Photo-Curing Behavior and Thermal Properties of Silicone Semi Interpenetrating Polymer Network (Semi-IPN) Organogels

Silicone hydrogels are receiving considerable interest due to their important biomedical application areas such as contact lenses and wound dressings. The applications of such materials are usually in the hydrated state, as hydrogels. However, manufacturing and molding processes are mostly carried out in the organically solvated state, as organogels. This thesis investigates the effects of some of the manufacturing parameters such as curing time and thermal processing on thermal, mechanical, viscoelastic and adhesive/cohesive fracture properties of silicone semi-interpenetrating polymer network organogels. Curing time may affect the extent of reaction and the crosslink density of a gel network. In order to investigate the effect of this parameter, materials were photo-cured for different times within the range of 150s to 1800s. Gel content, uniaxial tensile, dynamic mechanical, adhesive fracture and cohesive fracture properties were obtained as a function of photo-curing time and results were correlated with each other in order to have a better understanding of the effects on the material properties. Additionally, thermal properties of the gels were studied in detail. Crystallization and melting behavior of one of the solvents in the organogel were investigated by differential scanning calorimetry and thermal optical microscopy. Correlation between the thermal properties of the solvent and the gel network structure was shown. Dynamic mechanical analysis experiments were performed to investigate the effect of solvent crystallization on the mechanical properties. Finally, the effect of thermal processing parameters such as the heating rate and the minimum cooling temperatures on the crystallization and the thermo-mechanical properties were studied.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Macromolecular Science and Engineering

Department dc:contributor.department

Macromolecular Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2013

Author dc:creator

• Kaymakci, Orkun

Chair dc:contributor.committeechair

• Moore, Robert Bowen III

Committee members dc:contributor.committeemember

• Dillard, David A.
• Batra, Romesh C.

• organogel
• semi-interpenetrating polymer network
• photo-curing
• modulus
• adhesive/cohesive fracture
• dynamic mechanical analysis

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:154

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/49577