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.
Ageing of PC/PBT blend: Mechanical properties and recycling possibility
A polycarbonate (PC) and poly (butylene terephthalate) (PBT) blend is extensively used for moulded automobile parts. PC is tough and stable to 300 °C and PBT has relatively good solvent resistance. An alloy formed with those two polymers produces a material with good chemical resistance as well as good heat and impact resistance. In this work, a PC/PBT blend, with and without pigment, was aged by natural and accelerated methods. Tensile and impact properties and melt flow index were evaluated before and after aging, and also after recycling. The rupture elongation of the recycled material was very good, showing the recycling potential of this material. Tensile modulus and tensile strength were not affected by the processes to which the blend was submitted. The impact strength of the recycled material showed a decrease after ageing.
Contractor Failure: Analysis
The possibility exists for any construction contractor to fail to filfill the contract requirements associated with a facility. Contractor failure occurs when a contractor is unable to perform his/her contractual duties, thus requiring the facility owner to invoke the contract's nonperformance clause. This paper provides aggregate contractor business failure statistics and outlines potential causes for failure. A framework to identify and quantify the associated costs is also introduced. Several case studies are presented to examine the cause and cost of failure and the means by which the facilities were completed. Alternatives available for project completion when contractor failure occurs are discussed. Recommendations to identify and monitor contractors at high risk for failure are outlined as well. This paper provides facility owners with a greater awareness of the possibility of contractor failure, how to quantify costs of contractor failure, and avoidance techniques.