ABSTRACT

ABSTRACT

Fillers are most important additives in a polymer formulation. A reinforcing filler enhances the modulus and any failure property while the filler, which is an extender, serves to reduce the cost without drastically affecting the properties of the compound. In the polymer industry, it is usual to prepare masterbatches of additives for uniform mixing of ingredients. The masterbatch is later on mixed with the virgin polymer during compounding. Thus, it is highly useful to optimize the various types and quantities of the additives, processing conditions, etc. in this context Design of Experiments has clearly emerged as the popular technique for arriving at the best combination of variables of a polymer system to obtain the desired properties. DoE may be based on a factorial design, CCD or Taguchi Design. These experiments provide maximum information with minimum trials.

In this project report, the effect of calcium carbonate as a filler on the mechanical properties of HDPE compounds is studied. A masterbatch of the filler was prepared using linear low-density polyethylene as the matrix. Subsequently, HDPE compounds were prepared using different let down ratios. A CCD for two factors was used for optimizing the formulations. Experiments were carried out according to the design and properties were evaluated. They include tensile strength, elongation and modulus, impact strength, flexural properties and water absorption.

The data were used to generate a quadratic equation based on the regression analysis. For each property, contour diagrams and response surface plots were generated using MINITAB and MATLAB. Contour diagrams provide information about achieving a desired property with different combinations of the two variables (filler content and let down ratios). The various contour plots were overlaid in order to obtain the best combination of the two factors to give PE compounds, which satisfy the specifications.

For any clarification regarding the above Project: poly.nura@gmail.com