LowDensityPoly(ethylene)Low Density Polyethylene gives in comparison withPE-HD a less compact molecular structure with verygood flexibility,,good general chemical resistancebut less chemical resistance to organic solvents thanPE-HD. The temperature of use is limited to about80 ℃.Low density poly(ethylene) are more generally usedfor materials that need to bend and stretch such asshampoo bottles, toys, and grocery bags, pipes andlow loss electrical wire coverings
Low Density Poly(ethylene) ◼ Low Density Polyethylene gives in comparison with PE-HD a less compact molecular structure with very good flexibility, good general chemical resistance but less chemical resistance to organic solvents than PE-HD. The temperature of use is limited to about 80 ℃. ◼ Low density poly(ethylene) are more generally used for materials that need to bend and stretch such as shampoo bottles, toys, and grocery bags, pipes and low loss electrical wire coverings
LowDensityPoly(ethylene)Glass Transition Temperature = -25 ℃Melting Temperature: 120-130℃Decomposition Temperature >330℃Tensile Strength = 8-31 MPaThermoplasticImpact resistance = no break
Low Density Poly(ethylene) Glass Transition Temperature = -25 ℃ Melting Temperature: 120-130℃ Decomposition Temperature >330℃ Tensile Strength = 8-31 MPa Thermoplastic Impact resistance = no break
LowDensityPoly(ethylene Other Properties: Good electric properties: high volumeresistance, low dielectric loss; Good weather resistance; Good processability. Non toxic
Low Density Poly(ethylene) ◼ Other Properties: ◼ Good electric properties: high volume resistance, low dielectric loss; ◼ Good weather resistance; ◼ Good processability. ◼ Non toxic
ZieglerProcessesZieglerprocesses are based onco-ordinationreactions catalysed which is the complex preparedfrom titanium tetrachloride and triethylaluminium.Reaction is carried out at low pressures and lowtemperatures, typically no more than 7o℃Theis ofpolyethylene produced by such processes0.945intermediate density, giving values of aboutg/cm3
◼ Ziegler Processes Ziegler processes are based on co-ordination reactions catalysed which is the complex prepared from titanium tetrachloride and triethylaluminium. Reaction is carried out at low pressures and low temperatures, typically no more than 70℃ The polyethylene produced by such processes is of intermediate density, giving values of about 0.945 g/cm3
HighDensityPoly(ethylene)The Phillips Process and the Standard Oil (Indiana) Process:the Phillips and the Standard Oil (Indiana) Processes bothyield high-density polyethylene, using relatively lowpressuresandtemperatures.ProcessPressure/Temperature/CatalystDensity of℃product/atmg/cm30.96Phillips15~35130~1605%CrO,infinelydividedsilica/aluminaStandard40~800.96230~270SupportedMoO3Oilwith Na, Ca(Indiana)metal or hydridepromoters
High Density Poly(ethylene) ◼ The Phillips Process and the Standard Oil (Indiana) Process: the Phillips and the Standard Oil (Indiana) Processes both yield high-density polyethylene, using relatively low pressures and temperatures. Process Catalyst Pressure/ atm Temperature/ oC Density of product/ g/cm3 Phillips 5% CrO3 in finely divided silica/alumina 15~35 130~160 0.96 Standard Oil (Indiana) Supported MoO3 with Na, Ca metal or hydride promoters 40~80 230~270 0.96