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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 Diserahkan: 8
Julai 2015/Diterima: 22 Oktober 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;
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*Pengarang
untuk surat-menyurat;
email: jclai@cheme.utm.my
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