Polysiloxane Additives Research Articles

Safety and efficacy of a new hydrogel based on hyaluronic acid as cosmeceutical for xerosis.

Hyaluronic acid (HA) is among the most effective and safe ingredients frequently used in cosmetics. However, a more economical and efficient formulation is still required. We sought to assess the safety and efficacy of a novel hydrogel manufactured only by irradiation containing cross-linked HA and polyethylene glycol polymers with addition of polysiloxane. The study included 30 people with normal skin and 30 patients with xerosis. In the normal skin group, to evaluate the safety, a patch test and a photopatch test were performed, and patients' discomfort was investigated. In those with xerosis, to assess the efficacy, a skin barrier function test was performed at baseline and at 2, 4, and 8 weeks after the application of the novel hydrogel. Additionally, the xerosis severity scale (XSS), patient satisfaction, Investigator's Global Assessment (IGA), and adverse responses were evaluated. In the safety study, there was no significant discomfort in the experimental group compared with the control group. In the efficacy study, at 2, 4, and 8 weeks after the application of the novel hydrogel, the mean value of skin hydration and sebum content increased and the mean value of XSS decreased with time in the experimental group, and a difference was observed when compared with the control group. IGA showed improvement in 97%, 77%, and 80% at each visit and the proportions of satisfied patients were 90%, 87%, and 90%, respectively. The novel HA-based hydrogel tested herein could be a safe and effective therapeutic remedy for xerosis.

Improving Needleless Electrospinning Throughput by Tailoring Polyurethane Solution Properties with Polysiloxane Additives

Improving Needleless Electrospinning Throughput by Tailoring Polyurethane Solution Properties with Polysiloxane Additives

Universal polysiloxane additives for self-cleaning surfaces

Universal polysiloxane additives for self-cleaning surfaces

Are telechelic polysiloxanes better than hemi-telechelic for self-cleaning applications?

HypothesisPolysiloxanes are becoming new trend in self-cleaning (oil- and water‐repellent) applications due to their low-cost and environmentally friendly nature. Lower phase separation of polysiloxanes in coating matrix is critical to obtain excellent self-cleaning properties. We hypothesize that telechelic polysiloxanes can bind to coating matrix at both ends and thus will suppress phase separation of polysiloxane as compared to hemi-telechelic analog and thus will offer excellent self-cleaning properties. ExperimentEight PDMS additives were prepared via the free-radical polymerization of telechelic and hemi-telechelic methacryloxypropyl-based PDMS precursors with methylmethacrylate (MMA) and glycidylmethacrylate (GMA). The compositions of the prepared polysiloxane additives were optimized to obtain excellent self-cleaning performance. FindingsOur breakthrough development confirms that telechelic polysiloxanes (PDMS-T) incorporated into epoxy-based anti-smudge coatings outperform hemi-telechelic polysiloxanes (PDMS-HT) by offering excellent repellency against difficult to repel liquids. These breakthrough findings will vertically advance Science and innovations in the self-cleaning field by offering robust guidelines for choosing suitable polysiloxane for self-cleaning applications.

Properties of foamed glass upon addition of polysiloxane

ABSTRACT Changes in the pore size, porosity, compressive strength, and thermal conductivity of closed-pore foam glass with a pore size of 450 µm upon the addition of 0–24 wt% of polysiloxane at a low sintering temperature of 750 °C were investigated. Micro-Raman analysis demonstrated the uniform dispersion of polysiloxane after sintering, and it was confirmed that the entire foam glass processed to have closed pores. With increasing polysiloxane, the pore size decreased from 452 μm to 131 μm, and the porosity decreased from 62% to 41%. The compressive strength increased from 2.0 to 5.7 MPa, and the thermal conductivity also increased from 0.146 to 0.233 W/m·K. However, when more than 15 wt% of polysiloxane was added, the thermal conductivity exceeded 0.160 W/m·K, rendering unsuitable as an insulating material. Therefore, we fabricated closed-pore foam glass with proper pore size and porosity, a strength of 4.1 MPa, and a low thermal conductivity below 0.160 W/m·K by adding 15 wt% of polysiloxane at a low sintering temperature.

Effect of PSO and TiB2 content on the high temperature adhesion strength of SiBCNO ceramic

In the present work, SiBCNO-based ceramic as high temperature adhesives are fabricated by polymer derived ceramic route. The effect of polysiloxane (PSO) and TiB2 on the microstructure and high temperature strength is studied, and the toughing effect of TiB2 is discussed. The highest adhesion strength of the joint (S12) reached up to 18.95 MPa at room temperature and 12.3 MPa at 1000 °C in vacuum after pyrolysis at 1000 °C in air for 2 h. It is interesting to find that the crystallization of nano-SiO2 reinforces the strength and thermal stability of glass phase with the addition of PSO, besides, the TiB2 plays the important role in improving adhesion strength by bearing load and facilitating the formation of stable SiO2-B2O3-TiO2 glass.

Eugenol-modified polysiloxanes as effective anticorrosion additives for epoxy resin coatings

Eugenol-modified polysiloxane additives can significantly increase the performance of epoxy resin coatings in terms of thermal stability, hydrophobicity and resistance to water penetration.

Preparation and Characterization of a Graphene Oxide Film Modified by the Covalent Attachment of Polysiloxane

Hybrid materials consisting of polydimethylsiloxane (PDMS) and polycyclohexyl-methylsiloxane (PCHMS) grafted graphene oxide (GO) were obtained by condensation polymerization in toluene. Fourier transform infrared spectroscopy indicates that the composites were synthesized through the formation of Si-O bond. The X-ray diffraction, scanning electron microscopy and thermogravimetric indicate that the hydrolysis polycondensation can accelerate the graft reaction. The hybrid films were prepared by simple filtration of the dispersed system of PDMS/GO/water, PCHMS/GO and PCHMS/GO/water in dimethylformamide. Tensile tests indicate the mechanical properties of the films varied with their structure. The rigid PCHMS/GO/water films have a tensile strength of 17.83 MPa, and the pliant PDMS/GO/water films have an elongation at break of 3.14%. UV-Vis spectra of GO and the hybrids indicate that the addition of polysiloxane caused a red-shift (10–20 nm) of the absorption peak.

Studying the role of polysiloxane additives and nano-SiO2 on the mechanical properties of a typical acrylic/melamine clearcoat

Effects of conventional polysiloxane additives and nano-SiO2 on the mechanical properties of an automotive acrylic/melamine clearcoat (CC) are studied. Clearcoats formulations were prepared by addition of different concentrations of polysioloxane additives (with different modifications) and hydrophobic nano-SiO2 particles. Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) and atomic force microscope (AFM) were utilized to evaluate the effects of nano-SiO2 and polysiloxane additives on the surface properties of the CCs. The mechanical properties of the surface and the bulk of the CCs were studied by nano-indentation and tensile tests, respectively. Results showed that polysiloxane additives can mostly affect the mechanical properties of the surface of the CC. Additives with shorter side chains and therefore higher surface activity caused higher changes on the surface properties the CC. Unlike conventional polysiloxane additives, the nano-SiO2 particles mainly influenced the mechanical properties of the bulk of the CC.

A new approach to investigate scratch morphology and appearance of an automotive coating containing nano-SiO 2 and polysiloxane additives

Attempts have been carried out to verify whether gonio-spectrophotometry could be utilized as a new scratch testing approach to investigate scratch morphology and its effect on appearance of an acrylic–melamine clearcoat separately containing nano-silica or polysiloxane additives. The results of gonio-spectrophotometry/colorimetry illustrated that this new approach is capable of differentiating between plastic and fracture types scratches. Furthermore, this approach was found to be suitable for analyzing the self healing abilities of such coatings. The accuracy and reproducibility of such results were checked against the results of scanning electron microscope (SEM) and illustrated great potential as a new approach for such studies.

Effect of polysiloxane additives on the scratch resistance of an acrylic melamine automotive clearcoat

Many attempts have been carried out to increase the scratch resistance of clearcoats using various appropriate additives. These additives may increase surface hardness or surface slippage, and/or enhance the bulk mechanical strength of the clearcoat. In the present study, the influence of various added loads of three differently structured polysiloxane additives on the scratch resistances of an acrylic melamine clearcoat was investigated. A series of analytical instruments, such as a laboratory carwash simulator, a scanning electron microscope, an optical microscope and an attenuated total reflectance Fourier transform infrared spectroscope, and others were used to compare the effects of the various added contents of polysiloxane additives on changes in the viscoelastic properties and scratch morphologies of the resultant clearcoats. The results illustrated that all polysiloxane additives improve the scratch resistance of such clearcoats, yet the optimum load varied for each individual additive. There is also a good indication that polyether-modified polysiloxanes improve scratch resistance by increasing surface hardness, while the fluorocarbon-modified polysiloxane tends to change the viscoelastic properties of the clearcoats. It was also found that scratch resistance varied linearly with Micro-Vickers’ hardness for brittle clearcoats.

Influence of additives segregation on surface composition of automotive coatings: effects of an ethanol cleaning

The automotive topcoat is constituted of a pigmented basecoat, covered by a transparent and shiny clearcoat. This layer protects the basecoat from the environment damage and determines the paint appearance. For white plain colour, the basecoat/clearcoat system is replaced by a layer of lacquer. The surface analyses are used to determine the influence of the topcoat composition on the adhesion of pressure-sensitive adhesives. X-ray photoelectron spectroscopy (XPS) and secondary ions mass spectrometry (ToF-SIMS) study the automotive topcoats chemistries. These analyses point out that polysiloxane additives are detected on the clearcoats but not on the lacquers. The impact of the different additives families (anti-UV agents and surface levelling additives) on the topcoat surface chemistry is identified. Moreover, the aluminium pigments do not appear on the metallic basecoat surface because of a siloxane additives layer, which also covers the polyester–polyurethane network. XPS studies on the basecoats covered by a clearcoat formulated without additive bring to the fore that the basecoat siloxane additives segregate towards the clearcoat/air interface during the curing process. The clearcoats additives can be removed with an ethanol cleaning according to the XPS analyses but this solvent cleaning is not able to remove all the additives from the basecoat surface, which seem to be partly cross-linked with the basecoat polyurethane network.

Surface tension studies of levelling additives in powder coatings

In powder coatings, melt surface tension plays a decisive role in the film formation. The surface tension is controlled and adjusted by adding levelling additives to powder coating formulations. The influence of additive properties like molecular weight and chemical structures (homopolymeric and copolymeric polyacrylates and polyestermodified polysiloxanes) on surface tension of a typical powder coating binder (DER 664 UE, an epoxy resin) is studied by means of axisymmetric drop shape analysis in a temperature range from 138 to 184°C. The high accuracy of the method allows small differences in surface tension values to be distinguished. It is shown that all additives considerably decrease the surface tension of the epoxy resin. In addition, notable differences in the effect of the two groups of additives (acrylates and siloxanes) were found. Consequently, differences are expected in levelling and wetting of powder coatings formulated with polyacrylate or polysiloxane additives. Moreover, viscosity measurements have been performed in order to investigate whether these additives also affect the viscosity of the epoxy resin.