The phloem bundles, supplying the nectary, do not enter into direct contact with the secretory tissues.The morphological and histological differences that can be found between the nectary of cvs. ‘Konstantinápolyi’ and cvs. ‘Dunabogdányi’, as well as between the gland of the investigated apple-shaped cultivars and pear-shaped ones, can have taxonomic importance and could refer to the various degree of susceptibility of the cultivars to
In Hungary increasing problems are caused by hemp found in cultivated fields and waste areas. Results of nation-wide weed surveys demonstrate that area covered by and importance of the plant show a growing trend. The taxonomic status of weed hemp is not unambiguously cleared up in Hungary. Certain authors argue that weed hemp is the crop escaped and naturalized while others opinion is that in Hungary wild hemp is present spontaneously, too. Based on her ten years observations and surveys, the author gives the morphological characters of uncultivated hemp and attempts to clarify its taxonomic status accordingly.