Sains Malaysiana 40(7)(2011): 713–718

Tensile and Water Absorption Properties of Biodegradable Composites Derived from Cassava Skin/Polyvinyl Alcohol with Glycerol as Plasticizer

(Sifat-sifat Tegangan dan Penyerapan Air oleh Komposit Biorosot daripada Kulit Ubi Kayu/Polivinil Alkohol dengan Gliserol sebagai Bahan Pemplastik)

Dayangku Intan Munthoub* & Wan Aizan Wan Abdul Rahman

Department of Polymer Engineering, Faculty of Chemical Engineering and Natural Resources

Universiti Teknologi Malaysia, 81310 Skudai, Johor D.T. Malaysia

Received: 23 October 2009 / Accepted: 25 October 2010

ABSTRACT

Natural organic and abundant resources biopolymers received more attention due to their low cost, availability and degradability after usage. Cassava skin was used as natural fillers to the polyvinyl alcohol (PVA). Cassava skin/poly vinyl alcohol blends were compounded using melt extrusion twin screw extruder and test samples were prepared using the compression method. Various ratios of cassava skin and glycerol were investigated to identify suitable composition based on the water absorption and tensile properties. The water absorption of the cassava skins/PVA samples increased at higher composition of cassava skin due to their hydrophilic properties but decrease with glycerol content. The strength of the cassava skins/PVA samples increased with the higher composition of cassava skin up to 70 wt% while gradually decreased with the increasing composition of glycerol. The Young modulus increased with glycerol content but decreased with fibre loading up to 70 wt%. Elongation at break decreased with fibre loading and glycerol up to 70 wt% and 30 phr, respectively.

Keywords: Biodegradable; cassava skin; polyvinyl alcohol; tensile properties; water absorption

ABSTRAK

Bahan organik semula jadi dan sumber biopolimer lebih mendapat perhatian disebabkan oleh kos yang rendah, mudah diperoleh dan mudah terurai. Kulit ubi kayu digunakan sebagai pengisi semula jadi kepada polivinil alkohol (PVA). Adunan kulit ubi kayu/PVA diadun menggunakan kaedah penyemperitan skru berkembar dan sampel disediakan melalui kaedah pemampatan. Gliserol ditambah sebagai bahan pemplastik untuk pemplastikan PVA dan menggalakkan kebolehgerakan adunan. Penyerapan air oleh adunan kulit ubi kayu/PVA meningkat apabila komposisi kulit ubi kayu yang tinggi digunakan disebabkan sifat hidrofilik bahan tersebut tetapi menurun dengan pertambahan gliserol. Kekuatan adunan kulit ubi kayu/PVA meningkat dengan pertambahan komposisi ubi kayu sehingga 70 wt% tetapi menurun dengan pertambahan komposisi gliserol. Modulus Young meningkat dengan pertambahan kandungan gliserol di dalam adunan tetapi menurun apabila kandungan kulit ubi kayu sehingga 70 wt%. Pemanjangan pada takat putus berkurangan dengan pertambahan kulit ubi kayu sehingga 70 wt% dan 30 phr gliserol.

Kata kunci: ; Alkohol polivinil; biourai; kulit ubi kayu; penyerapan air; sifat-sifat tegangan

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*Corresponding author; email: dkim_4585@yahoo.com