Crash-resistant property

Introduction. A variety of different adhesives, sealants, and coating compounds with a wide spectrum of properties, from high-strength structural adhesives with energyabsorbing properties (crash resistance) to highly elastic surface-coating compounds, are used in modem automobile manufacture. The boundary between adhesives and sealants is fluid and cannot be defined precisely. It is intended here to discuss only products... 

A polymer type has its own set of physical and chemical properties that can set it apart from other polymers. For example, some are intrinsically rigid in nature, whereas others are more flexible. Some may exhibit good energy absorption charactcri.stics. whereas others have a resistance to moisture penetration. These properties make them ideal for. say, insulation, cushioning, crash pads, or floatation applications respectively. 

In 1995, FE from a multiwalled CNT (MWCNT) film was reported by De Heer et al. [14], and the FE property of an isolated MWCNT was reported by Rinzler et al. [15]. FE of electrons from individually mounted CNTs was found to be dramatically increased when the nanotube tips were opened by laser evaporation or oxidative etching. Emission currents of 0.1-1 (xA were readily obtained at room temperature with bias voltages of less than 80 V. Dai et al. [16] attached individual nanotubes with a length of several micrometers to the silicon cantilever of a conventional atomic force microscope (AFM) using a soft acrylic adhesive. Because of their flexibility, the tips are resistant to damage from tip crashes, whereas their slenderness permits the imaging of sharp recesses in surface topography. 

PVC blended with ABS or impact-modified PMMA has improved processability and good fire resistance, along with impact properties superior to those of the parent polymers. ABS/PVC is used as calendered sheet thermoformed into car crash-pad skins (subsequently back-filled with semirigid PU foam), also in moulded power tool handles, sanitaryware and electrical housings. Impact PMMA/PVC is used for seat backs for public transport and industrial panelling. 

Mechanical strength is a property of utmost importance for the industrial use of heterogeneous catalysts. Abrasion resistance and radial crash strength (for pellets) and attrition resistance (for powders) should be routinely measured for quality control of industrial catalysts before reactor loading or better before catalyst purchasing. Such measurements can be conveniently performed using the respective ASTM standard methods, whose possible improvements are suggested. 

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