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A cost-effective stereolithography for medium-scale components is developed to fabricate 3D components with high build speed and resolution from photo-curable resin. The developed SLA utilizes a focused light beam of wavelength range (300 nm–700 nm) coming from the DLP projector and passes through the objective lens and finally imposed on the platform containing a layer of photo-curable resin. After focusing the light beam on the liquid resin layer, the photo-polymerization reaction occurs and the liquid resin becomes solid. Thus, the 3D object is fabricated layer by layer curing of liquid resin. The photopolymer used in this experimentation is polyethylene glycol di-acrylate and Irgacure 784 as photo-initiator. The Creo 3.0 software is used for modelling of 3D objects. A special MATLAB code is developed for slicing of the 3D model and displaying the sliced image one by one through DLP projector. The Arduino microcontroller with stepper motor and ball screw is used to control the motion of Z-stage platform. The Creation workshop software is also used to control motion of the Z-stage and period to display the sliced images through DLP projector. The medium-scale 3D objects with rectangular, square, and circular cross-sections are obtained by curing the aforementioned photo-curable resin. It is observed that the 3D objects are best cured for two seconds curing time with 0.1 mm curing depth along Z-axis.

Background and objectives: Adequate retention is a basic requirement for the acceptance of complete denture. The aim of this study was to evaluate the retention quality of fluid denture base materials and compare it with conventional acrylic denture base materialsMethod: Sixteen edentulous male patients with an age 45-60 years participated in the study. For each patient two denture bases were constructed, one of them made from fluid denture base materials and the other made from hot acrylic denture base materials. A specially designed strain gauge measuring device was used to measure the force required to dislodge the two dentures from basal seats. Six measurements of retention of newly inserted denture base were recorded for each patient (three for maxillary acrylic denture base and three for maxillary fluid denture base).Results: The results of the retention test showed that the fluid denture base materials required more force in order to dislodge denture than the heat cure denture base materials, which means a significant improvement in retention quality obtained by fluid denture base materials. Conclusions: It has appeared that the fluid acrylic denture base materials produce denture base material with excellent retentive efficiency to the underlying tissue when compared to conventional denture base materials.

The chloride penetration resistance of the near-surface concrete cover depth is greatly influenced by the type and extent of curing provided. Very short or ineffective curing regimes result in less cement hydration and a more porous surface due to early evaporation of capillary water. The resultant depth-dependent capillary pore structure results in a depth-dependent resistance to ingress of aggressive fluids, such as chloride solutions. Without reliable performance test methods for pre-qualification and quality assurance, minimum requirements for curing in specifications for concrete structures exposed to chlorides are typically prescriptive. In this paper, a series of modified rate of absorption tests is used to describe and quantify the effect of curing on the chloride penetration resistance of two concretes subjected to four different curing regimes, including accelerated moist curing. The proposed test method can be used to optimize curing for durability performance and allow credit for use of accelerated curing.

Biomass-derived dynamic covalent thermoset has been considered as a promising solution to the high dependence on fossil resources and the difficulty in recyclability after curing of conventional bisphenol A epoxy resins. However, the design and preparation of a dynamic covalent biobased epoxy thermoset with both comparable thermal and mechanical performances to bisphenol A epoxy resins and reprocessibility remains a significant challenge. Herein, based on imine chemistry, a novel Schiff base-containing dynamic covalent epoxy thermoset was facilely fabricated from biobased protocatechualdehyde and synthetic siloxane diamine. Due to the more reactive epoxides in the epoxy monomer than in bisphenol A epoxy oligomer, the thermoset exhibited a high cross-linking density, resulting in high thermal stability and glass transition temperature. The rigid aromatic Schiff base moieties endowed the thermoset with excellent mechanical properties: thanks to the plasticization of the flexible siloxane, the thermoset displayed high impact strength. Meanwhile, owing to the high segmental mobility, the fast exchange of imine bonds was guaranteed; and the thermoset was able to be recycled through reprocessing. Taking these features, this work provided great potential for designing and preparing sustainable substitutes for bisphenol A epoxy resins in the high-performance applications.

An attractive approach to reduce the carbon dioxide footprint of deep soil mixing (DSM) is to replace Portland cement-based binders by geopolymers based on metakaolin. Safe design requires a good understanding of the mechanical and hydraulic properties of the improved ground, but very little is known about metakaolin–soil mixtures. For instance, shrinkage during curing is a significant issue for metakaolin-based concretes but has not been previously studied in soilcretes. In this work the permeability and strength of sand- and silty sand-based metakaolin soilcretes are studied under different curing conditions. The development of microcracks induced by geopolymer shrinkage is confirmed through a microstructural study using mercury intrusion porosimetry, scanning electron microscopy and X-ray computed tomography. The influence of microporosity and binder filling on permeability and strength is clarified adapting well-established soil models. A modified Kozeny–Carman formulation is proposed for permeability. A mixture ratio model is calibrated to represent strength. In general, the metakaolin-stabilised materials present excellent mechanical and hydraulic properties, although these are very sensitive to curing conditions.

The purpose of this study was to determine the effect of partial replacement of cement with diatomaceous earth (DE) on the compressive strength and absorption of mortar. The cement volume was replaced by different contents of replacement levels of 0%, 10%, 20%, 30% and 40% DE. Ordinary Portland Cement (OPC) and Portland Composite Cement (PCC) were used while the binder and sand were mixed at 1: 2 and 1: 4 vol ratios. Moreover, 5 × 5 × 5 cm3 cubes were used as the test specimens and their compressive strength was determined at 1, 3, 7, and 28 days while the absorption was evaluated at the curing age of 28 days. The results showed that the compressive strength of mortar with OPC for both 1: 2 and 1: 4 ratios decreased with the increment in the content of the DE. However, at 40% cement replacement, the mortar with OPC was categorized as type M according to SNI 6882:2014 or ASTM C270-10 with 28 days compressive strength observed to be greater than 17.2 MPa. Meanwhile, the mortar with PCC for 1: 2 was observed to have the highest compressive strength of 36.63 MPa at 20% cement replacement and 25.39 MPa at 10% cement replacement for 1:4. Furthermore, the absorption of mortar with DE was observed to be greater than for mortar with cement only.

Bio-based epoxy thermoset prepared from renewable biomass raw materials can alleviate fossil energy crisis and reduce environmental pollution, which satisfies the needs of sustainable social development. In this study, a bio-based epoxy thermoset precursor (MGOL-EP) was synthesized from a naturally occurring magnolol through a facile and efficient one-step process. And the fully bio-based epoxy thermoset (MGOL-EP-SC) was obtained by self-curing without adding any other hardener. MGOL-EP-SC revealed an extremely high glass-transition temperature (Tg) of 265 °C and char yield of 53.2% (in N2), which were at the highest level among the fully bio-based epoxy thermosets reported so far. In addition, when the MGOL-EP was cured with 4,4′-methylenedianiline (DDM), Tg of the MGOL-EP/DDM was decreased by 61 °C and the other comprehensive performance had also been decreased, which was due to a reduction in biphenyl structure content and cross-linking density by adding the external curing agents. Moreover, the MGOL-EP-SC presented certain killing rate (48.4%) to Staphylococcus aureus. These findings provide a new design strategy for engineering high-performance and functional epoxy thermoset with high biomass content.

Carbon fibers reinforced SiCN ceramic matrix composites (C/SiCN) were prepared by PIP with homemade polysilazanes (PSN-T03). The PSN-T03 had a viscosity of less than 500 mPa·s and favorable good chemical stability at 80 ℃, which made it quite applicable for PIP process. PSN-T03’ curing reactions happened at temperatures ranging from 149℃ to 205℃, and conversion to amorphous SiCN ceramics could be finished at temperatures above 700℃ with a 70+ wt% ceramic yield. Tensile strength of C/SiCN composites were 230 MPa and 350 MPa respectively at room and high temperature (1400℃), and bending strength reached 380 MPa and 530 MPa. SiCN ceramics began to lose weight at 1400℃ due to the carbothermic reduction of the silicon nitride phase under inert atmosphere, which results in collapse of the mechanical properties of C/SiCN composites above 1400℃.

Molecular self-assembly is the most important strategy for the development of chiral aggregates and chiral functional materials. In this study, we rationally designed and synthesized chiral fluorescent heteroclusters that were self-assembled into microscale cubosomes with a three-dimensional (3D) bicontinuous cubic phase nanostructure. The cubosomes exhibited chirality, indicating that chirality is transferred from the molecules to the 3D nanostructure. Therefore, we confirmed the formation of a chiral bicontinuous cubic phase nanostructure for the first time. We also showed that this chirality originates from the continuous change in the saddle-splay distortion of the molecules within the curved bilayer. At the same time, transparent films of chiral composites were prepared by mixing the chiral cubosomes with an epoxy resin and then curing the mixture. Therefore, we demonstrated an effective method for preparing chiral composites.

The primary objective of this study is to demonstrate the possibility of developing silica, alumina, and zircon-based photocurable ceramic suspensions that can be used for visible light photopolymerization (> 450 nm) and to optimise the binder formulations for the purpose of LCD-based ceramic 3D printing applications. Reference ceramic components for this work are ceramic cores employed in the investment casting of high-pressure turbine blades and vanes. Arguably, one of the most critical steps in photoinduced ceramic 3D printing is developing suitable ceramic suspensions, having high ceramic loading, low viscosity, and short curing times. Ceramic suspensions with four different novel binder formulations and commercial ceramic powders used in core manufacturing (SiO2, Al2O3 and ZrSiO4) were investigated to achieve the best trade-off between: (1) their curing performance (cure depth and curing speed), (2) rheological properties of the binder mixtures at the solid loadings of 60 vol.% for SiO2, 55 vol.% for ZrSiO4, and 45 vol.% for Al2O3; and (3) the green body mechanical properties of the mixtures after printing. The effect of ceramic particles on the selected binders was examined individually, and the correlation between cure depth (Cd), volumetric loading, and curing speed are evaluated. The results show all binders designed in this study provide an adequate cure depth, even at high ceramic loadings. When the curing behaviour of all unloaded binder mixtures from the previous study [ 1 ] compared with the 10 vol.% SiO2 loaded mixtures, the cure depth of all formulated binder mixtures increased 50–55 % and the curing thickness of 60 vol.% SiO2 loaded suspensions were still slightly higher than their unloaded counterparts. The rheology outcomes indicate that lower viscosity binders always result in lower viscosity of the ceramic loaded inks, even without taking the effect of dispersants into account. Besides, the addition of N-Vinyl-2-Pyrrolidone (NVP) monofunctional monomer to the binder mixtures significantly reduces the viscosity and changes the normally linear relationship of the mix viscosity and its silica loading content. Among the binder formulations loaded with 60 vol.% of SiO2, the formulation providing the lowest viscosity and highest mechanical property consists of 5 wt.% of NVP, 45 wt.% of HDDA and 50 wt.% of Photocentric 34 resin. Although this binder mixture showed the highest green flexural strength when loaded by 55 vol.% ZrSiO4, all other mixtures loaded with zircon flour also demonstrated a near-fluid behaviour, below 200 s−1. In Al2O3 loaded mixtures, the HDDA di-functional binder formulations present lowest viscosity and the di- and multifunctional monomer blends (HDDA-Photocentric27) showed the highest mechanical properties when used in a 50/50 ratio. This work summarises the best binder choices for silica, alumina and zircon based ceramic suspensions used in core printing for investment casting applications through LCD screen printing.

Geopolymer is an eco-friendly material used as an alternative to Portland cement and it can be used in construction practices as a repair material to concrete/as a structural element in construction/ as a whole. This study was mainly intended to understand the efficiency of geopolymers in the structural system when special concretes are involved in construction. Shear bond strength was evaluated for the combination of self compacting geopolymer concrete (SCGC) and normal self compacting concrete (SCC). SCGC was developed under external exposure curing conditions enabling it to be used in cast-in-situ production. This was achieved by binary blending of mineral admixtures, use of activator solutions, and superplasticizer. Comparative study on two types of push-off tests namely (1) Conventional Push-off test (Type 1) and (2) Push-off test with normal load acting over the shear interface (Type 2) were conducted to evaluate the interface shear strength. Test results were compared with selected shear friction models available from literature and the effect of introducing self compacting geopolymer concrete in composite interfaces were analyzed.

The possibility of printing conductive ink on textiles is progressively researched due to its potential benefits in manufacturing functional wearable electronics and improving wearing comfort. However, few studies have reported the effect of conductive ink formulation on electrodes directly screen-printed on flexible substrates, especially printing UV curable conductive ink on common textiles. In this work, a novel UV curable nano-silver ink with short-time curing and low temperature features was developed to manufacture the fully flexible and washable textile-based electrodes by screen printing. The aim of this study was to determine the influence of ink formulation on UV-curing speed, degree of conversion, morphology and electrical properties of printed electrodes. Besides, the application demonstration was highlighted. The curing speed and adhesion of ink was found depending dominantly on the type of prepolymer and the functionality of monomer, and the type of photoinitiator had a decisive effect on the curing speed, degree of double bond conversion and morphology of printed patterns. The nano-silver content is key to guarantee the suitable screen-printability of conductive ink and therefore the uniformity and high conductivity of textile-based electrodes. Optimally, an ink formulation with 60 wt% nano-silver meets the potential application requirements. The electrode with 1.0 mm width showed significantly high electrical conductivity of 2.47 × 106 S/m, outstanding mechanical durability and satisfactory washability. The high-performance of electrodes screen-printed on different fabrics proved the feasibility and utility of UV curable nano-silver ink. In addition, the application potential of the conductive ink in fabricating electronic textiles (e-textiles) was confirmed by using the textile-based electrodes as the cathodes of silver-zinc batteries. We anticipate the developed UV curable conductive ink for screen-printing on textiles can provide a novel design opportunity for flexible and wearable e-textile applications.

The potential of utilising alkaline industrial waste with weak or no cementitious properties for carbon dioxide (CO2) capture and for new binders by accelerated carbonation was studied; steel slag (SS), calcium carbide residue (CCR) and waste hydrated cement (WHC) were compared. The carbon dioxide uptake and strength development of SS, CCR and WHC were studied and the relationship of strength development with carbon dioxide uptake and characteristics of carbonation products was analysed. The results indicate that carbon dioxide uptake of SS, CCR and WHC strongly depends on the mineral composition: calcium hydroxide (Ca(OH)2) and calcium silicate hydrate (C–S–H) show relatively higher carbonation activity; dicalcium silicate (Ca2SiO4) absorbs less carbon dioxide than calcium hydroxide and C–S–H. The carbon dioxide uptake of SS, CCR and WHC are 6.1, 23.2 and 17.9%, respectively, after 2 h carbonation curing. Compacted SS, CCR and WHC specimens displayed a compressive strength of 74.9, 20.5 and 28.6 MPa after carbonation for 2 h. Compressive strength development depends on carbon dioxide uptake and mechanical properties of raw materials and carbonation products. Calcium carbonate (CaCO3) and amorphous products fill the pore structure, making the matrix denser; improvement of pore structure relates positively to carbon dioxide uptake. The highest compressive strength of compacted SS is mainly caused by the high elastic modulus of SS and formation of C–S–H gel in the carbonation process.

Material Jetting (MJ), also known as poly-jet printing, is one type of additive manufacturing (AM) process that involves selectively curing materials using UV light and drops over a selected area. The material can be either jetted when required or continuously depending upon the type of object to be created. In this article, an attempt is made to describe the fundamentals of the material jetting process. The characteristics of the parts printed using material jetting, such as dimensional accuracy, surface quality, and other mechanical properties, are discussed thoroughly. Furthermore, the factors which affect the mechanical properties of the parts created by the material jetting process are highlighted in this study. Also, various applications of the material jetting process in modern times are explored briefly as material jetting is a unique additive manufacturing process that can be used to print multi-colored parts.

Red mud (RM) is an industrial by-product created during the production of alumina/aluminium that has engendered severe environmental concerns arising from its improper disposal. To mitigate the negative environmental impact of RM waste and produce a sustainable material having high mechanical performance (particularly ductility) for a variety of applications, this study developed an alkali-activated fiber reinforced composite (AAFRC) using RM, ground granulated blast-furnace slag (or slag), and silica fume as the precursors. The effects of two different curing conditions (ambient-curing and heat-curing) on the mechanical properties and microscopic characteristics of the material were systematically investigated. The heat-cured RM-derived AAFRC exhibited excellent tensile strain capacity (or ductility) of up to 5.6%, which was significantly higher than that of its counterpart that was cured under ambient condition. Despite the reduction in strength caused by heat-curing, AAFRC retained adequate tensile and compressive strengths of 4.0 and 75 MPa, respectively. The results of three-point bending, single crack tensile, and single fiber pullout tests provided reasonable explanations for the tensile behaviors of the studied material. Scanning electron microscopy revealed that a less compacted matrix was formed in the RM composite due to heat-curing. The combined results from energy dispersive spectroscopy and nanoindentation tests indicated that adding red mud did not alter the types of reaction products for the material, which were similar in composition to conventional alkali-activated slag while also including C-A-S-H and N-A-S-H gels in addition to a type of layered double hydroxide. These findings can serve as theoretical guidelines for the future design and application of eco-friendly, high-ductile cementless composites prepared from RM waste.

A new type of explosive ink formulation that can be quickly cured was prepared with unsaturated polyester as binder, styrene as active monomer, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide as photoinitiator, and hexanitrohexaazaisowurtzitane (CL-20) as the main explosive. Then the explosive ink direct writing technology was used to charge the micro-sized energetic devices, the curing mechanism of the explosive ink was discussed, and the microstructure, safety performance and explosive transfer performance of the explosive ink molded samples were tested and analyzed. Results indicate that the composite material has a fast curing molding speed, its hardness can reach 2H within 8 min. The crystal form of CL-20 in the molded sample is still e type. The CL-20 based UV-curing explosive ink formulation has good compatibility, its apparent activation energy is increased by about 3.5 kJ/mol. The composite presents a significant reduction in impact sensitivity and its characteristic drop height can reach 39.8 cm, which is about 3 times higher than the raw material. When the line width of charge is 1.0 mm, the critical thickness of the explosion can reach 0.015 mm, and the explosion velocity is 7129 m/s when the charge density is 1.612 g/cm3.

Ceramic mask stereolithography additive manufacturing technology has the abilities of fast and accurate printing complex and personalized ceramic parts. However, since the ultraviolet light is strongly blocked by the ceramic particles in the slurry during exposure, the slurry with high refractive index ceramic particles has low cure depth, and serious light scattering. This investigation developed a curable silicon nitride slurry with a high refractive index liquid phase, which significantly reduced the refractive index difference between the liquid phase and the silicon nitride ceramic particles. The high refractive index acrylate monomer and solvent were chosen to increase the cure depth while ensuring the curing accuracy. Compared with the slurry whose liquid phase was pure HDDA, the addition of OPPEA and ACMO in the liquid phase showed a better refractive index increasing effect and the strongest cure depth and dimensional accuracy improvement. POE was verified as a suitable non-reactive high refractive solvent. The composition of 20 wt% OPPEA, 10 wt% ACMO, 40 wt% HDDA, and 30 wt% POE were optimized as the high refractive index liquid phase for 40 vol% solid phase silicon nitride slurry. A finite element analysis model of silicon nitride slurry was established, and the distribution of ultraviolet light intensity in silicon nitride slurry with high refractive index liquid phase was numerically simulated.

Worldwide, precast concrete elements are becoming the primary construction materials, and there have been conducted numbers of studies on their manufacturing process, mechanical properties and curing regime. However, the energy consumption of the precast concrete manufacturing process and specifically the curing process is ignored by researchers. In this study, a thermal model of a curing unit, including three main sections: a curing room, a steam transfer system and a boiler, is developed. Besides, based on the mathematical formulation of heat transfer, a MATLAB code is prepared to determine the heat transfer, the mass of steam, the mass of fuel and the annual fuel cost. By the MATLAB code, the effect of different parameters on the curing process energy consumption and the fuel cost is investigated. Eventually, a smart control system that is based on the condition of the curing unit in every moment is suggested. This system leads to a reduction of 30% of energy consumption and the annual fuel cost.

The main objective of this work is to develop a new polymer based composite material having different reinforcement angle orientations and studies its tensile behavior. For fiber reinforced polymer matrix composites E-2 glass fiber reinforcement and epoxy resin for matrix is used. E-2 g1ass fiber has high strength, chemical resistance and good insulating properties. Epoxy being less viscous allows good adhesion to fibers used in laminate preparation, without misalignment of fibers. Hand layup technique has been adopted for preparation of laminate. Glass fibers are laid, mixture of epoxy resin and hardener is smeared on it alternately, until laminate of desired thickness is achieved, and is left to atmosphere for curing. 2.5 mm laminate is prepared by placing glass fibers of 0.25 mm thickness one above the other. The prepared laminate is then taken for cutting according to ASTM standards (D3039) of 3 sets of rectangular specimens. For first set comprises of 90° angle-oriented specimen, second and third sets for 45° and 30° respectively. These specimens are subjected to tensile test in Lloyd UTM and load being applied gradually at the rate of 2 mm/min is continued until the material fails. The computer simulation plots the graph during the entire testing process and stops when the material fails.

The research carries out the simulation of the growth of the polyurethane foam inside a mold, in order to optimize the resources. The aim finds the accurate option within a production process both in the incorporation of a new product as in improving an existing one. Using the Moldex3D program, the project obtains a mathematical model to calculate parameters such as the viscosity of the material, pressure, volume, temperature, curing, foaming, heat capacity, thermal conductivity and mechanical properties of the material. The density obtained for the material analyzed experimentally is 59.09 kg·m−3 with a uniform watering at the base with a 10 degrees mold inclination with 1740 g of material and air outlets that help to obtain better conditions of mold, seeking to reduce the time used by 25% and reduce manufacturing costs.

In recent decades, natural fibers have emerged as a rising trend in materials research as a reinforcement for polymer matrix materials and as a replacement for non-biodegradable, non-renewable, and high-density synthetic fabrics. The main objective of this research is to examine the mechanical characteristics of hemp and flax-based hybrid composites reinforced with epoxy resin at cryogenic and room temperatures. The composites were made using a hand lay-up approach, with both fibers being prepared with a NaOH solution for 4 h to improve interfacial adhesion. It is apparent from this research that cryogenic temperature has a significant impact on the flexural, tensile and impact characteristics of polymer composites, and that these qualities vary depending on the amount of cryogenic treatment. After being submerged in liquid nitrogen for 15, 30, and 45 min, the specimens are tested for tensile, flexural, and impact characteristics. An untreated specimen has the highest tensile strength of 27.89 MPa, a flexural strength of 58.95 MPa, and impact strength of 10.94 kJ/m2, with the value decreasing as the curing period rises.

Thermally conductive (TC) adhesive tapes consisting of adhesives and TC fillers are widely used as thermal interface materials because of their tack properties for temporary fixation and high peel strength for permanent bond. However, the trade-off between peel strength and thermal conductivity with increasing filler loading impedes the manufacture of high-performance TC tapes. Therefore, a technique to realize high thermal conductivity of TC adhesives with lower filler loading is crucial. In this study, epoxy-based adhesives (EAs) was used to fabricate TC adhesive tapes. To secure high peel strength of EAs, a cyclic carbonate-terminated oligomer (CCO) was synthesized and employed as a component. The simultaneous reactions between epoxy resin, CCO and curing agent were analyzed using FTIR spectroscopy. Thanks to tack, the partially cured EAs could be used to fabricate tapes which were temporarily fixed and then permanently bonded via complete curing. Next, EAs and h-BN fillers were admixed to produce TC adhesive tapes. Because h-BN fillers were partially aligned to the in-plane direction by bar-coating, the in-plane thermal conductivity of the TC-1 adhesive containing only 20 wt% h-BN fillers was as high as 2.73 W/m K, which was slightly lower than that (2.97 W/m⋅K) of the TC-4 adhesive containing 35 wt% h-BN fillers. In addition, the peel strength of the TC-1 adhesive tape reached 2307 (± 64) gf/in.

Lignosulfonate (LS) was successfully introduced into the epoxy resin matrix with the aid of ethylene glycol (EG) dissolution. Both the rigid LS and soft EG segments were linked into the cross-linked network structure of epoxy resin via esterification of hydroxyl groups in LS and EG molecules with anhydride. The ultimate properties of cured samples were adjusted effectively by changing the proportion of LS and EG components. Curing reaction and kinetics were analyzed, by which the optimal curing process parameters were determined. Although thermal stability of LS itself was relatively lower than that of neat epoxy, the thermal performance was significantly enhanced for the modified sample of epoxy/LS0.5-EG0.5. At the same time, the flexural strength, flexural modulus and impact strength were found to be increased by 23.1, 35.7 and 15.1% respectively compared with the neat epoxy. In addition, the excellent shape memory behavior and improved mechanical stability with LS addition were exhibited by the cured LS-EG modified specimens. This work reveals that lignin can be used as an efficient functional additive to regulate thermal, mechanical and shape memory properties of epoxy resin.

The sustainable utilization of demolition wastes in the production of building materials is regarded as an eco-efficient approach for conserving naturally-occurring resources accompanied by resolving the environmental problems caused by these wastes. Accordingly, the motivation behind this work is evaluating the single and combined effect of nano-waste ceramic (NWC) and nano silica (NS) on the performance of Portland cement concrete. Portland cement was individually replaced by different contents of NWC (2-10 wt. %) and NS (1-4 wt. %). Another mixture was designed to evaluate the synergetic impact of NS and NWC mixture (3 and 6 wt. %) on the performance of concrete. The mechanical (flexural, splitting tensile and compressive strengths) and nondestructive tests (Ultrasonic Pulse Velocity ‘UPV’) were carried on the control and nano-modified hardened concrete. The results showed that the increase of NWC content up to 6wt. % has resulted in a noticeable increment in strengths at all curing ages, followed by a reduction in strengths when NWC content reaches 10 wt. %. However, the usage of 10% NWC illustrates a slight enhancement in strengths compared to control sample. All over the mixtures, the nano-silica modified samples demonstrate a slight enhancement in the mechanical properties compared to NWC. The highest mechanical properties accompanied by the shortest transmitted waves were achieved by the hardened samples having the mixture of 3 wt. % NS and 6 wt. % NWC. This means that the sustainable utilization of NWC not only improves the performance of concrete but also resolves the environmental problems caused by this waste. The sustainable utilization of demolition wastes in the production of building materials is regarded as an eco-efficient approach for conserving naturally-occurring resources accompanied by resolving the environmental problems caused by these wastes. Accordingly, the motivation behind this work is evaluating the single and combined effect of nano-waste ceramic (NWC) and nano silica (NS) on the performance of Portland cement concrete. Portland cement was individually replaced by different contents of NWC (2-10 wt. %) and NS (1-4 wt. %). Another mixture was designed to evaluate the synergetic impact of NS and NWC mixture (3 and 6 wt. %) on the performance of concrete. The mechanical (flexural, splitting tensile and compressive strengths) and nondestructive tests (Ultrasonic Pulse Velocity ‘UPV’) were carried on the control and nano-modified hardened concrete. The results showed that the increase of NWC content up to 6wt. % has resulted in a noticeable increment in strengths at all curing ages, followed by a reduction in strengths when NWC content reaches 10 wt. %. However, the usage of 10% NWC illustrates a slight enhancement in strengths compared to control sample. All over the mixtures, the nano-silica modified samples demonstrate a slight enhancement in the mechanical properties compared to NWC. The highest mechanical properties accompanied by the shortest transmitted waves were achieved by the hardened samples having the mixture of 3 wt. % NS and 6 wt. % NWC. This means that the sustainable utilization of NWC not only improves the performance of concrete but also resolves the environmental problems caused by this waste.

The present study aims to apply an electrostatic dry powder coating process to coat aspirin tablets with polymer blends to produce a single-layer coating film, which potentially allows an advantageous delayed sustained drug release profile. The coating formulations containing polymer blends of enteric polymer (hydroxypropyl methylcellulose phthalate or hydroxypropyl methyl cellulose acetate-succinate) and insoluble polymer (Eudragit® RL) were successfully developed and optimized. Results of scanning electron microscopy and acid resistance test demonstrated that curing conditions had a significant impact on the qualities of the produced film. Drug dissolution experiments revealed that changes in the coating level and the coating formulation with different ratios of the enteric polymer to the insoluble polymer achieved an altered and adjustable drug release profile. All of the results suggested that electrostatic powder coating technology is capable to produce a satisfactory coating film with polymer blends, allowing an advantageous functionality of delayed sustained drug release.

High–temperature proton exchange membrane fuel cells (HT–PEMFCs) are pursued worldwide as efficient energy conversion devices. Great efforts have been made in the area of designing and developing phosphoric acid (PA)–based proton exchange membrane (PEM) of HT–PEMFCs. This review focuses on recent advances in the limitations of acid–based PEM (acid leaching, oxidative degradation, and mechanical degradation) and the approaches mitigating the membrane degradation. Preparing multilayer or polymers with continuous network, adding hygroscopic inorganic materials, and introducing PA doping sites or covalent interactions with PA can effectively reduce acid leaching. Membrane oxidative degradation can be alleviated by synthesizing crosslinked or branched polymers, and introducing antioxidative groups or highly oxidative stable materials. Crosslinking to get a compact structure, blending with stable polymers and inorganic materials, preparing polymer with high molecular weight, and fabricating the polymer with PA doping sites away from backbones, are recommended to improve the membrane mechanical strength. Also, by comparing the running hours and decay rate, three current approaches, 1. crosslinking via thermally curing or polymeric crosslinker, 2. incorporating hygroscopic inorganic materials, 3. increasing membrane layers or introducing strong basic groups and electron–withdrawing groups, have been concluded to be promising approaches to improve the durability of HT–PEMFCs. The overall aim of this review is to explore the existing degradation challenges and opportunities to serve as a solid basis for the deployment in the fuel cell market.

Curtains with light-to-heat conversion capacity can warm up a room under solar radiation and improve the thermal energy efficiency of buildings, thereby reducing energy consumption during winter. Herein, a photothermal silk fibroin aerogel is synthesized by freeze-drying and curing method, using silk fibroin (SF) as template and scaffold, copper sulfide nanoparticles (CuS NPs) as photothermal conversion material, polyethylene glycol (PEG) as plasticizer, and polydimethylsiloxane (PDMS) as the package agent. The results reveal that SF as the template may guide the growth of CuS NPs, and the introduction of PEG improves the flexibility of the prepared CuS@SF aerogel. The composite CuS@SF-PEG/PDMS aerogel not only preserves the initial characteristics of SF aerogel but also integrates hydrophobic, rapid antibacterial ability, high-performance photothermal conversion efficiency, and stable switching effect. The lightweight, self-heating SF-based aerogel can be applied to the preparation of home textiles such as smart curtains. Additionally, it can be used as absorbent for cleaning up viscous oil from water, which could expand the applications of SF-based biomaterials toward meeting the requirements of sustainable developments.

The present work studies the influence of zinc borate (ZB), magnesium hydroxide (MH) and ammonium polyphosphate (APP) as flame retardants on the curing, mechanical, thermal and flammability performances of Kevlar fibre (KF)-reinforced ethylene propylene diene monomer (EPDM) rubber composites. The flame retardant EPDM/KF composites were prepared with variable ratio of ZB, MH and APP. Thereafter, physicomechanical and thermal properties of the fire retardant EPDM/KF composites were analysed with density analysis, tensile testing, TGA analysis, SEM and cone calorimeter tests. The TGA analysis and cone calorimeter tests showed the enhancement in the flame retardant properties of the EPDM/KF composites with the addition of combined fillers with respect to the virgin counterparts. The synergistic effect of ZB and APP containing flame retardant-incorporated composites exhibited a prominence in the thermal stability and fire retardancy. Heat release rate (HRR) and total heat release rate (THR) of the ZB and APP combined fire retardant-incorporated composites were lower than the virgin EPDM.

Stress-induced damage in a MOSFET can be cured by Joule heating, which can be produced by an intentional forward junction current ( ${I}_{\textbf {FWD}}$ ). This curing effect can be further enhanced by the simultaneous application of gate biasing, which does not influence the ${I}_{\textbf {FWD}}$ . A MOSFET was intentionally degraded by harsh hot-carrier injection (HCI) then the damage was cured and nearly returned to its pristine state. The improved self-curing effect was quantitatively verified using low-frequency noise (LFN) analyses. Self-curing by internal heat from the ${I}_{\textbf {FWD}}$ more effectively cured the HCI damage than a nonself-curing using external heat from a hot chuck.

Digital light processing (DLP)-based ceramic stereolithography has attracted significant attentions due to the high printing speed and high dimensional accuracy of DLP printers. However, undesired dropping of unfinished ceramic parts during printing, owing to inadequate adhesion between the first cured layer and the substrate of the building platform, still remains a challenge. In this study, the relationship between the adhesion properties of ultraviolet (UV)-curable alumina (α-Al2O3) suspensions and the functionalities and structures of UV-curable acrylate monomers was investigated. With an increase in the proportions of monofunctional monomers, the adhesion abilities of UV-curable alumina suspensions enhanced because of reduced volume shrinkage, however, inferior curing performances were observed due to a decrease in the double bond densities. Furthermore, the large-volume branched chain structures in monofunctional monomers and ethyoxyl groups in polyfunctional monomers effectively decreased the volume contraction, improving the adhesion performances of UV-curable alumina suspensions and facilitating the conversion of double bonds to provide excellent curing properties, further guaranteeing strong adhesion of these suspensions to the substrate.

Soilcrete properties modified with two types of polymer up to 0.20 % (% wt. dry weight of cement) were tested and quantified. The stress–strain curve of modified soilcrete with polymers was examined for curing periods up to 28 days and modeled using two different mathematical models. The flowability of the soilcerte was maintained within the range of 105 to 110% as recommended by ASTM standard. Polymers decreased the water/cement ratio ( w / c ) by 14.5 to 25.5%, based on the type and amount of polymers. The compressive strength and modulus of elasticity of soilcrete increased by 72% to 153% and by 55% to 195%, respectively, when the soilcrete was modified with 0.20% of polymers. The nonlinear Vipulanandan p-q equation was employed to predict the stress–strain behavior of the modified soilcrete with polymers and was compared with the β model prediction. Based on the statistical evaluation tools, the Vipulanandan p-q model predicted the stress–strain relationships better than β model. Linear (LM) and nonlinear relationships (NLM) were also used to predict the compressive strength, modulus of elasticity, and toughness of the soilcrete as a function of w/c, curing time, and polymer contents.

Chloride attack on reinforced concrete is considered the most important aspect in concrete durability investigation. This study is carried out to investigate effect of curing condition on the chloride binding capacity of fly ash geopolymer pastes containing a range of cast in chloride contents (NaCL), varying from 1%, 2% and 4% by mass of binder. The applied curing regimes were normal, oven, steam and microwave. The impact of induced chlorides on the compressive strength and on the chloride binding capacity of fly ash geopolymers under different curing conditions is determined. A detailed microstructure and phase composition analysis were conducted through SEM and XRD tests. It was observed that applying thermal curing conditions could increase the chloride binding capacity to the formed geopolyric hydration product. High curing temperatures promote the precursor dissolution reactions and will increase the overall generation of polymerization reaction products, while under normal curing a lot of fly ash grains did not fully react. Therefore, thermal curing is important in the activation of geopolymerization process that increase aluminosilicate gel and result in dense and less porous geopolymer matrix and yields in high compressive strength. This results in the physical adsorption and chemical binding of chloride ions on the gel surface, and hence reducing the rate of chloride ingress. It was concluded that the ingress of chlorides can be particularly controlled better through binding the free chloride ions under steam and microwave curing in the fly ash geopolymer concrete.

Purpose: To verify the color change and contrast ratio of resin composites after curing and after 30 days of storage in water. Methods: Dentin A2 shades of different light-cured dental resin composites (Vittra APS, FGM, Brazil; Z350 XT, 3M ESPE, EUA; Tetric N-Ceram, Ivoclar Vivadent, Liechtenstein, and Charisma Diamond, Heraeus Kulzer, Germany) were tested. Ten rounded specimens (8 mm × 2 mm) were prepared for each material. Reflectance for all samples was obtained using a spectrophotometer (Minolta CM 3700d, Konica Minolta, Japan) before curing, immediately after curing, and after 30 days of storage in water. The color change (ΔE*lab) and contrast ratio (CR) data were analyzed using a one-way analysis of variance with Tukey's and paired t-tests (α = 1%). Results: For all materials tested, significant color changes were noticeable after curing and after 30 days in water (p 0.01). Conclusion: The CR values and color changes after curing and 30 days of storage in water varied depending on the material tested. This study corroborates the clinical practice of curing a small amount of unpolymerized resin composite on the tooth surface to select the desired shade before undertaking esthetic restorative procedures.

Stereolithography is one of the most widely used additive manufacturing techniques for preparing high precision and complex ceramic components. Due to the high optical absorbance and refractive index of SiC powder, the rapid stereolithography of SiC ceramics components has become a key challenge. Here, we innovatively use graded silica to improve the curing thickness, rheological and settling performance of the slurry. And we presented a preparation method of SiC ceramic slurry for stereolithography with high solid content, low viscosity, low sedimentation rate and high curing thickness. The printable precision of the slurry is more than 75 μm, the dynamic viscosity is less than 2 Pa·s, and the 24 h sedimentation height is less than 5%. This strategy demonstrates a tantalizing possibility and promising prospect to rapid stereolithography of large size SiC ceramic green body.

Metakaolinis the principal raw material utilized in the synthesis of geopolymers, although its ratio of silica and alumina contents is not ideal. Normally, the SiO2 content is adjusted with the use of silicates present in the activating solution. An eco-efficient alternative would be the use of glass waste as an additional source of silica.This work evaluates the efficiency of the alkaline activation of metakaolin, using potassium hydroxide and silicate, with and without the substitution of 12.5% of metakaolin by microparticles of glass. The efficiency of the alkaline activation was evaluated by X ray diffractometry, spectroscopy in the infrared region with the Fourier transform, nuclear magnetic resonance spectroscopy of 27Al and 29Si, specific mass and compressive strength. The results indicate the occurrence of geopolymerization with and without the use of glass waste. It was observed that the substitution of 12.5% favors the mechanical performance of the compounds at 28 days, with increases by 37% and 47% in the mechanical strength of the material with thermal curing and ambient temperature curing, respectively. Resumo O metacaulim é a principal matéria-prima utilizada na síntese de geopolímeros, embora a relação entre os teores de sílica e alumina não seja a ideal. Normalmente, o teor de SiO 2 é ajustado com o uso de silicatos presentes na solução ativadora. Uma opção ecoeficiente seria o uso de resíduos de vidro como fonte adicional de sílica. Este trabalho avalia a eficiência da ativação alcalina do metacaulim, utilizando hidróxido e silicato de potássio, com e sem substituição de 12,5% de metacaulim por micropartículas de vidro. A eficiência da ativação alcalina foi avaliada por difratometria de raios x, espectroscopia na região infravermelha com transformada de Fourier, espectroscopia de ressonância magnética nuclear do 27 Al e 29 Si, massa específica e resistência à compressão. Os resultados indicam a ocorrência de geopolimerização com e sem uso de resíduo de vidro. Observou-se que a substituição de 12,5% favorece o desempenho mecânico dos compósitos aos 28 dias, com aumentos de 37% e 47% da resistência mecânica do material com cura em estufa e na temperatura ambiente, respectivamente.

This paper presents an experimental investigation on influence of different curing methods on the performance of M30 grade concrete. Different curing methods such as air curing, pond curing, intermittent curing, gunny bags curing, chemical curing and using Super Absorbent Polymer (SAP) by 0.3% of weight of cement are considered. Slump and compacting factor tests are performed to know the workability of fresh concrete. Compressive strength of hardened concrete is determined for concrete specimens cured by different curing methods. Durability in terms of carbonation resistance on hardened concrete is also performed as per IS 516 (Part 5/Sec 3, 2021) codal provisions. Depending upon the site conditions and availability of potable water, curing methods such as pond curing, intermittent curing, gunny bags curing, chemical curing and SAP curing can be adopted in site to achieve the expected strength and durability requirements. Keywords: Curing methods, Compressive strength and Carbonation resistance.

The limited applicability of very high dielectric permittivity ceramic materials such as copper calcium titanium oxide, commonly known as CCTO (er = 100,000 at room temperature and nearly independent of frequency from 1 Hz to 1 MHz), could be improved through the fabrication of polymer matrix composites. Ceramic is brittle while polymers are materials that are ductile and have excellent flexibility but low er. Another contrast between the two materials is the fabrication process where ceramic, specifically, requires pressing and a high sintering temperature. Hence, the right combination of ceramic and polymeric materials should theoretically produce a composite with excellent mechanical and electrical properties. Therefore, a study on CCTO ceramic powder blended with 25 mol% of epoxidised natural rubber (ENR-25) was carried out. The CCTO powder was initially synthesised through solid-state reaction followed by compounding with ENR-25 formulations with different CCTO loadings (0, 20, 40, 60, 80, 100, and 120 phr) in an internal mixer. Small blocks of the composite were cast into ~ 2 mm of mould thickness and then hot compressed into square shapes. Samples were characterised by curing, mechanical, electrical, and microstructural properties. As a result, the addition of CCTO was found to have lowered the curing time, i.e. tc90 at 20 phr, compared to composites without CCTO loading. Then, the curing time gradually increased with filler loading from 2.05 to 2.48 at 20 to 120 phr loading, respectively. Mechanical testing of the composites showed an increase in tensile strength from 5.91 to 16.46 MPa. However, with content higher than 40 phr content, the tensile strength's magnitude gradually decreased with increasing filler loading from 13.63 to 6.49 MPa. In comparison, hardness properties increased with an increase of filler loading from 30.5 to 44.7 Shore A. Meanwhile, LCR meter showed that increased CCTO content could improve er value from 6.134 to 12.114 at 75 kHz and decrease the dielectric loss (tan δ) from 0.179 to 0.150 at 2 MHz. The composite's microstructure also shows CCTO crystals embedded in the ENR-25 with excellent surface contact. The surface morphology showed that samples with filler content of 60 phr onwards had a lot of CCTO particle pore agglomeration, which reduced its mechanical strength from 16.46 to 6.49 MPa.

Objectives To evaluate the biaxial flexural strength (BFS), flexural modulus (BFM), and Knoop microhardness (KHN) of incremental and bulk-filled resin-based composites (RBCs) using extended curing exposure times. Materials and methods Disc specimens (n = 8; 6-mm diameter) were fabricated using three stacked molds (0.5-mm thick for the top and bottom molds, and a 1-mm-thick center mold for the conventional and 3-mm thick for the bulk-fill RBCs). Conventional (Tetric EvoCeram/TCE and Filtek Z250/FIZ) and bulk-fill RBCs (Tetric EvoCeram Bulk Fill/TBF and Filtek One Bulk Fill Restorative/FOB) were evaluated. The stacked RBC-filled molds were light-cured for (1) the manufacturer-recommended exposure (MRE) duration; (2) 50%, and (3) 100% extension of the MRE. The BFS, BFM, and KHN of the top and bottom discs were measured. BFS and BFM were analyzed by three-way ANOVA (material*curing time*depth) and Tukey's post hoc (α = 0.05). KHN was analyzed by two-way ANOVA (curing time*depth) and Tukey's post hoc (α = 0.05). Results Extending the exposure duration did not change the BFS and BFM on the top of the RBCs, but the BFS and KHN increased at the bottom of bulk-fill RBCs. For the conventional RBCs, TCE showed the highest increase on BFS at the bottom, going from 53.6 MPa at T1 to 69.9 at T3. Among the bulk-fill RBCs, FOB presented the highest increase on the bottom BFS (T1: 101.0 ± 19.9 MPa, T3: 147.6 ± 12.9 MPa). For all RBCs and exposure times, BFS and KHN were lower at the bottom. Only FIZ and FOB reached a bottom-to-top hardness ratio of 80%, at T3 and T2. Conclusion A significant increase on the BFS and KHN on the bottom of bulk-fill RBCs can be observed when the time of exposure to the curing light is double the MRE. However, extended exposure does not eliminate differences on the BFS and KHN between the shallow and deep regions of RBCs. TCE and TBF failed to reach an acceptable B/T hardness ratio at all evaluated exposure times. Clinical relevance Mechanical properties of RBCs can be affected by insufficient polymerization, specially at deeper regions of the increment. Therefore, clinicians should consider applying twice the MRE to curing-light to polymerize the maximal increment thickness of bulk-fill RBCs.

The development of materials with high thermal stability and good hydrophobicity is important in the field of coatings. Fluorinated benzoxazines are good choices for coating applications; however, fundamental discussion among structure, curing mechanism, and properties is still scarce. Thus, a series of new fluorinated benzoxazines, including totally new meta-fluoroaniline-, ortho-fluoroaniline-, and para-fluoroaniline-based benzoxazine, is successfully synthesized. The effect of different substituted positions of fluorine atoms on the curing mechanism, thermal stability, and surface properties of polybenzoxazines is discussed in detail based on experimental and theory analysis. The structural and geometrical parameters were investigated by NMR (1H, 19F) and FTIR spectroscopy. The curing peak temperature of fluorine-substituted benzoxazines was found to be in order of meta-fluoroaniline benzoxazine (m-Bf, 235.9 °C)

The profiles, mechanical performance, and structure of the hybrid coatings cured at three cure windows (25 ± 2 °C, 3 h; 120 °C, 1 h, and 250 °C, 1 h) were investigated in this paper. Why SiO2/resole hybrid coatings at 250 °C, 1 h have excellent mechanical performance is revealed, suggesting a new way for preparing other inorganic/organic hybrid coatings. The influences of elevating curing temperature on the film performance are mainly determined by two factors: more cross-linking reactions and breaks of Si-O-Si bonds. The break and rearrangement of Si-O-Si bonds relieve the brittleness caused by more crosslinking so that SiO2/resole hybrid coatings cured at 250 °C, 1 h still exhibit excellent adhesion and mar resistance. The color change of the coatings cured at 250 °C, 1 h is ascribed to the presence of FTIR band at 1658 cm−1, suggesting part of methylene groups between phenolic rings being transformed into aceto groups by oxidation. Owning to the presence of the excellent high-temperature adhesion, the hybrid coatings used as primers can meet the temperature demand for curing any organic coatings applied on them.

Corin is a type of artificial stone that is produced without the use of cement and is actually a type of polymer concrete. Unsaturated polyester resin is used as an adhesive and aluminum trihydrate ATH powder is used as a filler to produce artificial stone. This stone usually composed of 25 wt% of unsaturated polyester resin and75 wt %of ATH which has low bulk density. Because of this and also other advantages such as non-porous structure result in low water absorption and anti-bacterial properties, Corian artificial stone has many applications. One of the disadvantages of this type of stone is its high price, which is due to the high price of ATH . Another disadvantage of Corinne is its low compressive strength. In this research, in order to reduce the cost price of Corinne and increase the compressive strength, additional materials such as ceramic tile waste powder, stone powder, gypsum and cement have been used. The study was divided into 4 phases. In each phase, one of the additives was substituted forATH by a certain weight. Hardener is a material that is added to the resin as a part of curing. The hardener used in this study is methyl ethyl ketone peroxide of 2 wt % resin. After mixing the resin and hardener, the powder and ATH were added to the mixture and finally, cobalt as catalyst was added to the mixture of 1 wt % resin. After mixing and curing at ambient temperature, compressive strength of samples at1 ,3 ,7 ,14 and 28 days were measured. At each stage, one of these materials replaces part of theATH . Then the compressive strength of the samples at different ages1 , 3 ,7 , 14 and28 were measured. The results showed that by replacing 15% ceramic tile waste, 60% rock powder, 50% gypsum and 50% cement, compared to the weight of , it increased the compressive strength of the samples by20.9 ,16 ,18.6 and 31.2 percent

Different mechanical properties characterise the materials of 3D printed components, depending on the specific additive manufacturing (AM) process, its parameters, and the post-treatment adopted. Specifically, stereolithography (SLA) uses a photopolymerisation technique that creates solid components through selective solidification. In this study, 72 specimens were 3D printed using 12 commercial-grade methacrylate resins and tested under uniaxial tensile loads. The resin specimens were evaluated before and after curing. The recommended cure temperature and time were followed for all materials. The stress-strain curves measured during the testing campaign were evaluated in terms of maximum tensile strength, Young’s modulus, ductility, resilience, and toughness. The results reveal that the curing process increases the material stiffness and resistance to tensile loads. However, it was found that the curing process generally reduces the plasticity of the resins, causing a more or less marked brittle behaviour. This represents a potential limitation to the use of SLA 3D printing for structural elements which require some plasticity to avoid dangerous sudden failures.

Background: Many recent studies have focused on the potential hazards of blue light exposure to ocular health. One group with a unique blue light exposure risk is dentists, who use curing lights that emit intense blue light during restorative procedures. During these procedures, dentists often experience brief ocular exposure to these lights. The purpose of the present study was to explore whether such exposures may have an effect on the vision and ocular health of dentists. Methods: A group of 12 dentists who had experienced curing light exposure over a period of 10 or more years were compared to a group of eight control subjects with no such exposure. The subjects were tested for visual acuity and contrast sensitivity. Their retinas were examined using fundus imaging and optical coherence tomography. Macular pigment optical density was measured. The likelihood that brief blue light exposure could lead to ocular effects was further explored by subjecting a retinal pigment epithelial cell (RPE) line to such exposures. Results: Although no visual defects or ocular pathologies were found in either group, the dentist group differed from the control group in having increased macular thickness (P < 0.02), a higher incidence of macular vessel tortuosity (P < 0.05), and greater variance in their macular pigment optical density values (P < 0.01). RPE cells that received blue light exposure similar to those sustained by dentists demonstrated a change in physiology. Conclusions: Retinal changes were found in dentists, which, while not pathological in themselves, are associated with some retinal pathologies. Further studies are necessary to determine whether these signs correlate with the degree of curing light exposure and to determine whether they eventually develop into pathological conditions.

To meet the processing requirements of resin transfer moulding (RTM) technology, reactive diluent containing m-phenylene moiety was synthesized to physically mixed with phenylethynyl terminated cooligoimides with well-designed molecular weights of 1500−2500 g/mol derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 3,4'-oxydianiline (3,4'-ODA) and m-phenylenediamine (m-PDA). This blend shows low minimum melting viscosity (