Applications of Silicone Rubber

Silicone rubber is a versatile engineered elastomer with a wide range of useful properties and applications. Since its discovery in the early 20th century, the development of silicone rubber has enabled its growing use across many industries. From aerospace to automotive, healthcare to cookware, silicone rubber has become a staple material improving safety, performance and efficiency.

Silicone in Medical Applications

One of the most common and critical uses of silicone rubber is in the healthcare industry. Silicone is an ideal biomaterial for medical implants and devices because of its biocompatibility, flexibility, heat resistance and chemical stability. Some medical applications of silicone rubber include:

Implants

Silicone-based implants are extensively used in cosmetic and reconstructive surgeries. Breast implants, chin and cheek implants, pacemakers and artificial joints utilize medical grade silicone rubber.

Tubing

From IV and drainage tubing to catheters and oxygen tubes, silicone's flexibility and temperature resistance makes it suitable for fluid transport in healthcare.

Wound care

Silicone-based wound dressings, medical tapes and scar treatment gels leverage silicone's moisture permeability and non-stick properties to aid healing.

Labware

Due to its chemical inertness, products like petri dishes, test tubes and medical hoses are often made of silicone.

Orthopedics

Cushioning parts in braces, pads and prosthetics are made of silicone rubber for its compressibility and impact absorption.

Dentistry

Soft tissue fillers, bite guards, seals and impressions utilize silicone rubbers.

Silicone Rubber Material

Silicone rubber is often referred to as polysiloxane. It consists of a silicone chain backbone with methyl side groups attached to silicon atoms: (-Si-O-)n [-Si(CH3)2-O-]m

Silicone rubber combines the heat resistance of inorganic siloxane polymers with the flexibility of organic methyl side chains. This chemistry gives it special properties.

Key traits of silicone rubber material include:

Temperature stability from -100 to 300°C
UV radiation resistance
Low thermal conductivity
High elongation and elasticity
Excellent electrical insulation
Low chemical reactivity and toxicity
Resilience and impact absorption
Resistance to moisture and weathering
Bio-inertness

These versatile properties enable the varied applications and performance capabilities of silicone-based rubber products across industries.

Types of Silicone Rubber

There are several classes of silicone rubber, each with somewhat different properties and best suited to certain applications

High Temperature Vulcanized (HTV)

HTV rubbers cure with heat and catalysts to create molded parts, seals, gaskets and insulation with high heat resistance.

Room Temperature Vulcanized (RTV)

RTV silicones cure at room temperature into adhesives, sealants, caulks, coatings and encapsulants valued for flexibility.

Liquid Silicone Rubber (LSR)

Flowable LSRs are two-part compounds that react via injection molding to produce intricate, soft rubber parts like gaskets, seals and medical devices.

Fluorosilicone

Fluorinated silicones offer fuel and oil resistance ideal for automotive, aviation and chemical applications where petroleum fluids are present.

Silicone Foam

Aerated foam silicone provides impact absorption, vibration damping, insulation and cushioning for varied uses.

Silicone Gel

Soft silicone gels have properties ideal for medical products, sports protective gear and pressure sore cushions.

Silicone Rubber Density

An important property of silicone rubber is its density, which generally ranges between 1.1 to 2.0 g/cm3, less dense than natural rubber. Density influences qualities like compressibility, resilience and permeability.

Factors that affect the density of silicone rubber include

01/

Base polymer viscosity - Higher viscosity base polymers create denser cured silicone.

02/

Fillers - Adding fillers like silica or clays increases silicone density and hardness.

03/

Pigments - Dense pigments like iron oxide increase density versus lighter titanium dioxide pigments.

04/

Curing method - Addition-cured silicones are denser than peroxide or platinum-cured types.

05/

Formulation - Plasticizers, crosslinkers, vulcanization agents and functional groups influence density.

06/

Cell structure - Aeration lowers silicone density by creating foam silicone.

Silicone Rubber Temperature Range

A major advantage of silicone rubbers is their ability to maintain flexible and resilient properties across a wide service temperature range from -100 to 300°C.

Factors influencing the usable temperature range include:

Base chemistry - Different silicone backbone variations impart distinct temperature capabilities.

Curing system - Certain addition-cure silicones withstand higher temperatures than condensation or peroxide-cured.

Plasticizers - Plasticizers may improve low temperature flexibility but reduce heat resistance.

Fillers - Mineral fillers like fumed silica enhance high temperature stability.

Fluorination - Fluorosilicones offer better resistance to fuels and oils at extreme temperatures.

Service conditions - Compression, tension, chemical exposure and other factors impact working temperature range.

With proper formulation and curing, silicone rubbers can perform consistently through freezing conditions up to 300°C heat while retaining elastomeric properties much better than organic rubbers.

What are the Common Uses of Silicone Rubber?

Silicone rubber provides an ideal balance of heat resistance, chemical stability, biological inertness and retention of elastomeric properties across a wide temperature span. Common uses in various industries include.

Cookware

Silicone oven mitts, baking mats, pot holders and lids withstand oven and stove temperatures.

Electronics

Silicone rubber insulates conductors, seals sensitive components and coats wire.

Automotive

Silicone hoses, gaskets, seals and lubricants perform under-hood at high heat.

Aerospace

Silicones function as adhesives, sealants and lubricants in extreme atmospheres.

Gas/chemical

Excellent chemical stability suits silicone for seals, gaskets, hoses and protective equipment where harsh chemicals are handled.

Food processing

Heat and oil resistance enables silicone rubber utensils, molds, gloves and non-stick surfaces touching food.

Automotive

Low compression set suits LSR for molded seals, O-rings, connectors, and insulation.

Food contact

Inert LSR enables molding kitchenware, bakeware, and water bottle valve parts resistant to food acids and oils.

Infant care

BPA-free, sterilizable LSR works well for pacifier, baby bottle and teething ring parts.

Consumer goods

Versatile LSR molds anti-vibration parts, grips, mouthguards, earphone tips and more.

From micro-molded medical components to cushioning grips and valves, liquid silicone rubber delivers an exceptional combination of biocompatibility, heat resistance, and manufacturing precision.

What Silicone is Used for Rubber?

There are a few major types of silicone used to create silicone-based synthetic rubber.

Polydimethylsiloxane (PDMS) - The most common silicone rubber is based on PDMS, providing versatility and stability.

Fluorosilicone - Fluorinated PDMS offers enhanced fuel and solvent resistance.

Phenylmethylsiloxane - Phenyl siloxanes add rigidity, hardness and heat resistance.

Vinylmethylsiloxane - Vinyl groups allow chemical crosslinking to customize mechanical properties.

Chlorosilanes - Chlorosilanes enable bonding silicone to inorganic surfaces as an adhesive.

Silicone Resins - Silicone resins dissolved in xylene create room temperature vulcanizing (RTV) sealants.

Key properties these silicones impart to rubber include:

Temperature stability from -100 to 300°C
Flexibility and elongation
Hydrophobicity and chemical resistance
Electrical insulation
Biocompatibility and physiological inertness
UV/ozone/weathering stability

Their unique capabilities make silicone-based synthetic rubbers essential across many modern industries and technologies.

What is the Difference Between Rubber and Silicone Rubber?

While both are elastomers, there are several key differences between traditional rubber and silicone rubber.

Composition

Rubber is organic, made of long hydrocarbon chains. Silicone has an inorganic silicone-oxygen backbone.

Heat resistance

Silicone withstands over 200°C temperatures versus 70-80°C for organic rubbers.

Chemical stability

Silicone exhibits greater resistance to oils, solvents, acids, ozone and weathering than rubber.

Biostability

Silicone demonstrates bio-inertness and stability in bodily contact lacking in natural rubbers.

Electrical properties

Silicone is an excellent insulator which rubber is generally not.

Manufacturing

Silicone cures without vulcanization required for rubber and can be liquid injection molded.

Cost

Silicone costs more per pound than organic rubber compounds.

Applications

Silicone and rubber both have indispensable but distinct applications based on their differing material strengths.

While silicone rubber shares elastomeric behavior with rubber, its inorganic silicone-oxygen backbone imparts unique properties advantageous for specialized applications.

Conclusion

With its inorganic backbone and organic side chains, silicone rubber offers the elasticity of rubber combined with extreme temperature stability, chemical and biological inertness. These properties make silicone an essential material technology across healthcare, engineering, electronics, food service and other fields. Useful silicone varieties include HTV, RTV and LSR, selected based on manufacturing needs and product environments. From silicone oven mitts to liquid molded gaskets and medical implants, silicone rubber spans diverse applications not feasible with organic rubbers alone. With ongoing development, formulations and blends continue expanding silicone rubber's capabilities.

Rolifyx is a supplier specializing in R&D, production, sales, service, and operation of silicone polymer materials. It continues to provide customers with silicone materials, novel technologies, and high-quality products and can customize them according to customer needs. It allows liquid silicone to be better modified and provides the best solution for customer needs.

In particular, it has outstanding advantages in innovative organic liquid foam rolls, sheets, foamed silicone strips, foamed silicone rings, thermal conductivity, potting, sealing, room temperature vulcanization rubber, research and production technology, etc.