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Building Materials - Engineering

Q1:

Pick up the correct statement from the following:

A Plastics have generally low melting point

B The coefficient of thermal expansion of plastics is about three times than that of steel

C The acoustical boards prepared by impregnating fibre-glass with phenolic resins has absorption coefficient of about 0.67

D All the above.

ANS:D - All the above.

PVC (polyvinyl chloride, don't melt this one, its toxic) melts at about 160 degrees C.

HDPE (High-Density Poly Ethelene) 120-180°C.
MDPE (Medium Density Poly Ethelene) 120-180°C.
LDPE (Low-Density Poly Ethylene) 105-115°C.
PET(E) (polyethylene terephthalate,don't melt toxic) 250-250°C.
PP (poly Propylene VARIES) 130°,160°,170°C.
PS (Poly Styrene,don't melt,toxic) 240°C.
PLA (Poly Lactic Acid, biodegradable plant plastic) 173-178°C.