Sarifuddin, Norshahida (2015) Mechanical, Physical, Thermal And Biodegradability Studies Of Low Density Polyethylenethermoplastic Sago Starch Kenaf Core Flour Biocomposites. PhD thesis, Universiti Sains Malaysia.
|
PDF
Download (419kB) | Preview |
Abstract
Permasalahan alam sekitar berkait dengan penggunaan plastik tipikal atau lebih dikenali sebagai polimer sintetik telah mengarahkan kepada penggunaan polimer terbiodegradasi dan pengisi semulajadi untuk menghasilkan satu gabungan komposit terdegradasi. Usaha kini dijalankan dalam menghasilkan komposit yang sedemikian dengan menggunakan kanji sagu termoplastik (TPSS) dan pengisi teras kenaf (KCF) di dalam polietilena berketumpatan rendah (LDPE). Dalam kajian ini, kesan nisbah adunan, rawatan pengisi semulajadi dan penghibridan dengan pengisi mineral bukan organik terhadap sifat mekanikal, fizikal, termal dan ciri-ciri terbiodegradasi telah dikaji. Pertama sekali, komposit LDPE/TPSS/KCF yang mengandungi 0-40 % berat TPSS dan 0-40 phr KCF telah disediakan dengan menggunakan kaedah pencampuran adunan lebur dan pengacuanan mampatan. Penambahan 10 % berat TPSS bersama 10 phr KCF telah menghasilkan kekuatan tegangan tertinggi. Persamaan kimia diantara TPSS dan KCF telah membentuk ikatan hidrogen seperti yang ditunjukkan pada spectrum IR dan interaksi tersebut menunjukkan lekatan antara muka yang lebih baik dikesan melalui morfologi SEM. Malah, penambahan kedua-dua TPSS dan KCF, juga menunjukkan peningkatan terhadap kestabilan termal dan meningkatkan peratusan penyerapan air disebabkan sifat hidrofilik mereka. Kesan pemerosotan komposit disebabkan oleh pendedahan kepada pencuacaan semulajadi boleh dilihat dengan penurunan keseluruhan sifat-sifat tegangan akibat penambahan TPSS dan KCF. Spektrum IR seterusnya mengesahkan yang foto-degradasi berlaku dengan kemunculan puncak karbonil (C=O). Begitu juga, ciri-ciri tegangan, FTIR, SEM dan kehilangan berat oleh sampel yang ditanam di dalam tanah membuktikan bahawa berlakunya aktiviti degradasi sepanjang waktu yang telah ditentukan. Berikutnya, kesan cantuman kopolimer metil metakrilat terhadap KCF serta pemuatan mereka di dalam komposit telah diperiksa. KCF tercantum menunjukkan darjah penguatan yang boleh menambah kekuatan tegangan, khususnya pada pembebanan sebanyak 10 phr dan ini dibuktikan oleh SEM morfologi yang menunjukkan lekatan matriks pada permukaan pengisi. Keputusan FTIR juga mengesahkan bahawa, KCF tercantum membentuk kumpulan karbonil ester yang di kenal pasti menghubungkan pengisi dan matriks. Seterusnya, KCF tercantum menunjukkan penurunan sifat-sifat tegangan komposit yang kecil walaupun terdedah kepada cuaca. Walaubagaimanapun, mereka masih terdedah kepada degradasi kerana kehadiran sejumlah kecil monomer dan ia disahkan oleh FTIR, SEM dan keputusan kehilangan berat. Akhir sekali, pengaruh penambahan pengisi mineral bukan organik (iaitu bentonit dan haloisit) di dalam komposit pada pelbagai pembebanan (3-15 phr) telah dinilai. Penambahan pengisi meningkatkan kekuatan tegangan sehingga pembebanan 12 phr. Bila pembebanan pengisi melebihi 12 phr, kekuatan tegangan semakin merosot. Sehubungan dengan itu, sifat termal komposit ternyata lebih stabil dengan penambahan pengisi silikat. Pendedahan kepada pencuacaan semulajadi telah menyebabkan kemerosotan sifat tegangan secara berterusan pada sampel komposit dengan haloisit berbanding sampel kawalan. Kecenderungan yang sama telah diperoleh daripada sampel yang ditanam di dalam tanah. Tahap perosotan degradasi telah disahkan dengan pembentukan liang-liang yang lebih besar dan rekahan serta kehilangan berat yang banyak. _______________________________________________________________________________________________________ Environmental problems associated with the use of typical plastics or so called synthetic polymers have direct to the utilization of biodegradable polymer and natural fiber for producing a degradable composite. The efforts currently are underway in producing such composites with the use of thermoplastic sago starch (TPSS) and kenaf core fillers (KCF) in the low density polyethylene (LDPE). In this work, the effect of blend ratio, treatment of natural filler and hybridization with inorganic mineral fillers on the mechanical, physical, thermal and biodegradability properties of composites were studied. Firstly, the LDPE/TPSS/KCF composites containing 0-40 wt. % of TPSS and 0-40 phr KCF were prepared by using melt-blended mixing and compression molding method. The addition of 10 wt. % of TPSS as well as 10 phr KCF had resulted the highest tensile strength. Chemical similarity of TPSS and KCF formed hydrogen bonding as shown in IR spectra and such interaction indicated better interfacial adhesion detected by SEM morphology. As such, the addition of both TPSS and KCF showed an improvement in thermal and has boosted up the water absorption percentages due to their hydrophilic nature. The deteriorating impact of composites due to exposure to natural weathering can be seen with the collapse of overall tensile properties upon addition of TPSS and KCF. The IR spectra is further confirming the photo-degradation occurred with the appearance of carbonyl (C=O) peaks. Likewise, tensile properties, FTIR, SEM and weight loss of soil burial samples also proved the degradation activities over a predetermined time. Next, the effects of graft copolymerization of methyl methacrylate (MMA) onto KCF as well as their loading on the composites were examined. Grafted KCF is found to be a promising reinforcement to augment the tensile strength, particularly at 10 phr loading and this is evidenced by the adhesion of matrices onto the filler surface in SEM morphology. This is further confirmed by FTIR results whereby grafted KCF formed ester carbonyl groups which are assumed to provide linkage between filler and matrix.Subsequently, the tensile properties of composites with grafted KCF are somehow slightly retained upon exposure to weathering. However, they are still susceptible to degradation due to the presence of monomer and it is verified by FTIR, SEM and weight loss. Lastly, the influences of inorganic mineral filler (halloysite clay) incorporation into the composites at various loadings (3-15 phr) were evaluated. Addition of filler raised the tensile strength up to 12 phr loading. When the filler is loaded beyond 12 phr, the strength tended to decline. Correspondingly, the composites became thermally stable upon inclusion of this silicate fillers. Upon weathering, composite samples with halloysite results a progressive decay in tensile properties compared to the control samples. Similar tendency was obtained from soil burial samples. The severity of deterioration upon degradation was confirmed by the formation of the larger pores and cracks as well as greater weight loss.
| Item Type: | Thesis (PhD) |
|---|---|
| Uncontrolled Keywords: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4641 |
| Subjects: | T Technology T Technology > TN Mining Engineering. Metallurgy > TN263-271 Mineral deposits. Metallic ore deposits. Prospecting |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 13 May 2019 02:28 |
| Last Modified: | 13 May 2019 06:35 |
| URI: | http://eprints.usm.my/id/eprint/44310 |
Actions (login required)
 |
View Item |
