Addition Of Talc Research Articles

Formulation and Evaluation of Sustained Release Preparation of Ibuprofen Fast-Disintegrating Tablet (FDT)

The objective of this study was to enhance the utilitization of Ibuprofen (IBU) by introducing the fast-disintegrating tablet (FDT) form. Presently, IBU is being widely used as a tablet or syrup form. But in contrast to these two formulations, IBU as FDT is not only convenient but also increases the control over the time release of the drug, noted by using Alginate beads. This study was carried out with Sodium Alginate and IBU at the ratios of 1:0, 1:0.5, 1:1, and 1:2 in order to produce a series of beads with different ratios. During the drying process of the beads, talc was added in beads to compare the effects with and without the talc. The final product was scanned with SEM imaging to determine the difference in the surface of the beads. The parameters assessed were the diameter, content assay, dissolution test and effectiveness of time-release. Direct compression method was used to prepare FDT containing IBU bead. The properties of FDT, such as hardness, disintegration time, were investigated. The dissolution profiles of FDT were tested using KP dissolution apparatus 1 (basket method). The results suggest addition of talc and drying the beads made the surface smooth and less vulnerable to clutter into chunks. The size of beads was less than 300 um which did not create a sandy feeling in the mouth. Thus, the beads formulation model made the sustained release of the drug possible, the hardness of FDT (1.25~1.50 Kg/cm2) was acceptable and all the values of dissolving period were less than 30 seconds. The dissolution profile of FDT was same as that of IBU bead. The efficient dissolution profile and low price of IBU bead containing Sodium Alginate, the FDT formulation prepared from IBU bead can save the expenses and can improve the convenience of application of this drug.

Efeito da incorporação de talco nas características térmicas, mecânicas e dinâmico-mecânicas de poliuretanos termoplásticos

O objetivo deste trabalho foi investigar o efeito da adição de talco, um agente nucleante amplamente empregado em formulações de termoplásticos em geral, no comportamento de cristalização e nas propriedades mecânicas de dois poliuretanos termoplásticos (TPUs) de diferentes massas molares. Foram realizadas análises de calorimetria exploratória diferencial (DSC), termogravimetria (TGA), dinâmico-mecânica (DMA), além de ensaios mecânicos. Observou-se que a adição de talco aumentou a temperatura de cristalização e a de decomposição média do TPU de maior massa molar média, no entanto, não foi observada mudança para concentrações superiores a 0,5% (m/m). Análises de DMA indicaram um aumento do módulo de armazenamento com a aditivação somente para o TPU de maior massa molar média. Nos ensaios mecânicos, não foi possível observar alterações significativas nas propriedades. O estudo realizado demonstrou a importância do conhecimento do efeito da adição de talco como agente nucleante em compostos de TPU, visando o melhoramento do desempenho destes materiais.

Effect of Nucleating Agents on Physical Properties of Poly(lactic acid) and Its Blend with Natural Rubber

Poly(lactic acid) (PLA) presents high strength and modulus, but very low toughness as well as slow crystallization. Natural rubber (NR) was blended to enhance the toughness and nucleating agent was added to improve the crystallization. Cyclodextrin (CD), considered as a green compound, as well as calcium carbonate (CaCO3) and talc were used as nucleating agents. Effects of these nucleating agents on crystallization, mechanical properties and morphology of neat PLA and PLA/NR blend were investigated. It was found that the addition of talc and CD decreased cold crystallization temperature (Tcc) of the PLA. Same result was obtained in PLA/NR blend containing talc. All nucleating agents increased the degree of crystallinity (ΧC) of PLA, whereas only talc and CaCO3 increased ΧC of PLA in PLA/NR blends. The enhanced toughness of PLA by the addition of nucleating agent was attributed to its increased crystallinity, as well as decreased spherulite size. For PLA/NR blends, the increase in toughness was mainly contributed by the presence of the rubber.

A batch foaming visualization system with extensional stress-inducing ability

In typical plastic foaming processes, plastics are subjected to various amount of stress/strain, which can induce cell nucleation and affect the final cell morphology of plastic foams. Despite many valuable insights in previous work on stress-induced foaming, further studies are needed to clarify the subject. While in-line observations of foaming processes provide useful cell growth and interaction data, a controllable stress/strain field cannot be easily induced in a plastic sample to evaluate its effect. This study presents a novel batch foaming in-situ visualization system that was developed to capture the foaming process of a plastic specimen under controllable extensional strain. Using the in-situ visualization system, this study explored the effects of extensional stress/strain on the foaming behaviors of polystyrene blown by carbon dioxide under various processing conditions. It was observed that cell density increased with the application of extensional strain and that this effect was more apparent at low processing temperatures and with the addition of talc.

Optimization of the Abencor system to extract olive oil from irrigated orchards

AbstractStudying the composition of olive oil requires cold‐press olive oil extraction. One of the most common laboratorial mills is the Abencor system. However, its operation protocol was formulated decades ago for Spanish olive varieties from traditionally rain‐fed orchards. We modified this protocol for use with “Barnea” and “Picual” olives from irrigated orchards that are characterized by high water content. Independent effects of malaxation time, temperature, water addition and talc addition on extraction efficiency, and major quality indices of virgin olive oil were studied. Overall, addition of talc to the fruit paste was the most significant treatment in terms of yield and quality of the oil although its effect was cultivar dependent. Improved oil yield was particularly significant for “Picual.” Extended malaxation time was also effective in improving oil extractability. Addition of talc generally improved oil‐quality parameters, while water addition had the opposite effect. Yet, quality parameters remained within the extra virgin level. Temperature increments reduced oil quality. The need to adapt a modified protocol for use with fruits from irrigated orchards that will facilitate critical comparison of results obtained from different agronomic theses and different laboratories is highlighted. It is recommended that each laboratory develops an appropriate protocol for the operation of the Abencor system in accordance to the characteristics of the olive fruit they are working with.Practical applications: Abencor system serves as the major laboratorial mill world‐wide. Those mills allow the researchers to characterize olive oil in accordance to the treatments received by the trees. This cannot be done in commercial mills. The system operation protocol was established decades ago for fruits from rain‐fed orchards. In the past decade there was a rapid increase in the use of irrigation in olive orchards and therefore it is crucial to optimize the operation protocol for fruit with relatively high water content. In the current work we have evaluated the influence of a series of technological parameters (i.e., talc and water addition, malaxation time, and temperature) on the extraction efficiency and quality indices of olive oil. This allowed us to present a modified protocol for the Abencor system operation suitable for olive fruit of irrigated orchards that will facilitate a reliable representation of the influence of different treatments on the yield and characteristics of the olive oil.

A New Biodegradable Flexible Composite Sheet from Poly(lactic acid)/Poly(ε‐caprolactone) Blends and Micro‐Talc

AbstractThe influence of talc loading on phase morphology of PLA/PCL/talc composites and improvement in resulting properties are reported. Talc‐based composites of PLA/PCL blends were prepared by melt blending. SEM analysis demonstrates that PLA appears as discrete domain phase, while PCL acts as a bulk phase in the blend. Talc addition decreases PLA domain sizes and voids in the matrix. This results in significant improvement of oxygen and water vapor barrier properties of composite by 33 and 25%, respectively, at 3 wt.‐% talc loading. DSC shows that talc acted as nucleating agent for PCL phase in the composite and improves its crystallinity. Various theoretical models based on dispersion and filler geometry are used to predict the tensile modulus and oxygen permeability.magnified image

Effects of chemical treatments of hybrid fillers on the physical and thermal properties of wood plastic composites

Hybrid filler reinforced composites are considered as a high performance materials, but limited numbers of researches on hybridizations of wood fibers and mineral fillers were reported. Generally, high amount of filler content in composites can lead to the reduction of interfacial adhesion between matrix polymer and fillers, and it limits their applications. In this study, we measured the changes of tensile strength, water absorption, and thermal properties of composites after chemical treatments to wood fibers and mineral fillers. Coupling agent had its own optimum amount for wood fibers and talc to obtain the highest tensile strength. Talc addition showed little effect of the tensile strength with alkali treated wood fibers. Talc addition and silane treatment showed opposite effects on water absorption. Melting enthalpy was decreased by addition of the fillers because of the reduced amount of the crystallizable resin and because of the interference of the fillers for crystallization process.

Impact of talc on pulp and froth properties in F150 and 1-pentanol frother systems

The role of frother controlling bubble size and froth properties is reasonably well understood in the air–water system. A concern is how well this relates to the three-phase flotation condition. As a model hydrophobic solid talc was used. A column was run at fixed froth depth and air rate with overflow and underflow recycled. Four frothers were examined, two polyglycols, polypropylene glycol (F150), polypropylene methyl ether (DF250), and two alcohols, 1-heptanol and 1-pentanol. At steady state, pulp zone gas holdup and bubble size were measured along with water and solids overflow rate as a function of talc addition. For 1-heptanol and DF250 there was no impact of talc on bubble size or gas holdup. For 1-pentanol the presence of talc had no effect on bubble size but gas holdup increased; in contrast, for F150 addition of talc increased bubble size and decreased gas holdup. There was a reversal in water overflow rate between the F150 and 1-pentanol on adding talc, the 5:1 ratio in favour of F150 in air–water becoming 3:1 in favour of 1-pentanol at 5 wt% talc. The solids overflow rate likewise favoured 1-pentanol in presence of talc. The increase in bubble size in the talc/F150 system implies coalescence, as further evidenced by the bubble size distribution becoming bi-modal. The mechanism proposed was a combination of talc adsorbing frother from solution, demonstrated by TOC analysis of residual frother, and directly from the bubble surface due to the orientation of adsorbed F150. In the talc/pentanol case the increase in gas holdup was attributed to bubbles not being at terminal velocity and attached talc particles increasing deceleration, i.e., slowing bubble rise. The increase in water overflow rate in the talc/pentanol system corresponds to increased froth stability imparted by hydrophobic solids. Froth stabilization by talc with F150, however, is offset by the increased bubble size that means less water is carried into the froth. The reversal in water overflow ranking of the frothers can, therefore, be interpreted as due to frother/solid interactions. Similar interactions may account for reversals noted in other systems.

Structures and properties of the compression-molded istactic-polypropylene/talc composites: Effect of cooling and rolling

Talc-loaded isotactic polypropylene (iPP) composites with various contents of talc were fabricated by compression molding, following slow- and fast-cooling processes, to obtain slow-cooled samples (SCS) and fast-cooled samples (FCS), respectively. Lamellar thickness of the α-crystal of iPP in the SCS is observed to be larger than that in the FCS by X-ray diffraction study. Rolled fast-cooled samples (RFCS) were also prepared at 25 °C in order to examine the crystal growth of iPP. An epitaxial growth mechanism of the α-crystal of iPP from the talc crystal is proposed. Surface of talc-loaded FCS appears with a smaller particle size than that of talc-loaded SCS and RFCS as observed by a scanning electron microscope. Young’s modulus and tangent modulus of FCS are found lower than those of SCS with the addition of talc up to 20 wt% and higher above this concentration, except microhardness which is higher in SCS at all contents of talc. From thermal studies, talc-loaded SCS and FCS are found to show higher melting temperature than the neat samples. Effect of cooling and rolling on the structures and properties of the fabricated composites are elaborately discussed.

Production of d-glucose from pseudo paper sludge with hydrothermal treatment

Abstract To convert cellulosic organics contained in industrial paper sludge into glucose, reaction of pseudo paper sludge composed of cellulose and inorganic compounds (calcium carbonate (CaCO 3 ), talc (Mg 3 (Si 4 O 10 )(OH) 2 ), kaolin (Al 2 (Si 2 O 5 )(OH) 4 )) under hydrothermal conditions was studied. Significant amounts of glucose ( ca. 23%) could be produced from cellulose in the absence of CaCO 3 for reaction in water at 523 K and 12 min reaction time. On the other hand, in the presence of CaCO3, most glucose decomposed over all conditions, whereas the addition of talc and kaolin to the mixtures increased the glucose yield to about 30%. For the case of chemical recycle of paper sludge with hydrothermal treatment to obtain d -glucose, it can be concluded that it is preferable to separate the calcium carbonate from the paper sludge before hydrothermal treatment.

Mechanical Properties of Thermoplastic Olefin Composites: Effect of Fillers Content, Strain Rate and Temperature

The mechanical properties of thermoplastic olefin (TPO) composites with rubber content ranged from 17 to 23 wt% and talc content ranged from 19.5 to 25.5 wt% have been investigated at different strain rates and temperatures. Tensile tests were conducted at temperature of −30, 23, and 80°C, respectively, and strain rate from 10−3 to 10−1/s, respectively. The results showed that that the mechanical properties were modified significantly with the addition of rubber and talc, strain rate and temperature. The necking process of the TPO was rate dependent. At low strain rate, the deformation was close to the isothermal drawing.

Influence of Suspended Talc Particles in Oil And Nature of Material Microconstituents on Sliding Wear Characteristics of Cast Iron and Zinc-based Alloy

This investigation pertains to some observations on the sliding wear behaviour of a zincbased alloy and grey cast iron as influenced by the content of talc particles suspend in SAE40 oil lubricant. Tribological parameters evaluated using a pin-on-disc machine were wear rate, frictional heating and friction coefficient. The study suggests that the presence of suspended talc particles in the oil lubricant brought about improved wear response of the samples. However, the degree of improvement was strongly dependent on the talc content and even adverse effect of talc addition beyond a limit was noted. The observed wear response of the samples has been eXplained in terms of characteristics like compatibility, lubricating and cracking tendency of various microconstituents of the specimen materials and formation and stability of lubricant film during sliding. Characteristic features of wear surfaces, subsurface regions and debris particles enabled to further substantiate the wear response of the samples.

Kneading olive paste from unripe ‘Picual’ fruits: I. Effect on oil process yield

Olive growers start earlier to harvesting in order to obtain high quality oils, however unripe olives show different characteristics affecting technological and rheological properties. This work is aimed to study the effect of malaxation conditions on process oil yield for unripe ‘Picual’ olives. Experiments were carried out using Picual fruits harvested at early dates for three consecutive crops seasons. The malaxation conditions assayed using a factorial design were: time (60, 90 min), temperature (18, 30, 40 °C) and micronised talc addition (0, 1%). Olive paste from unripe Picual fruit are classified as difficult pastes. The main factor affecting oil yield was the crop year, while for each crop year the effect of each factor varied considerably. Results indicated as increasing time and temperature gave lower pomace oil losses although its effect varied on crop year. Micronised Natural Talc addition lowered pomace oil content on dry weight. Therefore for early harvesting dates knowing olive characteristics ‘on line’ is essential to adapt the kneading conditions.

Microcellular extrusion foaming of poly(lactide)/poly(butylene adipate-co-terephthalate) blends

Foamed poly(lactide) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends were processed via the microcellular extrusion process using CO2 as a blowing agent. Talc has been added to promote heterogeneous nucleation. Two types of PLA/PBAT blend systems were investigated: Ecovio, which is a commercially available compatibilized PLA/PBAT blend; and a non-compatibilized PLA/PBAT blend at the same PLA/PBAT ratio (i.e., 45:55 by weight percent). Six different formulations were investigated: pure PLA, PLA-talc, Ecovio, Ecovio-talc, non-compatibilized PLA/PBAT blend, and non-compatibilized PLA/PBAT-talc. The effects of various processing parameters such as die temperature, talc and compatibilization on various foaming properties such as cell morphology, volume expansion ratio (VER), open cell content (OCC) and crystallinity were investigated. As per the DSC thermograms, it was observed that compatibilization has merged the two distinctive melting peaks of PLA and PBAT into a single peak while lowering the peak temperature. In general, the addition of talc has decreased the average cell size and VER and increased the cell density and crystallinity; however, it has varying effects on the open cell content. Compatibilization has reduced the average cell size and volume expansion but increased the cell density and had varying and no effects on the OCC and crystallinity, respectively. Similar to compatibilization, the die temperature was found to have varying and no effects on the OCC and crystallinity, respectively. Except for PLA and non-compatibilized PLA/PBAT blend, the cell size and VER of all other formulations did not vary much throughout the entire temperature range (130–150°C). The cell density was found to be insensitive to die temperatures except for Ecovio and Ecovio-talc.

Microcellular extrusion‐foaming of polylactide with chain‐extender

AbstractThe effects of adding epoxy‐functionalized chain‐extender (CE) and processing conditions such as die temperature on the cell morphology, volume expansion ratio (VER), open cell content (OCC), and crystallization of microcellular extruded polylactide (PLA) were investigated. When compared with pure PLA, the addition of talc decreased the average cell size and increased the cell density. Moreover, the simultaneous addition of talc and CE led to denser and more uniform cell structure up until 1.0% CE content. In general, the volume expansion ratio and open cell content of all the formulations decreased with the die temperature. The addition of talc decreased both VER and OCC, whereas the addition of CE increased both. The die temperature did not affect the degree of crystallinity significantly. The addition of talc increased the crystallinity, but the addition of CE decreased it. Finally, the molecular weight of PLA increased significantly with the addition of CE. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Prediction of physical properties of Al2TiO5‐based ceramics containing micro and nano size oxide additives by using artificial neural network. Vorhersage der physikalischen Eigenschaften von Al2TiO5‐basierenden Keramiken mit Mikro‐ und Nanoadditiven mittels künstlicher neuronaler Netze

AbstractRecently, artificial neural networks (ANN) are being used as an interdisciplinary tool in many applications. There are various training algorithms used in neural network applications. The aim of this study is to investigate the effect of various training algorithms on the learning performance of the neural networks in the prediction and modeling of the effect of micron and nano size oxide material additives on reaction sintering and physical properties of Al2TiO5‐based ceramics. Aluminum‐titanate (tialite) based ceramics have found widespread applications due to their good thermal shock resistance and low thermal expansion. Eutectoid decomposition in the initial oxides and low mechanical strength limit the well‐known properties of aluminum‐titanate. In the present work, first, good stabilizing behavior was achieved by addition of micron size talc and appropriate properties were obtained by adding nano boehmite and colloidal silica that result in mullite phase formation. Then, the effect of the weight percentages of these different additives and also the temperature on the bulk density was predicted with four different training algorithms using a back‐propagation neural network. The training sets for the neural network were selected from experimental results. After training ANN, a regression analysis was used to check the system accuracy for each training algorithm. In conclusion, Levenberg–Marquardt (LM) learning algorithm gave the best prediction for the bulk density behavior of Al2TiO5 based ceramics. The response surfaces between the response variables, i.e. weight percent of additives and temperature of the tialite and the processing parameter are presented. The trained artificial neural network can be used for optimizing the sintering process of Al2TiO5‐based ceramics.

Crystallization of PLA/Thermoplastic Starch Blends

Abstract In this paper, the crystallization of PLA in PLA/thermoplastic starch (TPS) blends was investigated. The TPS was used as the minor component at a concentration varying between 0 and 42 %. The effect of interfacial area was studied by compatibilizing the blend using maleic anhydride grafted PLA. To further enhance the crystallization rate in PLA/TPS blends, the addition of talc and acetyl triethyl citrate, as nucleating agent and plasticizer respectively, was also studied. The crystallization rate was monitored using DSC analysis under both isothermal and non- isothermal conditions. The isothermal data was used to determine the crystallization half-life and to determine the optimum crystallization temperature. The crystallization half-time of PLA was decreased significantly in presence of the TPS phase and this effect was strengthened by the blends interfacial modification. By applying proper plasticization and nucleation strategy, crystallinity in excess of 50 % was achieved even at cooling rates as high as 80°C/min. Fully crystallized PLA/TPS samples were obtained by injection molding in a hot mold (80°C). Crystallized parts showed improved thermal resistance at temperatures above PLA's glass transition.

Desenvolvimento de massas de revestimento cerâmico com argila caulinítica e nefelina sienito

Este trabalho tem por objetivo adicionar tanto o fundente nefelina sienito, disponível no Estado do Rio de Janeiro, quanto o talco, fornecido por uma mineradora, em uma argila caulinítica para a obtenção de revestimento cerâmico gresificado. Foram preparadas formulações com 0%, 30% e 50% em peso de nefelina sienito em mistura com a argila, com e sem a adição de 3,5% em peso de talco. O comportamento de queima das formulações foi avaliado por dilatometria óptica. Corpos-de-prova foram obtidos por prensagem uniaxial a 30 MPa para queima a 1175 ºC. Nas amostras queimadas foram realizados ensaios tecnológicos para determinação da densidade aparente, retração linear, resistência mecânica por flexão em três pontos e absorção de água. Análise microestrutural foi feita por microscopia eletrônica de varredura e difração de raios X. Os resultados mostraram que a as formulações com nefelina sienito e talco apresentam potencial para a obtenção de revestimento gresificado, reduzindo significativamente a porosidade da cerâmica argilosa pura.

Thermal and Mechanical Properties of Wood Flour/Talc-filled Polylactic Acid Composites: Effect of Filler Content and Coupling Treatment

Wood flour (WF) and talc-filled polylactic acid (PLA) composites are prepared by melt compounding and injection molding. The effects of filler loading and silane treatment, the thermal and mechanical properties of the composites are studied. Loading of WF and WF/talc mixture into neat PLA results in a small decrease in the glass transition and crystalline temperatures of the composites. The use of WF, talc and silane in the composites causes successively larger decreased in the composite crystallinity. The addition of talc and silane to PLA/WF composites improved the tensile modulus. The tensile strength of the composites decreases slightly with the addition of talc, but it considerably improves with the use of 1 wt% silane. Morphological analysis shows improved interfacial bonding with silane treatment for the composites.

Influence of talc on the fire retardant properties of highly filled intumescent polypropylene composites

AbstractIntumescent systems have been developed since many years for a wide range of applications, even if they are mainly used in coatings nowadays. The objective of this paper is to determine if the intumescent concept can be applied to highly filled reinforced polypropylene (PP) composites containing talc. Formulations that meet the electrical industry requirements have been developed, even if it has been observed that the addition of talc into intumescent PP leads to a decrease in the fire retardancy of the systems. A thermal stabilization of the material is noted at high temperature in the presence of talc. An increase in the crystallinity of the intumescent structure is suspected to be, at least partially, responsible for the decrease in the performance. Copyright © 2008 John Wiley & Sons, Ltd.