The processing characteristics of PVC compounds play a major role on the ability of the equipment to control the final properties of the product. Therefore, information on the effect of processing conditions on such characteristics. and its influence on the final properties can lead to an optimization of the extrusion process. In this work. a statistically based experimental design was used in order to investigate the role of the operating conditions on the extrusion of a simple lead based PVC formulation. Both a single and a twin screw extruder were used - they were instrumented, and data collected by computer. A die was designed for the formulation used. with both shear and extensional flows being taken into account. These experiments produced both core samples along the screw(s) and final products with varying states of fusion. The fusion mechanism on processing was monitored with the help of electron and light microscopy techniques. thermal analysis and density measurements. In both types of extruders the primary particles were found to fuse well before the grains, but the overall mechanism differs for each type of machine. An experimental technique was developed for the study of the Residence Time (RT) and Residence Time Distribution (RTD) of the material in the processing equipment. These functions were related to the operating conditions and compared with the available models for extrusion. The degree of fusion of the processed products was assessed by rheology and thermal analysis. A range of mechanical properties, relevant to the general end - use of rigid PVC formulations. was analysed: flexural. tensile and impact properties were found to be directly related with fusion level. Hardness, measured using a newly developed apparatus. proved to be a potential technique for the degree of gelation of PVC formulations.

Since 1950, the plastic production has increased radically from 1.5 to 280 million tons in 2012. The increased production of plastic has led to oceans becoming more polluted than ever. Micro plastic particles originate from large floating plastic debris by undergoing degradation caused by UV-radiation. Due to their small size, density and colour micro plastic particles resemble marine organisms’ natural prey and are therefore ingested. This report discuss the hypotheses that there are micro plastic particles present in oceans outside of the Costa Rican west coast (hypothesis 1), that the location between the South and North Pacific gyres will result in an accumulation of plastic (hypothesis 2) and that different sampling methods will generate different types of data which makes it difficult to compare results (hypothesis 3). A manta trawl was used to collect samples in size range 1-2mm and they were quantified with a microscope. To simplifying transportation and storing, aluminum foil was used instead of glass jars to collect samples. Thereby the need of transferring material from a glass jar to a flat surface for quantifying with microscope was eliminated. One area contained 56.5 % of all gathered particles together. The result also showed that micro plastic particles are present even in protected areas.