CLEAR family resins

Proportion of Hard Segments. As expected, the modulus of styrenic block copolymers increases with the proportion of the hard polystyrene segments. The tensile behavior of otherwise similar block copolymers with a wide range of polystyrene contents shows a family of stress—strain curves (4,7,8). As the styrene content is increased, the products change from very weak, soft, mbbedike materials to strong elastomers, then to leathery materials, and finally to hard glassy thermoplastics. The latter have been commercialized as clear, high impact polystyrenes under the trade name K-Resin (39) (Phillips Petroleum Co.). Other types of thermoplastic elastomers show similar behavior that is, as the ratio of the hard to soft phase is increased, the product in turn becomes harder. 

In combination with a resin or reductase inhibitor, niacin normalizes LDL in most patients with heterozygous familial hypercholesterolemia and other forms of hypercholesterolemia. These combinations are also indicated in some cases of nephrosis. In severe mixed lipemia that is incompletely responsive to diet, niacin often produces marked reduction of triglycerides, an effect enhanced by marine omega-3 fatty acids. It is useful in patients with combined hyperlipidemia and in those with dysbetalipoproteinemia. It is clearly the most effective agent for increasing HDL and the only agent that may reduce Lp(a). 

Several conclusions have to be drawn. The first is related to the obvious gap between the empiricism and even archaism of most of industrial cationic polymerization processes and the level of fundamental science devoted for decades to these reactions. Previous chapters in this volume clearly illustrate the situation. This feature was pointed out in the early book of Kennedy and Marechal [1], and the explanation based on the very favorable price/performances characteristics of the products is still realistic. Nevertheless it is noteworthy that recent improvements or new processes based on more scientific approaches led to a better control of the polymerization, of polymer structure, and to high-performance commercial products which will increasingly occupy the market. This is the case for the recently marketed reactive BF3-based polybutenes with high content of exomethylenic chain ends, for the strongly developing pure monomer hydrocarbon resins ( + 8% in 1994), or for the new benzyl halide-based halobutyl rubber, and it is revealing that these products represent the three families of cationically prepared industrial polymers... 

When a balsam is distilled, a volatile oil and a resin are obtained. This latter is an amorphous mass, which is softened by heating and melts to a clear, viscous and sticky liquid. A typical balsam is biosynthetically related to the terpenes and phenylpropane derivatives of volatile oils. Balsams are found in several plant families, e.g. Anacardiaceae,... 

This is a thermoplastic polymer resin of the polyester family and is usually referred to as polyester. PET can be semi-rigid to rigid depending on its thickness and is very lightweight, clear, strong and impact resistant, has good gas- and moisture-resistant barrier properties and is widely used for soft drink bottles. 

Coumarone-indene resin n. Any of a family of resins produced by polymerizing a coal-tar naphtha containing coumarone and indene. The naphtha is first washed with sulfuric acid to remove some impurities, then is polymerized in the presence of sulfuric acid or stannic chloride as a catalyst. Remaining impurities determine the quality of the resin, which can range from a clear, viscous liquid to a dark, brittle solid. Coumarone-indene resins have no commercial applications when used alone. 

However, the samples from Noen U-Loke do not demonstrate a clear-cut correspondence to the modem Dipterocarp resins as neither hydroxydammarenone (G), which is not detected at all in these samples, nor ursolic aldehyde (J2) dominate. Instead, a-amyrin (D) is the usually largest peak by far. Although this is the case, the composition of the archaeological material is quite dissimilar to the triterpenoid Canarium resin, but does exhibit a range of the terpenoid components present in Dipterocarp resins suggesting that this family may be the botanical source of die resin used as a coating on these ceramics. 

The name alkyd resins clearly distinguishes these polymers from thermoplastic polyesters (PET, PBT, PC, etc.) as well as from unsaturated polyesters (UP), which are also part of the family of three-dimensional polymers (see Section 16.2). 

At its most basic form, a material specification should describe the material in a clear, unambiguous manner. While this can be done by referencing a product code from a resin supplier, it can also be done in a narrative form, by describing the chemical family, the common name, the additives, etc. An example is given below. It is highly advisable to provide a reference to an international standard and require the material supplier to verify that the material meets that standard. The advantage of a narrative specification is that it provides a reader with descriptive information, which may not be immediately obvious from only a product code. 

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