Thermoplastics general properties

Examples of major plastic families Thermoplastic thermal properties are compared to aluminum and steel General properties of thermoplastic General properties of thermoset plastic General properties of reinforced thermoplastic General properties of reinforced thermoset plastic Examples of drying different plastics (courtesy of Spirex Corp.)... 

These materials were first introduced by Du Pont in 1956 and are now known as Teflon FEP resins. (FEP = fluorinated ethylene-propylene.) Subsequently other commercial grades have become available (Neoflon by Daikin Kogyo and Teflex by Niitechim, USSR). These copolymers may be regarded as the first commercial attempt to provide a material with the general properties of PTFE and the melt processability of the more conventional thermoplastics. 

Tabic 3.41. General Properties and Uses of Thermoplastic Materials [54]... 

Polyether sulfones (PES) are another class of engineering thermoplastics generally used for objects that require continuous use of temperatures around 200°C. They can also be used at low temperatures with no change in their physical properties. 

In general, properties of polyether sulfones are similar to those of polycarbonates, but they can be used at higher temperatures. Figure 12-6 shows the maximum use temperature for several thermoplastics. Aromatic polyether sulfones can be extruded into thin films and foil and injection molded into various objects that need high-temperature stability. 

PET, PTT, and PBT have similar molecular structure and general properties and find similar applications as engineering thermoplastic polymers in fibers, films, and solid-state molding resins. PEN is significantly superior in terms of thermal and mechanical resistance and barrier properties. The thermal properties of aromatic-aliphatic polyesters are summarized in Table 2.6 and are discussed above (Section 2.2.1.1). 

Thermoplastic polyurethanes do not require compounding as do the conventional rubbers, and exhibit the same general properties as the cast and millable types. 

Within the past several years, improvements in the toughening of high-temperature epoxies and other reactive thermosets, such as cyanate esters and bismaleimides, have been accomplished through the incorporation of engineering thermoplastics. Additions of poly(arylene ether ketone) or PEK and poly(aryl ether sulfone) or PES have been found to improve fracture toughness. Direct addition of these thermoplastics generally improves fracture toughness but results in decreased tensile properties and reduced chemical resistance. 

For this comparison, a melt-spinning process was chosen. Each special thermoplastic process influences the structure and thus the properties of the obtained polymer samples differently. This is particularly pronounced for fibers, since especially melt spinning is a process which makes extremely high demands on the deformation ability of the polymer melts at high deformation speeds. Particularly the tensile stress within the fiber formation zone is a very important factor to reach a high orientation of the macromolecules along the fiber axis and a stress-induced crystallization. This crystallization should be discussed in relation to PLA and PHB multifilaments, and at the same time the general property spectrum of these polymers should be represented. 

Copolymers of tetrafluoroethylene were developed in attempts to provide materials with the general properties of PTFE and the melt process-ability of the more conventional thermoplastics. Two such copolymers are tetrafluoroethylene-hexafluoropropylene (TFE-HFP) copolymers (Teflon FEP resins by Du Pont FEP stands for fluorinated ethylene propylene) with a melting point of 290°C and tetrafluoroethylene-ethylene (ETFE) copolymers (Tefzel by Du Pont) with a melting point of 270°C. These products are melt processable. A number of other fluorine containing melt processable polymers have been introduced. 

Thermoplastic resins are, for convenience, referred to using abbreviations or acronyms listed in Appendix 15. The general properties of a range of thermoplastics, which are all used... 

Thermoplastic or injection-moulded large quantities, smaller components, good general properties... 

Description and general properties. Polymer matrix composites (PMCs) consist of a pol)oner matrix or resin reinforced with glass fibers and to a lesser extent carbon, boron and pol)r-aramide fibers. The resin systems used to manufacture advanced composites are of two basic types thermosets and thermoplastics (see Chapter 11). Thermosetting resins predominate today, while thermoplastics have only a minor role in advanced-composite manufacture. Thermoset resins require the addition of a curing agent or hardener and impregnation onto... 

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