Thermal crystallization

As typical examples of crystal-to-crystal thermal reactions, the cyclization of allene derivatives to four-membered ring compounds and the transformation of a racemic complex into a conglomerate complex are described. 

Thermal Properties. The DPP portion of block copolymers crystallizes on heating at 290°C and then melts at 480°C. The DMP portion of block copolymers does not crystallize thermally but can be caused to crystallize by treatment with a suitable solvent, such as a mixture of toluene and methanol the crystallized DMP then melts at 258°C. The glass-transition temperatures of the homopolymers are too close (221°C for DMP, 228° for DPP) to permit observation of separate transitions, either in block copolymers or blends of the homopolymers. 

Fig 24 Induction Period vs Total Dose Data for Irradiated and Unirradiated Ammonium Perchlorate Single Crystals Thermally Decomposed at 227° (Ref 224)... 

DMP homopolymer, unlike that from DPP, does not crystallize thermally, and no evidence of such crystallinity has been observed in thermally... 

Keywords Liquid crystal Mechanical stimuli Phase transition Photoluminescence Stimuli-responsive liquid crystal Thermal stimuli... 

Swenson, C.A. (1999) Heat capacities (1 to 108 K) and linear thermal expansivities (1 to 300 K) of LuH0.i48 single crystals Thermal relaxation effects and pairing transition, Phys. Rev. B 59, 14926-14935. 

In the temperature range 530-660 K in the investigated ZnO crystals, thermally stimulated ionic processes were detected, at the first stage of which (T = 530-630 K) "pure" anionic vacancies disappear and at the second... 

Cr(mesityl)4 4 Dark brown crystals thermally stable... 

Green and Maddock (S3) subsequently found that the retention of chromium-51 in potassium chromate could be increased by heating the neutron-irradiated crystals. Thermal and radiation annealing have since been observed in a nmnber of systems (4, S, 9, 20, 21, 31, 35, 39, 4I, 50, 52, 53, 54, 60, 66, 67, 74, 77, 91). In general, annealing returns a part of the initially separable recoil atoms to the foim of the parent compound. 

The instruments built with AOTFs as monochromators are often connected to fiber optics to obviate problems with polarized light. The instruments are also always designed in such a manner as to stabilize the crystal thermally, as the wavelength emitted per frequency applied is quite temperature sensitive. 

Getsis A, Balke B, Felser C et al (2009) Dysprosium-based ionic Uquid crystals thermal, structural, photo- and magnetophysical properties. Cryst Growth Des 9 4429 437... 

Fig. 4.20. XRD traces of active sample derived from milled glassy iron-zirconium alloy after 20 h (top) and 450 h of activation under 9 bar of a 3 1 mixture of hydrogen and nitrogen at 700 K [4.44], The top inset shows a high-resolution scan over the Fe (222) reflection, which consists of two doublets arising from the CuK /CuK. splitting. The central inset compares the Fe (200) reflection of a sample exposed to in situ activation for 60 h (a) and of a sample crystallized thermally in an inert gas atmosphere (b)...

As shown in the following diagram, given as 4.2.45 on the next page, the overall Verneuil apparatus consists of a sealed hopper to contain the powder, the TORCH itself, a refractory pedestal to hold the growing crystal, and an after-furnace to anneal the crystal. Thermal stability is important in this method because the high temperatures reached may be sufficient to cause decomposition of the material. 

EDPE/PP 1 5 RT vac X 300-1500 Crosslinking, scission, crystallization, thermal analysis, density 5... 

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