Elastomer Characterization Method for Trapped Rubber Processing.

Pooria Khalili,Thomas Boulanger,Brina J Blinzler

doi:10.3390/polym12030686

Pooria Khalili, Thomas Boulanger + Show 1 more

Open Access

https://doi.org/10.3390/polym12030686

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Journal: Polymers	Publication Date: Mar 19, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Chalmers University of Technology

Abstract

The increasing high-volume demand for polymer matrix composites (PMCs) brings into focus the need for autoclave alternative processing. Trapped rubber processing (TRP) of PMCs is a method capable of achieving high pressures during polymer matrix composite processing by utilizing thermally induced volume change of a nearly incompressible material inside a closed cavity mold. Recent advances in rubber materials and computational technology have made this processing technique more attractive. Elastomers can be doped with nanoparticles to increase thermal conductivity and this can be further tailored for local variations in thermal conductivity for TRP. In addition, recent advances in computer processing allow for simulation of coupled thermomechanical processes for full part modeling. This study presents a method of experimentally characterizing prospective rubber materials. The experiments are designed to characterize the dynamic in situ change in temperature, the dynamic change in volume, and the resulting real-time change in surface pressure. The material characterization is specifically designed to minimize the number and difficulty of experimental tests while fully capturing the rubber behavior for the TRP scenario. The experimental characterization was developed to provide the necessary data for accurate thermomechanical material models of nearly incompressible elastomeric polymers for use in TRP virtual design and optimization.

Highlights

As the demand for carbon fiber reinforced polymers (CFRPs) increases, the need for autoclave alternatives for high performance composite processing that allows faster throughput while maintaining performance becomes more pronounced
Pressurized bladder molding (PBM) is another alternative processing technique where the composite preform is placed in a hard cavity mold and pressurized with an internal bladder
Future advanced Trapped rubber processing (TRP) will eliminate the need for ovens because the heating technology can be incorporated directly into the rubber material at discrete locations where it is needed for the best cure profile

Summary

Introduction

As the demand for carbon fiber reinforced polymers (CFRPs) increases, the need for autoclave alternatives for high performance composite processing that allows faster throughput while maintaining performance becomes more pronounced. The autoclave is heated in a way that increases temperature in the air that is transferred to the surface of the part This procedure is somewhat inefficient and can take a matter of hours for the part to go through the full cure cycle [1,2]. Pressurized bladder molding (PBM) is another alternative processing technique where the composite preform is placed in a hard cavity mold and pressurized with an internal bladder This allows for the cure cycle to be reduced to under an hour for thin parts but can be susceptible to bladder rupture and is typically only used for small parts due to the cost of the exterior tooling [4,5]

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