Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape-memory polymer networks

The objective of this work is to characterize and understand structure- mechanical property relationships in (meth)acrylate networks. The networks are synthesized from mono-functional (meth)acrylates with systematically varying sidegroup structure and multi-functional crosslinkers with varying mole fraction and functionality. Fundamental trends are established between the network chemical structure, crosslink density, glass transition temperature, rubbery modulus, failure strain, and toughness. The glass transition temperature of the networks ranged from -29 to 112 °C, and the rubbery modulus ranged from 2.8 to 129.5 MPa. At low crosslink density (Er < 10 MPa) network chemistry has a profound effect on network toughness. At high crosslink densities (Er > 10 MPa), network chemistry has little influence on material toughness. The characteristic ratio of the mono-functional (meth)acrylates components is unable to predict trends in thermoset toughness as a function of chemical structure, as is accomplished for thermoplastics. The cohesive energy density is a better tool for prediction of network mechanical properties. Due to superior mechanical properties, networks with phenyl ring sidegroups are further investigated to understand the effect of phenyl ring distance on toughness. This work provides a fundamental basis for designing (meth)acrylate shape memory polymer networks with specific failure strain, toughness, glass transition temperature, and rubbery modulus.

Department dc:contributor.department

Materials Science and Engineering

Grantor dc:publisher

Georgia Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Safranski, David L.

Advisor dc:contributor.advisor

• Gall, Ken

Committee members dc:contributor.committeemember

• David Bucknall
• Karl Jacob

• Shape memory
• Toughness
• Polymers
• Mechanical properties
• Chemical structure
• Acrylate

Handle dc:identifier.uri

http://hdl.handle.net/1853/22635

OAI identifier oai:identifier

oai:repository.gatech.edu:1853/22635