Use Of Release Agents Research Articles

Influence of Biodegradable Release Oils on the Physical and Mechanical Properties of Light-Colored Architectural Concrete.

In the article, unique formulations of biodegradable, non-toxic, edible oil-based release oils were developed and tested on architectural concrete. The produced agents have physicochemical properties similar to diesel fuel, but at the same time, are renewable and biodegradable products. An ultrasound was used to properly combine the liquid phase of edible oil and the liquid phase of glyceryl trioleate and/or water. Based on the PN-B-19305 standard, seven-component configurations were designed and then tested. The wettability of the concrete was determined by contact angle (CA) analysis. After the application of the formulations produced, the architectural concrete still had good wettability. The vapor permeability test showed that the tested release agents did not inhibit water vapor diffusion from the tested samples. The O65G35 (65% unique edible oil formula and 35% glyceryl trioleate) concrete had the best absorption. In this case, the CA was 56° after oil application and 46° before. The new agents did not impair the adhesion of the plaster to concrete. The O90W10 concrete showed the best adhesion of plasters made with it—51.9 kN/m2. The study also showed that the concrete surface had excellent paint absorption despite the use of release agents. The architectural concrete was evenly covered with paint without any problem. There were no difficulties in applying it, e.g., greasy places preventing the concrete from being coated with emulsion. The suitability of the produced release oils for lightweight architectural concrete structures intended for facades was confirmed. The best results were obtained after using formulations O65T35 and O90W10.

Manufacture of polyurethane foam parts for automotive industry using FDM 3D printed molds

Metal molds have traditionally been used in the manufacture of polyurethane foam parts. This type of molds presents several disadvantages: have a high cost; need a long time for their manufacture; involve the use of release agents during the demolding operation. As an alternative, the use of molds manufactured by fused deposition modeling is proposed. These 3D printed molds have a poor surface finish, which complicates the demolding operation. To overcome this handicap, materials that can be chemically polished have been studied: acrylonitrile butadiene styrene and high impact polystyrene. Acrylonitrile butadiene styrene can be polished by exposure to acetone vapors and high impact polystyrene by immersion in limonene. This post-processing operation allows to reduce the surface roughness of the 3D printed mold. To simulate the industrial use of the mold, seven molding-demolding cycles have been performed. To measure the ease of demolding of each material, a pull-off test has been used. The results indicate that high impact polystyrene has less affinity with polyurethane foam than acrylonitrile butadiene styrene. In addition, although release agent is used in cycle 1, with high impact polystyrene specimens, it is not necessary to use it in cycles 2, 3 and 4; this means a saving of release agent. Furthermore, the chemical polishing of high impact polystyrene by immersion in limonene has several advantages: it is performed in a short time; it allows to obtain an excellent finish regardless of the initial surface roughness; it is done using a biodegradable solvent of organic origin. To experimentally demonstrate the viability of the proposed solution, a mold for the back of a car seat has been printed in high impact polystyrene via fused deposition modeling and chemically polished by immersion in limonene (1min); the geometrical deviations generated were less than 1mm.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods.

We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications.

Assured Use of Release Agents and Adhesives in the Same Production Process

Assured Use of Release Agents and Adhesives in the Same Production Process

Optimization of plasma surface modification parameter for fabricating a hot embossing mold with high surface finish

Hot embossing is a low-cost processing approach for polymer-based microfabrication. However, the time and cost are two major problems in the mold industry to produce a precision hot embossing mold with high surface finish for the pilot run in the new product development phase. This study investigates the optimum process parameters of plasma surface modification to fabricate a precision micro-hot-embossing mold without the use of release agent. The first silicone rubber mold with the lowest surface roughness can be utilized for fabricating a precision hot embossing mold using rapid tooling technology. It was found that the dominant factor affecting the surface roughness of the first silicone rubber mold is the plasma-arc distance. The optimum process parameters to fabricate a hot embossing mold with high surface finish are plasma power of 70 W, treatment time of 3 min, gas flow rate of 25 sccm, and plasma-arc distance of 40 mm. The replication rates for depth and width of the fabricated Al-filled epoxy resin mold about 92.4 and 98.1% can be obtained using the optimum process parameters. The improvement rate of the surface roughness of the fabricated Al-filled epoxy resin mold about 39.4% can be reached.

Development of a Micro-Hot-Embossing Mold with High Replication Fidelity Using Surface Modification

Micro-hot-embossing is an efficient method for manufacturing micro-components in polymeric materials. In the fabrication of micro-components by micro-hot-embossing, a precision mold with microfeatures is crucial. To reduce the manufacturing cost, rapid tooling has been employed to fabricate a precision epoxy resin mold. However, the release agent must be used in the fabrication process, leading to the reduction of the replication fidelity and surface finish of epoxy resin mold. The aim of this study is to present a method for fabricating a precision epoxy resin mold without the use of release agent in the manufacturing process through the surface modification of the first silicone rubber mold using a low-temperature plasma system. The advantages of this method include not only to increase the replication accuracy but also to improve the surface finish of the epoxy resin mold. The performance of a precision micro-hot-embossing mold was investigated to fabricate Fresnel lens on polymethylmethacrylate substrate using micro-hot-embossing. Fresnel lens with the transcription rate up to 99% can be obtained.

Methods to ease the release of thin polydimethylsiloxane films from difficult substrates

Silicone elastomers are used as dielectric electroactive polymers for making actuators, generators, sensors, and as artificial muscles in medical applications. Current requirements in the actuator manufacturing put a strict limitation on the thickness of the elastomers, such that a maximum permissible thickness is around 25–50 µm. The relatively small Young's modulus for these elastomers is a requirement for actuation capabilities. However, peeling and release of such films during manufacture processes are very difficult. To ease the release of the films, techniques such as the use of release agents like surfactants and detergents, incorporating resins in the silicone matrix and grafting/adding low surface energy functionalities to the silicone elastomer have been tested. The methods used are required not to interfere with the Young's modulus and the dielectric permittivity in a negative way. Polysorbate-20, a non-ionic surfactant, fulfills all requirements and gives the lowest peel forces for the films. Copyright © 2013 John Wiley & Sons, Ltd.

Characterization of shear stress at the tool‐part interface during autoclave processing of prepreg composites

AbstractIn this article, shear stress between an aluminum tool and a carbon fiber‐epoxy prepreg is characterized during cure using polymeric release agent and release film at the tool‐part interface. The effects of surface roughness, release materials, pull‐out speed, temperature, and normal force (autoclave pressure) on the shear stress are investigated using a customized friction rig. Results show that the interfacial shear stress decreases as the temperature increases and it increases as the normal force increases when using either the release film or the release agent. Additionally, changes in surface roughness from 1.35 to 0.18 μm decrease the shear stress 10–27% while the use of release agent shows a decrease between 23% and 51% in the shear stress. Furthermore, strong adhesion between the tool and the part is observed when using release agent and pull‐out speeds of 0.05 mm/min (static/dynamic friction ratio of 5.29 ± 0.19). Using the experimental data, a mathematical approach based on the Coulomb's friction model is proposed to predict the friction force at the tool‐part interface. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013