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.
Toughness behavior of gamma-irradiated polycarbonate
The toughness behavior of polycarbonate sheets was investigated, before and after gamma irradiation in air, using physicochemical (determination of viscosity-average molecular weight and Fourier transform infrared spectroscopy) and mechanical (tensile and fracture toughness) tests. The failure mechanisms were analyzed by microscopy and related to the test results. It was found that, as the gamma irradiation dose is increased, there is a decrease in the molecular weight and an increase in the chain scission on carbonyl groups, as detected by infrared spectroscopy analysis. The mechanical properties of polycarbonate were affected by gamma irradiation, showing that polycarbonate presents a ductile-to-brittle transition as radiation dose increases, as confirmed by fractographic analysis. These results are presented and discussed.
Chip scale packaging using chip-on-flex technology
An increasing number of electronic designers, fabricators and users see Chip Scale Packaging (CSP) as a way to obtain the benefits foreseen in multichip packaging and Chip-on-Board (COB) without the problems and limitations currently associated with each. The Chip-on-Flex (COF) multichip packaging technology has been demonstrated to be applicable to single chip packages that meet chip scale packaging goals. This paper looks at the Chip-on-Flex Chip Scale technology and addresses issues including the process, structure, assembly, yields and reliability.