Sains Malaysiana 40(7)(2011): 729–735

Blends of LNR with Unsaturated Polyester Resin from Recycled PET: Comparison of Mechanical Properties and Morphological Analysis with the Optimum Blend by Commercial Resin

(Adunan LNR dan Resin Poliester Tak Tepu daripada Hasil Kitar Semula PET: Perbandingan Sifat Mekanik dan Morfologi dengan Adunan Optimum daripada Resin Komersil)

Siti Farhana Hisham, Ishak Ahmad*, Rusli Daik & Anita Ramli

School of Chemical Sciences and Food Technology, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia

Ishak Ahmad & Rusli Daik

Polymer Research Centre, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia

Anita Ramli

Chemical Engineering Department, Technology University of PETRONAS, Bandar Seri Iskandar

31750 Tronoh, Perak, Malaysia

Diserahkan: 23 Oktober 2009 / Diterima: 12 Oktober 2010

ABSTRACT

In this study, poly(ethylene terephthalate) (PET) wastes bottle was recycled by glycolysis process using ethylene glycol. The unsaturated polyester resin (UPR) was then prepared by reacting the glycolysed product with maleic anhydride. The blend of UPR based on recycled PET wastes with liquid natural rubber (LNR) was carried out by varying the amount of LNR from 0 to 7.5 wt%. Mechanical tests such as tensile and impact were conducted to investigate the effects of LNR on the mechanical properties. Scanning Electron Microscopy (SEM) was used to analyze the morphology of the breaking area resulted from the tensile tests on the UPR and blend samples. From the results, the blend of 2.5 wt% LNR in UPR based recycled PET wastes achieved the highest strength in the mechanical properties and showed a well dispersed of elastomer particles in the sample morphology compared to other blends concentrations. This blend sample was then compared to the optimum blend of LNR with commercial resin through the glass transition temperature value Tg, mechanical strength and morphology properties. The comparison study showed that the Tg for UPR based recycled PET was higher than the value represented from commercial resin due to the degree of crystalinity in the molecular structure of the materials. LNR was found to be an effective impact modifier which gave a greater improvement in UPR from recycled PET wastes structure but not to the commercial one which needs 5% LNR to achieve the optimum properties. Thus, the compatibility between the UP resin based recycled PET and LNR was much better than with the commercial resin.

Keywords: Glycolysis; liquid natural rubber (LNR); recycled PET; unsaturated polyester resin (UPR)

ABSTRAK

Dalam kajian ini, bahan buangan botol minuman poli(etilena tereftalat) (PET) telah dikitar semula melalui proses glikolisis menggunakan etilena glikol. Kemudian, hasil glikolisis telah ditindak balas dengan malik anhidrida bagi menghasilkan resin poliester tak tepu (UPR). Adunan cecair getah asli (LNR) dengan UPR daripada hasil kitar semula PET disediakan dengan mengubah amaun penambahan LNR ke dalam UPR daripada 0 hingga 7.5% mengikut berat. Ujian mekanik seperti ujian tegangan dan hentaman telah dijalankan untuk mengkaji kesan penambahan LNR ke atas sifat mekanik UPR manakala Mikroskopi Elektron Imbasan (SEM) digunakan untuk menganalisis morfologi pada kawasan putus bagi sampel UPR dan adunan selepas melalui ujian regangan. Kajian ini menunjukkan adunan dengan 2.5% LNR dalam UPR daripada hasil kitar semula PET telah mencapai sifat mekanik yang paling tinggi dan mempunyai morfologi partikel getah yang tersebar dengan sekata ke seluruh bahagian matrik berbanding sampel dengan komposisi yang lain. Komposisi adunan ini kemudiannya dipilih untuk dibandingkan dengan sampel optimum adunan LNR dengan UPR komersil melalui nilai suhu peralihan kaca Tg, kekuatan sifat mekanik dan sifat morfologi. Hasil daripada perbandingan menunjukkan, UPR daripada hasil kitar semula PET mempunyai nilai Tg yang lebih tinggi daripada resin komersil kerana dipengaruhi oleh faktor darjah kehabluran dalam struktur molekul bahan tersebut. Penggunaan LNR sebagai bahan modifikasi dalam meningkatkan kekuatan hentaman adalah lebih efektif ke atas resin daripada hasil kitar semula PET berbanding penggunaannya ke atas resin komersil yang memerlukan sebanyak 5% LNR untuk mencapai sifat optimum. Tambahan lagi, keserasian adunan LNR dengan resin UPR daripada hasil kitar semula PET adalah lebih baik berbanding dengan adunan cecair elastomer tersebut bersama UPR komersil.

Kata kunci: Cecair getah asli (LNR); glikolisis; kitar semula PET; resin poliester tak tepu (UPR)

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*Pengarang untuk surat-menyurat; email: gading@ukm.my