Sains Malaysiana 42(4)(2013): 443–448

Fracture Toughness and Impact Strength of Hollow Epoxy Particles-Toughened Polyester Composite

(Keliatan Rekahan dan Kekuatan Hentaman bagi Komposit  Poliester Terisi Partikel Epoksi Berongga)

L.F. Low & A. AbuBakar*

School of Materials and Mineral Resources Engineering, Engineering Campus

Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia

Received: 6 June 2011/Accepted: 20 April 2012

ABSTRACT

Hollow epoxy particles (HEP) serving as reinforcing fillers were prepared using the water-based emulsion method in this study. HEP was incorporated into the polyester matrix at various loading, ranging from 0 wt% to 9 wt%, to toughen the brittle polyester thermoset. The polyester composites were prepared using the casting technique. The fracture toughness and impact strength of the polyester composites increased with increasing the HEP loading up to 5 wt%, after which there was a drop. The improvement in fracture toughness and impact strength is attributed to the good polymer-filler interaction. This finding was further supported by the scanning electron micrograph, in which it was shown that the polyester resin was interlocked into the pore regions of the HEP filler. The reduction in fracture toughness and impact strength of the polyester composite were believed to be attributed to the filler agglomeration. This filler-filler interaction would create stress concentration areas and eventually weakened the interfacial adhesion between the polymer matrix and the filler particles. Hence, lower fracture toughness and impact strength of the highly HEP-filled polyester composites (above 5 wt%) were detected.

Keywords: Filler loading; fracture toughness; hollow epoxy particles (HEP); impact strength; water-based emulsion

ABSTRAK

Partikel epoksi berongga (HEP) yang berperanan sebagai pengisi penguat telah disediakan dengan menggunakan teknik emulsi berasaskan air dalam kajian ini. Pengisi HEP ditambahkan ke dalam matrik poliester pada jumlah kandungan yang berlainan, iaitu daripada 0 % berat sehingga 9 % berat untuk meliatkan matriks poliester yang rapuh. Komposit poliester disediakan dengan menggunakan teknik tuangan. Keliatan rekahan dan kekuatan hentaman bagi komposit poliester bertambah dengan penambahan kandungan pengisi HEP sehingga 5 % berat, tetapi dengan penambahan kandungan pengisi HEP yang berlebihan akan menyebabkan kemerosotan ke atas keliatan rekahan dan kekuatan hentaman komposit poliester. Peningkatan ke atas keliatan rekahan dan kekuatan hentaman adalah disebabkan oleh interaksi antara matriks polimer dan pengisi yang baik. Keputusan ini dapat disokong dengan mikrograf mikroskop elektron imbasan, dan ia telah menunjukkan bahawa resin poliester terikat ke dalam kawasan berongga pada pengisi HEP. Kemerosotan ke atas keliatan rekahan dan kekuatan hentaman bagi komposit poliester dipercayai disebabkan oleh penggumpalan pengisi. Penggumpalan antara pengisi-pengisi akan mewujudkan kawasan penumpuan tegasan dan akhirnya melemahkan pelekatan antara muka antara matriks polimer dan partikel pengisi. Oleh itu, keliatan rekahan dan kekuatan hentaman yang lebih rendah bagi komposit poliester terisi dengan jumlah kandungan pengisi HEP yang lebih tinggi (iaitu melebihi 5 % berat) dapat diperhatikan.

Kata kunci: Emulsi berasaskan air; jumlah kandungan pengisi; keliatan rekahan; kekuatan hentaman; partikel epoksi berongga (HEP)

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*Corresponding author; email: azhar@eng.usm.my