Chapter: Mechanical - Engineering materials and metallurgy - Non-Metallic Materials

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Elastomer

POLYISOPRENE (NATURAL RUBBER), ELASTOMER BUTYL (ISOBUTENE-ISOPRENE), NEOPRENE (CHLOROPRENE), ELASTOMER SILICONE, THERMOPLASTICS.

ELASTOMER   

POLYISOPRENE (NATURAL RUBBER)


 

Excellent abrasion resistance; Excellent tear strength;

 

Excellent resilinence;

Excellent low temperature flexibility; Excellent dielectric strength;

 

Poor resistance to ozone and oxygen; Poor resistance to sunlight and heat; Poor resistance to solvents.

 

Applications: automobile tires, gaskets, hoses.

 

Elastomer

ELASTOMER BUTYL (ISOBUTENE-ISOPRENE)


Applications: inner lining of automobile tires, steam hoses and diaphragms.

 

ELASTOMER

NEOPRENE (CHLOROPRENE)

Property     Value in metric unit Value in US unit

Density       1.23 *10³    kg/m³ 76.8   lb/ft³

Tensile strength    25      MPa  3630  psi

Elongation  1000  %      1000  %

Glass transition temperature -50      ºC      -58    ºF     

Maximum work temperature 100     ºC      212    ºF     

Electric resistivity 103    Ohm*m       105    Ohm*cm

Dielectric constant         9        -        9        -       

 

Excellent abrasion resistance;

Good resistance to oil, fuel and petroleum based solvents; Excellent resistance to ozone;

Very good resistance to sunlight; Poor resistance to lacquer solvents.

 

Applications: oil and crude oil hoses, gaskets, diaphragms, lining of chemical vessels.

 

Elastomer

 

ELASTOMER ETHYLENE-PROPYLENE (EPDM)

 


Property     Value in metric unit Value in US unit

Density       0.86 *10³    kg/m³ 53.7   lb/ft³

Tensile strength    20      MPa  2900  psi

Elongation  300    %      300    %

Glass transition temperature -75      ºC      -103  ºF

Maximum work temperature 100     ºC      212    ºF

Electric resistivity 108    Ohm*m  1010

Dielectric constant         3.3     -        3.3     -

                                     

 

Excellent resistance to sunlight and heat;  Excellent resistance to ozone and oxygen;  Excellent resistance to water and steam;  Excellent low temperature flexibility;  Good dielectric strength;

 

 Good abrasion resistance;

 Poor resistance to fuel, oil, alcohol.

Applications: electrical insulation, shoe soles, hoses, conveyor belts.

 

ELASTOMER SILICONE


Excellent resistance to ozone and oxygen;  Excellent resistance to heat and sunlight;  Excellent weather resistance;

Wide work temperature interval: -150ºF…600 ºF (-100ºC…315 ºC)  Poor resistance to fuel, oil, hydrocarbons;

 

Poor abrasion resistance Poor tear resistance

 

Applications: high temperature sealant, adhesives, vibration damping components.

 

THERMOPLASTICS

Thermoplastics are polymers, which soften (becomes pliable and plastic) and melt when heated. In the melted conditions thermoplastics may be formed by various methods (injection molding, extrusion, Thermoforming). No new cross-links form (no chemical curing) when a thermoplastic cools and harden. Thermoplastics may be reprocessed (re-melt) many times.

 

Molecules of most of thermoplastics combine long polymer chains alternating with monomer units.

Thermoplastic materials may contain filler materials in form of powder or fibers, providing improvement of specific material properties (strength, stiffness, lubricity, color etc.).

 

Thermoplastic groups:

 

Polyolefines: Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polypropylene (PP).

 

Styrenics: Polysterene (PS), Acrylonitrile-Butadiene-Styrene (ABS), Styrene-Acrylonitrile (SAN), Styrene/Acrylic (S/A), Styrene-Maleic Anhydride

 

(SMA).

 

Vinyls: Polyvinyl Chloride (PVC), Chlorinated Polyvinyl Chloride (CPVC).

 

Acrylics: Polymethylmethacrylate (PMMA), Polyvinilchloride-Acrylic Blend (PVC/MA).

 

Fluoropolymers: Polychlorotrifluoroethylene         (CTFE), Polytetrafluoroethylene

 

(PTFE), Polyvinylidene Fluoride (PVDF).

 

Polyesters: Polyethylene Terephtalate (PET), Polyester PETG (PETG), Polybutylene Terephtalate (PBT), Polyarilate (PAR), Liquid Crystal Polyester (LCP).

 

Polyamides (Nylons): Nylon 6 (N6), Nylon 66 (N66), Nylon 11 (N11), Nylon

 

12 (N12), Polyphtalamide (PPA), Polyamidemide (PAI).

 

Polyimides: Polyimide (PI), Polyetherimide (PEI).

 

Polyethers: Polyacetal (POM), Polycarbonate (PC), Polyphenylene Oxide Blend (PPO), Polyaryletherketone (PAEK), Polyetheretherketone.

Sulfur Containing Polymers: Polyphenylene Sulfide (PPS), Polysulfone (PSF), Polyethersulfone (PES), Polyarylsulfone (PAS).

 

Properties and applications of some thermoplastics

Thermoplastic Low Density Polyethylene (LDPE) Thermoplastic High Density Polyethylene (HDPE) Thermoplastic Polypropylene (PP)

Thermoplastic Acrylonitrile-Butadiene-Styrene (ABS) Thermoplastic Polyvinyl Chloride (PVC)

Thermoplastic Polymethylmethacrylate (PMMA) Thermoplastic Polytetrafluoroethylene (PTFE) Thermoplastic Polyethylene Terephtalate (PET) Thermoplastic Polyamide (Nylon 6)

 

Thermoplastic Polyimide (PI)

Thermoplastic Polycarbonate (PC) Thermoplastic Polysulfone (PSF)


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