Table 1. Commonly Used Plastics and Their Physical Properties^a.

Plastic	Thermal properties				Strength		Density
Chemical name	Tm (°C)	Tg (°C)	Td (°C)	Cte (°C)	Tensile psi	Compressive psi	(g/cm3)
LDPE (Low-density polyethylene)	122				1900	0	0.914–0.940
	124				4000
HDPE (High-density polyethylene)	130		79	59	3200	2700	0.952–0.965
	137		91	110	4500	3600
PP (Polypropylene)	168	–20	107	81	4500	5500	0.900–0.910
	175		121	100	6000	8000
PS (Polystyrene)		74	68	50	5200	12000	1.04–1.05
		105	96	83	7500	13000
PVC (Polyvinyl chloride)		75	57	50	5900	8000	1.30–1.58
		105	82	100	7500	13000
PI (Polyimide)		310	277	45	10500	30000	1.36–1.43
		365	360	56	17100	40000
PMMA (Poly(methyl methacrylate)(		85	79	50	7000	10500	1.17–1.20
		105	107	90	11000	18000
PC (Polycarbonate)		150	138	68	9500	12500	1.2

^aT_m, crystalline melting temperature; T_d, heat distortion temperature (66 psi load); C_te coefficient of linear thermal expansion; T_g, glass transition temperature (the plastic becomes brittle below this temperature); compressive psi, compressive strength (load necessary to crush a sample of the plastic); tensile psi, tensile strength (load necessary to pull a sample of the plastic apart).