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Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The longevity of polymer-based sealant and jointing products, including elastomers, significantly depends on the level of exposure to sunlight and joint movement. These factors are particularly crucial in the application of polymers in construction due to their susceptibility to degradation under environmental conditions. For instance, diurnal cycles of contraction and dilation, arising from daily temperature fluctuations, impose significant stress on sealants and joints, impacting their durability over time. The elastic nature of polymeric sealants enables them to endure these cyclic mechanical loads. Athough there is considerable information on sealant durability obtained from laboratory accelerated aging, there is limited knowledge about the effect of climatic factors using historical and projected weather data on the durability and expected service life of these products. This study employed the Shephard crack growth model to predict the performance of sealants in a Canadian context; the crack growth and time-to-failure of hypothetical silicone sealants were investigated across 564 locations, for which historical climate data were obtained from 1998 to 2017, including gridded reanalysis data for the period of 1836–2015. The historical climate data were classified into four climate categories, and crack growth was estimated based on historical climatic data within the valid range for the Shephard model, revealing that locations in colder climates with lower levels of precipitation typically exhibit higher cumulative crack growth. The impact of climatic variation and environmental stressors on the longevity of sealants in the context of climate change was also investigated using future projected data. [ABSTRACT FROM AUTHOR]

The dealcoholized room temperature vulcanized (RTV-1) silicone sealant was prepared with α, ω-dihydroxy-polydimethylsiloxane as the base rubber, and fillers, crosslinking agents, coupling agents, and self-made titanium complex catalysts. The influence of the types of titanium complex catalyst on the viscosity, vulcanization rate, and mechanical properties of the sealant was investigated. The results show that compared to the primary titanium catalyst complex, the dealcoholized RTV-1 silicone sealant is not thicken significantly with the secondary titanium complexes. Instead, it has a higher the vulcanization rate, tensile strength, elongation at break, and storage stability. It has 8 minutes of surface drying time, the curing depth of 4. 9 mm after 24 hours, the tensile strength of 1.30 MPa, the elongation at break of 335%, and it also has the same surface drying time when cured at 65°C for 7 days in accelerated aging, and the mechanical performance retention rate is higher than 90%, showing good performance. [ABSTRACT FROM AUTHOR]

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A ceramifiable and flame‐retardant silicone sealant was prepared by adding aluminum oxide and crosslinkers, coupling agents, and catalysts into hydroxy silicone oil. After ablation at 1000°C for half an hour, a ceramic shell with a certain strength was obtained. The impacts of the viscosity of the hydroxy silicone oil and the content of aluminum oxide on the flame‐retardant properties, mechanical properties, surface properties, and ceramification compressive strength of the composite material were studied. The composite with the highest aluminum oxide content could reach an FV‐1 vertical flame rating and a limiting oxygen index of 29.6%, and the ceramification compressive strength could reach 0.15 MPa. This ceramifiable has a wide range of application prospects in industries such as building decoration and wire and cable. [ABSTRACT FROM AUTHOR]

The longevity of polymer-based sealant and jointing products, including elastomers, significantly depends on the level of exposure to sunlight and joint movement. These factors are particularly crucial in the application of polymers in construction due to their susceptibility to degradation under environmental conditions. For instance, diurnal cycles of contraction and dilation, arising from daily temperature fluctuations, impose significant stress on sealants and joints, impacting their durability over time. The elastic nature of polymeric sealants enables them to endure these cyclic mechanical loads. Athough there is considerable information on sealant durability obtained from laboratory accelerated aging, there is limited knowledge about the effect of climatic factors using historical and projected weather data on the durability and expected service life of these products. This study employed the Shephard crack growth model to predict the performance of sealants in a Canadian context; the crack growth and time-to-failure of hypothetical silicone sealants were investigated across 564 locations, for which historical climate data were obtained from 1998 to 2017, including gridded reanalysis data for the period of 1836–2015. The historical climate data were classified into four climate categories, and crack growth was estimated based on historical climatic data within the valid range for the Shephard model, revealing that locations in colder climates with lower levels of precipitation typically exhibit higher cumulative crack growth. The impact of climatic variation and environmental stressors on the longevity of sealants in the context of climate change was also investigated using future projected data.

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Calcium carbonate nanoparticles are important reinforcing fillers for silicone adhesives. α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, and nano calcium carbonate(CaCO3), were used as base materials, followed by the addition of crosslinking agents, catalysts, to prepare silicone sealant. The effects of 5 types of nano CaCO3 and 4 types of composite nano CaCO3 on the extrusion and tensile properties of the silicone sealant were investigated. The results showed that when using one single nano CaCO3 to prepare silicone sealant, with the increase of the specific surface areas or oil absorption value of nano CaCO3, the consistency value and extrudability of the silicone sealing paste decreased; the tensile strength and elongation at break of the rubbers improved. By selecting nano CaCO3 powders with different specific surface areas, the silicone sealant could be prepared with excellent comprehensive performance. [ABSTRACT FROM AUTHOR]

The compatibility of high conductive silicone rubber with polysulfide sealant and silicone aviation sealant was studied. The results show that the polysulfide sealant HM120 has a detrimental effect on the electrical properties of the high conductive silicone rubber, causing an increase in the surface resistance. The matrix of HM120 contains disulfide bond, which can react with the silver powder in the high conductive silicone rubber, thus reducing the conductive property of the rubber. However, the influence of silicone sealant HM304 on the conductivity is far less than that of HM120, and it has better sealing compatibility when it is used in highly conductive silicone rubber and other materials [ABSTRACT FROM AUTHOR]

Plastic products are used ubiquitously and can potentially release microplastics and nanoplastics into the environment, for example, products such as the silicone sealant used in kitchens. It is important to develop an effective method to monitor these emerging contaminants, as reported herein. By using advanced Raman imaging to characterize microplastics and nanoplastics from hundreds of spectra in a scanning spectrum matrix and not from a single spectrum or peak, the signal-to-noise ratio can be significantly increased, from a statistical point of view. The diffraction of the laser spot usually constrains the imaging resolution (such as at ∼300 nm), which is also pushed to the limit in this report by shrinking the scanning pixel size down to ∼50 nm to capture and image small nanoplastics effectively. To this end, image reconstruction is developed to successfully pick up the meaningful Raman signal and intentionally avoid the noise. The results indicate that the silicone sealant in a kitchen can release a significant amount of microplastics and nanoplastics. Overall, advanced Raman imaging can be employed to characterize the microplastics and even nanoplastics that are smaller than the diffraction limit of the laser via Raman imaging and image reconstruction toward deconvolution.

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is shown that a mixture of silicone sealant and methyl-methacrylate-based glue can be used as a binder for carbon fiber materials in the technology of flexible conductors. The structure and properties of the systems are studied. It has been established that the obtained composites exhibit homogeneity, a uniform distribution of the glue binder along the fibrous material, a high adhesion level of the components, which lead to simultaneously occurring controlled mechanical characteristics in the composite, together with a simultaneously high level of thermal and fire resistance. [ABSTRACT FROM AUTHOR]

Die Kenntnis der mechanischen Dichtstoffeigenschaften ist erforderlich, um Verhalten und Leistungsfähigkeit wetterseitiger Dichtfugen zu beurteilen. Fassadeningenieure und Projektplaner sind oftmals daran interessiert, Dichtstoffe über die in technischen Datenblättern genannten Grenzen hinaus einzusetzen oder suchen nach verlässlichen Messergebnissen als Basis für detaillierte Berechnungen, z. B. mit Finite‐Element‐Methoden bei seismischer Belastung oder sehr großen Fassadenelementen. Zur korrekten Auslegung von Dichtfugen ist die Kenntnis der maximal zu erwartenden Fugenbewegungen sowie anderer Einflussfaktoren erforderlich (z. B. Bewitterung, Strahlung, Verschmutzung, Fassadenreinigungsmittel). Ein in Europa verbreiteter Silikondichtstoff für Fassaden ist DOWSIL™ 791. Da für diesen Dichtstoff bisher nur wenige Daten bekannt waren, wurde eine Untersuchung zur Ermittlung der mechanischen Eigenschaften gestartet. Durchgeführt wurden verschiedene Standardtests sowie Prüfungen spezieller Proben mit realen Fugengeometrien. Mit den Erkenntnissen können Dichtfugen ausgelegt und der Versagenspunkt bestimmt werden. Evaluation of mechanical properties for a weatherproofing silicone. The knowledge of mechanical sealant properties is mandatory to understand and predict behaviour and performance of weatherproofing joints. Facade engineering consultants and project planners regularly rise questions to understand, if weatherproofing sealants could be used in applications requiring higher movement capabilities than declared in technical datasheets or if measured data are available for advanced calculation methods such as finite element analysis. This can be required in case of seismic events, for very large pane sizes or high movements. To specify correctly sealant dimensions it is mandatory to know the maximum movements. Applied movements must be safely below the maximum capability of the sealant, considering many load cycles and long‐term ageing (e. g. weathering, sun radiation, facade cleaning products, dirt and air pollution). One of the most commonly used silicone weatherproofing sealant for facades in Europe is DOWSIL™ 791. Because only few data are available for this product, an evaluation has been performed and should help to understand better the mechanical properties and behaviour of this product. Both sample testing following to standardized test methods and specifically designed sample shapes illustrating the joint in its function were used. Using the results of this evaluation, weatherproofing joints can be dimensioned more safely and the failure point can be predicted. [ABSTRACT FROM AUTHOR]

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One-component room temperature vulcanization deacetonized silicone sealant has been prepared with a, ordihydroxy polydimethylsiloxane (107 silicone rubber) as the basic polymer, nano ceria, fumed silica, crosslinking agent, silane coupling agent and catalyst. The effects of the amount of crosslinking agent, the proportion and amounts of different particle size, and the proportion of 107 silicone rubber with different viscosity on the performance of silicone sealants have been discussed. The results show that the optimal preparation conditions are: the cross-linking agent is 4% of the total mass, the amount is 75 phr and 50 phr respectively, with an average particle size of 2 µm and 5 µm, and the amount of nano-cerium oxide is 4 phr. 107 silicone rubber with a viscosity of 20 000 mPa·s and 5 000 mPa·s is compounded as base polymer at a mass ratio of 25:75. The deacetonized silicone sealant has the tensile strength of 4.52 MPa, the elongation at break of 172%, Shore hardness of 52 A, and the tensile strength retention rate of 42.2 % after aging at 350 °C for 30 min, the retention rate of elongation at break of 108.7%, and the retention rate of hardness of 71.2%. The sealant can be used in the bonding and sealing occasions at high temperature, such as electric heating appliances, induction cookers, electric irons, microwave ovens, and ovens, etc. [ABSTRACT FROM AUTHOR]

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the high reflection of nano-silica to specific wavelength ultraviolet light,a one-component silicone sealant filled with nano-silica with different content and specific surface area is designed. The effects of different nano-silica on the appearance, tensile properties,hardness,surface dryness and extrudability of one-component silicone sealant were compared and tested. The internal changes of the material were analyzed by infrared and thermogravimetric analysis. The improvement of artificial aging resistance of one-component silicone sealant by using nano-silica was studied. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavily loaded flanged joints should not only carry the mechanical loads that are imposed, but they should also provide a fluid seal Historically, such heavily stressed flanges were sealed with thin paper composition gaskets so that when flange joint was operated at critical load then high compressive forces were induced within the joints. Over the use of gaskets in the flange, they get deformed and due to this torque capacity, they get reduced hence creating some gaps which are potential leak paths. In recent years, chemical gasketing (liquid "formed in place gaskets "), has begun to surface as a possible solution for these dual function flanges. Hence liquid sealants have been introduced in this flange. In coming days, anaerobic and silicone sealants will be introduced in industry, in contrast with solid gaskets which deteriorate gradually with the atmospheric moisture. Anaerobic and Silicone sealants are mostly used because they are ideally suited to small flange gaps curing them rapidly. This paper focuses on the study of gaskets and liquid sealants effects on gearbox flanges. This work has revealed that structural anaerobic sealants significantly reduced the deformation by 6.7pm, and it improved the structural shearstrength and shear modules. This paper also investigates the numerical and experimental analysis of gearbox anaerobic sealant fange assembly and it determines the mode shape frequency. [ABSTRACT FROM AUTHOR]

Silicone sealant is usually interposed between panels of precast façades. In ordinary cladding panel configurations, relative sliding between panels occurs under lateral actions. The shear drifts and consequent stresses arising in the silicone strips may lead to a significant increase of the load demand in the cladding panel connections and affect the seismic behaviour of the structural system. This paper presents the results of experimental tests and numerical analyses carried out to clarify the role of the silicone sealant on the seismic response of precast structures with cladding panels. An experimental campaign including monotonic and cyclic tests on both silicone strips applied to small concrete blocks and two panel sub-assembly sealed with silicone, has been developed at Politecnico di Milano. Furthermore, cyclic and seismic pseudo-dynamic tests on a full-scale prototype of precast building with cladding panels sealed with silicone, have been performed at the Joint Research Centre of the European Commission. The results of the experimental tests are presented and compared with the results of numerical simulations. Some recommendations for seismic design of precast frame structures with cladding panels, considering the effect of silicone sealant, are finally provided. [ABSTRACT FROM AUTHOR]

Bonding of glass onto aluminum frames, known as “Structural Silicone Glazing”, has been applied for more than 40 years in glass curtain wall facades. Silicone sealants are being used in this application because of their outstanding resistance to weathering (UV, temperature, moisture, ozone), They also provide resistance to water egress and thermal insulation. Their role, structurally, is to resist to windloads and to compensate for differential thermal expansion of glass and aluminum frame. For windload resistance, silicone bite is calculated using a simplified equation which assumes a uniform stress distribution along the sealant bite. Finite Element Analysis (FEA) was used in this study calculate the stress distribution in the sealant as a function of sealant bite and thickness and show the importance of the sealant geometry (bite and thickness) on the local stress distribution. The study shows that for glass deflections in the 1% region (L/d=100), large sealant joints and/or high modulus sealants lead to higher local stresses.

Plastic products are used ubiquitously and can potentially release microplastics and nanoplastics into the environment, for example, products such as the silicone sealant used in kitchens. It is important to develop an effective method to monitor these emerging contaminants, as reported herein. By using advanced Raman imaging to characterize microplastics and nanoplastics from hundreds of spectra in a scanning spectrum matrix and not from a single spectrum or peak, the signal-to-noise ratio can be significantly increased, from a statistical point of view. The diffraction of the laser spot usually constrains the imaging resolution (such as at ∼300 nm), which is also pushed to the limit in this report by shrinking the scanning pixel size down to ∼50 nm to capture and image small nanoplastics effectively. To this end, image reconstruction is developed to successfully pick up the meaningful Raman signal and intentionally avoid the noise. The results indicate that the silicone sealant in a kitchen can release a significant amount of microplastics and nanoplastics. Overall, advanced Raman imaging can be employed to characterize the microplastics and even nanoplastics that are smaller than the diffraction limit of the laser via Raman imaging and image reconstruction toward deconvolution., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Fang, Luo and Naidu.)

With the aid of current sealant technologies, a double sealant comprising adjacent silicone and polyisobutylene sealants may be used to enhance the durability of buildings. The inner silicone sealant is quite durable owing to its intrinsic properties, and covering it with an outer polyisobutlylene sealant prevents fouling due to silicone sealant. This study indicates that the fatigue resistance of double sealant joints is strongly correlated with both the total sealant depth and the movement intervention of each sealant. Furthermore, the proposed section dimension factors enable the design of sealants with appropriate section sizes through better prediction of the fatigue resistance. [ABSTRACT FROM AUTHOR]

Abstract: Poly (dimethylsiloxane) (PDMS) sealant (SS) was modified with the addition of different protective compounds to conserve its physical-chemical properties during gamma irradiation. 2-Vinyl naphthalene (2-VN), bisphenol-A (BPA) and poly (vinyl carbazole) (PVK) were used to evaluate radiation protection through the crosslinking effect of radiation. The samples were irradiated with doses from 100kGy to 500kGy at room temperature in air, with a 60Co gamma source, and the changes in molecular weight, thermal behavior, elastic properties and infrared spectra (FTIR-ATR) absorbance analysis were determined. The molecular weight of unmodified silicone sealant increases with the absorbed dose because of crosslinking as predominant effect. However, the crosslinking effect was inhibited with the addition of protective agent due to the aromatic compounds present. Modified silicone sealant films present better radiation resistance than unmodified system. [Copyright &y& Elsevier]

In this work, we discuss heat- and photocurable silicone compounds that have different physical states in the cured condition ranging from the gel and elastomeric state (compounds, sealants, and adhesives of the SIEL brand) to the glassy state (compounds and adhesives of the STYK brand). The operating temperature range of the developed materials is −90 to +350°C. It is shown that the developed compounds and sealants exhibit good mechanical and dielectric properties, high heat and freeze resistance, optical and chemical purity, and are biologically inert. There are two- and one-package formulations of the compounds. [ABSTRACT FROM AUTHOR]

Investigations on the relationship between the adhesive and thermal chemical properties of Viksint U-2-28NT sealant at high-temperature modes of adhesive joint aging are presented. It is shown that, under these conditions, if nonporous substrates are used, an abnormal thermal oxidative reaction takes place both in the volume of the adhesive, i.e., Viksint U-2-28NT sealant, and at the interphase boundary of the adhesive joint. [ABSTRACT FROM AUTHOR]

A rheological approach has been devised for assessing the properties of a silicone sealant for its practical applications. It is found that the yield stress can be determined through creep and recovery tests. The sealant shows shear thinning and thixotropic behavior, which are two typical and significant nonlinear viscoelastic behaviors for the end-use performance. The Casson model is applicable to describe the relationship between shear stress and shear rate data collected from steady-state measurements. Stepwise rate tests were used to obtain some information on destruction and re-formation of structure of the sealant. Also, dynamic temperature sweep tests can be used to evaluate storage stability and re-structuring capability of the sealant by simulating environmental temperature variations. [ABSTRACT FROM AUTHOR]