PREPARATION AND STUDY ON SILICONE ACRYLATE MICRO-EMULSION OF MULTIPOLYMER

A silicone acrylate micro-emulsion of multipolymer was prepared by seed emulsion polymerization. The effects of polymerization process, emulsifier rate and amount, initiator rate and amount, polymerization temperature, functional monomers, titration time on performances of emulsion have been discussed in detail.

Water-soluble UV curable urethane methyl acrylate coating：preparation and properties

Two kinds of water-soluble and ultraviolet (UV) curable oligomers were synthesized and characterized. The oligomers were evaluated as resins for water-based UV curable coating. The rheology of the two oligomers' aqueous so-lutions was investigated in terms of solid fraction, pH dependence, and temperature dependence. The solutions were found to be Newtonian fluid showing rather low viscosity even at high solid fraction of 0.55. The drying process of the coatings and the properties of the cured coatings were studied by comparing them with water-dispersed UV-curable polyurethane methyl acrylate. It was evident that the water-soluble coating dried more slowly; and that the overall properties were inferior to those of the water-dispersed coating.

Nanomechanical Analysis of Hybrid Silicones and Hybrid Epoxy Coatings—A Brief Review

This review article is written on the investigations of nanomechanical properties of coatings by using nanoindentation techniques. The focus is on the studies that were conducted on epoxy polymer, silicones and their hybrid materials. The article describes a large number of developmental studies that are conducted on coatings. Materials properties such as nanoindentation hardness, modulus, scratch, wear and viscoelastic behavior have been described. Moreover, the article summarizes various studies that mention the use of different nanoparticles in coating formulations that could improve the mechanical strength and service life span of the coatings. The mode and mechanism of material’s failure has been outlined and discussed.

Preparation of Styrene-acrylate Latex Used in Ultralow VOC Building Internal Wall Coating

Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.

Adhesion of foulings on surface energy of silicone rubber coatings

All antifouling paints in use today are effective because toxic ingredients based on heavy metals are included in their formulation, the environmental effects of organotins in seawater have been a topic of much interest and concern in recent years. This study has found that the material of rich silicone rubber on coating surface based on the low discursive component of surface energy makes barnacle settling on them unable to attach permanently and is removed by moving water. The material Permits only small amounts of fouling to attach, such as algae, Ciona intestinalis, because the high polar interaction of coating surface may absorb water to form water film in sea, and cause very low adhesion of the fouling spotes.

Silicone Modified Polyesters Vulcanizable at Room Temperature for Anti-corrosion Coatings on Tinplate

Trimethoxysilyl Polyester(TMOS-PET)was prepared via hydrosilylation of trimethylsilane with acryl-terminated polyester.Copolymerization of TMOS-PET with trimethylmethoxysilane,tetramethoxysilane,and/or dimethyldimethoxysilane give silicone modified polyesters(Si-PET)containing=(SiO_(2))=,-(CH_(3)SiO_(3/2))=,and/or-((CH_(3))_(2)SiO)-units.Coatings from Si-PET were formed on tinplate surface via room temperature vulcanization with applicable curing time(the quickest tact free time and completely drying time are 2 h and 15 h,respectively).Mechanical properties,thermal stability,chemical resistance,and anti-corrosion of coatings were detected.Although the flexibility of the coatings were lowered by=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units,adhesion and thermal stability of coatings were both improved.On the contrary,(CH_(3))_(2)SiOunits seem to improve the flexibility,while decrease the adhesive force for less crosslink points.Generally,the silicone modified polyesters act as an effective shielding for tinplate.According to electrochemical impedance spectroscopy(EIS),the electric resistance of coatings(Rc)were improved about 25 times and open circuit potential(OCP)increased about 0.10 V compared to the control.The chemical resistance and anti-corrosion of the coatings were decreased slightly after=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units were added,but they could be greatly improved by-(CH_(3)SiO_(3/2))=units.Specially,after adding-(CH_(3)SiO_(3/2))=units,coatings give doubled Rc,and its OCP is about 0.20 V higher than the control.

PREPARATION AND PROPERTIES OF SILICONE-ACRYLATE COPOLYMER LATEX

Silicone-acrylate copolymer latex was prepared through three different polymerization processes, i.e., the batch process, preemulsified monomer addition and the monomer addition process. The results revealed that the monomer addition process is a desirable approach to produce narrow particle size distribution latex with higher polymerization conversion and less amount of coagulum. The effect of silicone content on the glossiness and water absorption of latex film was investigated and the results showed that the glossiness of latex film is improved up to a silicone content of 10% of total monomers, but becomes impaired thereafter, whereas water absorption is reduced accordingly.

Developing an atmospheric aging evaluation model of acrylic coatings:A semi-supervised machine learning algorithm

To study the atmospheric aging of acrylic coatings,a two-year aging exposure experiment was conducted in 13 representative climatic environments in China.An atmospheric aging evaluation model of acrylic coatings was developed based on aging data including11 environmental factors from 567 cities.A hybrid method of random forest and Spearman correlation analysis was used to reduce the redundancy and multicollinearity of the data set by dimensionality reduction.A semi-supervised collaborative trained regression model was developed with the environmental factors as input and the low-frequency impedance modulus values of the electrochemical impedance spectra of acrylic coatings in 3.5wt%NaCl solution as output.The model improves accuracy compared to supervised learning algorithms model(support vector machines model).The model provides a new method for the rapid evaluation of the aging performance of acrylic coatings,and may also serve as a reference to evaluate the aging performance of other organic coatings.

A review of the carbon coating of the silicon anode in highperformance lithium-ion batteries

In the development of rechargeable lithium ion batteries(LIBs),silicon anodes have attracted much attention because of their extremely high theoretical capacity,relatively low Li-insertion voltage and the availability of silicon resources.However,their large volume expansion and fragile solid electrolyte interface(SEI)film hinder their commercial application.To solve these problems,Si has been combined with various carbon materials to increase their structural stability and improve their interface properties.The use of different carbon materials,such as amorphous carbon and graphite,as three-dimensional(3D)protective anode coatings that help buffer mechanical strain and isolate the electrolyte is detailed,and novel methods for applying the coatings are outlined.However,carbon materials used as a protective layer still have some disadvantages,necessitating their modification.Recent developments have focused on modifying the protective carbon shells,and substitutes for the carbon have been suggested.

Preparation and electrochemical lithium storage performance of porous silicon microsphere composite with metal modification and carbon coating

This work adopts a multi⁃step etching⁃heat treatment strategy to prepare porous silicon microsphere com⁃posite with Sb⁃Sn surface modification and carbon coating(pSi/Sb⁃Sn@C),using industrial grade SiAl alloy micro⁃spheres as a precursor.pSi/Sb⁃Sn@C had a 3D structure with bimetallic(Sb⁃Sn)modified porous silicon micro⁃spheres(pSi/Sb⁃Sn)as the core and carbon coating as the shell.Carbon shells can improve the electronic conductivi⁃ty and mechanical stability of porous silicon microspheres,which is beneficial for obtaining a stable solid electrolyte interface(SEI)film.The 3D porous core promotes the diffusion of lithium ions,increases the intercalation/delithia⁃tion active sites,and buffers the volume expansion during the intercalation process.The introduction of active met⁃als(Sb⁃Sn)can improve the conductivity of the composite and contribute to a certain amount of lithium storage ca⁃pacity.Due to its unique composition and microstructure,pSi/Sb⁃Sn@C showed a reversible capacity of 1247.4 mAh·g^(-1) after 300 charge/discharge cycles at a current density of 1.0 A·g^(-1),demonstrating excellent rate lithium storage performance and enhanced electrochemical cycling stability.

Constructing a biomimetic robust bi-layered hydrophilic lubrication coating on surface of silicone elastomer

Silicone elastomers-based materials have been extensively involved in the field of biomedical devices,while their use is extremely restricted due to the poor surface lubricity and inherent hydrophobicity.This paper describes a novel strategy for generating a robust layered soft matter lubrication coating on the surface of the polydimethylsiloxane(PDMS)silicone elastomer,by entangling thick polyzwitterionic polyelectrolyte brush of poly(sulfobetaine methacrylate)(PSBMA)into the sub-surface of the initiator-embedded stiff hydrogel coating layer of P(AAm-co-AA-co-HEMA-Br)/Fe,to achieve a unified low friction and high load-bearing properties.Meanwhile,the stiff hydrogel layer with controllable thickness is covalently anchored on the surface of PDMS by adding iron powder to provide catalytic sites through surface catalytically initiated radical polymerization(SCIRP)method and provides high load-bearing capacity,while the topmost brush/hydrogel composite layer is highly effective for aqueous lubrication.Their synergy effects are capable of attaining low friction coefficient(COFs)under wide range of loaded condition in water environment with steel ball as sliding pair.Furthermore,the influence of mechanical modulus of the stiff hydrogel layer on the lubrication performance of layered coating is investigated,for which the COF is the lowest only when the modulus of the stiff hydrogel layer well matches the PDMS substrate.Surprisingly,the COF of the modified PDMS could remain low friction(COF<0.05)stably after encountering 50,000 sliding cycles under 10 N load.Finally,the surface wear characterizations prove the robustness of the layered lubricating coating.This work provides a new route for engineering lubricious silicon elastomer with low friction,high load-bearing capacity,and considerable durability.

Development of Siliconized Epoxy Resins and Their Application as Anticorrosive Coatings

The present work involves the development of siliconized epoxy resin to overcome the drawback of epoxy resin like poor impact strength, high rigidity and moisture absorbing nature because of which they are not applied as corrosion resistant coating. By embedding silicone into the back bone of polymeric resin the above drawback can be reduced to substantial level. For achieving this, siliconised epoxy resins were prepared by reacting amine terminated silicone resin with novolac epoxy resin and meta-phenylenediamine was used as curing agent. The applied films of coating were baked at 150oC. Cured films were evaluated for their thermal, mechanical, chemical and corrosion resistance properties to ascertain the commercial utility of these eco-friendly resin for use in anti corrosive formulations. The siliconized epoxy resins system was found to exhibit good thermal and anticorrosive properties.

MODIFIED ULTRAVIOLET-CURABLE WATER DISPERSIBLE POLYURETHANE-ACRYLATES

Three kinds of UV-curable self-emulsified polyurethane-acrylate (PUA) prepolymer, i.e., conventional, chain extended and grafted PUAs, were prepared. The relatively small particle size of the PUA dispersions indicates that the PUA prepolymers exhibit sufficient aqueous dispersibility. The PUA prepolymers can substantially lower the interfacial tension of water. Chain-extended PUA dispersions exhibit pseudoplastic behavior and thixotropy to a greater extent than do their conventional counterpart. The chain-extended and grafted PUA photocure to higher conversion than do the conventional PU equivalent. The results of DSC measurement suggest that there exists phase mixing between the hard and the soft segment phases for the PUAs based on PEG 400 that is the comparatively short soft segment in the prepolymer. For the PUA prepolymers based on PEG having higher M-n values, chain-extending and grafting could impede the phase separation between the hard and the soft segment domains. The adhesion, impact strength and flexibility of the photocured films were tested.

Optimizing Heavy-duty Anticorrosive Performances of Coating Films Formed by Acrylate-vinylidene Chloride Copolymer Latexes through Twice-painting Technique

Twice-painting technique was adopted to prepare heavy-duty anticorrosive coating films formed by aqueous latexes of copolymers of vinylidene chloride（VDC） with an acrylate, namely methyl acrylate（MA）, ethyl acrylate（EA）, butyl acrylate（BA） or 2-ethylhexyl acrylate（EHA）. Harsh salt-spray corrosion tests demonstrated that the optimized twicepainting technique was that the acidic latex solution was adjusted to p H 5-6 for the first painting, while it was utilized directly for the second painting. The test of 600 h of harsh salt-spray corrosion showed that MA-VDC85 coating could protect the steel excellently, whereas the other acrylate-VDC coatings with 75%-90% VDC content could not protect the steel so effectively. Further corrosion test showed that（1） MA-VDC85 coating protected steel from loss of metallic luster for at least 1000 h of salt-spray corrosion;（2） adhesion of MA-VDC85 coating to steel was excellent for at least 800 h of saltspray corrosion, but became very poor after 1000 h. Differential scanning calorimetry, thermogravimetric analysis, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy were used to evaluate the corroded MA-VDC85 film.

Protective Performance of Fiberglass Fabrics Coated by Silicone Resin Mixed with Nature Filler Powders

The coated fiberglass fabric was prepared to protect personnel and equipment from sparks, heat, and molten metals during hot work projects. Ferric oxide powder 2%,mica powder6%,wollastonite powder 4%,and white carbon black 8% were added in the phenyl methyl silicone to prepare the composite silicone solution. The french chalk and coupling agent can effectively solve the deposition of fillers in the coating solution. Compared with the original fiberglass fabric,heat resistance of the coated fabric under high temperature was greatly improved, and the temperature limitation in short period was higher than 900℃. Horizontal flammability tests showed that the coated fabric was non-combustible with no melting and no fragments. The temperature for long period usage of coated fabric was lower than 500 ℃. Welding drop test showed that the coating could prevent the molten metals,sparks and heat from transferring in the fabric. Test for toxic gas release showed that the toxic gases such as HCN,SO_2,HCl,and HF were not detected,only CO( 100 mg / m^3) and NO( 12 mg /m^3) were detected,and their concentrations were far lower than the limitation values CO( 4 375 mg / m^3) and NO( 134 mg /m^3). The breaking strength of coated fabric was almost twice the strength of the original fabric,and the coated surface had good water and oil repellency.

Pulsed Nd:YAG laser cladding of high silicon content coating on low silicon steel

A pulsed Nd：YAG （yttrium aluminum garnet） laser-based technique was employed to clad low silicon steel with preplaced Si and Fe mixed powders for high Si content. The surface morphology, microstructural evolution, phase composition, and Si distribution, within the obtained cladding coatings, were characterized by optical microscopy （OM）, field emission scanning electron microscopy （FE-SEM）, with associated energy dispersive spectroscopy （EDS）, transmission electron microscopy （TEM）, and X-ray diffraction （XRD）. The microhardness was also measured along the depth direction of the specimens, A crack- and pore-free cladding coating through excellent metallurgical bonding with the substrate was successfully prepared on low silicon steel by means of optimized single-track and multi-track laser cladding. The phases of the coating are a-Fe, T-Fe, and FeSi. The high microhardness of the lasercladding zone is considered as an increase in Si content and as the refined microstructure produced by the laser treatment. The Si contents of the cladding coatings were about 5.8wt% in the single-track cladding and 6.5wt% in the multi-track cladding, respectively.

Influence of Si Content on Properties of Ti1-xSixN Coatings

To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were deposited onto Si(100) and cemented carbide substrates using TiSi targets with different Si content by cathodic arc ion plating. The influences of Si on the microstructure and mechanical properties were studied. Nano-amorphous composite structure appeared in the Ti1-xSixN coatings when Si content in TiSi target was higher than 5 at%. However, further increase of Si content in TiSi target exhibited a negligible effect on the microstructure of Ti1-xSixN coatings. Hardness and deformation resistance were correlated to the content of Si in TiSi targets. Maximum hardness was obtained as the Si content in target increased up to 20 at%. Friction coefficient and wear rate significantly decreased with addition of Si in TiN coating, and then dually increased with the increase of Si content in targets.

Structure, properties and application to water-soluble coatings of complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole

The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.

Mullite Coating on Recrytallized Silicon Carbide and Its Cycling Oxidation Behavior

Mullite coating on recrystallized silicon carbide was successfully prepared by the sol-gel route. The cycling oxidation of coated recrystallized silicon carbide was performed at 1500℃. For comparison, the oxidation of uncoated recrystallized silicon carbide was also carried out at the same condition. The results in- dicated that a layer of compact, adhesive and crack free mullite coating was found on the recrystallized silicon carbide. After oxidation, the new coatings exhibit adherence and crack resistance under thermal cycling between room temperature and 1500℃, therefore the oxidation resistance capability of silicon carbide was enhanced. With the increase of the dipping frequencies, namely, the increase of the thickness of mullite coating, the oxidation resistance of silicon carbide would be futher improved. The formation mechanism of mullite coating was analyzed and discussed and the oxidation dynamics model of coatedmullite silicon carbide has been also proposed.

Influence of carbon coating on the electrochemical performance of SiO@C/graphite composite anode materials

Silicon monoxide(SiO) has been considered as one of the most promising anode materials for next generation highenergy-density Li-ion batteries(LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite(Si0@C/G) composite anode materials, with designed capacity of 600 mAh·g-1, are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25℃ and90.1% at 45 0 C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope(SEM) and electrochemistry impedance spectroscopy(EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode.