Baris Yalcin

Hollow Glass Microspheres in Thermoplastics

Abstract Reducing the weight of thermoplastics parts has been a high priority objective in various industries such as transportation, aerospace, hand-held electronics and sports and leisure. Hollow glass microspheres (HGMs) are currently used in a variety of lightweight automotive applications, including thermoplastics, sheet and bulk molding composites (SMC/BMC), underbody coatings (plastisols), structural foams and auto body fillers. HGMs are excellent strength/weight optimizers when they are used in filled polymer systems such as glass fiber, talc, and calcium carbonate filled thermoplastics. Reducing and replacing a certain percentage of these high density fillers with HGMs results in weight reduction while significantly maintaining the original mechanical properties of the composite. Hollow glass microspheres impart several benefits to thermoplastics in addition to density reduction. These include • productivity Benefits through faster cooling rates from the melt • dimensional stability (sink and warpage elimination) • increased stiffness (modulus) and heat distortion resistance • reduced thermal conductivity and dielectric constant All of these new functions and benefits can be achieved with class-a surface and with existing equipment enabling new design functions.

Improvements in processing characteristics and engineering properties of wood flour-filled high density polyethylene composite sheeting in the presence of hollow glass microspheres

Hollow glass microspheres were introduced into wood flour/high density polyethylene composites by melt compounding in a twin-screw extruder. The prepared composites were subsequently converted to extruded profiles in order to obtain composite sheeting. The presence of hollow glass microspheres highly reduced the density of the extruded sheets down to 0.91 g/cc, while improving its flexural modulus. The presence of hollow glass spheres further improved the visual appearance by eliminating warpage. Thermal conductivity of the sheets was reduced down to 0.25 W/mK without significantly changing the melt viscosity. The morphological analysis indicated a satisfactory state of dispersion of hollow glass microspheres in the sheeting. The presence of hollow glass microspheres resulted in sharper contours of the extruded profiles and improved nailability and screwability.