Amphiphilic networks. XI. Mechanical properties and morphology

✍ Scribed by Dongkyu Park; Balazs Keszler; Vassilios Galiatsatos; Joseph P. Kennedy

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 303 KB
• Volume: 66
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19971031)66:5<901::aid-app10>3.0.co;2-q

✦ Synopsis

The bulk properties of two types of amphiphilic networks, poly(2-hydroxyethyl methacrylate)-l-polyisobutylene (PHEMA-l-PIB, H-network) and poly( N,N-dimethylacrylamide)-l-polyisobutylene (PDMAAm-l-PIB, A-network), have been investigated. Tensile strengths decreased considerably by swelling, and the decrease was more severe by swelling in water than in n-heptane. Elongations increased by swelling in water; however, the change was not consistent upon swelling in n-heptane. The hardness of dry networks decreased with increasing PIB content, while for wet networks it was similar to dry networks containing 85 wt % PIB. Small-angle X-ray scattering showed that average interdomain spacings decreased with increasing PIB content. According to dynamic mechanical thermal analysis (DMTA) the glass transition temperatures (T g ) of the respective hydrophobic and hydrophilic components shift toward each other with increasing PIB content. A ''liquid-liquid transition'' ( T ll ) above the T g of the hydrophilic component was apparent by DMTA, but could not be found by differential scanning calorimetry (DSC).