Spreadable materials

Sherman [2] listed the following values of yield stress (in pascals) and their every-day significance for soft-solid, food-like, spreadable materials (such as margarine and butter) -... 

Next let us consider those difficulties associated with the determination of the amount of material deposited on the surface. We have already noted that the method of depositing insoluble monolayers by spreading permits the accurate determination of n. Since the spreading technique requires solvent volatility, care must be exercised to prevent the stock solutions from changing concentration due to evaporation prior to their application to the surface. Also, precise microvolumetric methods must be used to dispense the solution on the aqueous surface since the quantity used is small. The solvent (as well as the solute) must be free from contaminants. There is also the possibility that the solvent will extract spreadable contaminants from the waxed surfaces of the float, barriers, and tray. Some workers advocate addition and evaporation of one drop at a time to minimize this. Oily contaminants may also reach the water surface from the fingers and from the atmosphere. These last sources are particularly hard to control Tests for reproducibility and blank compressions (i.e., moving the barrier toward the float on a clean surface) are the best evidence of their absence. 

Besides the electrical and thermal aspects, carbon conductive additives influence the mechanical properties of the electrodes. In particular, due to its compressibility, graphite improves the electrode density and mechanical stability. The generally lower DBPA of graphite is the reason for the lower amount of binder material necessary to achieve a suitable mechanical stability of the electrode. Further, a more facile spreadability of graphitic filaments in the electrode mass is reported for primary lithium cells.92... 

Low-fat squeezable spreads and soft products (e.g., soft cheese, spreadable margarine) require a ratio of plastic stress to maximum stress of 0.95 to 1.0 (Kasapis, 2000). Typically around 15% of a high-dp fraction ( 25 dp) can be used in these products. Interestingly, the physical structure of the material does not develop immediately with formulation but requires 1 to 2 days of storage. 

Cone penetrometry has the advantages of being simple and economical to use. Also, its results correlate well with testing by sensory panels (Dixon, 1974 Rousseau and Marangoni, 1999). In addition, standardized tests and commercial standards of design are available. The most widely used method is that of the American Oil Chemists Society (AOCS) (Cc 16-60) (AOCS, 1960). According to this method, the depth (d) (in increments of 0.1 mm) to which the cone penetrates the sample is read (AOCS, 1989). This depth is an indicator of consistency and can be related to some structural parameter of the material. Penetrometry results, for example, are often translated into spreadability or hardness values. For example, spreadability (S), as... 

Most mechanical tests developed for fats are empirical in nature and are usually designed for quality control purposes, and they attempt to simulate consumer sensory perception (3, 4). These large-deformation tests measure hardness-related parameters, which are then compared with textural attributes evaluated by a sensory panel (3, 5). These tests include penetrometry using cone, pin, cylinder and several other geometries (3, 6-12), compression (13), extrusion (13, 14), spreadability (15, 16), texture profile analysis (2), shear tests (13), and sectility measurements (14). These methods are usually simple and rapid, and they require relatively inexpensive equipment (3, 4, 17). The majority of these tests are based on the breakdown of structure and usually yield single-parameter measurements such as hardness, yield stress, and spreadability, among others (4, 17-20). The relationship between these mechanical tests and the structure of a fat has, however, not been established. The ultimate aim of any materials science endeavor is to examine the relationship between structure and macroscopic properties. 

Polysulfone A number of adhesives have been found useful for joining polysufone to itself or to other materials. These include 3M Company s EC 880 solvent-base adhesive, EC 2216 room-temperaturecuring epoxy two-part paste, Bloomingdale Division, American Cyana-mid Company BR-92 modified epoxy with DICY curing agent, or curing agent "Z" (both spreadable pastes), vinyl-phenolics, epoxy-nylons, epoxies, polyimide, rubber-based adhesives, styrene polyesters, resorcinol-formaldehyde, polyurethanes, and cyanoacrylates. The EC 880, EC 2216, and the two BR-92 adhesives are recommended by the polysulfone manufacturer. Union Carbide (16) (17). 

Most absorbents are consumer products. For that reason, a new requirement is customer appeal. For absorbents this means that the material must be uniform, easily spreadable, and completely dust free with high abrasion resistance. In both areas... 

The adhesive bond strength between two surfaces, which most often involves an adhesive and a solid substrate, is a complex phenomenon. It is controlled (at least in part) by the values of surface tension and solubility parameters of the materials, and the viscosity of the adhesive. To obtain good wettability and adhesion between a polymeric substrate and an adhesive, the surface tension of the adhesive must be lower than that of the substrate. Usually, the difference between the two values must be at least 10 dynes/cm. Similarity in solubility parameters between the two phases indicates similarity of the intermolecular forces between the two phases. For good compatibility, the values of the solubility parameters must be very close. Low viscosity in the adhesive is necessary for good spreadability and wettability of the substrate. Adhesive bond strength is addressed in more detail in Section 6.3.1. 

Recently, a new series of fluoro-containing silicone fluids have been introduced. In addition to being nonyellowing softeners, these materials have been found to provide outstanding fiber to metal lubrication and good spreadability on surfaces. These compounds conform to the following structure ... 

Most fats are used for nutritional purposes or as animal feed, either directly or after isolation from the food raw materials. Part of what is consumed, that added during cooking or frying, or that used as a spreadable fat is obvious fat, while part is concealed from the consumer, who is not directly aware that the food contains hidden fat. The ratio of both types of fats in human diet is approximately 1 1. 

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