Drywall vs. Plastic HDPE

Compare Drywall vs. Plastic HDPE strength, stiffness, weight and thermal properties.

Plastic HDPEBulk polymer (molded or machined)

Mechanical	Drywall	Plastic HDPE
Yield strength	not given (tensile used)	24MPa1
Ultimate tensile strength	1–2MPa2	not stated (yield given)
Compressive strength	2.4MPa3	not sourced
Elongation at break	not sourced	not sourced
Young's modulus (stiffness)	1–2GPa2	0.9GPa1
Density	not sourced	950kg/m³1
Strength to weight	not sourced	25.3kN·m/kg
Stiffness to weight	not sourced	0.947MN·m/kg
Poisson's ratio	not sourced	base material0.4–0.454
Shear modulus	not sourced	0.316GPa
Bulk modulus	not sourced	2GPa
Speed of sound	not sourced	973m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Drywall	Plastic HDPE
Thermal conductivity	not sourced	base material0.4–0.49W/m·K4
Thermal expansion	16.7µm/m·K37.19x less	base material120µm/m·K4
100 mm part over a 50 °C swing	83.5µm growth7.19x less	600µm growth
Specific heat	1,090J/kg·K3	base material2,250J/kg·K42.06x higher
Heats up and cools (diffusivity)	not sourced	0.208mm²/s
Thermal shock resistance	not sourced	56.9W/m
Max service temperature	52°C5	not sourced

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources5 documents: LyondellBasell, USDA Forest Products Laboratory, Gypsum Association, INEOS Olefins & Polymers USA, USG

Drywall: 1/2 in. (12.7 mm) regular gypsum board (ASTM C1396), Gypsum Association GA-235-2019 typical/minimum properties; tensile and E from USDA FPL-co-authored review; service limit from USG Sheetrock 1/2 in. submittal
Plastic HDPE: LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values

1
Hostalen 23050 B Product DataLyondellBasellPlastic HDPE · Yield strength: typical, tensile stress at yield 23 °C, 50 mm/min ISO 527Plastic HDPE · Young's modulus (stiffness): typical, tensile modulus 23 °C ISO 527Plastic HDPE · Density: typical, ISO 1183
2
Mechanical Properties of Gypsum Board at Elevated TemperaturesUSDA Forest Products LaboratoryDrywall · Ultimate tensile strength: ambient range reported in review (Australian studies)Drywall · Young's modulus (stiffness): ambient range reported in review (Australian studies)
3
GA-235-2023 Gypsum Board Typical Mechanical and Physical PropertiesGypsum AssociationDrywall · Compressive strength: typical, 70 F / 50% RHDrywall · Thermal expansion: typical, unrestrained, 3.3-32 CDrywall · Specific heat: typical (from ASHRAE Handbook of Fundamentals, per GA)
4
Typical Engineering Properties of High Density PolyethyleneINEOS Olefins & Polymers USAarchived copyPlastic HDPE · Poisson's ratio: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Thermal conductivity: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Thermal expansion: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Specific heat: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
5
Sheetrock Brand UltraLight Panels Submittal Sheet (WB2501)USGarchived copyDrywall · Max service temperature: manufacturer sustained-exposure limit

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Mechanical

Is Drywall stronger than Plastic HDPE?

Plastic HDPE is stronger: its yield strength is 24 MPa against tensile strength 1.5 MPa for Drywall (16x).

Which is stiffer, Drywall or Plastic HDPE?

Drywall is stiffer: Young's modulus 1.5 GPa against 0.9 GPa for Plastic HDPE, so the same part in Drywall deflects less under the same load.

Thermal

Which expands less with temperature?

Drywall expands less: 16.7 µm/m·K against 120 µm/m·K for Plastic HDPE.