A novel potentiometric method for the determination of real crosslinking ratio of poly(aspartic acid) gels

Viktória Torma, Tamás Gyenes, Zoltán Szakács, Miklós Zrínyi

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

In order to obtain nontoxic functional polymer gels for biomedical applications, chemically crosslinked poly(aspartic acid) gels have been prepared using 1,4-diaminobutane as crosslinker. The presence of COOH and amino groups on the network chains renders these gels pH sensitive. Due to the specific hydrophobic-hydrophilic balance, these gels show a significant volume transition at a well-defined pH close to the pK value of uncrosslinked poly(aspartic acid). Since the magnitude of volume change critically depends on the degree of crosslinking, it is an important task to determine the topological characteristics of these networks. A novel method based on potentiometric acid-base titration has been developed to assess the crosslinking ratio, excluding physical crosslinks and entanglements. It turned out that only 25% of all crosslinker molecules forms real crosslinks between the poly(aspartic acid) chains; the rest react with one of its functional groups and forms short pendant side chains. At a nominal crosslinking ratio of 0.1, the number average molecular mass between crosslinks is found to be Mc = 2300.

Original languageEnglish
Pages (from-to)1186-1190
Number of pages5
JournalActa Biomaterialia
Volume6
Issue number3
DOIs
Publication statusPublished - Mar 1 2010

Keywords

  • Biocompatible gel
  • Poly(aspartic acid)
  • Potentiometric titration
  • Responsive polymer gel
  • pH sensitivity

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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