Papers by Keyword: Resin

Abstract: Polypropylene resins have been enfolded with the automotive industry and suppliers to produce several spare parts. This is aimed at achieving zero emissions, kenaf plant which in Latin is Hibiscus Cannabinus is a natural fiber replacement resin. Natural fiber composites come in many different types, but kenaf has been exploited extensively over the last few years. The pre-board flow process of kenaf-polypropylene starts from mixing kenaf about 40% with 60% polypropylene, forming a pre-mat as the first output, entering the main treatment with the hot press into pre-board as the final output. Kenaf-polypropylene door trim is very absorbent of CO₂, which is related to natural fiber base material. Door trim with kenaf-polypropylene as the base material reduces the weight by about 30% of the previous polypropylene resin and still provides high rigidity even at a reduced weight. The entire process is requiring 48382.4 kWh / month per cycle of total power consumption.

Abstract: The influence of chemical treatment on the mechanical properties of treated chicken feather fibre-reinforced unsaturated polyester resin (TCFF-UPR) composites was studied in this research. Redundant portions of chicken from poultry farms are comprehensively contaminating the environment. To minimize environmental pollution, these redundant portions need to use for the production of other materials. In this study, we used chicken feather for the preparation of useful composites combining with unsaturated polyester resin (UPR) to reduce environmental pollution. The composites were prepared successfully by conventional hand lay up technique using modified chicken feather as the reinforcing phase of composites. For preparing composites different percentages (2, 5, 7, 10, 12 and 15% by weight) of fibre were used. Attained tensile test results expressed significant enhancement in the tensile properties of composites, with the optimum combination of tensile strength presented by 5 wt% , tensile modulus presented by 10 wt% untreated chicken feather bio-fibre reinforcement and bending strength by 5 wt% chicken feather bio-fibre reinforcement.

Abstract: A density functional theory (DFT) is used to investigate the energetics of an epoxy resin adhere on a tin oxide and a hydroxylated-alumina surface within a supercell approach. Self—consistent geometry optimization is performed for models of adhesion interface, which is comprised of a fragment of epoxy resin and hydroxylated-Al₂O₃ (001), and SnO2(001) and (110) surface. The epoxy resin studied was simplified fragment based on diglycidyl ether of bisphenol A (DGEBA). It is found that the distance between the resin and the surface where the adhesion force is maximized is substantially the same for all models. Analysis of the energy-distance plot reveals that the fragment of DGEBA molecule adhere most strongly to the SnO₂(001) surface, suggesting that the adhesion force is induced by van der Waals (vdW) interaction.

Abstract: Surgical obturators are important oral prostheses given to patients after surgical treatment to minimize scar contracture and esthetic disfigurement that may affect patients’ functional appearance and psychological health. Poly-methyl methacrylate (PMMA) resin has been the material generally used for fabrication of surgical obturator. However, wearing of this resin appliance can raise a condition for microbial biofilm accumulation and infection of the patients due to the rough surfaces and internal porosities of the resin. Vanillin-incorporated heat-cured and auto-polymerized PMMA resin have been developed and demonstrated to have antimicrobial activity against several types of microorganisms. This study aimed to examine antimicrobial properties of vanillin-incorporated auto-polymerized surgical obturator resin on the biofilm formation of Streptococcus mutans and Candida glabrata. The auto-polymerized PMMA resin samples (Orthocryl® EQ, Germany) were prepared with vanillin incorporation (0.1% and 0.5% vanillin). All samples were coated with sterile saliva and incubated at 37 °C for 60 min. The suspensions of S. mutans ATCC 25715 and C. glabrata ATCC 15126 (10⁷ colony forming unit/mL) were prepared using McFarland standard No.1. Microbial biofilm formation was done in 96-well plate at 37°C for 24 h. The total vital biofilm formation was evaluated by Cell Counting Kit WST-8 (Dojindo Molecular Technologies, USA) at 450 nm. All tests were done in triplicate on three separate circumstances. One-way ANOVA and Tukey’s test were applied for the statistical analysis. A significant decrease of S. mutans biofilm mass was noticed in 0.5% vanillin incorporated resin group compared with a control, resin without vanillin. The percentage of biofilm reduction was 40.8%. No different effect was observed in 0.1% vanillin group. In the case of C. glabrata, no significant biofilm reduction was examined among all groups. In conclusion, the adding of 0.5% vanillin to surgical obturator resin could significantly inhibit biofilm formation of S. mutans, however, the effect was not demonstrated on 0.1% vanillin. C. glabrata was observed to be resistant to vanillin. Using PMMA resin incorporated with 0.5% vanillin, an obturator with antimicrobial property can be applied to prevent dental caries and other systemic diseases in patients after surgical treatment.

Abstract: The rectangular-structured resin with one of its triangular long-period fiber grating surface is designed and printed out by using a high resolution 3D printer, so called long-period fiber grating (LPFG) resin. This LPFG resin is directly pressed on the bare single-mode fiber by a digital force meter to filter out partial band of light inside the fiber. The grating period is expanded by tilting the resin from the initial fiber axis. The optical filter is observed as resonant wavelengths from the broadband wavelength. The results show that the resonant wavelength shift is a linear function of the grating period with the coefficient of determination over 0.99. The proposed scheme has a great potential to be employed as a sensor such as a selective optical filter and a buried intrusion sensor.

Abstract: Orthodontic retainers made of poly methyl methacrylate (PMMA) resin are generally used after finished orthodontic treatment to hold teeth in the right position and avoid the shift out from the alignment. The use of these devices can place patients at greater risk of dental caries through the biofilm accumulation of caries-associated bacteria and food debris on the rough surfaces or inherent porosities of PMMA surfaces of appliances themselves. Vanillin, the major component of flavoring agent vanilla, has been demonstrated to have antimicrobial activity against many types of microorganisms. This study aimed to evaluate antimicrobial property of vanillin-incorporated orthodontic retainer PMMA resin on the biofilm formation of cariogenic bacteria. The self-curing orthodontic retainer PMMA resin samples were produced according to the percentage of vanillin adding (0%, 0.1% and 0.5% vanillin) (SCG Chemicals, Thailand). All samples were coated with sterile unstimulated saliva. Then the cariogenic bacterial suspensions of Streptococcus mutans ATCC 25715, Streptococcus sobrinus ATCC 33478, Lactobacillus casei ATCC 334 and Lactobacillus acidophilus ATCC 314 were added and incubated at 37°C in 5% CO₂ atmosphere for 48 h to allow the biofilm formation. The amount of vital biofilm was determined by WST Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA) at 460 nm. One-way ANOVA and Turkey’s test were employed for the statistical analysis. A significant inhibitory effect against all tested bacteria was observed in 0.5% vanillin incorporated samples compared with 0% vanillin. The percentage of biofilm reduction was 23-45%. The adding of 0.1% vanillin showed suppressive effect only on Lactobacillus spp. In conclusion, the incorporation of 0.5% vanillin to self-curing orthodontic retainer PMMA resin could significantly inhibit biofilm formation of cariogenic bacteria (S. mutans, S. sobrinus, L. casei and L. acidophilus). Using this PMMA resin, removable orthodontic appliances with antimicrobial property can be applied to prevent dental caries or tooth demineralization in orthodontic patients.

Abstract: The objectives of this study were to estimate the effect of the blue light cure unit on the compression force and hardness for composite resin nanoCeram at different thickness. The basic material used in this study was Ivoclar Vivadent Tetric N-Ceram Light Cured Hybrid restorative composite resin. The samples were cured by applying a (LED.F) unit Blue phase in a wavelength emission spectrum (494 NM) was used.60 disc-shaped specimens [9 mm diameter at (0.5, 1) mm thickness and 10 mm diameter at (1.5) mm thickness] were prepared using a stainless steel mold for hardness and compressive strength measurements. A composite resin was polymerized with an aid of a ( DC 5V/1A) lamp for (10, 20 and 30) sec .Three specimens were used for each group.The results were analyzed using (linear logarithmic, quadratic, linear and power) test.The different groups showed significant variability in relation, with a significant interaction between the groups.The result showed that the greater thickness more efficient for polymerization than small thickness and the long irradiation time more efficient for polymerization than short irradiation time, long irradiation time diffusion in deep portions of the sample convert to polymer and this provide good polymerization and then good mechanicalproperties.

Abstract: The polymer-cement composites have special specifications, high strength compared to their low density, satisfactory deformability, deterioration resistance, tailored design. This enables the construction of new elements and the structural recovery of the existing parts made of traditional materials. two sets of mixtures were prepared that consist of mortar and polymer to produce the polymer-mortar composites were cured at room temperature and post-cure at 50 ͦ C. The set includes mortar (cement-sand) without water. The polymer was epoxy which is added to the mortar after mixing the hardener with resin. Set consists of the proportion of polymer (15, 20 and 30%).The effect of the polymer was studied on both sets by computing the density also measuring the hardness, compressive strength and flexural strength of specimens. The addition of polymer showed an improvement in these properties and post-cure have improvement properties .the lowest percent of the polymer showed The highest results were density 1133.3 kg/m3, the hardness of composites was 97.28 shore D. the compressive strength was about 100.816 MPa and the value of flexural strength was about 29.418 MPa.

Abstract: The dimension stone wrapping process is a method used before the sawing of the block which aims to enhance the integrity of the rock, thus ensuring that fractured or altered blocks remain intact while they are handling and splitting into slabs. This method increases safety and allows the processing of many materials once not commercialized. Nevertheless, the epoxy resin used in the process comes from a non-renewable resource and contains toxic substances on its composition. Therefore, in order to increase the eco-efficiency in the sector of dimension stones, a comparison of the epoxy resin with an ecological and non-toxic resin based on the castor oil, was carried out aiming to know the resulting tensile strength in the contact of the polymer with the stone surface. Two types of rocks were tested, a silicate and a carbonate one. The results indicated that the castor oil resin performed a higher tensile strength regarding carbonate rocks, suggesting that the castor oil resin could replace the epoxy resin when applied to this rock group, providing an environmental advantage and a global marketing differential.

Abstract: Relaxation-compression resin transfer molding under magnetic field is a new variant of VARTM (“vacuum assisted resin transfer molding”) process, which uses a flexible magnetic membrane controlled by a magnetic force, in order to govern the relaxation and compression phases by changing the permeability of the fabric preform. Thus permits to the resin to enter easily into the mold and to increase the resin impregnation velocity and the fiber volume fraction. This innovation is based on the application of the TRIZ theory (“the theory of inventive problem solving”), which allows us to answer to the shortcomings and the conflict links exist inside the VARTM processes. The objective of this paper is to present this new process and to study the effect of the current intensity and the separated gap between the flexible magnetic membrane and solenoid on the permeability of the preform.