SMA GF20
Reinforced grade
GF20 = 20% glass-fiber reinforced SMA
Mid-level stiffness/heat upgrade for structural brackets and IP carriers with moderate warpage.
Values for the GF20 condition
Other SMA grades and fills
SMA is listed in 10 conditions; see the grade overview at SMA.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Impact-modified | Choose for automotive instrument-panel substrates and housings needing ABS-like toughness with higher heat resistance. | 36 | 36 | 25 | 105 HRR |
High-MA compatibilizer / coupling resin | Additive grade (flake/pellet/powder) used at 1–10% to compatibilize ABS/PC, PA blends and to couple glass or mineral fillers — not for standalone molding. | 42 | 42 | 1 | 87 Shore D |
Mineral / talc filled SMA | Low-warpage, low-cost stiffening for large flat panels where isotropic shrinkage beats fiber strength. | 45 | 45 | 1.5 | 87 Shore D |
Flame-retardant compound | Use where UL 94 V-0 at 1.5–3 mm is required in heat-exposed electrical housings; slight loss of impact and flow. | 45 | 45 | 2 | 85 Shore D |
Low-MA transparent grade | Pick when optical clarity and easy flow matter more than maximum heat resistance. | 48 | 48 | 3 | 84 Shore D |
UFDefault Unfilled / Natural | Default choice for rigid, heat-resistant, dimensionally stable molded parts where impact loads are low. | 50 | 50 | 2.5 | 85 Shore D |
Heat-stabilized / high-heat molding grade | Select when HDT above ~130 °C is needed from an unreinforced styrenic, e.g. lighting bezels near lamps. | 52 | 52 | 2 | 86 Shore D |
GF20This page 20% glass-fiber reinforced SMA | Mid-level stiffness/heat upgrade for structural brackets and IP carriers with moderate warpage. | — | 90 | 1.8 | — |
30% glass-fiber reinforced SMA | The workhorse reinforced grade — highest stiffness/HDT combination for load-bearing heat-exposed parts. | — | 110 | 1.5 | — |
40% glass-fiber reinforced SMA | Maximum stiffness / lowest CTE version for rigid metal-replacement structures; very brittle and abrasive to tooling. | — | 125 | 1.3 | — |
What is SMA GF20?
SMA GF20 is SMA in the GF20 grade — mid-level stiffness/heat upgrade for structural brackets and IP carriers with moderate warpage. SMA GF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 90 MPa (13.1 ksi) — stronger than 52% of polymer grades. Elongation at break is 1.8% and the elastic modulus is 6.5 GPa (0.943 Msi). SMA GF20 has a density of 1.22 g/cm³ (0.0441 lb/in³), heavier than 61% of polymer grades. Its glass-transition temperature is 140°C (284 °F). UF is the default condition FabDigit quotes; GF20 is available on request or by drawing note.
Advantages
- Stiff — 6.5 GPa (0.943 Msi), better than 90% of polymer grades
- Low, predictable mold shrinkage — 0.3%, better than 90% of polymer grades
Limitations
- Limited ductility — 1.8%, worse than 97% of polymer grades
- Needs corrosion protection — 60/100, worse than 89% of polymer grades
- Difficult to machine — 40/100, worse than 82% of polymer grades
- Degrades in UV without stabilisers — 25/100, worse than 76% of polymer grades
- Poor heat conductor — 0.17 W/m·K (0.0982 BTU/hr·ft·°F), worse than 75% of polymer grades
SMA GF20 properties
Typical room-temperature values for SMA GF20; 13 are specific to this condition. Other listed values are SMA reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
SMA GF20 has a density of 1.22 g/cm³ (0.0441 lb/in³), heavier than 61% of polymer grades. Its glass-transition temperature is 140°C (284 °F).
Mechanical17
SMA GF20 has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 90 MPa (13.1 ksi) — stronger than 52% of polymer grades. Elongation at break is 1.8% and the elastic modulus is 6.5 GPa (0.943 Msi).
Thermal11
SMA GF20 is rated for continuous service to 115°C (239 °F). It conducts heat at 0.17 W/m·K (0.0982 BTU/hr·ft·°F), worse than 75% of polymer grades. Thermal expansion is 35 µm/m·K (19.4 µin/in·°F).
Electrical7
SMA GF20 is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 89% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of SMA GF20 takes about 95 MJ of energy and emits 3.6 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 0%.
Manufacturability8
SMA GF20's machinability is fair (40/100, worse than 82% of polymer grades); weldability good (55/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SMA GF20
Is SMA easy to machine?
Machines like SAN/PS — sharp carbide tools, high speed, light feed, air cooling; brittle so avoid sharp internal corners and pre-drill before tapping.
Can SMA be welded?
Ultrasonic, vibration and hot-plate welding work well; solvent bonding with MEK/methylene chloride blends; adhesives should be epoxy or cyanoacrylate, avoid amine-cured systems that react with anhydride.
Can SMA be formed, bent or molded?
Dry 2–4 h at 80–90 °C, mold at 230–270 °C melt / 55–90 °C tool with generous gates; keep residence time short as anhydride can hydrolyse and outgas, causing splay.
What surface finishes work on SMA?
Takes paint and hot stamping readily; can be vacuum metallized after base coat; polishes to a glossy surface but stress-cracks in aggressive solvent-based primers.
SMA chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| styrenemonomer, backbone | 68 – 92 | 85 |
| maleic anhydrideMA content sets Tg/HDT and reactivity | 8 – 32 | 15 |
| butadiene/acrylic rubberonly in impact-modified terpolymer grades | 0 – 20 | 0 |
| glass fiberreinforced grades only | 0 – 40 | 0 |
SMA GF20 — frequently asked
What is SMA GF20 used for?
SMA GF20 is typically used for automotive interior trim, appliance housings needing higher HDT, PC/ABS compatibilizer and instrument panel components. In short: highest-HDT styrenic copolymer; PC/ABS compatibilizer resin; glass-reinforced to 40 %.
What is the yield strength of SMA GF20?
SMA GF20 has a typical yield strength of 50 MPa (7.25 ksi) and a tensile strength of 90 MPa (13.1 ksi) — stronger than 52% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is SMA GF20 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 82% of polymer grades). Machines like SAN/PS — sharp carbide tools, high speed, light feed, air cooling; brittle so avoid sharp internal corners and pre-drill before tapping.
Can SMA GF20 be welded?
Yes — weldability is rated good (55/100). Ultrasonic, vibration and hot-plate welding work well; solvent bonding with MEK/methylene chloride blends; adhesives should be epoxy or cyanoacrylate, avoid amine-cured systems that react with anhydride.
What surface finishes work on SMA GF20?
Takes paint and hot stamping readily; can be vacuum metallized after base coat; polishes to a glossy surface but stress-cracks in aggressive solvent-based primers.
Can SMA GF20 be formed, bent or molded?
Dry 2–4 h at 80–90 °C, mold at 230–270 °C melt / 55–90 °C tool with generous gates; keep residence time short as anhydride can hydrolyse and outgas, causing splay.
What is the maximum service temperature of SMA GF20?
SMA GF20 is rated for continuous use to about 115°C (239 °F), and briefly to 130°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SMA UF and SMA IM?
UF is the default condition — default choice for rigid, heat-resistant, dimensionally stable molded parts where impact loads are low. IM: choose for automotive instrument-panel substrates and housings needing ABS-like toughness with higher heat resistance. Yield strength is 50 MPa in UF versus 36 MPa in IM.
Sources
- XIRAN SMA copolymer and compound datasheets — Polyscope Polymers (2023)
- Dylark SMA resin technical data — NOVA Chemicals (2005)
- CAMPUS / UL Prospector styrenic copolymer datasets — CAMPUS Plastics (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ISO 527 / ISO 178 / ISO 75 / ISO 306 test methods — ISO (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.