Ali G. Maadhah

Weather-Induced Degradation of Linear Low-Density Polyethylene: Mechanical Properties

Abstract Plastics degrade through the influence of such factors as the suns radiation, temperature, humidity, rain, the oxygen content of the air, and atmospheric pollutants. The most deleterious of these effects is radiation, which is responsible for breaking up polymer chains. The sun emits a complete spectrum of energy radiation, with waves similar in physical structure but varying in length and therefore in photon energy. Wavelength has an inverse relationship to quantum energy, as shown in Fig. 1.

WEATHER INDUCED DEGRADATION OF LINEAR LOW DENSITY POLYETHYLENE (LLDPE): MECHANICAL PROPERTIES

Unstabilized LLDPE is exposed to the natural weather of Dhahran, Saudi Arabia, and changes in its mechanical properties have been studied. It has been shown that Dhahrans weather is more damaging to exposed polyethylenes than other exposure sites in the world

Weather-Induced Degradation of LLDPE: Calorimetric Analysis

Abstract Studies of polymer degradation over the past decade have increasingly been carried out using thermoanalytical methods. These methods involve the measurement of a convenient variable during a gradual, linear increase in temperature. The most widely used of these techniques are thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The morphology of a polymer sample (i.e., the crystallinity, shape and size of the crystals, the structure of the surface of the crystals, and the strain of amorphous regions) influences the heat content and its dependence on temperature. The latter can be satisfactorily investigated by calorimetry measurement in a differential scanning calorimeter.

Weather-Induced Degradation of Plastic Pipes

Abstract A number of plastic materials, such as unplasticized poly(viny1 chloride) (uPVC), acrylonitrile-butadiene-styrene (ABS), high-density polyethylene (HDPE), poly-(vinylidene fluoride) (PVDF), and chlorinated poly(viny1 chloride) (cPVC), are available for numerous applications. uPVC and HDPE pipes are used in pressurized piping systems in Saudi Arabia for industrial, agricultural, domestic, and general-purpose applications. Some studies have been carried out to investigate the causes of failure in plastic pipes, which is very high in the area. In this chapter an overview of the failure of plastic pipes is presented, with emphasis given to failure of pipes due to severe weather conditions in Saudi Arabia.

The measurement of the extent of reduction of steam-reforming catalysts using thermal analysis techniques

The thermal decomposition, the nickel oxidation and other thermal changes in commercial NiO/Al,O, catalysts were studied over the temperature range 20-1000°C. The thermal analysis (TG and DTA) results of the reduced steam-re-forming catalysts were used to determine the extent of reduction of the catalyst to the active metal (nickel). The metallic nickel content in the reduced catalyst samples determined by the rapid thermal technique compared fairly quite well with results obtained by the longer chemical analysis method. The thermal analysis of the reduced steam-re-forming catalysts each showed, regardless of reduction conditions, one exothermic peak with a corresponding gain in weight in the temperature range 20-1000°C.