Optical properties opacity

Fig. 4 Optical properties (opacity) determined for S composite film (plasticized starch without natural filler in composition) in comparison with a S/FTN composite films b S/BL composite films c S/BS composite films...

Optical Properties (Opacity) of Nonwoven Fabrics (INDA) NWSP 060.1.R0 (15) ... 

Properties Mechanical, thermal, optical properties Opacity and translucency in insulators ... 

Optical. The optical properties of fillers and the influence that fillers have on the optical properties of filled systems are often misunderstood. The key parameters in understanding the optical properties of fillers themselves are filler psd, color, and index of refraction. These characteristics influence the optical properties of filled composition, such as color, brightness, opacity, hiding power, and gloss. 

Finally, the nature of the crystalline microstmcture, ie, crystal size and morphology and the textural relationship among the crystals and glass, is the key to many mechanical and optical properties, including transparency/opacity, strength and fracture toughness, and machinabiUty. These microstmctures can be quite complex and often are distinct from conventional ceramic microstmctures (6). 

Optical Properties. Owing to the high crystallinity of HDPE, most thick-waHed articles made from HDPE resins are opaque. Significant surface roughness can also add to the opacity. Thin HDPE film, in contrast, is translucent, but its transparency is significantly lower than that of LDPE or LLDPE film. The ultraviolet transmission limit of HDPE is around 230 nm. 

Difference in optical properties can be used as the basis to separate solids in a mixture. Optic properties include color, light reflectance, opacity, and fluorescence excited by ultraviolet rays or x-rays. Differences in elec trical conductance can also be used for separation. With appropriate sensing, the particles in a moving stream can be sorted by using an air jet or other means to deflect certain particles away from the mainstream (Fig. 19-10). The lower limit of particle size is about... 

Evaluation of these optical properties may be done by simple observation this approach is useful clinically (Knibbs, Plant Pearson, 1986), since acceptability of the colour match to the surrounding tooth material can be readily seen without the need for instrumental measurement. On the other hand, for quantitative evaluation of optical properties, some kind of instrumental measurement is necessary, and the property usually evaluated is opacity. 

Many inert pigments (often known as fillers) are incorporated into paper in addition to the cellulosic fibres. They may be added to improve certain optical properties—in particular opacity and brightness—or simply as a cheap replacement for costly fibre. The two most common pigments are kaolin (china clay) and chalk (limestone), but talc and speciality pigments such as titanium dioxide are also used. The particle size for general purpose fillers is normally expressed as an equivalent spherical diameter (esd) and this is determined from sedimentation data. Values for the common paper-... 

The optical properties of ceramics are useful in the ultraviolet, visible, and infrared ranges of the electromagnetic spectrum, and one key quantity used to describe the optical property of a material is the refractive index, which is a function of the frequency of the electromagnetic radiation. Other quantities used to characterize optical performance are absorption, transmission, and reflection these three properties sum to unity and are also frequency dependent. The last three properties govern many aspects of how light interacts with materials in windows, lenses, mirrors, and filters. In many consumer, decorative, and ornamental applications, the esthetic qualities of the ceramic, such as color, surface texture, gloss, opacity, and translucency, depend critically on how light interacts with the material. 

For some applications, a refractive index is important. A match between the particle size of some barium grades and the refractive index of matrix material allows the formulation of products with desirable optical properties. A series of synthetic barium sulfates is produced by Sachtleben Chemie which have particle sizes between 4 and 10 pm. If the particle size of these barium sulfates is well coordinated with the refractive index of the matrix polymer, semi-opacity combined with translucency results. This permits the foimulation of a light disperser in lampshades or in illuminated advertising displays. The coirect particle size can be calculated from the equation d = (lOOn - 141)/2, where n is the refractive index of the resin and d the particle size of barium sulfate. 

The use of edible films in food products packaging will depend on their functional properties, viscoelasticity, optical properties (color and opacity) and water vapor permeability, that depend on the structural cohesion of the polymer, considering the effect of the formulation on the structure of the macro-molecules.17,18 A macroscopic parameter, sometimes ignored, that could influence these films properties is their thickness.17,19... 

Barium sulfate (BaS04) has an industrial relevance due to its whiteness, inertness, high specific gravity, and optical properties, such as opacity to UV rays and X-rays [164-167]. It is mainly used as a radio-contrast agent, filler in plastics, extender in paints, coatings and additive in pharmaceutical products, and in printing ink. Nowadays, interest on this material has been renewed with the development of methods to produce nanosized particles, supraparticles of a well-controlled number of nanoparticles and mesocrystals that mimic biomineralization processes. 

Selecting, combining and matching colors is a complicated art that only well-trained individuals are able to perform correctly. There are hundreds of different colorants used in the plastic industry, and there are as many types of colorants as different applications for plastics. Similarly to measurement of optical properties of paper and paperboard, the characterization of a color for plastics is based on the measurement of color (hue), brightness, and opacity. Other important variables to be considered in colorant selection include dispersability in the plastic, migration, toxicity, light stability, and chemical resistance. 

The great economic and cultural success achieved by plastics can be attributed largely to their optical properties. The ability of semi-synthetics to mimic the rich colours and opacity or transparency of natural materials endeared them... 

---