Thermo-mechanical characterization of carbon-reinforced shape memory polymer

Shape memory materials (SMM) are those materials that possess the inimitable quality of remembering their shapes. They recover their original shapes upon exposure to external stimulus like heat, light, electric field, magnetic field, moisture etc. Types of SMMs include shape memory alloys (SMAs), shape memory polymers (SMPs) and shape memory ceramics. The most well-known and widely used SMMs are shape memory alloys. They have exceptional strength and shape memory characteristics with the most far-reaching applications. SMPs though have several advantages over SMAs and other shape memory ceramics. Few of those could be termed as light weight, low cost, good process ability, high deformability, high shape recoverability, soft texture and adjustable switching temperature. This work incorporates the manufacturing and use of polyurethane based shape memory polymers obtained from SMP Technologies, Inc. The study investigates the effect of adding carbon fiber fabric layers on mechanical properties of the pure polyurethane based SMPs. The SMP is thermo-mechanically characterized for its transition temperature (Tg) using Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Fold-deploy shape memory tests are conducted to obtain shape memory parameters like shape fixidity (or retention) and shape recovery. In addition, effect of shape recovery at different temperatures, Tg, Tg+15, Tg+30 is also investigated to examine the effect of temperature increase in recovery ratio of the samples. Furthermore, static uniaxial tensile tests are performed to evaluate the mechanical properties of carbon reinforced SMP with focus on three important parameters vis-a-vis Young’s Modulus, Tensile Strength and Tensile Strain at break. The samples are also analyzed if the samples undergoing single or multiple cycles of deformation and recovery had any effects on its mechanical properties. Finally, the effect of degree of deformation ranging from 45˚ bend to 135˚ bend is also studied for both pure SMPs and carbon fabric reinforced SMP samples (SMPC). Four-step shape memory cycle characteristics are also verified by conducting full scale finite element studies. The results indicated glass transition temperature for the manufactured SMP to be 62˚C, with excellent shape fixidity (99%) and shape recovery (98%) ratios. In addition, mechanical testing indicated considerable improvement in stiffness and strength of the composites compared to pure SMP (nearly 100% rise with 2% fiber volume fraction). These carbon reinforced composites could potentially be used for manufacturing structural components with insignificant loss of strength or stiffness after experiencing a number of characteristic shape memory cycles. Furthermore, the loss in strength/stiffness is independent of the high deformation angles in the shape fixidity step.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Ramani, Tanmay

Contributors dc:contributor

• Andrawes, Bassem

• Shape memory materials
• Carbon reinforced shape memory polymer

Statement dc:rights

• Copyright 2017 Tanmay Ramani

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/99432

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/99432