Impact resistance mechanical behavior

N. Devia, J. A. Manson, and L. H. Sperling, Simultaneous Interpenetrating Networks Based on Castor Oil Elastomers and Polystyrene. IV. Stress-Strain and Impact Loading Behavior, Polym. Eng. Sci. 19(12), 878 (1979). Castor oil-polyester/PS SINs. Mechanical behavior. Impact resistant plastics. 

K. Kircher, Kombinationswerkstoffe aus Polyurethan und Vinyl-polymeren, Angew. Mak-romol. Chem. 76/77, 241 (1979). Polymer blends and IPNs based on polyurethanes and poly(methyl methacrylate). SINs. Electron microscopy and mechanical behavior. Impact-resistant plastics. 

Mechanical data like stress/strain behavior, impact resistance in comparison to polystyrene... 

Physical and Mechanical Behavior of the Oils and SIN s. One of the most important properties of any polymer is its glass transition temperature. This defines its range of use, as well as a host of fundamental properties. This holds for IPN s and SIN s. In particular, for multiphase materials, the rubber phase must have a T below about -40°C if significant impact resistance is to be obtlined. 

The impact of the nanocomposite technology on polymers is huge, reflected in enhanced properties of the resulting PNs, such as enhanced mechanical, barrier, solvent-resistant, and ablation properties.12 The effect of nanocomposite technology on the thermal and fire performance of the polymers is primarily observed in two important parameters of the polymers (1) the onset temperature (7( ,nsct) in the thermogravimetric analysis (TGA) curve—representative of the thermal stability of the polymer, and (2) the peak heat release rate (peak HRR) in cone calorimetric analysis (CCA)—a reflection of the combustion behavior (the flammability) of the polymer. The Tonset will be increased and the peak HRR will be reduced for a variety of polymers when nanoscale dispersion of the nanoadditive is achieved in the polymer matrix. 

Their non-linear and often synergistic mechanical behavior which arises from their above mentioned multiphase morphology. Thus, both impact resistant plastics and thermoplastic elastomers have been bom. 

While IPNs can be and have been made extremely tough and impact resistant, many of the proposed applications involve such diverse fields and sound and vibration damping, biomedical materials, and non-linear optics. This is because the presence of crosslinks in both polymers reduces creep and flow, allowing relatively stable materials with a wide range of moduli to be prepared. Thus, those materials with leathery mechanical behavior, combinations of elastomers and plastics, are especially interesting to scientists, inventors, and engineers. 

For a very large proportion of polymeric materials in commercial use, mechanical properties are of paramount importance, because they are used as structural materials, fibers, or coatings and these properties determine their usefulness. Properties that also determine their utilization are compressive, tensile, and flexural strength, and impact resistance. Hardness, tear, and abrasion resistance are also of concern. In addition, polymers may be shaped by extrusion in molten state into molds or by deposition from solutions on various surfaces. This makes the flow behaviors in the molten state or in solution, the melting temperatures, the amount of crystallization, as well as solubility parameters important. 

TPU has been used to toughen PC, to enhance its mechanical behavior and ESCR. The blends have been used in industrial and medical applications (De Boer and Heuschen 1988 Pinchuck 1991). Blends of PC/PET/TPU with EVAc-GMA and optionally MBS or ABS have good flexural modulus, strength, weld-line strength, solvent resistance, and impact behavior (Laughner 1994). PC blends with a polycaprolactone-polyurethane resin, TPU Pellethane , and either MBS or MBA showed similar behavior (Henton et al. 1993). 

Standardized notched impact tests such as the Izod and Charpy tests (ASTM, ISO, DIN) are the most commonly used to characterize the impact strength of plastic materials. It is very difficult to use measured data from tests using idealized laboratory specimens to predict impact behavior of end-use polymeric material. The apparent lack of good correlation between measured impact fracture energy and end-use impact resistance is due to the extreme complexity of microscopic fracture processes. In particular, the influence of specimen geometry is sometimes poorly matched with the type of failure mechanism of defects present in the actual molded part subjected to end-use impact forces. 

This chapter will review the relationships among synthetic detail, morphology, and resulting mechanical behavior. While effects on the glass-rubber transition and modulus will be emphasized, aspects of toughness and impact resistance will be touched upon and applications discussed. In order to generalize this critique, polymer I is defined as the first synthesized polymer, and polymer II as the second synthesized polymer. Even when the order of synthesis is immaterial, as in mechanical blends, this notation will prove useful. Since the basis of this chapter lies in the two-phased nature of these materials, it is appropriate to examine first the fundamental reasons underlying phase separation. 

Of course, in many of these applications, the mechanical behavior of the materials is paramount. In fact, many such applications, such as impact resistance, arise because of the two-phased nature of the products. In this case, the size of the rubber phase domains and their glass temperatures are... 

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