外文翻譯---關(guān)于混有二氧化鈦的氧化鎂在pvc門窗型材中的可用性研究-在線瀏覽
2025-03-04 02:21本頁面
【正文】 ts fillers, and parts process aids per hundred parts by weight of the polyvinyl chloride resin.Polyvinyl chloride is subject to thermal degradation by dehydrochlorination. Since many processes for forming useful objects from polyvinyl chloride positions, such as extrusion and molding, subject the position to elevate temperatures, most include thermal stabilizing agents that tend to inhibit thermal degradation of the polymer during processing. Example of monly employed thermal stabilization agents includes barium/cadmium and organotins including mercaptides, maleates and carboxylates.Polyvinyl chloride is also subject to degradation by exposure to ultraviolet light. Articles formed from polyvinyl chloride positions, which are exposed to ultraviolet light such as vinyl siding and vinyl window and window frame ponents typically include an ultraviolet stabilizer.In this study, five different positions of PVC were used to fabricate door and window profiles. These profiles are faded under accelerated weathering conditions. Discoloration and some mechanical properties of the profiles are determined to choose the most suitable polyvinyl chloride position used to form the exterior articles.For window profiles up to nine repeated extrusion processes were investigated. The properties like impact strength, modulus, Vicat temperature, thermal stability, etc. of recycled window frame profiles from 20 to 25 years old windows are determined, it is shown that such recycled PVC is suitable for reprocessing. The heat impact of PVC bottle materials during the recycling process at 160– 180 ％ was investigated by IR and UVspectroscopy and by DSC. The bottle samples are slightly and considerably affected at these temperatures as shown by determination of the formed deposition products, colour change, loss of volatile ponents and peroxide formation in air. However, since these depositions occurred at about 30 min of experimental time which is about sixfold of that of real process times, the reclaimed material was found recyclable which makes the use of this material in the production of window sections, profiles, pipes and even bottles possible. Investigations on the mechanical properties of recycled PVC bottle material separated from the postconsumer waste stream show significant reduction in strength and ductility. It is believed that the main reason for this is the presence of impurities, especially PET, which although present at levels below % had a large effect on the properties. Also investigated was the degradation that occurs during multiple reprocessing of recycled PVC from postconsumer bottles using IRanalysis and molecular weight measurements. Batches of recycled flake and powder as well as pure but processed bottle flake materials were subjected to simulated multiple recycling using a torque rheometer. The results indicated a rapid degradation of the recycled material pared with purer bottle flake PVC. Multiple recycling of bottle flake mixed with % polyethylene showed that the PE impurities accelerate the degradation process. Restabilization by adding new bottle flake material surprisingly prevented degradation even at small levels of new material (30%) and even after 15 recycling steps. Recycled PVC bottle material can be used successfully in calcium–zinc stabilized PVC foam formulations to produce profiles of saleable quality. Increasing amounts of bottle recyclate had no significant effect on gelation time, melt rheology or plateout characteristic and gave rise to an improvement on thermal stability. Foam blends can be extruded to produce profiles of good surface finish and low foam density. Up to 100% PVC bottle recyclate did not affect the density, cell structure or impact properties of coextruded foam profiles. Foamed PVC recyclate can also be used for inner layers in tubes where densities at about g/cm3 arepossible. The reuse of recycled PVC in cable insulations is described in Ref. For this purpose, it is necessary to recover copper and PVC from cable forms originating from used motor cars. PVC can be dissolved and separated to be reused in cable and w
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