The effect of water absorption on the viscoelastic properties of poly(styrene-block-isobutylene-block-styrene) for use in biomedical applications

Mauro Fittipaldi, Luis A. Rodriguez, Landon R. Grace

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

The decrease in glass transition temperature and change in creep compliance due to water diffusion in a biocompatible thermoplastic elastomer was studied and quantified. Knowledge of the mechanical and viscoelastic performance of the styrene-isobutylene-styrene block (SIBS) copolymer is important to determine the feasibility of certain in-vivo applications. Furthermore, the deterioration in these types of properties due to the plasticizing effect of water must be well understood for long term usage. Samples were formed with an injection molding press and fully dried prior to immersion in distilled water at 37°C. Water diffusion kinetics were studied for four different SIBS copolymers of varying molecular weight and styrene content by measuring weight changes as a function of time. These gravimetric diffusion studies showed an inverse relationship between diffusivity and styrene content and molecular weight for the first thousand hours of immersion. Measurements of storage modulus, loss modulus, tangent delta, strain recovery and creep compliance were performed using a dynamic mechanical analyzer for the high molecular weight, high styrene content SIBS version at different absorbed water contents. A measurable and nearly linear decrease of the glass transition temperature and creep recovery with respect to water content was observed for the samples tested even at relatively low water content: an increase in water content of 0.27% correlated to a decrease of 4°C in glass transition temperature while a 0.16% weight increase corresponded to a 12.5% decrease in creep recovery. These quantified material properties restrict the use of SIBS in certain implantable operations that undergo cyclic strains, and in sterilization techniques that require high temperatures. As such, they are important to understand in order to determine the viability of in vivo usage of this biocompatible polymer.

Original languageEnglish (US)
Title of host publicationProceedings of PPS-30
Subtitle of host publicationThe 30th International Conference of the Polymer Processing Society - Conference Papers
EditorsSadhan C. Jana
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413092
DOIs
StatePublished - May 22 2015
Event30th International Conference of the Polymer Processing Society, PPS 2014 - Cleveland, United States
Duration: Jun 6 2014Jun 12 2014

Publication series

NameAIP Conference Proceedings
Volume1664
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other30th International Conference of the Polymer Processing Society, PPS 2014
CountryUnited States
CityCleveland
Period6/6/146/12/14

Keywords

  • Biopolymers
  • Plasticization
  • SIBS

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'The effect of water absorption on the viscoelastic properties of poly(styrene-block-isobutylene-block-styrene) for use in biomedical applications'. Together they form a unique fingerprint.

Cite this