Session: 03-05-01 Design, Material Processing, and Applications of Polymer Composites

Paper Number: 93930

93930 - Lightweight Approaches to Automotive Composites: Nanocellulose and Kaolin 

The focus of this study is to investigate how to lightweight SMC composites for automotive applications without compromising their performance. This is accomplished by replacing, at least partially, the heaviest materials such as the glass fibers (GF) or calcium carbonate (CaCO3) with nanocellulose or nanoclays. In addition, the chopped glass fibers are replaced by glass fabric in order to better control the location and orientation of the glass fiber reinforcement and thus engineer the mechanical properties. Unsaturated polyester resin (UPR) is used as the resin, and a pilot scale sheet molding compound (SMC) is used to make the SMC. The composites are made by stacking 3-5 layers of SMC layers in a mold, after appropriate conditioning of the SMC, and compression molding. The properties of interest are the tensile and flexural modulus and strength according to the corresponding ASTM standards and the density of the composites. The void content is also determined using acid digestion and scanning electron microscopy. Two different directions are explored. The first is to replace traditional chopped glass fibers (GF) used in SMC with unidirectional glass fabric coated with cellulose nanocrystals (CNC). The reasoning is to enhance properties with a better UPR/GF interface and controlled fiber orientation while reducing density. The glass fiber fabric is coated with nanocellulose using a scalable spraying technique that leads to homogeneous coatings. The four different glass fiber fabrics that were used in this study vary in CNC coating amount. 

The second is to replace the heaviest filler, calcium carbonate, of typical SMC resin paste with nanoclay, kaolin, responsible for reducing density without compromising properties. Using traditional chopped GF for SMC, different types of commercial kaolins were investigated according to particle size and surface treatment. 

To understand the effect of the nanocellulose or the kaolins, the glass fiber content of all composite formulations was kept constant at about 30 vol%. In addition, to determine the mechanical properties of the composites, the viscosity was verified for all formulations to adhere to SMC standards. SEM micrographs show the quality of the CNC coating on the glass fiber fabric. Moisture absorption of all composites were also analyzed via water uptake studies. 

The expected results will address design, processing, and testing challenges, as well as successes, and failures. The question to be addressed is whether or not CNC coated fabric and kaolin are significantly advantageous for SMC compared to chopped GF and calcium carbonate, respectively.

Presenting Author: Eric Biederman Georgia Tech

Presenting Author Biography: Georgia Tech, Master&#39;s Candidate in Mechanical Engineering<br/>Georgia Tech, BS in Mechanical Engineering 2021

Authors:

Eric Biederman Georgia Tech
Kyriaki Kalaitzidou Georgia Institute of Technology
Athina Bellonia Georgia Institute of Technology
Shadi Shariatnia Texas A&M
Dorrin Jarrahbashi Texas A&M
Amir Asadi Texas A&M