Polymers Flashcards
Amorphous traits
random transparent soft poor chemical resistance broad melting point low shrinkage low energy
PVC and PS
crystalline traits
regular chain transient good chemical resistance narrow melting point high shrinkage high energy
PE and PP
thermosetting
large cross linking
brittle
does not soft with heating
- expories and polyester resin
thermoplastic
little cross linking
ductile
soften with heating
- PE, PP, PVC, PS
Extrusion forming process
feed hooper (add plastic pellets) turing screw ( heaters on either side melting the plastic) shaping die extrudeate - tubing and pipe / sheet and film / structural parts
Blown film
resin extruder die chiller bubble of film cage film bubble gusset boards nip rolls bag-maker sepertaor indexer packer
calendering
mixing canlender rolls and heating quenching embossing cooling
injection moulding
purging and maintance
heating and melting
cooling and removal
compression moulding
cutting and preparation of the fabrics
stacking and pre-forming of the fabrics
laying-ip SMC snd prepregs
moulding and curing under heat and pressure
vacuum forming
clamp plastic sheet
heat plastic sheet
pre-inflate plastic steel and raise tool
vacuum plastic sheet against tool and cool
rapid prototyping
UV laser that cures liquid resin into plastic made into layers
Advantage of ploymers
low weight goof tensile strength thermal insulation water resiatnce recyclability low -cost
disadvantage of polymers
deformation under heavy load = break down of molecular chains
degradation = due to photolysis, hydrolysis, pyrolysis
short lifespan = aging
combustibility and production of toxic fumes
non-renewable resources
high-energy production
what is the recycling process of polymers
cleaning drying shredding filtering extruding spooling designing 3D printing
