silicone and their application
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This document discusses silicones and their applications. It begins with an introduction and overview of silicones, noting they are polymers made of repeating siloxane units. It then covers the nomenclature, manufacturing process involving chlorosilane synthesis and polymerization, and main types - fluids, elastomers, and resins. The document outlines the properties of silicones, including being water-repellent and thermally stable. It lists applications of silicones across many industries like aerospace, automotive, construction, electronics, and more. In closing, it emphasizes how silicones can enable transportation to operate safely in extreme conditions.
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Silicone polymers structure, prepartion, properties, uses
Silicone polymers structure, prepartion, properties, uses
INORGANIC POLYMERS
Polymers containing inorganic and organic components are sometimes called hybrid polymers, and most so-called inorganic polymers are hybridpolymers. One of the best known examples is polydimethylsiloxane, otherwise known commonly as silicone rubber.
Of synthetic polymers whose backbone is made of repeating silicone to oxygen bonds (siloxane bonds) with organic side groups, such as methyl, phenyl or vinyl.The basic repeating unit became known as siloxane and the most common available silicone is polydimethylsiloxane
Organo-silicone polymers contain chains or network of alternating silicone and oxygen atoms in their structures ,that is exhibited in some natural silicone minerals
Polymeric molecules in silicones held together by weak van der waals force results, they are liquids of varying viscosity or gums or solids containing polymeric molecules which generally soluble in organic mediaHydrolysis of dichloro dimethyl silane (CH3)2SiCl2 gives long chain polymers.As there is active OH group at each end .The length of the chain increasing.so it is called chain building unit
properties
1.The si-o-si bond in silanes is shorter than the expected si-o-si bond as calculated from the their radii.This indicates that there is some ionic character in si-o bond due to which it becomes quite stable.
2.This the the reason for why polysiloxanes are thermally stable and do not decompose even upto 350-400`C.
1. Highly polar character of si-o bond and the ability of si to expand its valency shell by utilizing its d-orbitals renders polysiloxanes susceptible to attack by several reagents.
2.The siloxanes may undergo hydrolysis and alcoholysis at elevated temperature in the presence of strong acids and bases
to give silanols and alkaxysilanes .In general, the greater the extent of substitution on Si atom, the greater is the case of hydrolysis in the presence of acids and greater is the difficulty of hydrolysis in the presence of bases.
thankingyou
ESWARAN .M -inboxeswaran@gmail.com
silicones
The document discusses the history and properties of silicones. It notes that during World War II, James Wright added boric acid to silicone oil to create a product that could stretch farther and bounce higher than rubber. Silicones are polymers made of repeating siloxane units consisting of alternating silicon and oxygen atoms. They can occur as fluids, gels, elastomers or resins. Silicones have applications in areas such as medical implants, sealants, and bouncy toys due to their thermal stability, flexibility and biocompatibility. Common processing methods include injection molding and extrusion. Leading manufacturers include Dow Corning and Wacker Silicones.
Silicon
This document provides an overview of silicones, including their manufacturing, properties, applications, and role in various industries. Silicones are polymers derived from silicon and oxygen, and can be manufactured in many forms including fluids, elastomers, and resins. They have properties like thermal stability, flexibility, and resistance to chemicals, UV rays, and mold/microbes. Major applications of silicones include construction, transportation, personal care products, and industrial manufacturing. Within these industries, silicones play an important role by enabling energy efficiency and durable, high-performance materials.
Silicones
Silicones are a group of organosilicon polymers which are also known as siloxanes. Organosilicon compounds are those in which organic group is attached to silicon. preparations properties, types and applications of silicones.
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PPT on "Silicones" by Deepak rawal, Speciality polymers
This document provides an overview of silicones/polysiloxanes including their history, production, preparation, and common types. Silicones are polymers made of repeating siloxane units and can exist as fluids, resins, or rubbers. The three main types discussed are silicone fluids which are lubricating and thermally stable, silicone resins which are heat resistant insulators, and silicone rubbers which are flexible and inert. Silicones find applications where thermal stability, chemical resistance, and flexibility are required such as in cookware, electronics, seals, and medical devices.
Silicon rubber
Silicone rubber is produced through a multi-step process beginning with reducing silica to silicon, which is then reacted with methyl chloride to form chlorosilanes. These chlorosilanes undergo hydrolysis or methanolysis to form siloxane oligomers, which are then cured using a peroxide or platinum catalyst to form cross-linked silicone rubber. Silicone rubber has advantages over organic rubbers including greater heat resistance, flexibility over a wide temperature range, chemical stability, and physiological inertness. It is used widely in applications such as electronics, seals and gaskets, medical devices, construction, office equipment, and leisure products.
Polysiloxanes 1
Polysiloxanes, also known as silicones, are synthesized via ring-opening polymerization of cyclosiloxanes. They can be prepared through cationic polymerization using initiators like Lewis acids, or anionic polymerization using bases. Cationic polymerization may proceed by acidolysis/condensation or generation of an active propagating center. Anionic polymerization yields higher molecular weight polymers through chain propagation and termination with end-capping. Copolymers and crosslinked polysiloxanes can also be synthesized. Hybrid polymers combining polysiloxane segments with other backbones can be prepared through step-growth condensation polymerization.
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INORGANIC POLYMERS
Polymers containing inorganic and organic components are sometimes called hybrid polymers, and most so-called inorganic polymers are hybridpolymers. One of the best known examples is polydimethylsiloxane, otherwise known commonly as silicone rubber.
Of synthetic polymers whose backbone is made of repeating silicone to oxygen bonds (siloxane bonds) with organic side groups, such as methyl, phenyl or vinyl.The basic repeating unit became known as siloxane and the most common available silicone is polydimethylsiloxane
Organo-silicone polymers contain chains or network of alternating silicone and oxygen atoms in their structures ,that is exhibited in some natural silicone minerals
Polymeric molecules in silicones held together by weak van der waals force results, they are liquids of varying viscosity or gums or solids containing polymeric molecules which generally soluble in organic mediaHydrolysis of dichloro dimethyl silane (CH3)2SiCl2 gives long chain polymers.As there is active OH group at each end .The length of the chain increasing.so it is called chain building unit
properties
1.The si-o-si bond in silanes is shorter than the expected si-o-si bond as calculated from the their radii.This indicates that there is some ionic character in si-o bond due to which it becomes quite stable.
2.This the the reason for why polysiloxanes are thermally stable and do not decompose even upto 350-400`C.
1. Highly polar character of si-o bond and the ability of si to expand its valency shell by utilizing its d-orbitals renders polysiloxanes susceptible to attack by several reagents.
2.The siloxanes may undergo hydrolysis and alcoholysis at elevated temperature in the presence of strong acids and bases
to give silanols and alkaxysilanes .In general, the greater the extent of substitution on Si atom, the greater is the case of hydrolysis in the presence of acids and greater is the difficulty of hydrolysis in the presence of bases.
thankingyou
ESWARAN .M -inboxeswaran@gmail.com
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The document discusses the history and properties of silicones. It notes that during World War II, James Wright added boric acid to silicone oil to create a product that could stretch farther and bounce higher than rubber. Silicones are polymers made of repeating siloxane units consisting of alternating silicon and oxygen atoms. They can occur as fluids, gels, elastomers or resins. Silicones have applications in areas such as medical implants, sealants, and bouncy toys due to their thermal stability, flexibility and biocompatibility. Common processing methods include injection molding and extrusion. Leading manufacturers include Dow Corning and Wacker Silicones.
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This document provides an overview of silicones, including their manufacturing, properties, applications, and role in various industries. Silicones are polymers derived from silicon and oxygen, and can be manufactured in many forms including fluids, elastomers, and resins. They have properties like thermal stability, flexibility, and resistance to chemicals, UV rays, and mold/microbes. Major applications of silicones include construction, transportation, personal care products, and industrial manufacturing. Within these industries, silicones play an important role by enabling energy efficiency and durable, high-performance materials.
Silicones
Silicones are a group of organosilicon polymers which are also known as siloxanes. Organosilicon compounds are those in which organic group is attached to silicon. preparations properties, types and applications of silicones.
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This document provides an overview of silicones/polysiloxanes including their history, production, preparation, and common types. Silicones are polymers made of repeating siloxane units and can exist as fluids, resins, or rubbers. The three main types discussed are silicone fluids which are lubricating and thermally stable, silicone resins which are heat resistant insulators, and silicone rubbers which are flexible and inert. Silicones find applications where thermal stability, chemical resistance, and flexibility are required such as in cookware, electronics, seals, and medical devices.
Silicon rubber
Silicone rubber is produced through a multi-step process beginning with reducing silica to silicon, which is then reacted with methyl chloride to form chlorosilanes. These chlorosilanes undergo hydrolysis or methanolysis to form siloxane oligomers, which are then cured using a peroxide or platinum catalyst to form cross-linked silicone rubber. Silicone rubber has advantages over organic rubbers including greater heat resistance, flexibility over a wide temperature range, chemical stability, and physiological inertness. It is used widely in applications such as electronics, seals and gaskets, medical devices, construction, office equipment, and leisure products.
Polysiloxanes 1
Polysiloxanes, also known as silicones, are synthesized via ring-opening polymerization of cyclosiloxanes. They can be prepared through cationic polymerization using initiators like Lewis acids, or anionic polymerization using bases. Cationic polymerization may proceed by acidolysis/condensation or generation of an active propagating center. Anionic polymerization yields higher molecular weight polymers through chain propagation and termination with end-capping. Copolymers and crosslinked polysiloxanes can also be synthesized. Hybrid polymers combining polysiloxane segments with other backbones can be prepared through step-growth condensation polymerization.
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This document discusses silicones, their manufacturing process, properties, and applications. Silicones are polymers derived from silicon and oxygen, and can be manufactured in over 2,000 forms as fluids, elastomers, and resins. They are thermally stable, resistant to chemicals and UV radiation, and can be formulated to resist or absorb water. Common applications of silicones include sealants, adhesives, lubricants, coatings, and more in industries like construction, transportation, consumer products, and healthcare.
Water repellents selection guide dow corning
This document discusses the benefits of using silicones in construction substrates. Silicone-based treatments can penetrate deeply into substrates, forming a protective repellent layer without significantly affecting vapor permeability. This provides long-lasting protection from water, abrasion, efflorescence, spalling and staining while strengthening fragile materials. The document outlines silicone chemistries including silanes, polymers, and blends that are suitable for various construction materials like concrete, stone, brick, wood and gypsum. It provides recommendations on silicone products from Dow Corning and Momentive Performance Materials suited for specific substrate applications and benefits.
Fascinating Silicone Chemistry.pdf
Silicone is a class of polymers with a backbone of alternating silicon and oxygen atoms. It is considered the "missing link" between organic and inorganic chemistry as silicon forms hybrid bonds between carbon's purely covalent bonds and oxygen's ionic bonds. Silicones have unique properties stemming from the silicon-oxygen bond such as flexibility, thermal stability, and chemical resistance. Common silicone products include oils, greases, rubbers, and resins which find applications as lubricants, sealants, and insulators due to their versatile properties.
hyperbranched polymers for coating applications
This document discusses the development of polyurethane-urea coatings using azide-alkyne click chemistry. It provides background on the chemistry of polyurethanes and their properties. It describes the concept of click chemistry and how copper-catalyzed azide-alkyne cycloaddition is a key click reaction. Schemes are proposed for synthesizing hyperbranched polyethers and fluorescent polyurethane coatings using click chemistry approaches. The document acknowledges contributions from researchers involved in the project.
Silicones
Wacker produces silicone compounds for use in medical applications. Their SILPURAN and ELASTOSIL lines offer solutions for medical devices, tubes, seals, and other applications. The silicones demonstrate biocompatibility, excellent heat and chemical resistance without stabilizers, and maintain properties after sterilization by various methods including steam, radiation, and ethylene oxide.
Wet Processing Tecnology
This document discusses different types of water repellent finishes for textiles. It describes paraffin, stearic acid-melamine, silicone, and fluorocarbon repellents. Paraffin repellents were one of the earliest used but do not repel oil. Silicone repellents provide high water repellency and a soft hand feel but have only moderate durability. Fluorocarbon repellents can achieve both oil and water repellency and provide the lowest surface energy finishes. The document explains the mechanisms of different repellent chemistries and how they interact with fiber surfaces.
Influence of reaction medium on morphology and crystallite size of zinc oxide
ABSTRACT : Zinc oxide nanoparticles were prepared by reacting zinc chloride and sodium hydroxide in different mediums such as chitosan, poly vinyl alcohol, ethanol and starch. The materials were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) studies, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Elemental analysis was done by energy dispersive X-ray Analysis (EDAX).
KEY WORDS : Nano zinc oxide, morphology, crystallite size
Silica Aerogel: Synthesis, Characterization, Applications, and Recent Advanc...
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catalyst, biomedical, absorbent, food packing, textile, etc., are also discussed.
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along with the futuristic development of silica aerogel.
Aerogel.pdf
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Material of hard contact lenses
This document discusses the ideal properties and materials for contact lenses. It begins by outlining the ideal characteristics a contact lens material should have, such as providing oxygen to the cornea, being optically transparent, and having stable dimensions. It then examines the physical properties important for materials, including wettability, flexibility, optical quality, and biocompatibility. The document focuses on the early rigid gas permeable materials like PMMA and improvements made to increase oxygen permeability, including cellulose acetate butyrate, siloxane methacrylates, and fluoro-siloxane methacrylates. It also briefly discusses flexible elastomeric lenses made of silicone rubber and acrylic rubber.
RSC 2015-NanoCoater
1. The document describes a study that developed silicone foul-release nanocomposites by incorporating Cu2O nanocubes into polydimethylsiloxane (PDMS) for use as environmentally friendly antifouling coatings.
2. A series of PDMS/Cu2O nanocube composites with different nanofiller concentrations were synthesized via solution casting and characterized. The addition of low amounts of Cu2O nanocubes improved surface properties like contact angle and surface free energy without changing bulk properties.
3. Laboratory assays showed that the nanocomposites with lower surface energy and elastic modulus exhibited less adherence of marine microfouling like bacteria and yeast over 30 days. The best
10.1007_s12633-015-9363-y
The document discusses nanocrystalline cristobalite powders doped with 10% copper. X-ray diffraction analysis showed that pure silicon dioxide consisted of quartz at 800°C, while the doped powder was nearly amorphous. At 900°C, the doped powder showed traces of cristobalite and tridymite phases. Increased temperature caused these phases to grow, with the most rapid cristobalite growth between 1100-1200°C. Photocatalytic tests showed the doped powder had higher degradation of methyl orange under visible light compared to pure silicon dioxide.
PCE-Lecture-1-3-Introduction to chemical engineering
1. The document provides an introduction to chemical engineering, including the roles of chemical engineers, unit operations and processes, and examples like combustion and nitration.
2. It describes the differences between a chemist and chemical engineer and discusses the history and development of chemical engineering as a profession.
3. The document outlines topics that will be covered, including unit operations, processes, and examples like distillation and polymerization that have important applications in chemical industries.
Production of crystalline silicon wafers a review
1. The production of crystalline silicon wafers involves multiple steps: quartz is converted to metallurgical grade silicon, then to polysilicon via chemical vapor deposition or fluidized bed reactors, then polysilicon is made into monocrystalline or multicrystalline ingots using Czochralski or float zone methods.
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Influence of reaction medium on morphology and crystallite size of zinc oxide
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The cost of information acquisition by natural selection
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waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
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Direct Seeded Rice - Climate Smart Agriculture
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•Biological
•Mechanical
•Chemical
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silicone and their application
- 1. Presented by Sushil Kumar Ranjan M.Sc. (1st Sem. (Roll No-11) Under the guidance of Dr. N.P. Singh Associate professor Department of chemistry, DDU Gorakhpur University, Gorakhpur Silicones and their Applications
- 2. – Introduction – Nomenclature – Manufacturing of silicones – Types of silicones – Properties of silicones – Applications
- 3. Silicones, also known as polysiloxanes It is made up by repeating unit of siloxanes, which is chain of alternating silicone atoms and oxygen atoms, combined with carbon, hydrogen or other Silicone fluid, silicone elastomer and silicone resin
- 4. nomenclature SILICON Si SILICA SILANE SILOXANES X X X X Si -O R R Si O- -O Si O- O O
- 5. Manufacture of silicone SiO2 + 2C Si + 2CO Production of silicones takes place in three stage a) Synthetic of chloro-silanes b) Hydrolysis of chloro-silanes c) Condensation polymerization
- 6. Chlorosilane synthesis xSi + yCH3Cl Cu 3000C MeSiCl3 Me3SiCl Me2SiCl2 Yield (weight %) B.P. ( oC) >50 10-30 <10 70.0 66.4 57.9
- 10. Silicone fluid Silicone fluids are linear polysiloxanes of 50-200 units Very low volatility, low surface tension and very good water repellence Silicone fluids are transparent, tasteless and odorless liquids with no known harmful effects. use as transformer oils, lubricants, dielectrics, defoamers and release agents for photocopiers and laser printers. cosmetics, pharmaceuticals and medicine Polydimethylsiloxanes
- 11. Silicone elastomers Silicone elastomers are long chain polymers made of 6000-600000 siloxanes units. Have high molecular weights. These can be vulcanised to give rubber. • Room Temperature Vulcanised (RTV) • High temperature vulcanized (HTV) Mold making, electronics, household appliances, machinery and industrial plant engineering, medical applications. Silica filler to enhance strength
- 12. Silicone resin Water resistance Made by hydrolysis of a blend of chlorosilanes High heat resistance dielectric behaviour is ideal Silicone resins as solvent-based and solvent-free systems, emulsions, but also powders. Typically methyl phenyl silicone Can be flexible or rigid used to make paints and coatings
- 13. Property of silicone Water repellent Very good thermo- oxidative stability Excellent dielectric properties Low chemical reactivity Low toxicity High thermal stability High gas permeability Low thermal conductivity Resistance to oxygen, ozone and UV light Electrical insulation
- 14. application of silicone aerospace Cook ware firestops Dry cleaning automotive opthalmology Mold makingPersonal care
- 16. As modern means of transport become faster, more reliable and more efficient, demands on materials to perform become tougher. As such, smaller parts must resist exposure to extreme heat, moisture, salt and fuels. Most materials deteriorate in these conditions, but not silicones. Silicones retain their properties and – most important – ensure that cars, ships, airplanes and trains operate safely for the long haul.
- 17. References • Industrial chemistry including chemical engineering by BK Sharma, IO-1040 (1991) (book.google.co.in) • Hans-Heinrich Moretto, Manfred Schulze, Gebhard Wagner (2005) "Silicones" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. (books.google.co.in) • https://en.wikipedia.org/wiki/Silicone • http://www.essentialchemicalindustry.org/polymers/silicones.html
- 18. Acknowledgement – I would like to express my special thanks of gratitude to my teacher Dr. N.P. Singh sir – I am also very thankful to the head, Department Of Chemistry D.D.U. Gorakhpur University, Gorakhpur Prof. O.P. Pandey Sir. – Secondly, I would also like to thank my parents and friends who helped me a lot in finalizing this presentation within the time frame. – Thanks again to all who helped me