Cloisite 20A Research Articles

Investigation of Combined Aging and Mullins Stress Softening of Rubber Nanocomposites

The present study investigated the effects of thermal aging, ultraviolet radiation (UV), and stress softening on the performance properties of rubber modified with Cloisite Na+ or Cloisite 20A. Tensile strength (TS), strain at break (SB), modulus, and the retention coefficient were measured before and after aging. Results showed that TS and SB decreased by about 50% after 7 days of aging for all tested samples due to the breakage of the chemical bonds between rubber and nanoparticles. The modulus at 300% elongation increased by 20%, 15%, and 7% after thermal aging for the unmodified sample, nanocomposites with Cloisite Na+, and Cloisite 20A, respectively. The shape retention coefficient of all samples was not affected by heat, except for the virgin rubber sample, which exhibited a decrease of about 15% under thermal aging. The virgin matrix and nanocomposites showed different values of aging coefficient during thermal aging and UV radiation. The dissipated energy of samples that were aged after stretching was slightly higher than that of samples that were aged after stretching due to the breakdown of the bonds within the nanocomposites. Loading-reloading energy results showed that the level of stress softening was lower when Mullins was applied after the aging of the samples. Differential scanning calorimetry results indicated a slight decrease in Tg1 in the aged and stretched samples and an increase in the temperature of the first endothermic peak due to the addition of nanofillers in the stretched and aged samples. Thermogravimetric analysis revealed that all tested samples exhibited similar thermograms, regardless of their state of stretching or aging. Scanning electron microscopy analysis showed that the fracture surface of the virgin unaged sample was rough with some holes, while it was flatter and less rough after aging.

High-pressure liquid impregnation of barbatimão bark extract into biopolymeric membrane composed of PBS/PLA and Cloisite 20 A blend

Renowned for its medicinal properties, barbatimão bark extract contains bioactive compounds susceptible to degradation, necessitating their safeguarding within a stable matrix for diverse biomedical applications. This study investigates using high-pressure liquid impregnation (HPLI) to load barbatimão extract into biopolymeric membranes at 30, 45, and 60 °C, and 11MPa. HPLI combines the simplicity of direct immersion with improved mass transfer rates under high pressure. Biopolymeric membranes made from poly(butylene succinate) (PBS), poly(lactic acid) (PLA), and Cloisite 20A (C20A) in a 50/45/5 (v/v) composition were created using electrospinning. Comparative analysis with conventional methods, along with evaluation of impregnated membrane properties using SEM, FTIR, and thermogravimetric analysis, demonstrated the effectiveness of HPLI. HPLI yielded markedly higher phenolic compound loadings, peaking at 43.79mg ETA/g membrane at 11MPa and 45 °C over 6h, compared to 25.44mg ETA/g membrane with conventional impregnation at ambient pressure and 45 °C over the same duration.

Arsenic removal from contaminated water using adsorptive electrospun nanofibrous membrane of polyacrylonitrile/organoclay

AbstractAdsorptive nanofiber electrospun membranes (ANEMs) show promise for heavy metal removal, particularly in dilute solutions. Nanofibrous polyacrylonitrile (PAN) membranes incorporating Cloisite 20A (C20) organoclay were fabricated via electrospinning for As(V) removal. The impact of C20 on structural properties and As(V) removal efficiency of the nanofiber membranes was investigated. The results indicated that the PAN‐C20 membranes morphology was uniform, with fiber diameters mostly falling within the 100–300 nm range. Incorporation of C20, especially in an exfoliated structure, led to increased hydrophilicity, mechanical strength, and roughness of the membranes. Batch adsorption results revealed that the adding C20 up to 1.5 wt.% significantly enhanced adsorption capacity due to the higher concentration and proper C20 dispersion. Dynamic filtration showed that the PAN‐C20(1.0) membrane achieved over 90% As(V) removal efficiency for 960 min and demonstrated excellent regeneration ability.Highlights Cloisite 20A organoclay was incorporated into PAN by electrospinning to prepare adsorptive membrane. Adsorptive membranes were used for As(V) removal from water. Type of Cloisite 20A dispersion in PAN in dynamic filtration was more important than in static adsorption PAN‐C20‐1.0 with exfoliated structure showed higher removal efficiency than PAN‐C20‐1.0 with intercalated structure. PAN‐C20‐1.0 membrane was usable for multiple adsorption–desorption cycles.

Ultrasound-Assisted Extrusion Compounding of Nano Clay/Polypropylene Nano Compounds.

The incorporation of nanoparticles can significantly enhance the properties of polymers. However, the industrial production of nanocomposites presents a technological challenge in achieving the proper dispersion of nanoparticles within the polymer matrix. In this work, a novel device is presented that can be seamlessly integrated with standard twin-screw extruders, enabling the application of ultrasonic vibration to molten polymeric material. The primary objective of this study is to experimentally validate the effectiveness of this technology in improving the dispersion of nanoparticles. To accomplish this, a comparative analysis was carried out between nanocomposites obtained through conventional compounding extrusion and those processed with the assistance of ultrasonic vibrations. The nanocomposites under investigation consist of a polypropylene (PP) matrix reinforced with nano clays (Cloisite 20A) at a target loading ratio of 5% by weight. To comprehensively evaluate the impact of the ultrasound-assisted compounding, various key properties were assessed, such as the melt flow index (MFI) to characterize the flow behavior, mechanical properties to evaluate the structural performance, oxygen barrier properties to assess potential gas permeability, and microstructure analysis using Scanning Electron Microscopy (SEM) for detailed morphology characterization. The results suggested an improvement in nanoparticle dispersion when using the ultrasound device, particularly when the intensity was adjusted to 60%.

Improving the compatibility of polylactic acid/polycarbonate blends with nanoclay and Joncryl as chain extenders

AbstractThis study aimed to optimize the compatibility and performance of PLA/PC blends by investigating the effects of Cloisite 20A nanoclay (NC) and Joncryl chain extender (CE). PLA/PC blends with varying NC and CE loadings were prepared, and the optimal formulation was identified. The optimal NC and CE content were then used to produce PLA/PC blends with varying PC ratios. The test specimens were produced by mixing the mixture in a twin‐screw micro compounder and subsequent injection molding into dog bone specimens to investigate the thermal, mechanical, and morphological properties of the blends. Scanning electron microscopy and dynamic mechanical analysis confirmed the immiscibility of the unmodified blend, but significant improvements in blend morphology were observed with high NC/CE ratios. The presence of NC/CE resulted in reduced droplet size of dispersed PC phase and a new intermediate glass transition temperature (Tg) in DMA, suggesting partial miscibility. The highest thermal stability improvement was achieved with 5 wt% NC alone or a combination of 5 wt% NC and 1 wt% CE. Composites containing NC/CE showed the most significant improvements in composite properties, demonstrating their effectiveness as compatibilizers and improved compatibility in PLA/PC blends. These results indicate that the use of NC/CE is a promising method for expanding the applicability of PLA/PC blends.

Functional Technical Textile-Based Polymer Nanocomposites with Adsorbent Properties of Toxins and Dyes also Have Antibacterial Behavior.

This is the first study of non-woven fabrics elaborated by melt-blowing from polymer nanocomposites made of Nylon 6 and nanoclay (Cloisite 20A) modified with an amine (1,4 diaminobutane dihydrochloride). Morphological and physical characteristics, adsorption capacity, and antibacterial properties are presented. From the X-ray diffraction (XRD) results, it was possible to observe a displacement of the signals to other 2θ angles, due to an α to ϒ phase shift. The scanning electron microscopy (SEM) images showed that the mean diameter of fiber decreased as the content of nanoclay increased. The mechanical tests showed that the tear strength force of neat nylon was 1.734 N, but this characteristic increased to 2.135 N for the sample with 0.5% modified nanoclay. The inulin adsorption efficiency of the Nylon 6/C20A 1.5% and Nylon 6/C20A 2% samples at 15 min was 75 and 74%, respectively. The adsorption capacity of Nylon 6/C20A 1.5% and Nylon 6/C20A 2% for methylene blue and methyl orange remained above 90% even after four adsorption cycles. In addition, non-woven fabrics present antibacterial activity against E. coli.

Colorless and transparent polyimide nanocomposites using organically modified montmorillonite and mica

In this study, we introduce a method for replacing the glass used in existing display electronic materials, lighting, and solar cells by synthesizing a colorless and transparent polyimide (CPI) film with excellent mechanical properties and thermal stability using a combination of new monomers. Poly(amic acid) (PAA) was synthesized using dianhydride 4,4′-biphthalic anhydride (BPA) and diamine 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (AHP). Various contents of organically modified montmorillonite (MMT) and mica were dispersed in PAA solution through solution intercalation, and then CPI hybrid films were prepared through multi-step thermal imidization. The organoclays synthesized to prepare CPI hybrid films were Cloisite 93A (CS-MMT) and hexadimethrine-mica (HM-Mica) based on MMT and mica, respectively. In particular, the diamine monomer AHP containing a –OH group was selected to increase the dispersibility and compatibility between the hydrophilic clays and the CPI matrix. To demonstrate the characteristics of CPI, the overall polymer structure was bent and a strong electron withdrawing –CF3 group was used as a substituent. The thermomechanical properties, morphology of clay dispersion, and optical transparency of the CPI hybrid films were investigated and compared according to the type and content of organoclays. Two types of organoclays, CS-MMT and HM-Mica, were dispersed in a CPI matrix at 1 to 7 wt%, respectively. In electron microscopy, most of the clays were uniformly dispersed in a plate-like shape of less than 20 nm at a certain critical content of the two types of organoclays, but agglomeration of the clays was observed when the content was higher than the critical content. Hybrids using HM-Mica had better thermomechanical properties and hybrids containing CS-MMT had better optical transparency.

In‐Depth Analysis of the Complex Interactions Induced by Nanolayered Additives in PHBV Nanocomposites

AbstractNew nanocomposites based on biopolymer poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) are processed via extrusion, using low content of calcined hydrotalcite (CHT) and cloisite 20A (C20A) as additives (3 wt%). The aim of this work is to characterize the thermal and viscoelastic response of the structures induced by the presence of the additives. Field‐emission scanning electron microscopy and laser profilometry are utilized to analyze the effect of the additives on the surface finish of extrusion filaments, detecting a smoother surface induced by additives. A lower degradation temperature is observed via thermogravimetry for composite containing CHT (PHBV+3%CHT), while such a phenomenon is not present in composite with C20A (PHBV+3%C20A). An increase in crystallinity due to the nucleating effect of additives is measured via differential scanning calorimetry. The intercalation of the biopolymer in the layered structure of the additives is observed via X‐ray diffraction, reflecting the effective interaction in the composite matrix. The viscoelastic behavior of the samples is evaluated by means of rheology and dynamic‐mechanical analysis, showing a non‐Newtonian behavior and an enhancement of the vitreous state response. All results converge to the conclusion that the incorporation of the additives induces the formation of long‐term structures that present variable sensitivity to temperature and frequency.

Enhancing the Cu (II) removal in water using functional hybrid membranes

This work developed composite and hybrid membranes of poly(butylene adipate-co-terephthalate) (PBAT) with nanocurcumin (NC) and/or cloisite 20A (C20A). The dispersed phases were characterized by DLS, ζ potential, XRD, SEM, and FTIR, while XRD, SEM, FTIR, mechanical properties, contact angle, and copper sorption evaluated the composite membranes. DLS analysis indicated that the dispersed phases present a nanometric size distribution; ζ potential measurements showed low electrostatic stability, explaining the agglomeration effects observed. Pure PBAT membranes presented macro-pores throughout their structure, which showed a slight size reduction with the inclusion of NC and C20A. The membrane's mechanical performance was affected by the presence of the pores that acted as stress-concentrating defects, and the inclusion of the dispersed phases increased the membrane elastic modulus and tensile strength, especially for PBAT/0.5%C20A with values 18.7 and 8.9% higher than those of pure PBAT, respectively. Composite membranes also showed a hydrophilic nature with all the contact angle measurements lower than 90º. The sorption tests using a high-concentration copper solution (1000 mg/L) showed that the composite membranes achieved a removal of around 25%. These results highlighted the development of new eco-friendly membranes using NC and C20A as dispersed phases with the potential to remove toxic elements from water.

Cloisite® 20A and polymer hydrogel as nano-vehicle for targeted and sustained release of amitriptyline

A class of nanomaterials known as anionic and cationic clays has drawn a lot of interest as a potential medication delivery vehicle. Therefore, cloisite® 20A (C-20A), chitosan hydrogel (CH) and sodium alginate hydrogel (Alg) were used as a carrier for sustained release of amitriptyline drug (AMT) as oral osmotic drug delivery system. AMT was intercalated inside the interlayer space of C-20A as well as wrapped inside CH and Alg hydrogels and prepared AMT/C-20A, AMT/CH and AMT/Alg hybrids. The intercalation of AMT inside the layer of C-20A and hydrogels were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The contents of intercalated AMT in the AMT/C-20A, AMT/CH and AMT/Alg was determined to be 10–12 %. The release of AMT from AMT/C-20A, AMT/CH and AMT/Alg were studied at a variable value of pH (1.2–7.4). The dissolution of AMT from the AMT/C-20A, AMT/CH and AMT/Alg into the release medium was found to be a maximum (97 %, 60 % and 80 %) at pH 6.8 as the optimum pH for AMT release, and further kinetics of the drug release from the hybrids were explored. The results were fitted well to Freundlich diffusion relationship. The high release of the AMT from C-20A and CH hydrogel indicates that C-20A and CH hydrogel enables the intercalation of the AMT and allows them to be released into the target site. By comparing the release of AMT from C-20A and CH hydrogel, AMT release from C-20A was quite efficient and fast. Thus, to make the release of the intercalated AMT in more sustained manner, and consequently reduce frequency of AMT administration, AMT/C-20A was further wrapped inside CH (AMT/C-20A/CH) and Alg hydrogels (AMT/C-20A/Alg) and found the release of AMT drug in more sustainable manner and reduced the frequency of AMT administration.

An experimental review on enhancing the low and high-velocity impact resistance of NFCs through nanoparticle reinforcement

Nanoparticles are widely used in biocomposite materials due to their ability to improve the mechanical properties of composites. This comprehensive review analyzes the use of nanoparticles to enhance the experimental low and high-velocity impact resistance of natural fiber composites. Various nanoparticles like carbon nanofibers, carbon nanotubes, boron nitride, zinc oxide, and titanium dioxide were investigated as reinforcements at different loading levels. The addition of nano-ZrO2 alone or with graphene oxide yielded the highest impact resistance and interlaminar shear strength of basalt fiber/epoxy composites. Cloisite 20A clay improved the mechanical properties of an epoxy matrix. Carbon/epoxy laminates showed improved maximum impact force, energy absorption, and displacement with 2wt% carbon nanofibers loading. Nanoparticles were found to enhance moisture and temperature resistance by strengthening the fiber–matrix interface. The literature demonstrated that small amounts of well-dispersed nanoparticles can meaningfully improve natural fiber composites’ impact resistance, strength, stiffness, toughness, and energy absorption through mechanisms like crack arresting and bridging. Hybrid carbon-basalt fibers and calcium carbonate nanoparticles also enhanced composite performance. Balancing the nanoparticle loading is crucial to prevent agglomeration effects. Future studies on their toxicity and environmental impacts would be needed for widespread commercial applications of Biocomposites.

Mechanical, thermal, and morphological properties of poly(3-hydroxy butyrate) nanocomposites prepared by melt mixing method

Abstract This research focuses on the preparation of poly (3-hydroxy butyrate) (PHB) nanocomposites using the melt mixing method. Two types of organically modified nanoclay, Cloisite 93A (C93A), and Cloisite 30B (C30B), were incorporated at various weight percentages into the PHB matrix to create the nanocomposites. Comparative analyses were conducted between PHB/C93A and PHB/C30B to assess their tensile and impact properties in relation to the matrix polymer. Between the nanocomposites, the PHB/C93A nanocomposites shows an optimum tensile modulus of 949 Mpa with a 3 wt% clay loading, while PHB/C30B nanocomposites demonstrated improved percentage elongation at break of 5.33 % and enhanced Izod impact strength of 39.67 J/m at 3 wt% of clay load. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) signifies the thermal behavior of both the matrix and nanocomposite. The degree of crystallinity is observed to be 47 % in case of the PHB/C30B nanocomposites as compared to the PHB/C93A nanocomposites as 38 %. Again in case of thermogravimetric analysis (TGA), the maximum % char of 5.198 is observed for the PHB/C30B nanocomposites. The enhanced viscoelastic behavior of the PHB/C93A nanocomposites was attributed at a peak of approx. 55–60 °C due to the incorporation of C93A nanoclay into the matrix in the study of dynamic mechanical analysis (DMA). The morphological investigation using WAXD analysis showcased particle clay intercalation and dispersion within the PHB matrix, indicating effective clay-matrix interactions. Overall, this study sheds light on the enhanced properties of PHB nanocomposites with the incorporation of organoclay, offering potential applications in various industries.

The role of nanoclay in processing immiscible polypropylene and poly (ethylene terephthalate) waste blends using twin screw extrusion

Polypropylene and poly(ethylene terephthalate) waste were blended with different types of nanoclay (cloisite Na+, cloisite 20A and CT4270) to understand the role of nanoclay in immiscible polymer blends. The blend morphology was investigated using scanning electron microscopy, the dispersion of the nanoclay was characterized using wide angle x-ray diffraction (WAXD) and rheology. WAXD results showed partial exfoliation for cloisite Na+ and intercalation for cloisite 20A and CT4270. It was predicted that cloisite Na + settled in the PET phase while cloisite 20A settled at the interface of PP and PET. Morphology analysis showed that increasing the concentration of nanoclay in the blend decreased the droplet size. The nanoclay was shown to inhibit coalescence of the droplets causing a decrease due to its rigidity.

Bio-efficacy and Persistence of Inert Dust Formulations as Stored-grain Protectants against Sitophilus oryzae (L.)


 
 
 Inert dust formulations of natural origin act as promising alternatives in controlling storage infestations caused by deleterious coleopteran insect pests. In that context, laboratory studies were conducted in order to evaluate the insecticidal activity, progeny inhibition and persistence of three commercially available dust formulations, namely, diatomaceous earth, zeolite and cloisite 20A against Sitophilus oryzae adults, a major coleopteran pest of stored grains, throughout 90 days of storage period. Adulticidal and persistence bioassays were conducted to evaluate the toxicity of binary combinations of inert dusts using their sub-lethal doses towards the test insect for 60 days of storage period. Further, ultrastructural architecture of the test insect pest species was examined via Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-Ray Analysis (EDX) to study the uptake/penetration pattern of inert dust particles through the cuticular layers of target insect pest. All inert dust formulations exhibited very efficacious toxic and progeny inhibition activities and extraordinary mortality percentages irrespective of the inert dust used at the end of initial 30 day-long storage period. Thereafter, mortality percentages gradually declined with the progress of the storage time period, declining in the order of, diatomaceous earth>zeolite>cloisite 20A. All the dust formulations successfully inhibited the progeny production and the lowest average progeny production was recorded at the end of initial storage period. Progeny inhibition decreased with the progress of storage time. Binary combinations of inert dust formulations exhibited additive and antagonistic effects against S. oryzae and similarly, the mortality percentages gradually decreased with the prolongation of the storage period. The FE-SEM and EDX micrographs clearly indicated the presence of dust particles and the distribution of their constituting elements on the cuticular layer of the exposed insect pests with the appearances of abrasions and scratches that may have led to dehydration and eventual death of S. oryzae. Thus, findings of the present study suggest that, naturally-derived diatomaceous earth, zeolite and cloisite 20A can be used as eco-friendly means as stored grain protectants against S. oryzae populations successfully in the storage grain systems.
 Keywords: Sitophilus oryzae, Diatomaceous earth, Cloisite 20A, Zeolite
 
 

Synthesis of hybrid organosilicon materials of various chemistries as efficient protective coatings for mild steels in NaCl media

This study focuses on optimizing the thermal, morphological, scratch resistance, and anti-barrier characteristics of newly developed hybrid sol-gel coatings. The coatings were formulated by varying the synthetic precursors and incorporating a clay additive. The hybrid coatings were prepared using a mixture of organosilane and zirconium propoxide precursors, and further modified with polydimethylsiloxane (PDMS) and Cloisite 20 A (C20A) clay additives. The coatings were applied onto mild steel substrates and their corrosion protection in 3.5 wt% NaCl solutions were evaluated through electrochemical and visual observation testing. Contact angle measurements revealed a hydrophobic nature of the developed coatings on the steel surfaces, primarily attributed to the presence of an organosilane precursor with a long C18-alkyl chain functionality in all formulations. Electrochemical testing data demonstrated that the coating formulation containing the polydimethylsiloxane precursor exhibited good corrosion protection. After 14 days of immersion in a saline medium, this sample exhibited impedance values higher than 106 Ω.cm2 and a low corrosion rate of 3.5 × 10−3 mpy, as determined by electrochemical impedance spectroscopy (EIS) and polarization testing, respectively. Morphological analyzes confirmed the homogeneous and integrated coating layer of this sample, which contributed to its enhanced corrosion protection. Furthermore, the inclusion of the Zr-propoxide precursor in a formulation containing only silane precursors demonstrated favorable effects on the desired coating properties. The hybrid sol-gel coatings exhibited excellent anti-barrier characteristics, which can be attributed to the formation of highly cross-linked Si-O-Si networks. Overall, the reported hybrid coating formulations offer promising alternatives to commercially available toxic conversion coatings, as they exhibit excellent anti-barrier properties and can be considered environmentally friendly.

PREPARATION AND FLAME RETARDANT APPLICATION OF CLAY POLYURETHANE NANOCOMPOSITES

In recent years, clay-based organic thermosetting polyurethane polymer nanocomposites have more attracted attention in academia and industries because they exhibit different properties from conventional materials. In this study, we investigated novel thermoplastic Polyurethane (TPU) by adding nanoparticles of clay as a fire-retardant property. By employing an in-situ polymerization technique with a 2:1 ratio of tolylene 2,4-diisocyanate (TPI) and polyethylene glycol (PEG2000), the NCO terminated TPU prepolymer was created. Cloisite 25A (C25A), an organo-modified montmorillonite clay, was utilized to provide sufficient compatibility with the PEG/TPI matrix. The synthesized nanocomposite was examined using thermogravimetric analysis (TGA), SEM analysis, and X-ray diffraction (XRD). FTIR analysis provides information on functional groups. Compared to pure polyurethane, the nanocomposites showed superior thermal stabilities, as determined by thermogravimetric analysis (TGA). The results from X-ray diffraction and Scanning Electron Microscopy confirm the successful formation of an exfoliated polymer clay nanocomposite under all conditions, evidenced by the absence of the distinct peak (2θ = 4.79º) corresponding to the d-spacing of the organoclay. The relationship between clay loading and TPU matrix type and the mechanical characteristics of nanocomposites was examined. As the amount of clay in the Young's TPU/Cl25A nanocomposites grew, so did their tensile strength and modulus. The fire-retardant experiment was studied by a cone colorimeter. There have been notable advancements in the fire-retardant qualities, including smoke, CO output, and heat release rate. Comparing polyurethane integrated with 5-weight percent organoclay to ordinary polyurethane polymer, a noteworthy 53% reduction was observed.

Impact of Nanoclays Addition on Chickpea (Cicer arietinum L.) Flour Film Properties.

Chickpea flour is an affordable natural blend of starch, proteins, and lipids, which can create films with suitable properties as an eco-friendly packaging material. Nanoclays' incorporation into natural biopolymers enhances the barrier properties of the resulting nanocomposites, so they could improve the properties of flour films. The objective of this work was to assess the influence of three types of nanoclays (halloysite, bentonite, and Cloisite 20A) at two concentrations on the characteristics of chickpea flour films. In general terms, when the lowest dose (5%) was added, no or very slight significant differences with the control were observed in most parameters, except for thermal stability and opacity, which increased, and solubility, which decreased. At the highest concentration (10%), films containing any of the nanoclays demonstrated greater thermal stability, opacity, and rigidity while being less soluble than those without nanofillers. Bentonite exhibited superior film structure distribution compared to other nanoclays. At the highest concentration, it had the most significant impact on modifying the properties of chickpea flour films, increasing their tensile and puncture strengths while decreasing elasticity and water vapor permeability. The incorporation of nanoclays into chickpea flour films could be a useful technique to enhance their properties.

X-ray study on crystalline morphology in iPP/MMT nanocomposite fibers

Nanocomposite fibers based on isotactic polypropylene (iPP) and an organically modified montmorillonite (MMT), Cloisite 15A, were formed from the melt at different take-up velocity. The studies were performed for pure iPP fibers and fibers containing three different concentrations of MMT. The supermolecular structures of the fibers at the crystallographic and lamellar levels were examined by means of X-ray scattering methods (WAXS and SAXS). It was found that the dominant crystal form of iPP is α modification. The increase of take-up velocity induces the orientation of iPP crystals parallel to the fiber axis. The cross-hatching crystallization of iPP was also observed in the tested fibers. Only for the gravity spun fibers containing MMT, the β modification of iPP was observed. Assuming that nucleation does not occur on the surfaces of clay platelets but rather in the interlayers of MMT particles, a probable β-phase nucleation mechanism has been suggested. This mechanism was confirmed by the isothermal crystallization experiment. During heating, the β crystalline form transformed into α-form. The degree of transformation depended on the annealing temperature. The studies also revealed that lamellar stacks of iPP are perpendicular to the MMT layers surfaces.

Cure characteristics, compression set, swelling behaviors, abrasion resistance and mechanical properties of nanoclay (Cloisite 15A, Cloisite 20A and Cloisite 30B) filler filled EPDM/NBR blend system

Cure characteristics, compression set, swelling behaviors, abrasion resistance and mechanical properties of nanoclay (Cloisite 15A, Cloisite 20A and Cloisite 30B) filler filled EPDM/NBR blend system

Two different routes to prepare porous biodegradable composite membranes containing nanoclay

AbstractThe method employed for membrane preparation and nanoparticle incorporation in membrane systems can affect their properties. This work aims to compare the better strategy to obtain membranes from the preparation of PBAT [Poly(butylene adipate co‐terephthalate)] containing nanoclay Cloisite® 20A (C20A) (0, 0.5, and 1 wt.%) by combined Evaporation/Non‐solvent Induced Phase Separation (EIPS/NIPS) or dip coating methods. The SEM, TGA, contact angle measurements, FTIR, XRD, mechanical testing, and cost analysis characterized EIPS/NIPS to dip coating membranes. EIPS/NIPS membranes had smaller pores (0.3–0.5 μm), with a more homogeneous pore diameter distribution due to C20A nanoclay insertion. PBAT/0.5% C20AEIPS/NIPS was the more hydrophilic membrane (37°) with better mechanical properties proven by statistical analysis. The cost analysis showed that EIPS/NIPS membranes production cost per square meter (m2) was lower (US$ 73.4–73.8) than dip coating (US$ 89.0–99.2). The EIPS/NIPS method was the most economically and statistically advantageous, and its properties can favor future applications for PTEs removal in aqueous media.