Mechanical strength and stability of bulk insulation materials: A study on hollow glass microspheres and expanded perlite

Abstract This paper presents a lab study on the uniaxial compression behavior of hollow glass microspheres (3M Glass Bubbles) comparing it to commercial cryo-insulation grade expanded perlite. Stress-compression data of bulk hollow glass microspheres was generated in a proprietary test setup and correlated with true density measured in a gas pycnometer. Consequently, the macroscopic uniaxial compression data can be interpreted with respect to mechanical damage of the Glass Bubbles on the microscopic scale. This allows engineers to assess if the respective insulation material meets their requirements. The paper presents the stress-compression behavior of various commercial grades highlighting the potential to also serve demanding applications. A cyclic testing mode was implemented allowing the simulation of application conditions such as thermal cycling. Data shows that the Glass Bubbles remain undamaged even after undergoing a 1000x cycle test if the maximum stress is appropriately chosen. This information can help to select suitable Glass Bubble grades based on anticipated stresses or dimensional changes.