Advanced FBG Sensor Technique to Measure Effective Chemical Shrinkage and Modulus Evolutions of Polymers with High Polymerization Exothermic Heat

Abstract

An advanced technique based on a fiber Bragg grating (FBG) sensor is proposed to measure the critical mechanical properties of polymeric materials during polymerization: effective chemical shrinkage and modulus evolutions. Based on the existing technique implemented with convection oven and two different specimen configurations using same size of FBG, challenges associated with implementation are identified and solutions are proposed. Challenges include temperature instability due to high exothermic heat generated during polymerization inside polymer substrate, temperature controllability due to limitations of convection oven, and mechanical constrain on polymer and fiber during measurement. The proposed system provides modifications to provide easier implementation with accurate results. Modifications such as fabrication of FBG on special fiber, enhancement of heating system, and optimization of system design are combined to provide a tool for rapid but accurate measurement of polymer properties. The proposed technique significantly improves the ability to characterize the mechanical properties of polymeric materials during polymerization which will enhance the accuracy of predictive modeling for design optimization of a microelectronics product at the conceptual stage of product development.