PCB Board FR-4, 2 copper planes vs. Plastic Polycarbonate

Compare PCB Board FR-4, 2 copper planes vs. Plastic Polycarbonate strength, stiffness, weight and thermal properties.

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PCB Board FR-4, 2 copper planesComposite

Plastic PolycarbonateBulk polymer (molded or machined)

Mechanical
Try it on a partA sample part to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD
Yield strength	not given (tensile used)	65MPasourcetypical, tensile yield
Ultimate tensile strength	246–385MPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D3039)	65MPasourcetypical, stress at break
Flexural strength	not sourced	97MPasourcetypical, flexural strength
Elongation at break	not sourced	125%sourcetypical, strain at break
Young's modulus (stiffness)	21.9–25.8GPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D790-15e2); the copper planes are left out	2.4GPasourcetypical
Density	not sourced	1,200kg/m³sourcetypical
Strength to weight	not sourced	54.2kN·m/kg
Stiffness to weight	not sourced	2MN·m/kg
Poisson's ratio	0.171–0.177sourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction	0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1)
Shear modulus	10.2GPa11.7x stiffer in shear	0.87GPa
Bulk modulus	12.2GPa	3.33GPa
Speed of sound	not sourced	1,414m/s
Thermal
Thermal conductivity	not sourced	0.2W/m·Ksourcetypical, through-plane, 23 C
Thermal expansion	13–14µm/m·Ksourcethe bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)	65µm/m·Ksourcetypical, 23-55 C, parallel and normal
100 mm part over a 50 °C swing	67.5µm growth4.81x less	325µm growth
Specific heat	not sourced	1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766
Heats up and cools (diffusivity)	not sourced	0.142mm²/s
Thermal shock resistance	not sourced	51.7W/m
Glass transition	not sourced	144°Csourcetypical, DSC 10 C/min
Max service temperature	not sourced	125°CsourceUL 746B RTI, tensile strength, 1.5 mm
Values for	A whole circuit board read as one orthotropic plate: the JEDEC high-K thermal test board (JESD51-7, "2s2p"), 0.062 in (1.575 mm) thick with two internal solid copper planes 0.0014 in (1 oz) thick, as Texas Instruments SZZA017A Table 1 gives it. Copper C110 and the Isola 370HR laminate from this library; the layers conduct in parallel along the board and in series through it (boardStackup.ts). Its two 0.0028 in trace layers cover little of the board and are left out; vias are ignored. Mechanical values are the bare laminate's.	Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is PCB Board FR-4, 2 copper planes stronger than Plastic Polycarbonate?

PCB Board FR-4, 2 copper planes is stronger: its tensile strength is 315 MPa against yield strength 65 MPa for Plastic Polycarbonate (4.85x).

Which is stiffer, PCB Board FR-4, 2 copper planes or Plastic Polycarbonate?

PCB Board FR-4, 2 copper planes is stiffer: Young's modulus 23.9 GPa against 2.4 GPa for Plastic Polycarbonate, so the same part in PCB Board FR-4, 2 copper planes deflects less under the same load.

Which expands less with temperature?

PCB Board FR-4, 2 copper planes expands less: 13.5 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.

Among 73 materials

Stiffness against density

Strength against density