คำอธิบาย
Polypropylene raw material is classified three types :
PP-H PP-B PP-R
The followings is molecular chain structure :
Homopolymer ( PP-H)
-P-P-P-P-P-P-P-P-P-P-P-P
Block copolymer ( PP-B) :
[ P-P-P-P-P-P-P-P-P-P-P-P ] + EPR + PE
Random copolymer ( PP-R) :
-P-P-P-P-E-E-P-P-E-P-P-P-E-E-E-P- —
P———-Propylene
E———-Ethylene
PE——–Polyethylene
EPR——Ethylene propylene rubber
@ Easy way to differentiate PP-H PP-B PP-R
Melting temperature of PP-R is lower than 150 oC , but melting temperature of PP-H and PP-B is higher than 160oC
so PP-R can be judged by melting temperature.
@ Difference between PP-R112 pipe and PP-R80 pipe
Essential difference is that hoop stress of PP-R 112 is 11.2 MPa and hoop stress of PP-R 80 is 8.0 MPa for long
50 years service under constant 20 oC , Obviously PP-R 112 pipe has better pressure resistant and longer service
life than PP-R 80 pipe.
Ref : data from DISMY / RNT