Effect of Recycling on the Rheological, Mechanical and Optical Properties of Polycarbonate
The research was aimed at analyzing the polycarbonate scrap arising during production and its possible secondary utilization. The analysis of morphological, rheological and thermal data revealed significant differences between the original pellets and the reground material obtained from injection molded parts. Test specimens were injection molded from various mixtures of the virgin and the reground material, and their mechanical and physical properties were analyzed. Based on the results the reground material may be used in less than 20% proportion, as the mechanical properties of the products do not deviate significantly from those of the products made from virgin polycarbonate.
A bezel of an automotive headlamp: scrap/virgin ratio effects on its physicochemical properties due to the use of recycled polycarbonate
Automotive bezels of polycarbonate (PC) were prepared in this work by varying the amount of recycled polymer in order to estimate an acceptable scrap/virgin ratio that maintains the material properties. Conducted tests allow us to define the limit to don't compromise the performance of recycled pieces. The studied properties were their chemical structure, molecular weight distribution, mechanical and surface properties of the samples. Results showed no change in the chemical structure of PC chains. However, variations in molecu lar distribution was observed by the addition of recycled material. Last one ascribed to chain scission at the carbonyl group of the PC molecules, and the formation of physical cross-linking as a consequence of degradation due to injection process. Both stiffness and surface proper ties of the material increased as the percentage of recycled PC rose. Therefore, although the chemical structure of the PC is preserved during the recycling process, fluid and elastic properties are modified limiting their operating conditions and industrial tolerance. Con ducted analysis allows to establish that the addition to virgin PC of 20% of recycled material don't affect the physical-chemical properties of pieces, also maintains the quality standars of cosmetics tests.
Polymer toughness and impact resistance
This report is a review of the factors that influence the impact resistance of high polymers, with an emphasis on crystalline polymers. The phenomenology of polymeric fracture is examined, including brittle and ductile failure, and the ductile-brittle transition temperature (DBTT). An in-depth discussion of the effects of crystalline morphology follows, with special attention given to the influence of spherulite size, fillers, processing conditions, transitions/relaxations, and multilayer coextrusion. Next, rubber phase addition is considered, including mechanisms, morphology, rubber type and particle size, and test conditions. Finally, common impact test methods are surveyed, including pendulum, falling weight, tensile impact, and tensile elongation tests.