Nanofilled Composites Research Articles

Challenges and opportunities in using ionic liquids-modified carbon allotropes as emerging anticorrosive nanomaterials

• Ionic Liquids-Modified Carbon Allotropes (ILMCAs) were surveyed as noble anticorrosive materials. • ILMCAs act as nanofillers and are gaining growing attention as they strongly enhance corrosion resistance. • ILMCAs act as much more effective nanofillers than polymer composite nanofillers. • ILMCAs can be regarded as environmentally substitutes for polymer composites. • The challenges and opportunities of ILMCAs as nanofillers are described. Ionic Liquids-Modified Carbon Allotropes (ILMCAs) embody an emerging class of carbon allotropes-based nanocomposite materials. The materials are associated with various salient features that qualify them for many applications. The use of ILMCAs as nanofillers in polymer coating is gaining growing attention as they strongly enhance the corrosion resistance property of polymer coating. Literature studies showed that ILMCAs manifest relatively high anticorrosive properties as compared to their constituting. For example, a study showed the IL, ROG and RGO-IL-based epoxy resin coatings demonstrate the %IE of 51.96%, 78.46% and 95.02%, respectively. In ILMCAs, ILs enhance the adhesion property whereas carbon allotropes avoid the diffusion of electrolytes. ILMCAs act as effective nanofillers than traditional polymer composite nanofillers. The use of ILMCAs can be regarded as eco-friendly substitutes for traditional nanofillers. The present perspective describes the collections and advancements in ILMCAs as nanofillers in polymer coatings.

Crosslinked poly (vinyl alcohol) composite reinforced with tunicate, wood, and hybrid cellulose nanocrystals: Comparative physicochemical, thermal, and mechanical properties

The development of sustainable and biodegradable composites has gained increasing attention in recent years. Effective interaction and adhesion between polymers and fillers are crucial. In this study, the effect of different aspect ratios of cellulose nanocrystals (CNCs) and their hybrid within a crosslinked poly (vinyl alcohol) (PVA) nanocomposite has been investigated to develop biodegradable materials. The physicochemical, thermal, and mechanical properties of the specimens have been studied. SEM images indicate that the addition of CNC reduced the porosity of the films. The XPS results confirmed the significant formation of covalent bonds for all composites except those reinforced with wood-CNC, which showed a lower amount of crosslinking and CC formation. EDS maps reveals that the dispersity of the CNCs could be different depending on the aspect ratio of the CNCs. Results from the solubility in water (SW) tests indicated that the use of hybrid-CNC in a crosslinked system decreased the SW significantly. The crosslinking and addition of CNC to the PVA composite led to improved mechanical properties. Elongation at break (EB) decreased significantly for the crosslinked hybrid-CNC nanocomposite. Overall, the results of this study indicate that the aspect ratio of CNCs as fillers in nanocomposites may contribute to their physicochemical, mechanical, and thermal properties for the development of biodegradable materials.

Natural aging of heterogeneous arc-welded AA6061-AA7075 joints with nanocomposite filler

We report the dissimilar joining of aluminium alloys 6061 and 7075 using filler rods nano-treated with TiC nanoparticles. TiC enables the formation of a fine and equiaxial weld metal microstructure while preventing the formation of hot cracks. Dissimilar joints were also naturally aged, and their strength evolutions were tracked over 8 weeks and compared to a nano-treated, homogeneous AA7075 joint. Heterogeneous weld metals regained over 30 HV with a mix of MgZn2 and Mg2Si strengthening phases. Nano-treatment thus shows great promise, being able to facilitate the fusion welding of a traditionally difficult-to-weld system and enable a natural aging response between two artificially aged alloys.

Clinical Performance of Direct Posterior Composite Restorations in Patients with Amelogenesis Imperfecta.

The objective of this study was to analyze and assess the clinical performance of direct composite restorations using a nanohybrid and a nanofill composite material for posterior teeth in patients with amelogenesis imperfecta (AI). This study involved 15 patients between the ages of 14 and 30 years suffering from amelogenesis imperfecta (AI). During the study, the patients received direct composite restorations using either the Clearfil Majesty ES-2 (Kuraray Medical Inc, Tokyo, Japan) and Clearfil Universal Bond (Kuraray) or Filtek Ultimate Universal Restorative (3M ESPE, St Paul, MN, USA) and Single Bond Universal Adhesive (3M ESPE). The evaluations of the restorations were conducted per the modified USPHS criteria at the time of baseline as well as during the first-, second-, third-, and fourth-year follow-up sessions. After four years, it was observed that the cumulative success rate of direct posterior restorations was 98.1% for Clearfil Majesty ES-2 and 92.2% for Filtek Ultimate. During the study one Clearfil Majesty ES-2 restoration and four Filtek Ultimate restorations failed. There was a significant difference between Clearfil Majesty ES-2 and Filtek Ultimate in the color match in posterior restorations after three and four years. The causes of failure included marginal discoloration and caries, as well as fracture of the restoration. Hence, it can be stated that the use of nanohybrid or nanofill composites in posterior direct restorations in patients with AI looks promising. The failure rate of Clearfil Majesty ES-2 was found to be lower than that of Filtek Ultimate restorations. Clinically, the rate of optimum restorations conducted for partial discoloration, marginal adaptation, color match, and surface texture were observed to be higher when Clearfil Majesty ES-2 was used. However, additional studies are needed to assess the clinical performance of direct posterior composite materials in patients with AI.

Clinical Performance of Direct Posterior Composite Restorations in Patients with Amelogenesis Imperfecta.

The objective of this study was to analyze and assess the clinical performance of direct composite restorations using a nanohybrid and a nanofill composite material for posterior teeth in patients with amelogenesis imperfecta (AI). This study involved 15 patients between the ages of 14 and 30 years suffering from amelogenesis imperfecta (AI). During the study, the patients received direct composite restorations using either the Clearfil Majesty ES-2 (Kuraray Medical Inc, Tokyo, Japan) and Clearfil Universal Bond (Kuraray) or Filtek Ultimate Universal Restorative (3M ESPE, St Paul, MN, USA) and Single Bond Universal Adhesive (3M ESPE). The evaluations of the restorations were conducted per the modified USPHS criteria at the time of baseline as well as during the first-, second-, third-, and fourth-year follow-up sessions. After four years, it was observed that the cumulative success rate of direct posterior restorations was 98.1% for Clearfil Majesty ES-2 and 92.2% for Filtek Ultimate. During the study one Clearfil Majesty ES-2 restoration and four Filtek Ultimate restorations failed. There was a significant difference between Clearfil Majesty ES-2 and Filtek Ultimate in the color match in posterior restorations after three and four years. The causes of failure included marginal discoloration and caries, as well as fracture of the restoration. Hence, it can be stated that the use of nanohybrid or nanofill composites in posterior direct restorations in patients with AI looks promising. The failure rate of Clearfil Majesty ES-2 was found to be lower than that of Filtek Ultimate restorations. Clinically, the rate of optimum restorations conducted for partial discoloration, marginal adaptation, color match, and surface texture were observed to be higher when Clearfil Majesty ES-2 was used. However, additional studies are needed to assess the clinical performance of direct posterior composite materials in patients with AI.

Neutron Reflectivity Study on the Suppression of Interfacial Water Accumulation between a Polypropylene Thin Film and Si Substrate Using a Silane-Coupling Agent.

We measured the neutron reflectivity (NR) of isotactic polypropylene (PP) thin films deposited on Si substrates modified by hexamethyldisilazane (HMDS) at the saturated vapor pressure of deuterated water at 25 °C and 60 °C/85% RH to investigate the effect of HMDS on the interfacial water accumulation in PP-based polymer/inorganic filler nanocomposites and metal/resin bonding materials. We found that the amount of water accumulated at the PP/Si interface decreased with increasing immersion time of the Si substrate in a solution of HMDS in hexane prior to PP film deposition. During the immersion of the Si substrate, the HMDS molecules were deposited on the Si substrate as a monolayer without aggregation. Furthermore, the coverage of the HMDS monolayer on the Si substrate increased with increasing immersion time. At 60 ° C and 85% RH, only a slight amount of interfacial water was detected after HMDS treatment for 1200 min. As a result, the maximum concentration of interfacial water was reduced to 0.1 from 0.3, where the latter corresponds to the PP film deposited on the untreated substrate.

Comparative Evaluation of Surface Roughness and Wettability of an Alkasite with Nano Bulk-Fill and Nanofilled Resin Composite Restorative Materials: In vitro Study.

Surface characteristics of resin-based composites (RBCs) can change with polishing and over time. The aim of the study was to compare the surface roughness and wettability of three different posterior RBCs after polishing and the change in these surface characteristics over time, after aqueous aging. Experimental in vitro study. Eleven disc-shaped RBC specimens were fabricated. The RBCs used were, alkasite composite, bulk-fill nanocomposite, conventional nanofilled composite. All the specimens underwent polishing with Soflex Diamond Polishing System and then analyzed for roughness and wettability at baseline and after aqueous aging for 3 months with the help of an atomic force microscope and a contact angle goniometer respectively. One-way ANOVA and Tamhane test were used for the multiple comparisons. Alkasite composite showed significantly higher surface roughness (P = 0.028 and P < 0.001, respectively) and lower wettability (P = 0.023 and P = 0.020, respectively) than conventional nanofilled composite at baseline and 3 months. Surface roughness of alkasite composite was also significantly higher than bulk-fill nanocomposite (P = 0.009 and P < 0.001, respectively) at both the time points. Alkasite has higher surface roughness in comparison to conventional nanocomposite and bulk-fill nanocomposite and lower wettability than conventional nanocomposite after polishing and aqueous aging over a 3-month period. In terms of surface characteristics, alkasite composite may be advantageous in preventing initial plaque adhesion to the material surface, but the lower surface roughness of nano-filled composites may be more advantageous in terms of plaque retention prevention.

A combined method to probe the behaviour of the filler in polymer blend nanocomposites via X-ray diffraction and thermal measurement

We have demonstrated the use of XRD and thermal measurements to diligently probe the location of nano-scaled boron carbide (B4C-type compounds) fillers. Herein, the XRD diffraction Bragg and amorphous peaks were successfully fitted from the parameters determined by a deconvolution process using the Pearson VII function, with a fitting error of less than 4%. Thermal measurement was achieved by measuring the thermal conductivity of the composite. A filler loading of 4%wt was found as a threshold. Beyond this value, a significant increase in the thermal conductivity was observed. There was no further decrease in the HDPE crystallinity above the threshold, but rather a considerable increase. Below the threshold value, the addition of fillers disturbed the HDPE crystal arrangement, leading to a reduction of both the HDPE crystallinity and the thermal conductivity. The influence on the ordered structure, intrinsic thermal conductivity and radius of gyration of the fillers, together with their interactions, elucidated the trend of the thermal conductivity.

Effect of Polymerization on the Color of Resin Composites.

The initial shade of a resin-based restorative material should be the same as that after polymerization. In this study, the color changes of translucent and opaque composites from nine different brands were assessed after polymerization using a spectrophotometer and cross-polarization (CP) photography. Thirteen nano-hybrid (Essentia LE, GC Corp; Ceram.x Duo SphereTEC A2E/A2D, Dentsply Sirona; Harmonize A2E/A2D, Kerr Dental; IPS Empress Direct A2E/A2D, Ivoclar Vivadent; Mosaic EN/A2, Ultradent Products; Clearfil Majesty Es-2 A2E/A2D, Kuraray Noritake; Charisma Topaz A2/OL, Kulzer), two supra nano-hybrid (Estelite Asteria NE/A2B; Tokuyama), two nano-filled (Filtek Ultimate A2E/A2D; 3M) light-curing resin composites, and one micro-hybrid (Essentia MD, GC Corp) light-curing resin composite were tested. Disc-shaped specimens (n=5) were prepared using silicone molds (12 × 5 mm) and polymerized from both sides using an LED curing light (Elipar Deepcure S, 3M) at a light intensity of 1470 mW/cm2. Measurements were performed before and 1 day after polymerization using a contact-type dental spectrophotometer (Easy Shade 5, VITA Zahnfabrik, Bad Säckingen, Germany) and a combination of CP photography and Photoshop CC software (Adobe Inc, San Jose, CA, USA). Spectrophotometry and CP photography ΔE* values were calculated; the perceptibility threshold was a ΔE* value of 1.2. VITA spectrophotometry color change scores were also calculated and evaluated. The overall ΔE* values ranged between 0.34 and 12.56. Two-way analysis of variance (ANOVA) showed that color change was associated most strongly with composite brand (p<0.001), followed by shade (p=0.002). Color change (p=0.002) and degree of darkening/lightening (p<0.001) were significantly greater for dentin compared to enamel shades. Clearfil Majesty Es-2 (Kuraray Noritake) showed significant lightening, whereas all other composites showed darkening after polymerization. All composite brands presented perceptible (ΔE*≥1.2) color changes. Estelite Asteria (Tokuyama), Ceram.x Duo SphereTEC (Dentsply Sirona), and Harmonize (Kerr Dental) were considered the most reliable brands regardless of the shade. The spectrophotometry and CP photography methods were positively correlated (p<0.001). Also, CIEDE2000 and CIELCH (also referred to as CIE L*c*h) color systems were positively correlated based on the ΔE* values (p<0.001). Despite improvements in the chemical composition of, and fillers for, contemporary resin-based composites (RBCs), all tested composite brands showed perceptible color change after polymerization, except for some shades. Under the conditions in this study, it is preferable to polymerize the composite during the trial phase, before identifying the most appropriate shade. CP photography in combination with Photoshop analysis appears to be a reliable and promising approach for color evaluation.

Fabrication of anti-icing/de-icing superhydrophobic composite coating based on hydrangea-like ZnO@CuS

Considering the destructive effect of ice accumulation on material surfaces, substantial attention has been devoted to fabricating anti-icing superhydrophobic coatings. However, most superhydrophobic coatings cannot deice. Herein, a special nanofiller was designed and fabricated as the main component of a superhydrophobic coating for simultaneously improving its anti-icing and de-icing performance. Firstly, hydrangea-like ZnO@CuS (H–ZnO@CuS) was synthesized via a precipitation process at room temperature. Then, a superhydrophobic composite coating composed of epoxy resin (ER), H–ZnO@CuS, and polydimethylsiloxane (PDMS) was fabricated on the Al surface via a layer-by-layer spraying process. The results demonstrate that, after 100 tape peeling tests and 40 abrasion cycles, the hydrophobicity of the ER/H–ZnO@CuS/PDMS composite coating remains basically unchanged, and its water contact angle (WCA) can still reach 156.3°, thus exhibiting excellent superhydrophobicity and mechanical durability. More importantly, the composite coating displays outstanding anti-icing and de-icing performance, which can prolong the static freezing time of water droplets from 3 to 13 min at −15 °C and prevent the formation of ice when water is dripped continuously for 20 min at −10 °C. Additionally, the melting time of ice at −15 °C can be shortened from 5 to 1 min due to the photothermal behavior of H–ZnO@CuS. Therefore, this work presents a promising strategy to endow coatings with simultaneous anti-icing and de-icing performance. This approach can not only improve the current efficiency of de-icing/anti-icing processes but also reduce the energy consumption by effectively reducing or eliminating the accumulation of water on the structure surface before it freezes. • A special hydrangea-like composite nano-fillers as the main component of superhydrophobic coating was fabricated. • The composite coating exhibited superhydrophobicity with water contact angle of 163.5 ± 1.9° and slide angle of 3.1 ± 0.2°. • Photothermal micro/nano structure endows coating with good anti-icing and de-icing performances simultaneously • The de-icing process of ice bead on the superhydrophobic coating at −15 °C completed within 1 min by photothermal effect. • This method provides new ideas for the preparation of anti-icing and de-icing coatings for practical outdoors applications.

Properties of clay/graphene/thermoplastic nanocomposites in relation to their composition: Synergetic effect of hybrid nanofillers and role of matrix

The structural, rheological, thermal and mechanical properties of composites, constituted of a polyamide 12 filled with commercial graphene nanoplatelets and organically modified nanoclays, were investigated. Different graphene/clay ratios were used in order to better understand the role played by each kind of filler in the improvement of the end-use properties of prepared composites. With this aim in view, the dispersion state of fillers in ternary nanocomposites was evaluated in comparison with those of graphene PA and clay PA binary composites. Measured rheological and mechanical properties of ternary systems were discussed in comparison with those calculated as the sum of the contributions of graphene and clay in the PA matrix, underlining the combined roles of both fillers in the improvement of composite properties. On the other hand, structural and end-use properties of the 5 wt% graphene 5 wt% clay PA material were compared with those obtained in the past for the composite constituted with a high viscous polyethylene/maleic anhydride grafted polyethylene matrix filled with same commercial graphene nanoplatelets (5 wt%) and similar organically modified montmorillonite fillers (5 wt%). This comparison aimed at understanding the role played by the matrix in the dispersion states of both clay and graphene fillers, and consequently in the end-use properties of composites.

Testing of Rubber Composites Reinforced with Carbon Nanotubes.

Carbon nanotubes (CNTs) have attracted growing interest as a filler in rubber nanocomposites due to their mechanical and electrical properties. In this study, the mechanical properties of a NR/BR/IR/SBR compound reinforced with single-wall carbon nanotubes (SWCNTs) were investigated using atomic force microscopy (AFM), tensile tests, hardness tests, and a dynamical mechanical analysis (DMA). The tested materials differed in SWCNT content (1.00–2.00 phr) and were compared with a reference compound without the nanofiller. AFM was used to obtain the topography and spectroscopic curves based on which local elasticity was characterized. The results of the tensile and hardness tests showed a reinforcing effect of the SWCNTs. It was observed that an addition of 2.00 phr of the SWCNTs resulted in increases in tensile strength by 9.5%, Young’s modulus by 15.44%, and hardness by 11.18%, while the elongation at break decreased by 8.39% compared with the reference compound. The results of the temperature and frequency sweep DMA showed higher values of storage and loss moduli, as well as lower values of tangent of phase angle, with increasing SWCNT content.

Polydopamine-modified graphene with cellulose nanofibers to act as fillers in epoxy nanocomposites for application in the next generation of green electronic packaging materials

In this work, eco-friendly polydopamine (PDA) modifies graphene (PDA-G) through a π-π stacking interaction. Then, eco-friendly and biodegradable cellulose nanofiber (CNF) polymers are employed to combine with PDA-G to form a 3D thermal transport network. More significantly, their abundant functional groups, including hydroxyl groups and carboxyl groups, form interfacial hydrogen bonding with PDA-G to reduce the thermal interfacial resistance. With fundamental understanding of the interfacial engineering between CNF and PDA-G and with an effort to balance the effects of filler connection and thermal insulation of CNF, the resultant epoxy nanocomposites achieved a high through-plane thermal conductivity of 0.58 W/mK at only 3.05 wt% loading. In addition, the epoxy nanocomposites have a low CTE and high thermal stability. Meanwhile, the potential application of epoxy nanocomposites as thermal interface materials (TIMs) in semiconductor packaging has been demonstrated by both experimentations and simulation. These tests result in new pathways to design and modify fillers to meet the demands of next generation green polymer composites in 2.5D/3D semiconductor packaging.

PREPARASI FILM NANOKOMPOSIT POLIVINIL ALKOHOL (PVA)/NANOKARBON DARI CANGKANG BUAH SAWIT (NCCS) DENGAN METODE PENCAMPURAN LARUTAN

Polyvinyl alcohol (PVA) has good compatibility when added as filler in the form of nanocarbon so that it can produce environmentally friendly nanocomposite products. Thus, the addition of nanocomposites to PVA-based films is expected to increase and improve the mechanical properties of the resulting PVA films. This study aims to utilize palm fruit shells as raw materials for nanocarbons and as fillers for nanocomposites, as well as to determine the mechanical properties and thermal strength of nanocarbon nanofibers in the PVA matrix. Composite films were made using the solution mixing method. The research was conducted by mixing PVA solution (3.5 g) with various concentrations of nanocarbon from palm fruit shells (NCCS) and 2 ml of glycerol and 1 g of PEG 400. Film characterization includes tensile test, scanning differential calorimetry (DSC), and conductivity test. Tensile test of PVA/NCCS nanocomposite resulted in tensile strength of 0.314 MPa and an elongation of 4.21925 %. The thermal test of PVA/NCCS nanocomposite with DSC yielded a melting point of around 146.06oC. Electrical conductivity of PVA/NCCS 107.1 (1.07 x 10-3) s/cm. PVA/NCCS nanocomposite based on conductivity scale including a semiconductor material.

Preparation and reinforcement performance of RGO-CNTs-SiO2 three-phase filler for rubber composites

Rubber reinforcement technology is developing towards the direction of high efficiency and multi-functionality, and the reinforcement of rubber by a single-component filler can no longer meet the requirements. Nanocomposite fillers have become the development trend of high-performance reinforcing fillers due to the complementary advantages and synergistic reinforcing effects of each component. Reduced graphene oxide-carbon nanotubes (RGO-CNTs) composites were prepared by a method of electrostatic assembly. The non-covalent modified RGO-CNTs was used as a substance to grow in situ SiO2 nanoparticles (RGO-CNTs-SiO2), and the RGO-CNTs-SiO2 three-phase fillers were obtained. The RGO-CNTs-SiO2 three-phase fillers were further used to study the reinforcing properties of hydrogenated nitrile rubber (HNBR). Furthermore, the effects of RGO-CNTs-SiO2 with different component contents on the reinforcing properties of HNBR were systematically studied. The TEM images of RGO-CNTs-SiO2 show that the RGO and CNTs promotes mutual dispersion, and the SiO2 nanoparticles (average diameter 7 nm) are highly dispersed on the surface of RGO-CNTs. The characterization of RGO-CNTs-SiO2/HNBR indicates that the RGO-CNTs-SiO2 efficiently weaken the filler network and improve the filler-rubber interaction. The results show that the three-phase fillers produce obvious synergistic reinforcing effects. The highest tensile strength (30.1 MPa) of RGO-CNTs-SiO2/HNBR is achieved at the RGO:CNTs mass ratio of 1:5, the RGO-CNTs mass percentage of 2%, and the filler loading of 50 phr. This work demonstrates the considerable promise for developing three-phase filler-based rubber composites.

Facile and Scalable Synthesis of Whiskered Gold Nanosheets for Stretchable, Conductive, and Biocompatible Nanocomposites.

Noble metal nanomaterials have been studied as conductive fillers for stretchable, conductive, and biocompatible nanocomposites. However, their performance as conductive filler materials is far from ideal because of their high percolation threshold and low intrinsic conductivity. Moreover, the difficulty in large-scale production is another critical hurdle in their practical applications. Here we report a method for the facile and scalable synthesis of whiskered gold nanosheets (W-AuNSs) for stretchable, conductive, and biocompatible nanocomposites and their application to stretchable bioelectrodes. W-AuNSs show a lower percolation threshold (1.56 vol %) than those of gold nanoparticles (5.02 vol %) and gold nanosheets (2.74 vol %), which enables the fabrication of W-AuNS-based stretchable nanocomposites with superior conductivity and high stretchability. Addition of platinum-coated W-AuNSs (W-AuNSs@Pt) to the prepared nanocomposite significantly reduces the impedance and improved charge storage capacity. Such enhanced performance of the stretchable nanocomposite enables us to fabricate stretchable bioelectrodes whose performance is demonstrated through animal experiments including electrophysiological recording and electrical stimulation in vivo.

Functionalization of few-layer graphene sheets and carbon nanotubes for generation of hybrids and their effect on the piezoresistive properties of polymeric nanocomposites

Functionalization of few-layer graphene sheets (GSs) and multilayer carbon nanotubes (MWCNTs) for the generation of hybrid nanostructures is investigated. MWCNTs were oxidized by a mixture of nitric and sulfuric acids, while GSs were functionalized with varying concentrations of branched polyethyleneimine (PEI), investigating the role of the PEI concentration. PEI functionalization of the GSs is assessed by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and zeta potential measurements. Successful functionalization of the GSs is conspicuously proved through new XPS bands associated with PEI, such as CONH, as well as a sign change in the zeta potential (from −12.7 mV to +11.8 mV). The concentration of 0.266 μl of PEI per ml of distilled water (0.46 mmol/L) proved to be the most effective for functionalizing the GSs, and such a concentration was further used for generating GS-PEI/oxidized MWCNT hybrids as fillers for nanocomposites. The application of such hybrid carbon nanostructures to increase the piezoresistive sensitivity of smart polymeric nanocomposites under bending loading is reported. An increase in the piezoresistive sensitivity (gauge factor) at the tensile side of the flexural coupon is observed for nanocomposites containing hybrid functionalized nanostructures.

Surface Microhardness Of Microhybrid And Nanocomposite After Storage In Mouth Washes.

Dental composites are aesthetic direct restorative material. However, the effect of mouthwashes on the durability of the material is controversial. This study evaluated and compared the influence of mouthwash composition on the surface hardness of nanofilled (Z350XT) and microhybrid (P60) resin composites. Comparative in-vitro study was conducted over 6 months at Multan Medical & Dental College. Sixty-four disc-shape specimens of each {nanofilled (Z350XT) and microhybrid (P60)} resin composite were prepared and stored in distilled water at 37°C for 24 hours. The baseline microhardness reading (To) was recorded by Vickers micro-hardness tester. Samples were then randomly divided into four groups (n=16) and stored in Listerine Cool Mint, Colgate Plax, Clinica and distilled water (control). The hardness test was repeated after 12 hours and 24 hours of storage. Nanocomposite (Z350XT) had statistically (p<0.01) higher surface hardness. A significant reduction (p≤0.05) in microhardness was observed after immersion of samples in mouthwashes. The reduction in surface hardness was dependent on the immersion time and composition of mouthwashes. Listerine Cool Mint (alcohol-based mouthwash) had greatest degradation effect. Mouth rinses negatively impacted the surface microhardness of the tested resin-based materials. Alcohol-based mouthwashes had greater potential for reducing microhardness. Microhybrid composite appears to be a more suitable material for restoring teeth in patients accustomed to using regular mouthwashes.

In Vitro and In Vivo Cytotoxicity of Boron Nitride Nanotubes: A Systematic Review.

Boron nitride nanotubes (BNNTs) are an exciting class of nanomaterials due to their unique chemical and physical characteristics. In recent decades, BNNTs have gained huge attention in research and development for various applications, including as nano-fillers for composites, semiconductor devices, hydrogen storage, and as an emerging material in biomedical and tissue engineering applications. However, the toxicity of BNNTs is not clear, and the biocompatibility is not proven yet. In this review, the role of BNNTs in biocompatibility studies is assessed in terms of their characteristics: cell viability, proliferation, therapeutic outcomes, and genotoxicity, which are vital elements for their prospective use in biomedical applications. A systematic review was conducted utilising the databases Scopus and Web of Science (WOS) (2008–2022). Additional findings were discovered manually by snowballing the reference lists of appropriate reviews. Only English-language articles were included. Finally, the significant analysis and discussion of the chosen articles are presented.

Effects of urea and glycerol mixture on morphology and molecular mobility in thermoplastic starch/montmorillonite-type nanofiller composites studied using XRD and NMR

Effects of urea and glycerol mixture on morphology and molecular mobility in thermoplastic starch/montmorillonite-type nanofiller composites studied using XRD and NMR