Date of Graduation
Statler College of Engineering and Mineral Resources
Mechanical and Aerospace Engineering
Nithi T. Sivaneri
Use of recycled plastics started gaining momentum in the U.S. in 1980s due to growing environmental concerns and decreasing landfill capacities. Thermoplastics make up to 80% of the plastics produced today and are widely used in consumer, automotive, and electronic industries. Recycled plastics are being researched and employed for several non-structural and limited structural applications. However, their widespread usage will depend on developing mass manufacturing techniques, value added structural products, and cost effective processing methods. This study focuses on developing and evaluating several structural products such as rectangular grids, rectangular ribbed panels, hexagonal ribbed panels, signposts, signboards, and window panels made of recycled ABS (Acrylonitrile-Butadiene-Styrene) polymers with glass fabrics. These products were manufactured at a reduced scale with the use of compression molding process. Process parameters used for typical manufacturing of structural components were 5 to 7 minutes of preheating followed by 8 to 15 kips of load application at 475° F for about 3 to 5 minutes.;In order to evaluate mechanical properties of recycled ABS, coupon specimens were manufactured conforming to ASTM standards, with and without glass fabrics and tested in tension, bending, compression, and impact. Reinforcement consisting of 1, 3, and 5 layers of 12 oz bidirectional fabric was used to manufacture coupon specimens. With the use of continuous fabric up to 5 layers (12% FVF), increases in tensile, bending, and impact strengths were found to be 147%, 54%, and 1017%, respectively. Corresponding increase in stiffness for coupon specimens in tension and bending was found to be 101% and 45%, respectively.;Structural components manufactured in this study with open cell geometry were tested by using edge stiffeners at supports. Flexural tests were carried out under various loading conditions using line load/patch load (rectangular grids, panels with hexagonal/rectangular ribs) or three/four-point bending load (signpost). Finite element modeling and analysis was carried out for rectangular grid, and panels with hexagonal/rectangular ribs. Good correlation (within 10%) was found between FEM and experimental results for specimens without stiffeners. Recycled polymers exhibited excellent mechanical properties with the use of glass fabric reinforcement. Response of several composite products manufactured under this study and tested under bending loads indicate significant potential for their widespread use in structural and non-structural applications.
Varthakavi, Santosh Amarnath, "Manufacturing, testing, and evaluation of structural products with recycled polymers" (2006). Graduate Theses, Dissertations, and Problem Reports. 1955.