Bambang Sunendar

Hardness Evaluation of Dental Composite with Ceramic Fillers

In this study, new dental composites materials were developed. The two composites systems composed of zirconia (ZrO2), alumina (Al2O3) and silica (SiO2) (composites A) and zirconia (ZrO2), calcium (CaO), and silica (SiO2) (composites B) were synthesized through sol-gel method. These two systems were combined with urethane dimethacrylate and tetraethylene glycol dimethacrylate with 1% chitosan as coupling agent to build up the dental composites material. The resulting composites were subject to evaluation by microvickers hardness test and X-ray diffraction. The microvickers hardness test revealed that the hardness value for composites A and B were 24.48 and 21.9 VHN, respectively. Furthermore, the data were submitted to t-test (α=0,01) and it showed t count of both samples was 0,871 which means between the -t1-½α< t <t1-½α thus showing statistically the same average hardness value of both samples. Eventually, the new dental composites could be anticipated to apply in dental composites filler. The hardness results support the XRD result revealed that tetragonal crystal phase will help the transformation toughening mechanism and cubical crystal phase of zirconium dioxide. Both of the crystal phases were formed to stabilize the zirconia.

Synthesis and Characterization of Silica-Lavender Microencapsulation by Sol Gel-Emulsion Method for Anti Mosquito Textile

Microencapsulation is a new breakthrough in the field of nanotechnology that can be used for various applications, in particular for the application of controlled release material for functional textiles which were added by certain active substances and gave effects when used such as fragrance and anti mosquito textile. In this research, the synthesis of silica-lavender microencapsulation for anti-mosquito textile had been conducted successfully via sol-gel emulsion process. Sodium silicate solution which was emulsified into the lavender oil as an active ingredient acted as oil phase and ethanol solution acted as water phase. The addition of chitosan as surfactant and polymer for encapsulation with starch as soft template affected the rod-structure formation of nanorod. SEM result showed the morphology of silica-lavender. The rod has the average diameter size of 0.042-0.206 μm. The optimum result of rod-structure was obtained by adding 1% (v/v) of chitosan. FTIR analysis indicated the presence of absorbance peaks at wavenumber of 1411.89, 958.62, and 1078.2 cm-1 respectively for C-H (alkanes), C-H (alkenes) and ester functional groups which indicated the lavender compound in silica-lavender. UV-Vis analysis showed the maximum absorbance at wavelength of lavender at 350 nm. The combination of morphology and chemical properties of silica-lavender modified by chitosan-starch made this material as a candidate material for application in functional textile.

The Study of Red Mud Addition Influences in Metakaolinite-Based Geopolymer Characteristics

Bauxite tailing waste or commonly known as red mud is considered to be a very hazardous material. The using of red mud to make alternative building material has been widely studied for many years. Geopolymer as one of the breakthrough in the searching of ordinary portland cement/concrete substitution provides many options and possibilities of using different types of pozzolanic or alumina-silica materials. In this study, the using of red mud in metakaoline-based geopolymer paste has been studied in three different curing conditions for 7 days of sample age. Each sample then characterized both, macroscopically and microscopically including compressive strength testing, SEM photograph, XRD and FTIR spectroscopy

Evaluation on the Temperature and Calcination Time During Sol-gel Coating of TiO2 on Iron Foam substrate

Iron foam is iron based material which is widely applied due to its unique properties. However since corrosion is also a problem for this material, coating with innert material is required in enhancing its applications. In the present research, TiO 2 coating is performed on iron foam suface by sol-gel dipping method. Focus is given on the study of the effect of calcinations temperature and time on the coating characteristics. TiCl 4 is used as the precursor with concentration of 0.3 M, added with 1M HCl solution and chitosan soluation with concentration of 1%. Calcination is performed at temperature of 400, 500 dan 600 o C and calcinations time of 1 and 3 hours inside controlled gas furnace using nitrogen atmosphere. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) characterization data shows that TiO 2 particles form on the iron foam substrate. SEM characterization on the sample heated at 400 o C and heating time of 1 hour shows the formation of nano particle titania (0.06 μm) which is homogeneously distributed with less agglomeration than others and considered as the best sample in the present research. As the temperature and time of calcinations increase, more inhomogeneous particle distribution and bigger particles form.

Structural and Morphological Analysis of Nanocomposite SnO2-Graphene Synthesized by Sol-Gel Method

Gas sensor performance is strongly influenced by the crystal structure, composition and morphology of the material used. In this paper, structural and morphological analysis of nanocomposite SnO2-Graphene synthesized by Sol-Gel method with the composition of 1:1, 1:2, 1:3 will be described. Analysis of the morphology and structure of nanocomposite SnO2-Graphene is investigated using XRD, SEM and TEM with the purpose of obtaining the crystal structure, morphology, composition and size of the resulting particles. The XRD results showed that the formation of the crystalline phase can be recorded at 2θ = 26.64; 34.2; 51.92, where the results of SEM show that the nanomaterial SnO2 has tetragonal structure while the graphene has hexagonal structure. The nanocomposite SnO2-Graphene has nanorod pattern. Furthermore, the surface analysis using TEM of nanocomposite SnO2-Graphene shows that the surface has the rod diameter in the range of 5-8 nm. The unique nanopattern of SnO2-Graphene will have potential applicability as the sensing material for CO gas sensor.

High Performance Carbon Monoxide Sensor Based on Nano Composite of SnO 2 -Graphene

SnO₂-graphene nanocomposite thick films have been successfully synthesized using polyol method. Reflux with ethylene glycol as medium was employed to produce the nanocomposite. Crystal structure characterization using X-Ray diffraction shows the nanocomposites have good crystalinity without any impurity. Scanning electron microscopy and transmission electron microscopy characterization results show SnO₂ has spherical shape and well distributed on the graphene layer. The size of SnO₂ particles is around 5–8 nm. To confirm the improvement effect of grapheme addition to SnO₂, sensor testing was conducted toward 30 ppm carbon monoxide (CO) gas at 150 °C compared with pure SnO₂ and pure graphene. The sensor responses are 88.11%, 52.84%, and 0.93%, respectively.

Naturally Derived Biomaterials and Its Processing

The rich Indonesian biodiversity has been viewed as an infinite resource of naturally inspired and derived biomaterials. The utilization of these natural materials for biomaterial applications necessitates additional steps to the currently established conventional synthesis methods. Some of these steps have been successfully developed at a lab scale with suitable controlling parameters resulting into an optimum overall synthesis processes. Further optimization and fine tuning on the parameters are required to translate the innovation into a commercialization. More efforts from biomaterial researchers and a supportive policy from the Government are essentially needed to foster the development of biomaterial and its applied technology resulting into low-cost yet effective medical devices to support the national health care program. This chapter concentrates its discussion on selected naturally derived biomaterials, their sources and their processing which have been developed in Indonesia. These include synthesis of hydroxyapatite from coral, land snail and egg shells via precipitation reaction, sol-gel, hydrothermal and biomimetic methods, new synthesis of membrane and encapsulation using template derived from a flower plant, and synthesis of zirconia for dental restoration.

Utilization of Fly Ash, Red Mud, and Electric Arc Furnace Dust Slag for Geopolymer

Geopolymer is an aluminosilicate material that can be prepared from thermal activation of solid material containing alumina and silica as precursor and alkali activator solution. The precursor is an eco-friendly material and has a potency to replace Portland cement (cementless material). In this work, cementless geopolymer mortar was prepared by mixing fly ash as main precursors, red mud, and electric arc furnace dust slag, followed by addition of activator solution containing sodium hydroxide solution and waterglass. X-ray diffraction and Fourier transform infra-red spectroscopy demonstrated the formation of albite in geopolymer mortars, indicating that geopolymer mortars have been successfully formed. The best compressive strength of mortars was 72.80 MPa achieved by using fly ash and red mud with NaOH 12M under ambient curing.

The effect of CHA-doped Sr addition to the mechanical strength of metakaolin dental implant geopolymer composite

The prospective material for implant plate required sufficient mechanical properties to maintain fracture fixation and resist physiological stress until bone healing process finished. Various problem implant plate based on metal and polymer materials when used as fixation for bone defect case induced developmental of bioceramic for implant plate materials. Materials that now has been attract a lot of attention is carbonate apatite and strontium as doping which known to have good biocompability along with biointegrity and mechanical charateristics. Other materials that have been known to have good mechanical properties are metakaolin and use of chitosan as coupling agent. Metakaolin and carbonate apatite can be produced by sol-gel methode which simpler, economical and energy-saving procedure furthermore use of chitosan which is widely found in the nature of Indonesia can be used to encourage the utilization of natural resources. The aim fo this paper is to investigated effect of CHA-doped Sr 5 (%) mol addi...

Effect of strontium addition and chitosan concentration variation on cytotoxicity of chitosan-alginate-carbonate apatite based bone scaffold

Bone scaffold is one of the most important component in bone tissue engineering. Basically, bone scaffold is a biocompatible structure designed to replace broken bone tissue temporarily. Unlike conventional bone replacements, an advanced bone scaffold should be bioactive (e.g: supporting bone growth) and biodegradable as new bone tissue grow, while retain its mechanical properties similarity with bone. It is also possible to add more bioactive substrates to bone scaffold to further support its performance. One of the substrate is strontium, an element that could improve the ability of the bone to repair itself. However, it must be noted that excessive consumption of strontium could lead to toxicity and diseases, such as osteomalacia and hypocalcemia. This research aimed to investigate the effect of strontium addition to the cytotoxic property of chitosan-alginate-carbonate apatite bone scaffold. The amount of strontium added to the bone scaffold was 5% molar of the carbonate apatite content. As a control,...