Impact toughness

Nylon A class of synthetic fibres and plastics, polyamides. Manufactured by condensation polymerization of ct, oj-aminomonocarboxylic acids or of aliphatic diamines with aliphatic dicarboxylic acids. Also rormed specifically, e.g. from caprolactam. The different Nylons are identified by reference to the carbon numbers of the diacid and diamine (e.g. Nylon 66 is from hexamethylene diamine and adipic acid). Thermoplastic materials with high m.p., insolubility, toughness, impact resistance, low friction. Used in monofilaments, textiles, cables, insulation and in packing materials. U.S. production 1983 11 megatonnes. 

Kerb-tier, n. insect, -tierkunde,/. entomology, -zahigkeit, /. (Mstal.) notch toughness, impact resistance or strength (in notched-bar test). 

Based on castor oil derived elastomers and crosslinked polystyrene, a simultaneous mode of polymerization can be successfully employed to synthesize prototype engineering materials such as tough, impact resistant plastics and reinforced elastomers. 

Metallocene enhanced toughness, impact and puncture strengths, better cold behaviour and optical properties. 

One the attempt to give improved mechanical properties to TPX is to laminate the polymer and a resin containing polar groups, such as ethylene vinyl acetate and PA. These polymers exhibit excellent gas barrier properties, and the lamination of TPX makes an improvement in the gas barrier properties. Furthermore, PA, in particular biaxially-oriented PA, shows an excellent rigidity, toughness, impact resistance (4). 

Impact Modifiers. Notched impact strength and ductility can be improved with the incorporation of impact modifiers, which also can lower the britde— ductile transition temperature and give much improved low temperature toughness. Impact modifiers are rubbers (often olefin copolymers) that are either modified or contain functional groups to make them more compatible with the nylon matrix. Dispersion of the mbber into small (micrometer size) particles is important in order to obtain effective toughening (29). Impact modifiers can be combined with other additives, such as glass fiber and minerals, in order to obtain a particular balance of stiffness and toughness. 

In an initially ductile polymer, failure properties (ultimate elongation, fracture toughness, impact resistance) decrease rapidly during a chain-scission aging process, whereas elastic and yield properties are practically unaffected at the embrittlement point. 

With large amounts (> 80%) of /3-pinene in the chain tough, impact resistant plastics may be anticipated. 

PPS with a styrene-grafted PPE and polyetherester rubber good toughness, impact and tensile strength Dainippon Ink Chem., Inc., 1982... 

Another advantage of using IPNs involves its thermosetting characteristics. By definition, IPNs will not flow when heated. A partial exception is the thermoplastic IPNs, which behave crosslinked at ambient temperatures, but flow at elevated temperatures. While some IPNs are tough, impact-resistant plastics, the crosslinking permits many other types of applications, such as sound and vibration damping, biomedical, adhesives and coatings uses, etc. (see Section 6.5). 

Commercial impact modified (elastomer blended) polycarbonates are used for the production of protective headgear, sporting goods, bobbins for textile industry and automotive components requiring high toughness. Impact modified PC has to compete with the more solvent resistant impact modified PBT/PC, PET/PC blends and polyamides in some of the applications. 

Keywords High-Performance, Lightweight, PVB, PVA (polyvinylalcohol) Fiber, Interfacial Transition Zone, Density, Fracture Toughness, Impact... 

Strength and toughness, impact and thermal shock resistance as well as optical transparency at high temperatures. 

It is well established in the literatme, that the incorporation of rigid micro-scaled fillers usually increases composite stiffness, but at the expense of ductility. This is due to the stress concentration regions that exist in close proximity of the reinforcement. In the case of nanoscaled fillers, in contrast, the stress concentrations are significantly reduced. Hence, composite ductility can be retained at a constant level or even improved, in comparison to neat polymer [8]. It has been shown that some nanocomposites may lead to significant and simultaneous improvements in stiflhess, fracture toughness, impact energy absorption and vibration damping. These characteristics could be of particular importance in some structural apphca-tions such as in the automotive and aircraft industries [4]. 

These novel materials showed improved toughness, impact strength and creep properties compared with those of the siloxane-free counterpart, as shown in Fig. 20.6 for impact strength measurements. 

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