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Sains Malaysiana 45(4)(2016): 633–641 Study and Characterisation
of the Post Processing Ageing of Sago Pith Waste Biocomposites (Kajian dan Pencirian
Penuaan Pasca Pemprosesan Biokomposit Hampas Empulur Sagu) JAU CHOY
LAI1*,
WAN
AIZAN
WAN
ABDUL
RAHMAN1,2,
LUC
AVÉROUS3
& TECK
HOCK
LIM4 1Biopolymer Research Group, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim, Malaysia 2Centre for Composites,
Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim Malaysia 3BioTeam/ICPEES-ECPM,
UMR 7515, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg,
Cedex 2, France 4Department of Physical Science, Faculty of Applied Sciences & Computing, Tunku Abdul Rahman University College, Jalan Genting Kelang, Setapak 53300 Kuala Lumpur, Malaysia Received:
8 July 2015/Accepted: 22 October 2015 ABSTRACT This paper report the
post-processing ageing phenomena of thermoplastic sago starch
(TPS)
and plasticised sago pith waste (SPW), which were processed using
twin-screw extrusion and compression moulding techniques. Wide
angle X-ray diffraction (XRD) analyses showed that after processing,
starch molecules rearranged into VH-type
(which was formed rapidly right post processing and concluded
within 4 days) and B-type (which was formed slowly over a period
of months) crystallites. Evidence from Fourier transform infrared
spectroscopy (FTIR)
analyses corroborated the 2-stage crystallisation process, which
observed changes in peak styles and peak intensities (at 1043
and 1026 cm-1),
and band-narrowing. Thermogravimetric analysis (TGA)
studies showed that the thermal stability of plasticised SPW declined
continuously for 90 days before gradual increments ensued. For
all formulations tested, post-processing ageing led to drastic
changes in the tensile strength (increased) and elongation at
break (decreased). Glycerol and fibres restrained the retrogradation
of starch molecules in TPS and
SPW. Keywords: Retrogradation;
sago pith waste; thermoplastic starch; thermal degradation; tensile
properties ABSTRAK Kertas ini melaporkan
fenomena penuaan pasca pemprosesan kanji sagu termoplastik (TPS)
dan hampas empulur sagu memplastik (SPW) yang diproses menggunakan
teknik penyemperitan skru berkembar dan pengacuan mampatan. Analisis
pembelauan sinar-X (XRD) menunjukkan bahawa selepas pemprosesan, molekul kanji
disusun semula ke dalam hablur jenis VH (berlaku
dengan cepat selepas pemprosesan dan selesai dalam tempoh 4 hari)
dan jenis B (berlaku secara perlahan dalam tempoh beberapa bulan).
Bukti daripada analisis transformasi Fourier inframerah (FTIR) menyokong proses penghabluran
2-peringkat, yang menunjukkan perubahan dalam gaya dan keamatan
puncak (pada 1043 dan 1026 cm-1) dan jalur-penyempitan. Analisis
termogravimetri (TGA) menunjukkan bahawa kestabilan haba
untuk SPW terplastik menurun secara berterusan selama 90 hari
sebelum kenaikan secara beransur-ansur berlaku. Untuk semua formulasi
yang diuji, penuaan pasca pemprosesan membawa kepada perubahan
drastik dalam kekuatan tegangan (bertambah) dan pemanjangan pada
waktu rehat (menurun). Gliserol dan serat menghalang retrogradasi
molekul kanji dalam TPS dan
SPW. Kata kunci: Hampas empulur
sago memplastik; kanji termoplastik; penurunan terma; retrogradasi;
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*Corresponding author; email: jclai@cheme.utm.my
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