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Polyethylene - Coggle Diagram
Polyethylene
products from polyethylene
garbage containers
bottles
packaging film
bag plastic
LDPE
produced under high pressure in the presence of a free radical initiator
use for both rigid container and plastic film application : plastic bags
HDPE
produced by low pressure process in the presence of ziegler type catalyst
use in packaging products: detergent bottle , garbage container, water pipe
Slurry process
LLDPE
produced in the gas phase under low pressure
use in gas pipe and fittingsc packaging film, film wraps
Introduction
known as polyethene and use primariliy in packaging
obtained by polymerizing ethylene gas
LDPE and HDPE is widely used grade of polyethylene
physical properties
thermoplastic polymer
melting point range 120C to 180C
LDPE exhibits high flexibiltiy
chemical properties
excellent chemical resistances
burn slowly with a blue flame
equipments for polyethylene process
plastic extrusion process
manufacturing process use to make pipe, hoses, curtain tracks, rods and fibres
injection molding machine
calendering machine for foil and sheet
plastic film calendering machine
safety measure
hazard identification
eyes
dust may cause mechanical irritation to eye
heated polyethylene can cause serious thermal urns
vapours formed when polyethylene is heated may be irritating to the eye
inhalation
nuisance dust can be irritating to the upper respiratory product
irritating vapors may form when the polyethylene is process at high temperature
potential hazards
steamers
can create feed and product quality problems
can plug fibers, feeders, silo outlets and reduce resin flow
fires and dust
dry colorants and additives in powder form ca bring hazardous dust particles
dust particles dispersed in air form explosives dust cloud
static electricity
ungrounded metal piece present significant hazard
it can get charged from polyethylene resin to a high voltage
discharge entire metal surface in a single spark
exposure control/personal protection
engineering control- local exhaust ventilation is recommended for ontrol airborne dusts, fumes
respiratory equipment
personal protection
wear safety glasses with side shields
workplace exposure guidelines- OSHA
catalyst used
Ziegler-Natta catalyst
use in the synthesis of polymers of 1-alkene
use to polmerize terminal 1-alkenes
philips catalyst
used in polymerization process
enviromental issue
the pollution is causes by burning or disposal of polyethylene material
control by:
masssive awareness campaign
goverment should provide public waste bins in strategic position
segregate plastic waste from other solid waste
waste management
solid waste
polyethylene film manufacturers recycle this waste
using a contract recyler to turn the waste film back into pellets for re-use
air
stack emission monitoring
reaction & mechanism
polymerization of Ethylene monomer
polymerized by radical mechanism with addition of Ziegler Natta catalyst
step 1: initiation
dissociation of peroxide's oxygen bonds then quickly converted into carbon dioxide and 2 radicals
step 2: initiation
these radical act as electrophiles and attack the double bond of ethylene forming a stabler intermediate
step 3: propagation
the new radical can add on to itself by attack another ethylene molecule
step 4: termination
the reaction is terminated when two radicals react with each other to produce product with paired electron