Properties of ASA

The structure and mechanical properties of ASA and blends of ASA and poly(butylene terephthalate) (PBT) have been studied. 40/60 and 60/40 blends of ASA/PBT are composed of two phases, thus are dispersed, while a 50/50 blend shows a cocontinuous structure. With increasing processing temperature, the mechanical properties decrease, probably due to the degradation of PBT in the course of processing. The mechanical properties do not as much decrease for blends with a continuous structure (24). 

In most of the commercial products butyl acrylate is employed however, in the majority of the ASA patent literature, other acrylates, especially ethylhexyl acrylate, are mentioned. The advantage of the latter over poly(butyl acrylate) is its lower glass transition temperature (Tg), —65°C, compared with poly(butyl acrylate) with a value of —45°C. This lower Tg opens up the way for better low-temperature properties for the ASA. The low-temperature properties of ASA are touched on briefly in Section 5. 

The natural color of this material is an opaque, yellowish white but it is not often seen as this. Usually supplied in fully compounded form in a number of opaque shades which may be formulated to suit a particular type of use, for example, outdoor use. If dry colorants, or masterbatches, are to be blended with the natural polymer then, the selection of pigment type is important (so as not to damage the weather resistant property of ASA). It is for this reason that material suppliers prefer to supply the material in the compounded form. 

In comparison to ABS resin, ASA resin has somewhat greater specific gravity, somewhat less tensile strength, and somewhat greater elongation. The other properties of ASA are comparable to those of ABS. 

DR (Rohm and Haas) and Plex 8535-F (Rohm GmbH). Some typical properties of these materials compared with straight PMMA and with the competitive ABS and ASA polymers (discussed in Chapter 16) are given in Table 15.3. 

To summarize we have reproduced the intricate structural properties of the Fe-Co, Fe-Ni and the Fe-Cu alloys by means of LMTO-ASA-CPA theory. We conclude that the phase diagram of especially the Fe-Ni alloys is heavily influenced by short range order effects. The general trend of a bcc-fcc phase transition at lower Fe concentrations is in accordance with simple band Ailing effects from canonical band theory. Due to this the structural stability of the Fe-Co alloys may be understood from VGA and canonical band calculations, since the common band model is appropriate below the Fermi energy for this system. However, for the Fe-Ni and the Fe-Cu system this simple picture breaks down. 

However, just considering the individual properties of each amino acid type is not enough to determine its accessibility to the surrounding aqueous environment. There have been many attempts at developing analytical models with predictive value for determining buried or surface accessible amino acids in a folded polypeptide chain. These studies have concluded fractional assignments for each residue that relate to its accessible surface area (ASA) or its solvent exposed area (SEA). 

Alkenylbenzene by-products, 23 335 Alkenylborates, 13 653 Alkenyl coupling, 13 653 Alkenyl halides, 12 167 Alkenylpyridine derivatives, physical properties of, 21 94t Alkenylsuccinic anhydride (ASA),... 

Properties, processability and prices are intermediate between those of ASA and PC. The consumption is lower than that of ABS/PC. 

Thermal and physical properties of plastics (typical values) Unfilled PS Impact PS 30%. G asa fiUed PS... 

The most widely utilized method to improve the appearance properties of an ASA resin, is to blend the ASA resin with a second resin, which can supplement the weak properties of former resin. 

Further, methods for producing a thermoplastic resin with good physical properties and appearance properties and weatherability as well, use a three component blend of ASA, PMMA, and polycarbonate) (20). 

The properties and the methods of characterization of the of the ASA family are standardized (23). Some selected properties of an ASA polymer are shown in Table 12.4. 

Because of the intended outdoor applications of ASA materials, improved weatherability and color retention performance are of importance. These properties can be enhanced by additives. 

Shrestha, D. S., Van Gerpen, J., Thompson, J., and Zawadzki, A. 2005. Cold Flow Properties of Biodiesel and Effect of Commercial Additives. In Proc., ASAE Annual International Meeting. Warrendale PA Society of Automotive Engineers (Paper No. 056121). 

As noted earlier, experiments leading to a bacterially expressed recombinant protein from chromosome 4 of Arabidopsis with the properties of MIOase have provided opportunity to test the lull potential for AsA biosynthesis through the inversion pathway (Lorence et al., 2004). It remains to be determined whether this route is ancillary to the D-mannose/L-galactose (alternatively, L-gulose) pathway or is a major source of AsA via MIOase in plants. 

At first glance, ASA possesses a similar chemical structure to ABS, since both consist of a SAN matrix containing a graft rubber. However, while the core of the graft rubber of ABS consists of polybutadiene, that of ASA consists of poly(n-butyl acrylate) (Figure 16.8), and this accounts for important differences in the properties of the two plastics. 

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