I posted this message several weeks ago but couldn't access the group for a
long time.
Please help me.
TG
RoccoM wrote:
>
> I need to know the difference between HDPE and ABS used for making
> industrial safety helmets.
HDPE, or PE-HD is a polyethylene, which is polymerized under low
pressure. Under this conditions it is possible to get a polymer with M
up to 300000 and very high density. These polymers have a higher
"melting" temperature and have a higher tensile strength. Under special
copnditions (i guess quite secret) it is possible to obtain "high
molecular weight", "extra high..." and "ultra-high..." PE-HDs (HMW,
EHMW, UHMW-HDPE)
ABS is a polymer-blend: the continuous phase is a (statistic) copolymer
of acrylonitrile and styrene, the discontinuos phase is polybutadiene,
or some copolymers of polybutadiene with e.g. styrene.
> I posted this message several weeks ago but couldn't access the group for a
> long time.
>
> Please help me.
>
hope that helps...
Andi
Lock at the approx..! values below (ABS vs HD PE),
and you can see, the stiffness, the heatdeflection-temperature
and the price of ABS is higher.
However HD PE has a higher toughness & flexibility
Also i think HD PE has a better chemical resistant (solvent, acid..)
and a better UV-resistant as ABS.
ABS
Tensile modulus 2300
Yield stress 40 MPa
Yield strain 2.1
Charpy notched impact strength (+23°C) 22 kJ/m²
Temp. of deflection under load (1.80 MPa) 93°C
Temp. of deflection under load (0.45 MPa) 98°C
Vicat softening temperature (50°C/h 50N) 97
Density 1050 kg/m³
price 1,50-2 Euro/kg
HD PE
Tensile modulus 1200
Yield stress 28
Yield strain 9 %
Charpy notched impact strength (+23°C) N kJ/m²
Temp. of deflection under load (1.80 MPa) 44 °C
Temp. of deflection under load (0.45 MPa) 73 °C
Vicat softening temperature (50°C/h 50N) 80
Density 954 kg/m³
price 0,80-1 Euro/kg