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https://ptsldigital.ukm.my/jspui/handle/123456789/519460| Title: | Development of nanocomposite polyester/liquid natural rubber reinforced with cellulose nanocrystals from kenaf bast fiber |
| Authors: | Hanieh Kargarzadeh (P51338) |
| Supervisor: | Ishak Ahmad, Professor Dr. |
| Keywords: | Nanocomposite polyester/liquid natural rubber Cellulose nanocrystals Kenaf bast fiber Nanostructured materials |
| Issue Date: | 19-Aug-2013 |
| Description: | This research was undertaken to study the effects of cellulose nanocrystal (CNC) loading and its surface treatment on the mechanical and thermal properties of unsaturated polyester resin (UPR) and liquid natural rubber modified UPR nanocomposites. Cellulose nanocrystals (CNCs) were extracted and isolated from kenaf bast fiber (KF). Two different types of reactive liquid rubber called liquid natural rubber (LNR) and liquid epoxidized natural rubber (LENR) were used to modify the UPR. Nanocomposites were produced based on two types of system i.e. with and without rubber. The rubber content used as toughening agent to produce toughened polyester nanocomposites was 1.5 wt%. Kenaf fiber reinforced polyester composite was also prepared as reference. The filler loading for all composites and nanocomposites was varied between 0 to 6 wt%. Surface treatment of CNCs with silane coupling agent was carried out in an attempt to improve the interfacial adhesion between the fiber and matrix, reduce the hydrophilicity of CNCs and improve the dispersion of CNCs within the matrix. The physical, mechanical, thermal and morphological properties of all composites for both treated and untreated nanocomposites were investigated using tensile test, izod impact, dynamic mechanical thermal analysis (DMTA), thermogravimetry analysis (TGA), water absorption test, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). In general, polyester nanocomposite shows better mechanical properties compare to polyester composite due to the nano size and homogenous dispersion of the filler within the matrix. Tensile strength of polyester nanocomposites without rubber increased by 10 and 20% when CNCs and silane treated CNCs (STCNCs) were utilized, respectively. Significant improvement of the modulus and dynamic mechanical thermal properties were also observed after reinforcing with STCNCs whereas, inversed behaviour was observed for impact energy. The results for both LNR and LENR toughened polyester nanocomposites revealed that the presence of both untreated and treated CNCs overshadow the loss of properties (modulus and Tg) resulting from incorporation of rubber into UPR. For instance LNR and LENR modified polyester reinforced with CNCs showed 20 and 26% increment in tensile modulus, respectively. Moreover, it enhanced the impact energy of polyester further in parallel with the addition of natural rubber. Water absorption of nanocomposites with and without rubber decreased when treated CNCs were applied into the polyester matrix. The TEM observation of all types of nanocomposites showed that the nano size of rod-like structure of CNCs/TCNCs was preserved. Homogenous dispersion of CNCs and STCNCs for all nanocomposites was also observed from FESEM examination. Finally, nanocellulose was found to be a good candidate to replace raw kenaf fiber as reinforcing agent to improve the thermal and mechanical properties of polyester composites.,Ph.D |
| Pages: | 228 |
| Call Number: | TA418.9.N35.K347 2013 |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi |
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