Crystallization process and morphology structure of poly(aryl ether ether ketone ketone) containing meta-phenyl links

The crystallization process and morphology of poly(aryl ether ether ketone ketone) containing meta-phenyl links (PEEKmK) have been investigated by transmission electron microscopy and electron diffraction. The results indicate that the thin films of PEEKmK isothermally crystallized from both the glassy state and the melt at the temperature range of 180 similar to 250 degrees C consist of two kinds of morphological forms, i. e. large (order of mu m), flat-on single crystals and narrow, lath-like, edge-on lamellae, The latter consists of the spherulites. Meanwhile, the growing process of the two kinds of morphological forms has been discussed.

Synthesis and properties of poly(aryl ether ether ketone ketone) containing meta-phenyl links

A Series of poly(aryl ether ether ketone ketone) containing meta-phenyl link were synthesized, the general properties were studied by DSC, stretch, impact, etc.. The results indicated that with the raising of meta linkage monomer fractions, the glass transition point decreased, the melting temperature decreased at first, and then disappeared, but for all-meta-linked polymer, T-m appeared once more. And this kind of polymer had good stretch and impact resistance performance.

Synthesis and properties of poly(aryl ether ketone)s containing meta-phenyl links

A series of poly(aryl ether ketone)s containing meta-phenyl links are synthesized, DSC and wide-angle X-ray scattering, etc, are used to study the general properties of the polymers, With the increasing of meta linkage monomer percentage, the melting temperature decreases sharply at first, then rises steadily, the glass transition point. keeps a stable value, and crystallin;ty and crystallizing rate are reduced, A part of amorphous film of the polymer is annealed at different temperatures, DSC scan shows that besides T-m, a new melting peak (T-m') at low temperature appears, And with heat treating temperature rising, T-m' shifts to high temperature, and T-m keeps a stable value.

SPECTROPHOTOMETRIC DETERMINATION OF LANTHANUM AND SUM OF OTHER LIGHT RARE-EARTHS BY FLEXIBLE TOLERANCE SIMPLEX-METHOD

The absorptivities of color elements in a mixture can be obtained by using Gauas' elimination with selection of principal element in matrix to the standards. These values can be applied to flexible tolerance simplex method to give the composition of samples. In the exprimental design and data treatment, an effort was made to minimize the errors of results according the principal of optimization. When the difference of absorptivities of color material is significant to the exprimental error, the pr...

A Scheduling Algorithm for Flexible Manufacturing Cell

In this paper, a new scheduling algorithm for the flexible manufacturing cell is presented, which is a discrete time control method with fixed length control period combining with event interruption. At the flow control level we determine simultaneously the production mix and the proportion of parts to be processed through each route. The simulation results for a hypothetical manufacturing cell are presented.