Addition Of Talc Research Articles

Analysis of secondary metabolites and morphology in Streptomyces rimosus microparticle-enhanced cultivation (MPEC) at various initial organic nitrogen concentrations

The influence of talc microparticles on metabolism and morphology of S. rimosus at various initial organic nitrogen concentrations was investigated. The shake flask cultivations were conducted in the media with yeast extract (nitrogen source) concentration equal to 1 g YE L− 1 and 20 g YE L− 1. Two talc microparticle concentrations of 5 g TALC L− 1 and 10 g TALC L− 1 were tested in microparticle-enhanced cultivation (MPEC) runs. A high nitrogen concentration of 20 g YE L− 1 promoted the development of small agglomerates (pellets) of projected area lower than 105 µm2 and dispersed pseudohyphae. A low nitrogen concentration of 1 g YE L− 1 led to the limitation of S. rimosus growth and, in consequence, the development of the smaller number of large pseudohyphal agglomerates (pellets) of projected area higher than 105 µm2 compared to the culture containing a high amount of nitrogen source. In both cases talc microparticles were embedded into pellets and caused the decrease in their sizes. The lower amount of talc (5 g TALC L− 1) usually caused the weaker effect on S. rimosus morphology and metabolite production than the higher one. This correlation between the microparticles effect on morphology and metabolism of S. rimosus was especially noticeable in the biosynthesis of oxytetracycline, 2-acetyl-2-dicarboxamide oxytetracycline (ADOTC) and spinoxazine A. Compared to the control run, in MPEC their levels increased 4-fold, 5-fold and 1.6-fold respectively. The addition of talc also improved the production of 2-methylthio-cis-zeatin, lorneic acid J and milbemycin A3.

Macroparticle-enhanced morphology engineering of Cordyceps sinensis for high glucose fermentation to optimize the production of bioactive exopolysaccharides

Cordyceps sinensis is widely known for its therapeutic properties. Enhancing the yield of exopolysaccharides (EPS), which is crucial for its medicinal efficacy, is a major challenge. In this study, we applied high initial glucose concentrations with talc particles to enhance EPS production and assessed the cell morphology, intracellular biochemical reactants, and bioactivity contribution of glycoproteins. The use of 150 g/L glucose and 10 g/L 2000 mesh talc increased the EPS yield by 1.8-fold to 4.21 g/L. The addition of talc regulated cell morphology, facilitated the entry of oxygen molecules into the cells to produce a large amount of ATP for polysaccharide synthesis, and altered the cell wall structure to facilitate the secretion of EPS. Moreover, environmental stress resulted in a notable increase in intracellular reactive oxygen species levels, which can potentially enhance cell membrane permeability and promote EPS synthesis. Furthermore, the highest protein content in crude EPS corresponded to the maximum activation of alcohol dehydrogenase (ADH) of 44.2 %, suggesting a mechanistic relationship between the proteins and polysaccharides in the glycoproteins that influence the activation of ADH. These findings elucidate the intricate interplay between fermentation conditions and EPS production and provide new avenues for optimizing the fermentation process of CS-HKI to enhance its therapeutic applications.

A comprehensive study on the effect of small rates of walnut shell and talc fillers on the thermal,mechanical, and morphological properties of epoxy hybrid composites

AbstractEpoxy-based composites, valued for their cost-effectiveness and remarkable mechanical properties, attract considerable attention from researchers in academia and industry. This study explores the impact of low concentrations (1% to 3%) of walnut shell (WS) and talc additives on the density, water absorption, and mechanical (tensile, three-point bending, impact, hardness) as well as thermal (TGA, DSC) properties of epoxy composites. While prior research has extensively covered epoxy composites with high concentrations of walnut shell and talc, their utilization in lower concentrations remains underexplored. Findings highlight the substantial influence of incorporating low percentages of walnut shell and talc on the Tg temperatures of epoxy composites, with talc reducing Tg temperature and WS elevating it. TGA tests reveal that both WS and talc contribute to increased Tmax temperature and residue content compared to pure epoxy. Mechanical properties exhibit variations based on filler type and amount, with walnut shell enhancing the elastic modulus and talc decreasing it compared to pure epoxy. Impact resistance sees significant reductions related to particle size. Talc boosts density, while WS has a more pronounced effect on hardness. Water absorption tests demonstrate higher water absorption in WS-containing epoxy composites. Glossiness and surface roughness undergo changes, with talc increasing roughness and decreasing glossiness. In conclusion, even minor filler percentages noticeably impact epoxy composite properties compared to pure epoxy, providing avenues for customized modifications, particularly with challenging or costly fillers, offering viable alternatives for researchers in diverse fields.

INFLUENCE OF FILLERS ON THE STRUCTURE AND PROPERTIES OF POLYMER MATRIX

Purpose. Enhancement of the mechanical properties of the polymer matrix through the incorporation of finely dispersed fillers, namely aluminum oxide and talc, as potential modifiers.
 Research methods. Research was conducted on polymer specimens subjected to tensile testing according to DSTU EN ISO 527-5:2018. The tests were performed using a URM-5 tensile testing machine with a maximum force of 50 kN. Metallographic analysis was carried out using a KEYENCE VHX microscope at magnifications of 50 and 500. The microstructure of the polymer matrix was assessed through etching-free procedures.
 Results. The study demonstrates that the incorporation of finely dispersed aluminum oxide particles increased the strength parameter from 4.69 MPa to 13.07 MPa, as compared to the unfilled sample. Additionally, it was observed that the introduction of finely dispersed talc particles at a concentration of 0.75 % by mass led to an enhancement in strength values from 4.69 MPa to 12.74 MPa, in comparison to the unfilled sample.
 Scientific novelty. A polymer matrix with enhanced mechanical properties was achieved through the addition of fillers acting as modifiers. The optimal concentration of aluminum oxide and talc additives was determined. By comparing the results with previous studies involving aluminum oxide and talc at various concentrations in different types of polymer matrices, it can be concluded that the investigated concentrations of modifiers with epoxy resin ED-20 led to the production of a polymer composite with superior mechanical characteristics. The obtained results underscore the significant potential of aluminum oxide and talc as effective modifiers for improving the strength and other crucial properties of composite materials.
 Practical value. The obtained results highlight the significant potential of utilizing aluminum oxide and talc as modifiers for polymer matrices to enhance their mechanical characteristics. From a practical standpoint, the use of these fillers can exert a substantial impact on the development of new composite materials with improved properties, finding application in composite reinforcement production. Considering the heightened strength and resilience of the resulting materials, these composites can be effectively employed to create lighter and stronger structures in construction and other industries. Additionally, their application may lead to reduced repair and maintenance costs due to increased durability and resistance to mechanical loads. Thus, the implementation of the obtained results could have a substantial influence on the practice of composite material manufacturing, ensuring the creation of products with enhanced characteristics for various applications.

Influence of Talc on the Properties of Silicone Pressure-Sensitive Adhesives.

The article describes new silicone self-adhesive adhesives modified with the addition of talc. The obtained self-adhesive materials were characterized to determine their adhesive properties (adhesion, cohesion, and adhesion) and functional properties (pot life of the composition, shrinkage, and thermal properties of adhesives). Novel materials exhibited high thermal resistance above 225 °C while maintaining or slightly reducing other values (adhesion, cohesion, shrinkage, and tack). Selected composition: T 0.1 was used to prepare self-adhesives in industrial-scale production. Moreover, conducted test results revealed that the addition of talc delayed the thermal decomposition of the adhesive and provided reduced intensity of smoke emissions during combustion as well as the flammability of the adhesive layer.

Cavitation erosion of samples based on cordierite-talc ceramics

In the paper, the cavitation resistance of cordierite samples with the addition of 10%, 15% and 20% talc, sintered at 1200?C, was investigated. The ultrasonic vibration method with a stationary sample according to the ASTM G32 standard was applied. The formation and development of damage to the surface of the samples was monitored using a scanning electron microscope and the level of damage to the surface of the samples was quantified using image analysis. The change in the mass of the samples as a function of the cavitation time was monitored to determine the cavitation rate. By measuring the mass loss and morphological analysis of the pits formed on the surface of the sintered samples of the cordierite-talc ceramics, the mechanism of degradation and resistance to the effect of cavitation was monitored. The obtained results were compared with the results of earlier tests of cavitation resistance of sintered cordierite samples. The addition of talc in the mixture with cordierite significantly improved cavitation resistance of the sintered material compared to sintered pure cordierite. The tests were done to see the potential application of this material in hydrodynamic conditions, especially because of the strong corrosion resistance of these refractory materials.

Optimizing raw material composition to increase sustainability in porcelain tile production: A simulation‐based approach

AbstractReducing the environmental impact of porcelain tile production while maintaining cost‐effectiveness is challenging. This work introduced a novel modeling approach for optimizing a standard composition range comprising kaolinite (15–38 wt.%), illite (0–20 wt.%), quartz (20–40 wt.%), and feldspar (20–45 wt.%) to establish a robust composition interval for porcelain stoneware tiles. The proposed study considers several factors, such as composition impact on the manufacturing sequence, production costs, and CO2 emission. A flowsheet simulation database was generated by coupling the Dyssol framework with MATLAB. This study investigated the influence of raw material composition within the process sequence, the total CO2 emissions, and production costs within the contexts of Spain and Brazil, two of the top five global producers. Granules with a higher proportion of talc and illite exhibit reduced moisture content after spray drying, and these combinations have lower green body porosity after compaction. The addition of talc allowed for decreased porosity content after compaction reduced firing temperature, and lowered costs and CO2 emissions despite the higher prices associated with talc. The proposed simulation methodology offers a powerful decision‐making tool for optimizing raw material composition to minimize cost and CO2 emissions in the porcelain tile production. This methodology represents an early stride toward integrating digital twin methodologies within the ceramic tile sector, facilitating improved process regulation, and promoting the adoption of digital technologies.

Biodegradable blown film composite from poly (butylene adipate-co-terephthalate) and talc: Effect of uniaxial stretching on mechanical and barrier properties

This research focuses on improving the oxygen and water vapour barrier properties of blown PBAT films after adding talc particles (15 and 25 wt%) followed by uniaxial stretching in the machine direction. DSC analysis revealed that the addition of talc enhanced %crystallinity by ∼42 and ∼125% at stretch ratios 5.5 and 6.0, respectively, compared to unstretched neat PBAT films, due to the dispersion and platelets morphology of talc particles, followed by uniaxial orientation of polymer chains. This significantly impacted the mechanical properties of PBAT as elastic modulus gained by ∼1939 and ∼2486% for the stretched composite films containing 15 and 25 wt% talc, respectively, over unstretched neat PBAT. The water vapour barrier of the stretched composite films was improved by ∼61 and ∼62% after adding 15 and 25 wt% talc particles, respectively, compared to PBAT due to its increased %crystallinity and can be a sustainable alternative to single-use plastics in flexible packaging.

Synchrotron X-ray absorption spectroscopy and fluorescence spectroscopy studies of collagen type I-talc intercalated nanocomposites

We investigated the properties of collagen type I-talc intercalated nanocomposites using different techniques. Understanding the conformational changes of collagen induced by clay is noticeably lacking, which is pivotal for understanding the structure of collagen-clay hybrid nanocomposites. We aim to investigate the influence of talc clay minerals on the microstructure of collagen type I molecules. Our main goal is to understand the interaction between talc and collagen molecules and to elucidate the microstructure–property relation of intercalated hybrid nanocomposites. The FT-IR spectrum of collagen type I-talc confirmed the presence of collagen amide bands and talc silicate bonds. Also, the differential scanning calorimetry (DSC) result showed that the addition of talc to the matrix could increase the denaturation temperature (Td = 40.8 °C) compared to pure collagen (Td = 19 °C). The fluorescence intensity increased in collagen type I-talc nanocomposites, indicating that the interaction of talc with collagen chains in collagen type I-talc dispersion varies the micro-environment of the tyrosine amino acids in the collagen fibrils and its fluorescence. We also analyzed X-ray absorption spectroscopy (XAS) in total fluorescence yield (TFY) and total energy yield (TEY) modes of pure collagen and collagen type I-talc nanocomposites prepared at different concentrations of talc and at different temperatures (4 °C, 8 °C, and 14 °C). We have found that the synthesis conditions have a considerable effect on the local atomic environments of nitrogen, carbon, and oxygen atoms in collagen type I-talc nanocomposites. These results are of significance for developing new applications of talc and collagen-based biomaterials in different fields, such as cellular and molecular biology, and drug delivery that enhances the optical signals are needed.

Water-based lubricant containing protic ionic liquids and talc lubricant particles: Wear and corrosion analysis

Water-based lubricants have been used in different industrial applications in recent years. However, studies evaluating the tribological and electrochemical effects of lubricants with Protic Ionic Liquid (PIL) and talc particles (TC) as additives on SAE 1010 and SAE 1045 steels are still scarce in the literature, which is the objective of this work. Samples extracted from steel sheets were investigated in the normalized (SAE 1010) and quenched-tempered (SAE 1045) conditions. Wear tests in a ball-on-plate type tribometer and corrosion tests using potentiondynamic polarization curves were performed in the presence of different lubricant solutions (PIL 3% + DI water, commercial lubricant 3% + DI water, with and without talc particle additions 0.05 and 0.1 wt%). Analyses of viscosity, pH, wettability, and particle size distribution were conduted on the lubricant and talc samples. Wear and corrosion surfaces were analyzed by SEM/EDS, and Raman techniques. The results showed that the tribofilm formed from the interaction between PIL lubricants and steel substrates decreased the wear due to the increase of lubricity of these lubricants. When the PIL and the commercial lubricants are compared, PIL additives presented higher performance, despite the talc addition. The influence of talc on the corrosion of steel is associated with the differential aeration effect, mitigated by adding the PIL.

High strength insulating polymeric composite based on recycled/virgin polyethylene terephthalate (PET) reinforced with hydrous magnesium silicate (talc)

In the current work, post-consumer polyethylene terephthalate (PET) bottles were reclaimed and reinforced with hydrous magnesium silicate, Mg3Si4O10(OH)2 commonly known as talc and with virgin PET (VPET) for the development of high strength polymeric composites. The composite sheets were prepared using the thermomechanical melt processing method followed by a thermal press technique. VPET was mixed during melt processing of recycled PET (RPET) in a specific ratio to suppress thermal degradation and hydrolysis of developed composite. Various blends of the composite samples of VPET and RPET (RPETx - VPET1-x) with a fixed ratio of talc were prepared and investigated for their strength, conductivity and micro-properties. 45 μm talc particle in ratio 1 to 4 was used. The effect of the talc addition on mechanical properties of the composites at the sub-micron scale was investigated through nanoindentation with quasi-continuous stiffness mode (QCSM) to analyze the nano-mechanical properties as a function of contact displacement. Surface morphology and composition were studied through scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX), which showed a uniform dispersion of talc particles with no agglomerates on the surface. Compressive strength was determined with the universal testing machine (UTM) that revealed the highest compressive strength of RPET80 – VPET20 blend with a lowest thermal conductivity gradient value of 0.0213 W.m−1 observed, thus making it preferable material for insulation purposes. Load-displacement curves displayed the harder behavior of the composite sheet containing RPET80 – VPET20/talc as it needed 100 μN load to impose a penetration depth of 7.5 μm only. The elastic modulus and hardness of RPET80–VPET20/talc composite was significantly improved as compared to other samples.

Fabrication of talc reinforced transparent fire-retardant coating towards excellent fire protection, antibacterial, mechanical and anti-ageing properties

To enhance the fire safety of historic buildings, developing fire-retardant coatings with integrated decoration, fire protection, ageing resistance and antibacterial performances is imperative. Here, a novel multifunctional transparent fire-retardant coating with fire protection, smoke suppression, antibacterial and anti-ageing functions was successfully fabricated using talc as a multifunctional synergist. Mechanical tests show that the multifunctional coating containing talc shows an improvement in pencil hardness and adhesion classification while keeping a high transparency. Moreover, adding talc is conductive to fabricate a physical barrier with super compactness and intumescence, which endows the coatings with excellent fire protection and smoke suppression functions. Especially, when the mass ratio of PPB to talc is 95:5, the obtained MTPPB3 coating retains a high-level transparency of 85.8%, accompanying with a 72.6% reduction in flame spread rating and a 57.0% reduction in smoke density rating compared to MTPPB0 without talc. TG analysis shows that the multifunctional coatings containing talc exhibit sharp enhancements in thermal stability and char yield, and MTPPB3 retains 32.7% residue at 800 °C. Meanwhile, the addition of talc results in high antibacterial rate against E. coli bacteria and durable flame-retardant and smoke suppression effects, and MTPPB3 shows an antibacterial rate of 99.0% against E. coli bacteria. This work provides a promising way to fabricate multifunctional transparent fire-retarded coatings with outstanding functions of decoration and fire protection.

Rapid detection of talc content in flour based on near-infrared spectroscopy combined with feature wavelength selection.

Excessive illegal addition of talc in flour has always been a serious food safety issue. To achieve rapid detection of the talc content in flour (TCF) by near-infrared spectroscopy (NIRS), this study used a Fourier transform near-infrared spectrometer technique. The identification of efficient spectral feature wavelength selection (FWS), such as backward interval partial-least-square (BiPLS), competitive adaptive reweighted sampling (CARS), hybrid genetic algorithm (HGA), and BiPLS combined with CARS; BiPLS combined with HGA; and CARS combined with HGA, was also discussed in this paper, and the corresponding partial-least-square regression models were established. Comparing with whole spectrum modeling, the accuracy and efficiency of regressive models were effectively improved using feature wavelengths of TCF selected by the above algorithms. The BiPLS, combined with HGA, had the best modeling performance; the determination coefficient, root-mean-squared error (RMSE), and residual predictive deviation of the validation set were 0.929, 1.097, and 3.795, respectively. BiPLS combined with CARS had the best dimensionality reduction effect. Through the FWS by BiPLS combined with CARS, the number of modeling wavelengths decreased to 72 from 1845, and the RMSE of the validation set was reduced by 11.6% compared with the whole spectra model. The results showed that the FWS method proposed in this paper could effectively improve detection accuracy and reduce modeling wavelength variables of quantitative analysis of TCF by NIRS. This provides theoretical support for TCF rapid detection research and development in real-time.

Structural, Mechanical and Flammability Characterization of Crosslinked Talc Composites with Different Particle Sizes

The influence of filler particle size on selected physicochemical and functional properties of polymer composites was analyzed. The following test was carried out for the system: the bisphenol A glycerolate (1 glycerol/phenol) di-methacrylate (BPA.DM) was subjected to UV-polymerization in bulk with N-vinyl-2-pyrrolidone (NVP) as a polymer matrix and talc with particle sizes ranging from ≤8 to 710 µm as a non-toxic and cheap mineral filler. An effective method of preparing cross-linked polymeric composites with talc was developed. The obtained samples were subjected to structural analysis and the thermal, mechanical and flammability properties were assessed. It has been empirically confirmed that the talc particles are incorporated into the composite structure. However, with increasing particle size, the composite heterogeneity increases. In the case of the developed method of sample production, homogeneous systems were obtained for particles in the ≤8–250 µm range. The surface roughness of the samples correlates directly with the size of talc particles. The value of Young’s modulus during the axial stretching of samples decreases with the increasing size of talc particles. For the composites containing ≤15 and ≤35 µm talc particles, the highest values were obtained under bending conditions. There was no equivocal effect of particle size on the composites’ swelling in water. The addition of talc reduces the flame height and intensity slightly. The biggest difference was obtained for the composites containing relatively large talc particles. It was proved that the selected properties of polymer composites can be controlled depending on the size of the talc particles.

Surface Response Analysis for the Optimization of Mechanical and Thermal Properties of Polypropylene Composite Drawn Fibers with Talc and Carbon Nanotubes.

A large portion of the produced Polypropylene (PP) is used in the form of fibers. In this industrially oriented study, the development of composite PP drawn fibers was investigated. Two types of fillers were used (ultra-fine talc and single-wall carbon nanotubes). Optimization of the thermal and mechanical properties of the produced composite drawn fibers was performed, based on the Box-Behnken design of experiments method (surface response analysis). The effect of additives, other than the filler, but typical in industrial applications, such as an antioxidant and a common compatibilizer, was investigated. The drawing ratio, the filler, and the compatibilizer or the antioxidant content were selected as design variables, whereas the tensile strength and the onset decomposition temperature were set as response variables. Fibers with very high tensile strength (up to 806 MPa) were obtained. The results revealed that the maximization of both the tensile strength and the thermal stability was not feasible for composites with talc due to multiple interactions among the used additives (antioxidant, compatibilizer, and filler). Additionally, it was found that the addition of talc in the studied particle size improved the mechanical strength of fibers only if low drawing ratios were used. On the other hand, the optimization targeting maximization of both tensile strength and thermal stability was feasible in the case of SWCNT composite fibers. It was found that the addition of carbon nanotubes improved the tensile strength; however, such improvement was rather small compared with the tremendous increase of tensile strength due to drawing.

Crystallization behavior of polyvinyl alcohol with inorganic nucleating agent talc and regulation mechanism analysis

Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to study the effect of talc on the crystallization properties and morphology of PVA/talc composite films from the perspective of heterogeneous nucleation effect. The Mo Zhishen equation and Avrami equation were used to study the crystallization kinetics behavior, and successive self-nucleation annealing (SSA) method was used to analyze the wafer thickness at various melting temperatures. PVA films were prepared by flow-casting method, and talc was added as inorganic nucleating agent to improve the crystallinity of PVA. The results show that the addition of talc to the PVA film promotes its crystallization, and as the content of the nucleating agent increases, the crystallinity tends to increase. Due to the increase of nucleation point, the proportion of thinner wafers increases, and the gap of wafer thickness becomes smaller, and the wafer thickness becomes uniform. These results show that talc regulates the crystallization of PVA, improves the crystallinity and crystallization rate of PVA. Talc has heterogeneous nucleation effect on PVA films.

Research on performance optimization of Loess-based ceramic membrane supports with Bauxite-dolomite-talc as additives

Inorganic ceramic membranes have attracted much attention due to their advantages of long life, acid and alkali corrosion resistance, and easy cleaning, but they have not been widely used due to the high cost. In order to obtain a ceramic membrane with low cost and good performance, in this paper, loess-based ceramic membrane support was prepared by using loess as raw material, bauxite as aluminum source, dolomite as pore-forming agent and talc as plasticizer. Response surface optimization was used to determine the optimal addition parameters of ingredients. In addition, the factors affecting the performance of the supports were analyzed in terms of material composition, microscopic morphology, and porosity. The results show that the addition of talc conduced to avoid the negative impact of the pore-forming effect of dolomite on the mechanical strength of the support, and the optimum proportioning parameters are 48.85 wt% of bauxite, 9.93 wt% of dolomite and 8 wt% of talc. Under this condition, the bending strength was 42.24 MPa, the pure water flux was 8323.73 l·m−2·h−1·MPa−1, and the average pore throat radius was 5.15 μm. The performance of the best sample reaches the application performance of porous ceramic supports, which provides a theoretical basis for the wide application of low-cost ceramic membrane supports.

Crystallization behavior and properties of non-stoichimetric cordierite glass–ceramics: Effects of talc, MgO/SiO2 ratio, and Al2O3 content

Non-stoichimetric cordierite glass-ceramics were obtained by powder sintering method, using talc mineral as sintering aid. Effects of talc, MgO/SiO2(M/S) ratio and Al2O3 content on the crystallization behavior, densification behavior, physical properties and thermal expansion coefficients of the glass-ceramics were investigated. Results showed that, 15 wt% talc addition reduced the crystallization temperature of cordierite in the glass-ceramics from 1085 °C to 1052.2 °C by increasing the M/S ratio. Adding talc decreased the Al2O3 content and provided alkali oxides to promote the liquid formation. The decreasing Al2O3 content from 30.47 wt% to 21.67 wt% resulted in the dissolution–reprecipitation–recrystallization–redissolution process of cordierite due to the enhancing liquid formation. Adding talc could decrease the thermal expansion coefficient by increasing the cordierite content, and the low thermal expansion coefficient of 1.90 × 10−6 ℃−1 was obtained. The decreasing Al2O3 content promoted the densification behavior, but increased the thermal expansion coefficient of the glass-ceramics by increasing the amount of glass. The sample having the 15 wt% talc addition and the lowest Al2O3 content of 21.67 wt% obtained the low porosity of 0.3%, which was much lower than 25.1% of the original sample without talc addition.

3D printing of pharmaceutical oral solid dosage forms by fused deposition: The enhancement of printability using plasticised HPMCAS

3D printing (3DP) by fused deposition modelling (FDM) is one of the most extensively developed methods in additive manufacturing. Optimizing printability by improving feedability, nozzle extrusion, and layer deposition is crucial for manufacturing solid oral dosage forms with desirable properties. This work aimed to use HPMCAS (AffinisolTM HPMCAS 716) to prepare filaments for FDM-3DP using hot-melt extrusion (HME). It explored and demonstrated the effect of HME-filament composition and fabrication on printability by evaluating thermal, mechanical, and thermo-rheological properties. It also showed that the HME-Polymer filament composition used in FDM-3DP manufacture of oral solid dosage forms provides a tailored drug release profile. HME (HAAKE MiniLab) and FDM-3DP (MakerBot) were used to prepare HME-filaments and printed objects, respectively. Two diverse ways of improving the mechanical properties of HME-filaments were deduced by changing the formulation to enable feeding through the roller gears of the printer nozzle. These include plasticizing the polymer and adding an insoluble structuring agent (talc) into the formulation. Experimental feedability was predicted using texture analysis results was a function of PEG concentration, and glass-transition temperature (Tg) values of HME-filaments. The effect of high HME screw speed (100 rpm) resulted in inhomogeneity of HME-filament, which resulted in inconsistency of the printer nozzle extrudate and printed layers. The variability of the glass-transition temperature (Tg) of the HME-filament supported by scanning electron microscopy (SEM) images of nozzle extrudates and the lateral wall of the printed tablet helped explain this result. The melt viscosity of HPMCAS formulations was investigated using a capillary rheometer. The high viscosity of unplasticized HPMCAS was concluded to be an additional restriction for nozzle extrusion. The plasticization of HPMCAS and the addition of talc into the formulation were shown to improve thickness consistency of printed layers (using homogeneous HME-filaments). A good correlation (R2 = 0.9546) between the solidification threshold (low-frequency oscillation test determined by parallel-plate rheometer) and Tg of HME-filaments was also established. Drug-loaded and placebo HPMCAS-based formulations were shown to be successfully printed, with the former providing tailored drug release profiles based on variation of internal geometry (infill).

Laser sintering of coated polyamide 12: a new way to improve flammability

In this study coatings of kaolin and talc particles were successfully applied on the surface of polyamide 12 powder intended for laser sintering (LS). Microscopic observations revealed that using carboxymethyl cellulose (CMC) as surface modifier for fillers led to a better coverage of polymer grains with a surface coverage between 6 and 16% as a function of filler type and content. Differential scanning calorimetry measurements showed that the addition of talc and kaolin led to an increase in the crystallization temperature of PA12, but at the expense of processability. Process parameters were optimized in order to manufacture LS samples with the different coated powders. Fire behavior assessed by cone calorimetry showed that the use of CMC resulted in a significant decrease in the peak of heat release rate depending on the filler type and content. This behavior can be partially explained by an interaction between CMC, fillers and polymer, with the formation of amide linkage between carboxyl part of CMC and amine end groups of polyamide, resulting in an increase in the complex viscosity of materials.