Graphene nanoplatelets modified chemlok adhesive system for natural rubber-aluminium bonding

• Main Author: Zulkifl, Nor Syazana Adilah
• Format: Thesis
• Language: English; English
• Published: 2021
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/26682/1/Graphene%20nanoplatelets%20modified%20chemlok%20adhesive%20system%20for%20natural%20rubber-aluminium%20bonding.pdf; http://eprints.utem.edu.my/id/eprint/26682/2/Graphene%20nanoplatelets%20modified%20chemlok%20adhesive%20system%20for%20natural%20rubber-aluminium%20bonding.pdf; http://eprints.utem.edu.my/id/eprint/26682/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=121757

Nowadays, the engine mount in automotive undergoes various efforts for properties improvement due to the highest demand for better performance, more safety, and greater coziness. Generally, it is made from a combination of rubber and mild steel with a Chemlok adhesive system but the same adhesive system gives insufficient bonding strength between natural rubber and aluminum alloy. Therefore, this study is aiming to study the potential of a nano-manipulated adhesive system by modifying the existing Chemlok adhesive system in promoting better bonding strength between natural rubber-aluminum alloy (NR-Al). The GNPs modified Chemlok adhesives were prepared via two steps ultrasonic-assisted stirring process using an ultrasonic bath and hot plate. There are two main parts of this research project, Part A on the preparation and characterization of GNPs modified Chemlok 220 adhesive system and Part B on the properties and characteristics of the NR-Al bonded with the unmodified Chemlok 220 (control) and GNPs modified Chemlok 220 systems. In Part A, the modified Chemlok adhesive system was analyzed for gel time, XRD, Raman, FTIR, and DSC analyses. The analyses proved that the modification was successful with safe flash and gel time for utilization, and XRD, Raman, and FTIR showed that the modified system consists of GNPs characteristics peak that dispersed with certain intercalation with Chemlok matrix, presence of active functional groups, and showing the reinforcing effects and thermal stability. In Part B, the suitable substrates’ surface conditions (Al surface roughness and NR condition), the process parameters (sweeping time and primer presence), and the GNPs loading at 0wt%, 0.5wt%, 3wt%, and 7wt% for both unmodified and GNPs modified Chemlok adhesive were investigated. Three layers of the Chemlok adhesives were applied on the pre-treated aluminum alloy (Al) substrate. Then, the NR-Al substrates were bonded using a hot press machine under the pressure of 100 kgf/cm2 for 20 minutes at the temperature of 140C. Then, the samples were subjected to a 90-degree peel test based on ASTM D429 by UTM machine to evaluate the bonding strength and the peel-fractures surfaces were evaluated both physically and under SEM. The Al-surface prepared by sandblasting, uncured NR compound, sweeping time of 2 minutes with the presence of Chemlok 205 primer were selected as the suitable parameters for NR-Al bond preparation. The adhesive strength was observed to increase with the increment of GNPs in the GNPs modified Chemlok 220 adhesives and reached the percolation threshold at 3 wt% for the system without primer and at 0.5 wt% for the system with primer. The improvement in peel strength for the effect of suitable GNPs loading with primer in modified adhesive system is 30%. The GNPs modified Chemlok system introduced the combination of cohesive and adhesive failures that was further supported by the morphological characteristics at higher magnifications scale. The peel strength of the adhesive systems was highly correlated with the extent of the mode of failures experienced by the system. Therefore, this finding is significantly vital to improving the existing adhesive bonding system for natural rubber-aluminum alloy bonding in automotive components like the engine mounting.