Sains Malaysiana 38(3): 381-386(2009)
Pengisian Sekam Padi dan Tanah Liat ke dalam Matriks Polietilena Berketumpatan Tinggi-Getah Asli-Getah Asli Cecair
(Rice Husk and Clay Loadings into High Density Polyethylene-Natural
Rubber-Liquid Natural Rubber Matrix)
Ishak Ahmad*, Mohd Suzeren Jamil & Ibrahim Abdullah
Pusat Pengajian Sains Kimia dan Teknologi Makanan
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia
Diserahkan: 30 Januari 2008 / Diterima: 8 Oktober 2008
Abstrak
Kesan penambahan pengisi sekam padi dan tanah liat ke dalam matriks getah asli getah asli cecair polietilena berketumpatan tinggi (NR/LNR/HDPE), NR/HDPE dan HDPE terhadap sifat mekanik dan morfologi adunan telah dikaji. Pemprosesan adunan dilakukan pada suhu 140 oC dan kadar percampuran 50 r.p.m. selama 16 minit. Pra-pemanasan pengisi selama 4 minit pada suhu 80 oC dilakukan sebelum pengadunan dengan matrik bagi meminimumkan kesan lembapan. Getah asli cecair digunakan sebagai agen pengserasi dalam adunan komposit. Pengisian sekam padi (SP) dan tanah liat (TL) dalam matriks HDPE, NR/HDPE serta NR/LNR/HDPE umumnya menurunkan nilai kekuatan tensil dan kekuatan hentaman tetapi meningkatkan nilai modulus. Kehomogenan adunan komposit berpengisi yang dikenalpasti melalui pemeriksaan morfologi menggunakan mikroskop imbasan elektron (SEM) menunjukkan masalah aglomerasi dan interaksi antara muka dalam komposit berlaku. Kelikatan leburan dan interaksi antara bahan menentukan arah pergerakan serta serakan pengisi dalam komposit. Daripada keputusan yang diperolehi dan merujuk kedua-dua sifat pengisi, SP adalah lebih serasi dengan NR disebabkan potensi interaksi antara kumpulan berfungsi permukaan pengisi selulosa (SP) seperti –OH dengan ikatan ganda dua NR berbanding TL. Ciri fizik permukaan TL yang kurang bersifat hidrofilik berbanding SP pula menyebabkan TL lebih cenderung berinteraksi dan tersebar dengan baik dalam HDPE.
Kata kunci: Adunan
polimer; getah asli; polietilena; sekam padi
ABSTRACT
The effects of filling rice husk
and clay into high density polyethylene liquid natural rubber natural rubber
(HDPE/LNR/NR), NR/HDPE and HDPE matrix on the mechanical and morphological
properties of the blend were investigated. Blending of the mixture was done 140oC
and a mixing rate of 50 r.p.m. for 16 minutes. Preheating of the fillers was
done for 4 minutes at 80oC before loading with the matrix to minimize
the effect of moisture. Liquid natural rubber was used as a compatibilizer in
some blends. The addition of rice husk (SP) and clay (TL) into the HDPE,
NR/HDPE and NR/LNR/HDPE matrixes, caused the tensile and impact strength to
decrease but the modulus and hardness to increase. The filler distribution in the
composites was determined by scanning electron microscope (SEM) which showed
that the weak inter-phase interaction led to agglomeration in the composites.
The viscosity and interaction between the phases in the blend will affect the
movement and distribution of filler in the composites. Based on the results and
the properties of both fillers, SP is more compatible with NR because of the potential
interaction between the functional groups like –OH at the cellulose surface
with the double bonds of NR as compared to the inert interaction between clay
and NR. However, the physical nature of the TL surface which is less
hydrophilic as compared to SP, caused TL particles to have better interaction
and well dispersed in HDPE.
Keywords: Natural rubber; polyethylene;
polymer blend; rice husk
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*Pengarang untuk surat-menyurat; email: gading@ukm.my
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