Advanced Materials Research Vol. 812

Abstract: The aim of this study is to investigate the properties of Polydimethylsiloxane (PDMS)/MWCNT-Al₂O₃ nanocomposites. The multiwall carbon nanotubes MWCNT-Al₂O₃ hybrid compound was synthesized using chemical vapour deposition (CVD) method. The nanocomposites were produced by using Sonicator (ultrasonic processor) instrument and followed by casting in the vacuum oven. The content of MWCNT-Al₂O₃ was varied between 0.5 and 1.5% by weight. The results showed that the MWCNT-Al₂O₃ was well dispersed in PDMS. The interaction between PDMS and MWCNT-Al₂O₃ was investigated using Fourier transform infrared spectrometry (FTIR). The mechanical properties of the composite were examined by tensile test. The results showed that the greater of MWCNT-Al₂O₃ hybrid compound in PDMS composites resulted in lower tensile properties.

Abstract: Epoxidized oil (EO) is a sustainable oil that can be obtained form edible or non-edible naturals oil. The incorporation of epoxidized oil can increase the green component in rubber compound. It can contributes to worldwide technology specially in green tyre manufacturing. Epoxidized oil has the potential to replace aromatic oil (AO) to rubber and polymer industry. The effect of incorporation of EO and AO into natural rubber vulcanizates (NR) was studied via tensile and tear strength tests according to ISO 31-1977 and ISO 6133, respectively. Tensile strength of AO value showed greather value compared to EO. Gradual increases of elongation were observed form both AO and EO. Both moduli at 100% and 300% elongation, showed reductions as oil loading were increased. The tear strength results showed that tearing energy insignificantly increased with oil loading. EO compound was found to possess higher tearing energy compared to AO compound for most composition except for 15 pphr EO.

Abstract: We report here on the characterization of classical bulk poly (N-isopropylacrylamide) (PNIPAAm) hydrogel networks. The classical PNIPAAm hydrogels were prepared from N-isopropylacrylamide (NIPAAm) as a main monomer and N,N-methylenebisacrylamide (MBAAm) as a crosslinker. The viscoelastic character of bulk hydrogels was examined using rheological measurements under frequency sweep mode (20 °C). A range of frequency, ω from 0.1 to 100 rad/s, was employed as this is a typical range for rubber plateau. Within this range, almost frequency independent of storage moduli (G'; ~ 10⁴ Pa as a function of hydrogel compositions were obtained. Indeed, the perfect soft-rubbery behaviour of PNIPAAm hydrogels could be confirmed and thus enabled the estimation of mesh size. Interestingly, the mesh size rubbery hydrogels determined from rheological data was in a good agreement to that from swelling experiments (~ 4 to 9 nm).

Abstract: Epoxidized palm oil (EPO) can act as processing oil has the potential of non toxic, degradable, renewable resource and as the alternative safe process oils in rubber compounding. Epoxidized palm oil is used as some of additives in rubber compounding to provide function of softener or stabiliser thus, improve properties of rubber compounding performance. Rubber that is used in this study is styrene butadiene rubber (SBR); a synthetic rubber copolymer consisting of styrene and butadiene. SBR also has good abrasion resistance and good aging stability when protected by additives. Compared to natural rubber, SBR has better processability, heat aging and abrasion resistance but inferior elongation, hot tear strength, hysteresis, resilience and tensile strength. This study is focusing on the effect of EPO without the addition of carbon black into the compound via tensile and density test. This is very important as to study the physical and mechanical interaction between SBR and EPO without the influence of other fillers. Different loading of oil were used at 25 pphr, 30 pphr. 35 pphr, 40 pphr and 45 pphr in the compounding process as processing aid. EPO35 which contain 35 pphr of EPO shows the highest value of tensile strength which is 2.2 MPa. The vulcanizate that contain 30 pphr of EPO shows the highest value for Youngs modulus which is 0.22 MPa while the elongation at break increased as the oil loading increased. The highest value for density is 0.979 g/cm³ for the vulcanizate contain 25 pphr of EPO. The results indicates that EPO is potential to replace other processing oils as renewable resource and safe to human.

Abstract: nclusion complex of cholesterol:β-cyclodextrin (CβIC) was characterized for thermal analysis by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The difference of endothermic peak between inclusion compounds of cholesterol:β-cyclodextrin (CβIC) with pure cholesterol and β-cyclodextrin endothermic peaks confirmed the formation of inclusion complex. SEM results showed that of cholesterol:β-cyclodextrin inclusion complex (CβIC) observed in the form of irregular crystalline particles which has different morphology from CHO and βCD. The results obtained from this study will able to give valuable information about cholesterol-reduced egg yolk properties that could be useful to produce healthy-egg yolk based products.

Abstract: Carbon nanotube (CNT) reinforced polymer composites are of great interest, because their superior properties can produce composite materials with high strength, light weight, and multifunctional features. In this work, the thermal and tribological properties (wear) of Phenolic/CNT-Alumina Hybrid composites were studied. The CNT-alumina hybrid (chemically hybrid) was produced via Chemical Vapour Deposition (CVD). The Phenolic/CNT-Alumina Hybrid composites were fabricated using hot mounting moulding. The tribological properties were monitored using a Ducom TR-20 pin-on-disk tester, under dry sliding conditions. The thermal conductivity was measured using the Transient Plane Source (TPS) method, using a Hot-Disk^TM Thermal Constant Analyzer. The results show that CNT-Alumina hybrid enhanced the thermal and tribological properties of the polymer composites.

Abstract: This study is to determine the effects of tensile and flexural testing on the C.equisetifolia composite at different loading from 10 % to 50 % weight loading (wt%). The results for all composite samples on tensile strength and tensile modulus decreasing as the weight loadings of C.equisetifolia increases. However, the result from tensile modulus was not significant when the C.equisetifolia weight loadings increase in the composite. In addition, the result obtained from flexural modulus and strength at 20 % of C.equisetifolia weight loading, increased to 3.147GPa and 3.25 MPa respectively, while when C.equisetifolia weight loadings increase the results showed a decrease.

Abstract: The effects of epoxidized palm oil (EPO) content in carbon black filled styrene butadiene rubber (SBR) on tensile strength, elongation at break and crosslink density were investigated. Five different loadings of EPO in parts per hundred rubbers (phr) were used to test the tensile strength of the carbon black filled SBR which showed a decreasing trend as the content of EPO in the vulcanizates increased. In contrast, elongation at break showed the opposite trend where the elongation at break increased as the content of the EPO increased. The SBR vulcanizates with the highest content of EPO gave the highest value of elongation at break which is 2393.56%. In the case of swelling index, it was found to increase as the amount of EPO increased.

Abstract: Polymer nanocomposites containing polypropylene (PP) as the polymer matrix and nanofiller aluminium hydroxide (ATH) as the flame retardant filler were compounded with various loading of maleic anhydride grafted polypropylene, MAPP (0, 1, 2, 3, 5 wt %). All materials were mixed using melt mixing process and were further prepared using an injection moulding machine. The mechanical performances of the samples were characterized using tensile and impact tests. Improvements were observed for the tensile and impact properties of the PP/ATH samples after being loaded with MAPP. MAPP loading of 1 wt % was determined to be the optimum content of coupling agent addition as this loading enabled the best performance of the nanocomposite in tensile and impact tests. Different morphologies of the fracture surfaces for all samples were characterized using FESEM analysis.

Abstract: Nanoemulsion is a new class of emulsion with uniform and extremely small droplet sizes, typically in the range of 20-200 nm. Avocado oil was proven to be used as anti-aging and moisturizing agent. This study aimed to characterize nanoemulsion hydrogels prepared using avocado oil and sucrose ester laureate as surfactant. The nanoemulsion hydrogels were prepared by nanophase emulsification technique. These formulations were examined using zetasizer to determine the mean diameter of dispersed oil droplets, polydispersibility index (PDI) and zeta potential.The viscosity of the prepared nanoemulsion hydrogel was also studied. The results revealed that nanoemulsions prepared with 50% w/w oil, 30% w/w glycerol and 20% w/w surfactant showed droplets size below 200 nm with good polydispersibility index and zeta potential < -30 mV. The optimum formulation of nanoemulsion was prepared in the form of nanoemulsion hydrogel using carbopols 934 and 940. The results of the rheology for the nanoemulsion hydrogel showed that the storage modulus (G) which describes the elasticity of the component were greater than the loss modulus (G) values that reveals the viscosity of the component.