Polymers
Polymers
LDPE (Low Density Polyethylene) is defined by a density range of 0.910 - 0.940 g/cm3. It has a high degree of short and long chain branching, which means that the chains do not pack into the crystal structure as well. It has therefore less strong intermolecular forces as the instantaneous-dipole induced-dipole attraction is less. This results in a lower tensile strength and increased ductility. LDPE is created by free radical polymerization. The high degree of branches with long chains gives molten LDPE unique and desirable flow properties
LDPE Properties:
Semi-rigid, translucent, very tough, weatherproof, good chemical resistance, low water absorption, easily processed by most methods, low cost.
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LDPE Physical Properties: |
Value: |
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Tensile Strength: |
0.20 - 0.40 N/mm2 |
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Notched Impact Strength: |
no break |
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Thermal Coefficient of Expansion: |
100 - 220 x 10-6 |
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Max. Continued Use Temperature: |
65 oC (149 oF) |
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Melting Point: |
110 oC (230 oF) |
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Glass Transition Temperature: |
-125 oC (-193 oF) |
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Density: |
0.910 - 0.940 g/cm3 |
HDPE (High Density Polyethylene) is defined by a density of greater or equal to 0.941 g/cm3. HDPE has a low degree of branching and thus stronger intermolecular forces and tensile strength. HDPE can be produced by chromium/silica catalysts, Ziegler-Natta catalysts or metallocene catalysts. The lack of branching is ensured by an appropriate choice of catalyst.
HDPE Properties:
Flexible, translucent/waxy, weatherproof, good low temperature toughness (to -60'C), easy to process by most methods, low cost, good chemical resistance.
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HDPE Physical Properties: |
Value: |
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Tensile Strength: |
0.20 - 0.40 N/mm2 |
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Notched Impact Strength: |
no break |
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Thermal Coefficient of Expansion: |
100 - 220 x 10-6 |
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Max. Continued Use Temperature: |
65 oC (149 oF) |
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Melting Point: |
126 oC (259 oF) |
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Density: |
0.941 - 0.965 g/cm3 |
Polypropene, PP
The symbol for polypropylene developed by the Society of the Plastics Industry so that items can be labeled for easy recycling is:
Semi-rigid, translucent, good chemical resistance, tough, good fatigue resistance,
integral hinge property, good heat resistance.
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Physical Properties: |
Value: |
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Tensile Strength: |
0.95 - 1.30 N/mm2 |
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Notched Impact Strength: |
3.0 - 30.0 Kj/m2 |
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Thermal Coefficient of Expansion: |
100 - 150 x 10-6 |
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Max. Continued Use Temperature: |
80 oC (176 oF) |
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Melting Point: |
160 oC (320 oF) |
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Glass Transition Temp. (atactic): |
-20 oC (-4 oF) |
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Glass Transition Temp. (isotactic): |
100 oC (212 oF) |
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Density: |
0.905 g/cm3 |
Polyamides, PA
The majority of nylons tend to be semi-crystalline and are generally very tough materials with good thermal and chemical resistance. The different types give a wide range of properties with specific gravity, melting point and moisture content tending to reduce as the nylon number increases. Nylons can be used in high temperature environments. Heat stabilized systems allow sustained performance at temperatures up to 185oC.
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Physical Properties: |
Value: |
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Tensile Strength: |
90 - 185 N/mm2 |
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Notched Impact Strength: |
5.0 - 13.0 Kj/m2 |
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Thermal Coefficient of Expansion: |
80 x 10-6 |
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Max. Continued Use Temperature: |
150 - 185 oC (302 - 365 oF) |
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Melting Point: |
190 - 350 oC (374 - 662 oF) |
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Glass Transition Temp. (Nylon 66): |
45 oC (113 oF) |
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Density: |
1.13 - 1.35 g/cm3 |
PVC, PVC-U
The symbol for polyvinyl chloride developed by the Society of the Plastics Industry so that items can be labeled for easy recycling is:
A highly versatile polymer, PVC is compatible with many additives. It can
be plasticized to make it flexible for use in flooring or un plasticized (PVC-U) for use in building applications and window frames.
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Physical Properties: |
Value: |
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Tensile Strength: |
2.60 N/mm2 |
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Notched Impact Strength: |
2.0 - 4.5 Kj/m2 |
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Thermal Coefficient of Expansion: |
80 x 10-6 |
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Max. Continued Use Temperature: |
60 oC (140 oF) |
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Melting Point: |
212 oC (413 oF) |
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Glass Transition Temperature: |
81 oC (178 oF) |
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Density: |
1.38 g/cm3 |
SBR (Styrene Butadiene Rubber)
We have styrene butadiene rubber (SBR), SBR is a collection of synthetic rubbers from styrene and butadiene. These materials SBR have resistance to abrasion when mixed with suitable additives. The mixed styrene and
butadiene ratio affects the polymer's properties, so if the amount of styrene is high, rubber is hard. Styrene-butadiene is produced by cold emulsion copolymerization. Actually to properties such as high process
ability, high scrubbing resistance and also the environmental properties of the most widely used synthetic elastomer. Other name for SBR is AmeripolSynpol, Europrene, kralex, polysar, and plioflex, CopoCarbomix,
Nipol, and Solprene, cold emulsion styrene butadiene.
SBR without oil
SBR with oil
Properties SBR:
SBR has excellent corrosion resistance and with increasing cis and vinyl butadiene content, corrosion resistance continues to increase, wear resistance, good resilience, low resilience, cracking resistance, heat resistance
and resistance hit a shot.
Solvent SBR: Dimethylformamide DMF or (Dimethylformamide)
Density SBR: 0.92_0.95 g / cm3 (Depending on styrene percentage)
Melting Temperature (Tm) SBR: It does not melt in the cooked state.
Glass
transition temperature: varies from -52 to -13 ° C (Depending on the percentage of styrene)
Hardness grade: 50 to 90
Polar or non-polar state: Non-polar
SBR application
For the rubber industry, especially in the automotive industry, such as tire. This accounts for about 70 percent of global demand for products. Other markets of SBR, with the exception of tires, cover about 25-30% of artificial rubber request, including
mechanical parts and a range of other end products, Elastomer, Thermoplastic Elastomer TPE. Styrene Butadiene has different grades and varies depending on each grade, ranging from tire and rubber to shoe and mechanical
industries. The most important use of this product is the production of tires and rubber parts.
SBR without oil is used for Car tire, conveyor belt, shoes foam, cable, flooring, bike tire, toy, foam rubber, Industrial rubber articles, Rubber linings and other rubber items.
SBR with oil is used for Car tire, conveyor belt, shoes foam, cable and other rubber items.
One of the most important uses of SBR is its use in tire manufacturing, especially the part of the tire that comes in contact with the ground and the five important SBRs for this major use in the rubber
industry are: Rupture resistance, fatigue strength, flex resistance, abrasion resistance, slip resistance (has the property of grappling with asphalt).