DMA can be used to obtain information on the viscoelastic properties of materials. Applications of DMA include quality control of incoming material, evaluating material aging, optimizing process conditions, developing new materials, and aid in material selection. In this work, an Alpha Technologies APA 2000 and Rheometrics RDS II were utilized to study the quality of incoming material, material aging, and optimizing cure cycles. This seminar will examine the theory of DMA and cover some of its applications to sheet molding compound characterization. Thermoplastics are used in blow molding because of their ability to melt and solidify many times.
Blow molding has two basic steps.
A preform, called a parison is made first. Second, pressurized gas is used to inflate the parison to the shape of the mold cavity where it is cooled. Machines used to produce the parison can either be extrusion based or injection based depending on the application. Blow molding also allows for orientation of the molecules in the material by means of stretching the parison prior to blowing. This improves the properties of the final product.