Zulkifli Mohamad Ariff

Vulcanization kinetics study of natural rubber compounds having different formulation variables

Vulcanization kinetics of natural rubber (NR) compounds with efficient vulcanization system was studied through phenomenological approach using the experimentally cure data obtained from a moving die rheometer. The cure kinetic parameters were defined using the proposed models by Claxton–Liska and Deng–Isayev with the support of curve fitting software. The effects of the amount of accelerators, sulfur and silica in the formulations on the cure characteristics and cure kinetic parameters at high cure temperatures were investigated. Kinetic data results showed that the above two models were able to describe the curing behaviour of the studied compounds satisfactorily. It showed that the fitting of the experimental data with Claxton–Liska and Deng–Isayev could provide a good platform to investigate the cure kinetics of the prepared NR compounds.

Thermal properties of polyimide system containing silicone segments

The influence of the structure properties relationships of silicone incorporated polyimide (PI) on thermal stability was investigated by using single scan thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) in nitrogen. Four systems have been synthesized based on monomer 4-(4-(1-(4-(4-aminophenoxy) phenyl)-1-methylethyl) phenoxy) aniline (BAPP)/3,3′,4,4′-Biphenyltetracarboxylic dianhydride including parent PI (S-1), PI siloxane copolymer (S-2 and S-3), and PI siloxane hybrid (S-4). The derivative thermogravimetric analysis (DTG) and DSC curves indicate a double and single stage decomposition process and glass transition temperature (Tg), respectively. While the PI, PIS, and PSH showed distinctive features towards thermal analysis, it was found that the rate of degradation (δα/δt) was influenced by the flexibility of Si–O–Si in the backbone and in Si–O–Si itself. These results revealed that the presence of Si–O–Si in either the backbone or matrix indicates its stability with regard to high thermal service applications.

Numerical Study of Mold Filling during Encapsulation Process

3-D packaging is a technology that offers high density packaging and high performance. It enables chips to be stack in a single package and widely adopted in multi-media products. Thermosetting material is used for their encapsulation, is flowed through their thin space and wide filling area during package encapsulation process has become vital concern i.e. void formation. In this paper, such issue has been numerical studied due to the effect of transfer speed of the plunger head during encapsulation process. There are five transfer speeds of 1.6, 2.0, 3.4, 6.8, 9.04 mm/s have been chosen in order to investigate the quality of air entrapped (hereafter namely as void), where it degraded the package’s reliability. It is found that the longest transfer speed delivered to the best encapsulation process, which had lowest volume of air trap or void formation in the package.Keywords: Encapsulation, Transfer speed, Vent arrangement, Void Formation

The Influence Wall Thickness of Cement Hollow Spheres towards Compressive Properties of Cement Syntactic Foam

An innovative technique in producing cement syntactic foam (CSF) was proposed in this investigation. This cellular composite material basically consists of a cement matrix embedded with in-house developed cement hollow spheres (CHS). The produced foams incorporated with CHS having different wall thickness, were characterized for compressive strength and then compared with that of plain cement. It was observed that the CSFs were 37%-55% lighter than the plain cement but possessed compromised compressive strength. The comparative compressive properties of CSFs were also evaluated and reported. It was found that the CSF incorporated with thicker-coated CHS showed higher compressive strength compared to that of incorporated with thinner-coated CHS. The failure patterns within the test samples were also examined to determine the failure mechanism. These observations showed that both CSFs exhibited shearing type failure but exhibit different types of crack fractures due to the difference in CHS wall thickness.

Effects of Hydrocolloid on Compression and Morphological Properties of Kenaf Filled Natural Rubber Latex Foam

Corn starch has been used as hydrocolloids in kenaf filled natural rubber latex foam (NRLF). Kenaf filled NRLF was successfully prepared by using Dunlop method. This research was carried out to study the effects of hydrocolloid on compression and morphological properties of kenaf filled NRLF. From the graph of 50% compression, it was shown that kenaf filled NRLF with hydrocolloid has higher compression strength compared to kenaf filled NRLF without hydrocolloid. From the micrograph of Scanning Electron Microscope (SEM), it was observed that the pores size of kenaf filled NRLF with hdrocolloid was smaller than the pores size of kenaf filled NRLF without hydrocolloid. This showed the effect of hydrocolloid which contributes to the high compression strength.

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM).

Evaluation of Cadmould Software to Simulate the Filling Phase of a Natural Rubber Compound in Injection Moulding Process

The possibility of using Cadmould software to simulate the filling behaviour of a natural rubber compound during an injection moulding process was investigated. For the simulation process, the determination of required material input data involving the rheological and cure kinetics data of the designed rubber compound were conducted. It was discovered that the acquired data were able to function as reliable material input data as they were comparable with related data available in the Cadmould software materials database. Verification of the simulated filling profiles by experimental short shots specimens showed that the Cadmould Rubber Package was able to predict the realistic filling behaviour of the formulated natural rubber compound inside the mould cavity when the measured material data were utilized. Whereas, the usage of available material database from the software failed to model the mould filling progression of the intended natural rubber compound.