Engineering polymers advantages

PPS/PSE blends could offer an interesting compromise in properties with PPS offering chemical resistance and polysulfone offering toughness and excellent thermal stability. PA blends with PSE and PEI could offer advantages in chemical resistance offered by the PA and stiffness at higher temperatures and dimensional stability offered by the engineering polymers. Miscibility of PEI and... 

While biological synthesis of polymers confers many advantages, it also imposes some limitations. As described previously, there are several issues that must be considered when designing the monomer and concatamer gene sequences. Furthermore, the potential toxicity of the genetically engineered polymer to the expression host, and the resultant effect on the integrity of the product must be considered. 

A variety of specialty polyolefins and polyolefin alloys can now be made directly in the reactor taking advantage f the new technology. Examples are the catalloy materials from Himont, which are polyolefin alloys made by synthesis and not by the conventional route of compounding. Hivalloy is a polypropylene/polystyrene alloy made by synthesis and combines the properties of both crystalline and amorphous engineering polymers. Such materials could challenge the established positions of several thermoplastic elastomers. 

This semi-crystalline polymer belongs to the family of polyether ketones, Tg= 145 C Tm = 235 C. Developed in 1980 by ICI, it is a superb engineering polymer, showing excellent mechanical properties that are retained at elevated temperatures. Due to its extremely high price, its utility is still limited to the field of aviation and space (reinforced with carbon fibers), electronics and machinery. Another advantage is its stability towards fire or chemicals, although it is sensitive to UV radiation. 

Engineering polymers, such as PP can be reinforced at the macroscopic level with a variety of higher modulus materials such as fibres, beads, and cement, to form heterogeneous composites [4,5]. Thus, reinforcing PP with glass fibres as a co-woven mat has many advantages. Alternatively, reinforcement can also take place at the molecular level. These researchers have reported on the benefits of simultaneous... 

In the manufacturing flnished products, polymeric materials are useful for a variety of end use, which includes many light engineering applications. Advantages of polymers over metals can be quickly summarized as follows [2] ... 

Chapter 7, Polybutylene Terephthalate, from LG Chem, describes the science and technology of PBT blends, compounds, and composites. The chapter offers details on the advantages of different polymer blends, types of fiber, and mineral and fiber-mineral hybrid reinforcements as well as chemical and hydrolysis resistance, flammability, and other PBT attributes. The author states that the most important apphcations of PBT are automotive and electrical, electronics and telecommunications, as well as precision engineering and general mechanical engineering, and concludes that the ability to modify for various applications, combined with a range of reinforcement and blend, has enabled PBT as one of the most widely used engineering polymers. ... 

A big advantage of most engineering polymers over metals is tiiat tiiey eliminate the need for costly corrosion protection steps in manufacture. In addition, some engineering polymer formulations permit manufacturing with the color built in, as it were, thus eliminating painting steps (Figure 12.16 T). 

Polyolefin blends with crystalhne engineering polymers (e.g., polyamides, aromatic polyesters) offer specific cost/performance advantages over the individual components. As these blends are positioned between the commodity polyolefin polymers and engineering polymers, they wiU be discussed in this section. These blends are highly immiscible and also mechanicaUy incompatible as binary blends, thus the majority of the pubhshed investigations involve compati-... 

TABLE 1.37 Advantages and Disadvantages of Some Engineering Polymers and Modifiers... 

Perhaps the most widely used method for engineering polymers is the direct forced-vibration method. The method has the great advantage that the frequency of the excitation can be changed at will without changing the specimen. Hence it is readily possible to determine the frequency dependence of complex modulus and loss factor over a wide range. 

---