Drywall vs. Plastic Polypropylene

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

Plastic PolypropyleneBulk polymer (molded or machined)

Mechanical	Drywall	Plastic Polypropylene
Yield strength	not given (tensile used)	33MPa1
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	1.45GPa1
Density	not sourced	900kg/m³1
Strength to weight	not sourced	36.7kN·m/kg
Stiffness to weight	not sourced	1.61MN·m/kg
Poisson's ratio	not sourced	base material0.424
Shear modulus	not sourced	0.511GPa
Bulk modulus	not sourced	3.02GPa
Speed of sound	not sourced	1,269m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Drywall	Plastic Polypropylene
Thermal conductivity	not sourced	base material0.17–0.22W/m·K4
Thermal expansion	16.7µm/m·K3	base material80–100µm/m·K4
100 mm part over a 50 °C swing	83.5µm growth5.39x less	450µm growth
Specific heat	1,090J/kg·K3	not sourced
Heats up and cools (diffusivity)	not sourced	not sourced
Thermal shock resistance	not sourced	28.6W/m
Max service temperature	52°C5	HDT 0.45 MPa90°C1

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 Polypropylene: LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values

1
Moplen HP501H Product DataLyondellBasellPlastic Polypropylene · Yield strength: typical, tensile stress at yield ISO 527Plastic Polypropylene · Young's modulus (stiffness): typical, tensile modulus ISO 527Plastic Polypropylene · Density: typical, 23 °C ISO 1183-1Plastic Polypropylene · Max service temperature: HDT 0.45 MPa (ISO 75B), unannealed
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 PolypropyleneINEOS Olefins & Polymers USAarchived copyPlastic Polypropylene · Poisson's ratio: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)Plastic Polypropylene · Thermal conductivity: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)Plastic Polypropylene · Thermal expansion: base material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)
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 Polypropylene?

Plastic Polypropylene is stronger: its yield strength is 33 MPa against tensile strength 1.5 MPa for Drywall (22x).

Which is stiffer, Drywall or Plastic Polypropylene?

Drywall is stiffer: Young's modulus 1.5 GPa against 1.45 GPa for Plastic Polypropylene, 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 90 µm/m·K for Plastic Polypropylene.