HGMS/TPU Composite Foam Fabrication And Property Analysis

In the past couple of years, a lot of research work has been published on polymeric foams. This is probably due to the role they play in their application in many fields or their low weight which leads to light, impact absorbing structures where applied. However, these foams do not meet the requirements for high performance applications like withstanding high compressive strength at low density. Many researchers have concentrated on the development of foams by synthesis using new polymers and a number of papers have been published on reinforced thermoplastic polyurethane (TPU) foams using the mentioned approach.This study examined recent developments in hollow glass microspheres (HGMS) reinforced polymeric foams with particular reference to polyurethane composites. Thermoplastic polyurethane foams were successfully prepared from commercial grade TPU polymer using extrusion and compression molding. Hollow glass microspheres were selected as the reinforcing materials. To enhance interfacial adhesion between filler and the matrix, three methods of surface modification were studied. FT-IR and SEM were used to analyze and observe the modified surfaces and morphology of fabricated foam. Density, hardness and mechanical properties of the foam were also tested.FT-IR and SEM analysis showed that, using NaOH to hydroxylate the surface of HGMS led to a uniformly modified surface structure of the HGMS which was desirable for reinforcing TPU foam, although HCL gave good surface structure as per FT-IR, SEM observations showed lack of uniformity in the surface structure of the HGMS. Increasing the content of foaming agent from1%to2%decreased the tensile strength of the foam by about50%. The tensile strength decreased by about40%when the content of HGMS was increased from0%to3%. The compressive strength of the composite foam increased by47%when the content of HGMS was increased from0%to7%. Increasing HGMS content led to a decrease in the density and increase in hardness of the foam with lowest densities realized with compression molding. After a75%compressive force, SEM observation of7%HGMS reinforced TPU foam showed a more stable structure than5%HGMS reinforced foam.