Short glass fibre reinforced poly(butylene terephthalate) Part 2 - Effect of hygrothermal aging on mechanical properties

Z. A. Mohd Ishak, T. S.A. Tengku Mansor, B. N. Yow, U. S. Ishiaku, J. Karger-Kocsis

Research output: Article

9 Citations (Scopus)


The mechanical properties of injection moulded poly(butylene terephthalate) (PBT) containing various loadings of short glass fibres (SGF) have been investigated. Properties studied include tensile, flexural, and impact. Effect of hygrothermal aging on the mechanical properties was investigated by immersing the respective specimens in distilled water at 30, 60, and 90°C. All the materials tested showed poor retention in mechanical properties upon exposure to hygrothermal aging. The effect became particularly pronounced at an immersion temperature of 90°C. Fractographic inspection of the fracture surfaces revealed that both PBT and SGF-PBT composites embrittled owing to a hydrolitic degradation process. Hydrolysis not only suppressed the matrix ductility but also reduced the bonding quality between PBT and SGF. Poor interfacial bonding was indicated by the absence of polymer matrix adhering to the fibre surfaces. The decrease in the impact strength of hygrothermally aged SGF-PBT composites provided further evidence that hygrothermal aging at high temperature reduces the contribution of fibre related toughening mechanisms. The residual mechanical properties of both PBT and its composites were not fully recovered after redrying. The permanent damage to these materials was attributed to severe hydrolytic degradation of PBT.

Original languageEnglish
Pages (from-to)271-277
Number of pages7
JournalPlastics, Rubber and Composites Processing and Applications
Issue number6
Publication statusPublished - dec. 1 2000


ASJC Scopus subject areas

  • Engineering(all)

Cite this