Paste amorphous components

The lamellae slip rigidly past one another. Lamellae parallel to the direction of draw cannot slip thus, spherulites become anisotropic. At this stage, at which necking begins, the strain is accommodated almost entirely by the interlamellar amorphous component. 

The paste is a non-equilibrium system and Fig. 6.2b refleets only the erystal phases but not the amorphous components. It has been established that, when eertain types of lead oxide are used, the strongest diffraction line for the 4PbO PbS04 phase appears after one month shelf-storage of the paste at room temperature [7]. This indicates that nucleation of 4BS is a very slow process that depends strongly on temperature, initial materials (compounds) involved in the reaction and duration of the process of paste mixing. 

The basic components of the paste are crystal phases of 3BS or 4BS, small amounts of orthorhomb-PbO, tet-PbO and Pb. These are detected by X-ray diffraction methods. If a paste is prepared from crystal phases of 3BS and tet-PbO in the same proportion as in the paste prepared from leady oxide and H2SO4, and then grids are pasted with this paste and set to curing and formation, the obtained PAM is mechanically unstable and difficult to form, and hence the plates have low capacity. Valeriote has found that one of the reasons for the low energetic characteristics of positive plates is the lack of amorphous components in the paste [17]. The content of amorphous phases should amount to 15—10%. Such amorphous components in the paste are most often hydroxides. Some of the amorphous hydroxides are obtained as a result of oxidation of Pb in the leady oxide during paste preparation and plate curing. And the content... 

There are but scarce investigations into the role of amorphous components in the paste on battery performance. 

The aqueous aroma composition (solid, liquid, paste) includes components/supports able to form by freezing an amorphous matrix or a gel to immobilize aroma compounds. It will be transformed into an aroma powder, without modification of aroma, for easy storage. After freezing of the aroma composition, there is drying by sublimation of ice, usually under vacuum. The driving force for sublimation is the difference in pressure between the water vapor pressure at the ice interface and the partial pressure of water vapor in the chamber. Because of the low processing temperatures, thermal degradations reactions are excluded. 

The interest in multicomponent materials, in the past, has led to many attempts to relate their mechanical behaviour to that of the constituent phases (Hull, 1981). Several theoretical developments have concentrated on the study of the elastic moduli of two-component systems (Arridge, 1975 Peterlin, 1973). Specifically, the application of composite theories to relationships between elastic modulus and microstructure applies for semicrystalline polymers exhibiting distinct crystalline and amorphous phases (Andrews, 1974). Furthermore, as discussed in Chapter 4, the elastic modulus has been shown to be correlated to microhardness for lamellar PE. In addition, H has been shown to be a property that describes a semicrystalline polymer as a composite material consisting of stiff (crystals) and soft, compliant elements. Application of this concept to lamellar PE involves, however, certain difficulties. This material has a microstructure that requires specific methods of analysis involving the calculation of the volume fraction of crystallized material, crystal shape and dimensions, etc. (Balta Calleja et al, 1981). 

With respect to general criteria for craze initiation and growth, important contributions have been made for amorphous glassy polymers by many investigators during past years. Recognizing that crazing is also inherently a cavitational process for crystalline polymers leads to the criterion that craze initiation involves a dilatational stress component. In... 

---