Polyphthalamide PPA

Aromatic polyamide. The PA 6T repeat unit is -[NH(CH2)6NH-CO-C6H4-CO]-n, made from terephthalic acid and hexamethylenediamine

Also known as HTN 51G35HSL, Amodel

Polyphthalamide (PPA, sold as Amodel and as Zytel HTN) is a nylon in which most of the acid units are aromatic: Wikipedia gives the threshold as 55 mol% terephthalic and/or isophthalic acid.

8 sources · Updated 2026-10-26 · CC BY 4.0

Evidence level

2 of 5

Lab-measured

Heat deflection

288 degC

Melting point

310 degC

Stiffness with heat

5310 MPa at 175 degC

Electrical

4.1 at 1 MHz

Recipe, share of the weight

  • not statedTerephthalic acid
  • not statedHexamethylenediamine
  • not statedAdipic acid or isophthalic acid

Best for

Moulded connector housings and parts that replace metal at high temperature: the glass-filled grades keep a heat deflection temperature of 260 to 303 degC and a melting point of 300 to 310 degC

Weakest at

Water and long-term heat. The Zytel 35 % glass grade absorbs 3.5 % water at saturation, and its relative thermal index for impact is 125 degC. No UV, atomic-oxygen or vacuum result for PPA was found.

Risk at a glance

  • People None found. Monomers are corrosive; resin hazard data not read
  • If it fails Moderate. Loss of strength and stiffness in continuous heat
  • Corrosion Moderate. Relative thermal index is 125 degC for impact and 150 degC for electrical use, so long-life parts need a lower limit than the heat deflection temperature.

Quick facts: PPA

Key properties of PPA
PropertyValueBasis
Density1.45 to 1.47 g/cm³2 sourced values across conditions
Tensile strength210 to 220 MPa3 sourced values across conditions
Young's modulus11.5 to 12.1 GPa3 sourced values across conditions
Thermal expansion (CTE)15 ppm/K2 sourced values across conditions
Melting point300 to 310 °C2 sourced values across conditions

What is the density of Polyphthalamide (PPA)?

Polyphthalamide (PPA) has a density of 1.45 to 1.47 g/cm³. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the coefficient of thermal expansion of Polyphthalamide (PPA)?

Polyphthalamide (PPA) has a coefficient of thermal expansion of 15 ppm/K. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the melting point of Polyphthalamide (PPA)?

Polyphthalamide (PPA) has a melting point of 300 to 310 °C. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the tensile strength of Polyphthalamide (PPA)?

Polyphthalamide (PPA) has a tensile strength of 210 to 220 MPa. The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the Young's modulus of Polyphthalamide (PPA)?

Polyphthalamide (PPA) has a Young's modulus of 11.5 to 12.1 GPa. The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What are the other names and codes for Polyphthalamide (PPA)?

Polyphthalamide (PPA) is also written as HTN 51G35HSL, Amodel. Each code is printed in the source listed beside it in the designations table.

What is Polyphthalamide (PPA) used for?

Uses recorded in the sources include Electrical and electronic connector housings and surface-mount parts; Pump wear rings and motor bobbins.

Why it exists

Polyphthalamide (PPA) is an aromatic polyamide. Because most of its acid units are terephthalic or isophthalic acid, its chains are stiffer than those of aliphatic nylons. Glass-filled grades hold a heat deflection temperature of 260 to 303 degC and a melting point of 300 to 310 degC. That makes PPA a candidate where metal or ordinary nylon would be too heavy or too weak. The cost is moisture uptake and a relative thermal index that limits long-term use below the melting point.

Where it's used

Electronics

The Zytel HTN 51G35HSL datasheet lists automotive applications, connectors and electrical and electronic applications as its uses. Wikipedia names USB-C connectors and surface-mount parts assembled with lead-free soldering.

Mechanical parts

Wikipedia lists pump wear rings, motor bobbins, fuel and cooling lines and LED headlamps, and says PPA resins are moulded to replace metals where high temperature resistance is needed.

Space

No space flight, ground or outgassing test of PPA was found in the sources read.

Recipe

Aromatic polyamide. The PA 6T repeat unit is -[NH(CH2)6NH-CO-C6H4-CO]-n, made from terephthalic acid and hexamethylenediamine; commercial PPA adds adipic or isophthalic acid as comonomer

Polyphthalamide is a polyamide whose acid units are at least 55 mol% terephthalic and/or isophthalic acid (Wikipedia, citing ASTM D5336). The unmodified PA 6T is made from terephthalic acid and hexamethylenediamine. Commercial grades add a comonomer, such as adipic acid or isophthalic acid, because PA 6T melts too high to process.

What PPA is made of
IngredientShare of the weightWhat it does
Terephthalic acid not stated Aromatic diacid. Wikipedia says the glass transition temperature of PPA rises as the terephthalic acid share rises, which makes it the stiffening monomer.
Hexamethylenediamine not stated Diamine that forms the amide links with the diacid. PubChem records it as used to make nylon.
Adipic acid or isophthalic acid not stated Comonomer that lowers the melting point into a range that can be moulded. Wikipedia names PA 6T/66 as a commercial copolymer.

Weight shares are as printed in the sources.

What it can do

Heat deflection

288 degC

measured

Amodel A-6135HS (35 % glass) has a deflection temperature of 288 degC at 1.8 MPa without annealing (ISO 75-2/A). The annealed value is 291 degC.

Melting point

310 degC

measured

Both Amodel grades print a melting point of 310 degC (ISO 11357-3). The Zytel grade prints 300 degC.

Stiffness with heat

5310 MPa at 175 degC

measured

Amodel A-6135HS keeps a tensile modulus of 5310 MPa at 175 degC, against 11500 MPa at 23 degC (ISO 527-2).

Electrical

4.1 at 1 MHz

measured

Amodel AFA-6133V0Z (33 % glass) has a dielectric constant of 4.1 and a dissipation factor of 0.011 at 1 MHz (ASTM D150).

How it compares

PPA is a high-heat polyamide. Its melting point of 300 to 310 degC and its heat deflection temperatures of 260 to 303 degC are the figures read here for the glass-filled grades. It is not free of moisture effects, because the Zytel grade takes up 3.5 % water at saturation. The table compares melting point, heat deflection and stiffness across the grades read.

The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.

Benchmarks
MeasurementPPAPA 11PA 12PA 46PA 6PA 66
Thermal behavior and safety
Melting temperature, Zytel HTN 51G35HSL300 °C5181 °C184 °C295 °Cno data260 °C
Melting point, Amodel A-6135HS and AFA-6133V0Z310 °C6181 °C184 °C295 °Cno data260 °C
Heat deflection temperature, 1.8 MPa, unannealed, Zytel HTN 51G35HSLValue printed on the IDES copy of the datasheet260 °C7130 °Cno data190 °C200 °C75 °C
Heat deflection temperature, 1.8 MPa, unannealed (ISO), Zytel HTN 51G35HSLValue printed on the IDES copy of the datasheet264 °C8130 °Cno data190 °C200 °C75 °C
Heat deflection temperature, 1.8 MPa, unannealed, Amodel A-6135HSValue printed on the plastic database page288 °C9130 °Cno data190 °C200 °C75 °C
Heat deflection temperature, 1.8 MPa, annealed, Amodel A-6135HSValue printed on the plastic database page291 °C10130 °Cno data190 °C200 °C75 °C
Heat deflection temperature, 0.45 MPa, unannealed, Amodel A-6135HSValue printed on the plastic database page303 °C11130 °Cno data190 °C200 °C75 °C
Heat deflection temperature, 1.8 MPa, no annealing, Amodel AFA-6133V0ZValue printed on the plastic database page282 °C12130 °Cno data190 °C200 °C75 °C
Physical and electrical
Specific gravity, Zytel HTN 51G35HSL (35 % glass, dry)1.47 g/cm³11.04 g/cm³0.9 to 0.95 g/cm³1.18 g/cm³1.123 g/cm³1.13 g/cc
Density, Amodel A-6135HS (35 % glass)1.45 g/cm³21.04 g/cm³0.9 to 0.95 g/cm³1.18 g/cm³1.123 g/cm³1.13 g/cc
Temperature behavior
Glass transition temperature (DSC), Zytel HTN 51G35HSLValue printed on the IDES copy of the datasheet140 °Cno datano datano datano datano data
Other measurements
Water absorption at saturation, Zytel HTN 51G35HSL3.5 %31.6 %0.52 %3.7 %10 %2.8 %
Water absorption, 24 h at 23 degC, Amodel A-6135HS0.3 %41.6 %0.52 %3.7 %10 %2.8 %
Linear expansion coefficient, flow, 23 to 55 degC, Zytel HTN 51G35HSL1.5×10^-5 cm/cm/°C13no data1.09 x10-4 /K90 µm/m-°Cno data98 E-6/K
Linear expansion coefficient, flow, 0 to 100 degC, Amodel A-6135HS2.2 x10^-5/°C14no data1.09 x10-4 /K90 µm/m-°Cno data98 E-6/K
Tensile stress at break, 23 degC, dry, Zytel HTN 51G35HSL220 MPa1548 MPa45 N/mm2103 MPano datano data
Tensile stress at break, 23 degC, conditioned, Zytel HTN 51G35HSL210 MPa1648 MPa45 N/mm2103 MPano datano data
Tensile breaking stress, 23 degC, Amodel A-6135HS211 MPa1748 MPa45 N/mm2103 MPano datano data
Tensile breaking stress, 175 degC, Amodel A-6135HS82 MPa1848 MPa45 N/mm2103 MPano datano data
Tensile modulus, 23 degC, dry, Zytel HTN 51G35HSL12100 MPa19345 MPa1700 N/mm23300 MPano datano data
Tensile modulus, 23 degC, dry and conditioned (ISO), Zytel HTN 51G35HSL12000 MPa20345 MPa1700 N/mm23300 MPano datano data
Tensile modulus, 23 degC, Amodel A-6135HS11500 MPa21345 MPa1700 N/mm23300 MPano datano data
Tensile modulus, 175 degC, Amodel A-6135HSValue printed on the plastic database page5310 MPa22345 MPa1700 N/mm23300 MPano datano data
Tensile strain at break, 23 degC, Amodel A-6135HSValue printed on the plastic database page2 %23> 50 %20 %40 %no datano data
Flexural modulus, 23 degC, dry, Zytel HTN 51G35HSL10300 MPa24350 MPa1240 N/mm23000 MPano data2.9 GPa
Flexural modulus, 23 degC, Amodel A-6135HS11400 MPa25350 MPa1240 N/mm23000 MPano data2.9 GPa
Flexural strength, 23 degC, dry, Zytel HTN 51G35HSL304 MPa26no datano data117 MPano data100 MPa
Dielectric constant, 1 kHz, Zytel HTN 51G35HSLValue printed on the IDES copy4.3 -279 -no data3.9 -no datano data
Dielectric constant, 1 MHz, Amodel AFA-6133V0ZValue printed on the plastic database page4.1 -289 -no data3.9 -no datano data
Dielectric tangent, 1 MHz, Amodel AFA-6133V0Z0.011 -29no datano datano datano datano data
Dielectric strength, 23 degC, 1.60 mm, Zytel HTN 51G35HSL27 kV/mm3023 kV/mmno data25 kV/mmno datano data
Dielectric strength, 3.18 mm, Amodel AFA-6133V0ZValue printed on the plastic database page24 kV/mm3123 kV/mmno data25 kV/mmno datano data
Relative thermal index, impact, Zytel HTN 51G35HSL, 0.85 mm125 °C32no datano datano datano datano data
Relative thermal index, electrical, Zytel HTN 51G35HSL, 0.85 mm150 °C33no datano datano datano datano data

Why choose it, and why not

Good for

  • Heat resistance. Melting point 310 degC and heat deflection 288 degC at 1.8 MPa for an Amodel grade (ISO 75-2/A).
  • Stiffness at temperature. Amodel A-6135HS keeps 5310 MPa tensile modulus at 175 degC.

Watch out for

  • Moisture. The Zytel 35 % glass grade absorbs 3.5 % water at saturation, and the datasheet's own feature list contradicts that figure.
  • Long-term heat. The UL 746 relative thermal index for impact is 125 degC for the Zytel grade.
  • No space data. No vacuum, atomic-oxygen or UV test for PPA was found.

PPA is a high-temperature polyamide for moulded parts that must stay stiff above 150 degC. The datasheet values put it well above ordinary nylon, but moisture uptake and the relative thermal index limit long-term use, and no space test data were found, so space use needs a test.

Technical details

For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.

Other names and standards

The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.

Other names and standards
SystemCodes
Trade nameHTN 51G35HSL (Zytel HTN grade code, printed as Zytel® HTN 51G35HSL NC010), Amodel

Notes

The method, full conditions and any caveat for the numbered rows above.

Notes for the numbered rows
#MeasurementMethodConditionsCaveat
1Specific gravity, Zytel HTN 51G35HSL (35 % glass, dry)Typical value printed on the IDES copy of the DuPont datasheetgrade Zytel HTN 51G35HSL NC010, 35 % glass fibre, heat stabilised, lubricatedtest ASTM D792 (ISO 1183 also printed, same value)—
2Density, Amodel A-6135HS (35 % glass)Value printed on the plastic database page for Amodel A-6135HSgrade Amodel A-6135HS, 35 % glass fibre, naturaltest ISO 1183/A—
3Water absorption at saturation, Zytel HTN 51G35HSLValue printed on the IDES copy of the datasheet; the same page prints 4.5 % at saturation by ISO 62 on a 2.00 mm specimengrade Zytel HTN 51G35HSL NC010state saturation at 23 °Ctest ASTM D570The same datasheet's feature list says "Low to No Water Absorption", which does not match a 3.5 % saturation value. The printed value is used here.
4Water absorption, 24 h at 23 degC, Amodel A-6135HSValue printed on the plastic database page (ASTM D570, 24 h; the same page prints 0.29 % by ISO 62 at 23 degC)grade Amodel A-6135HS, 35 % glass fibretime 24 htemperature 23 °C—
5Melting temperature, Zytel HTN 51G35HSLValue printed as 572 degF (300 degC) on the IDES copy; ASTM D3418 is also printed on the same rowgrade Zytel HTN 51G35HSL NC010test ISO 11357-3 printed beside the valueThe copy prints two test-method labels against one value, so the method is given as printed.
6Melting point, Amodel A-6135HS and AFA-6133V0ZValue printed on the plastic database pages for both Amodel grades (ASTM D3418 is also printed as 310 degC)grade Amodel A-6135HS (35 % glass, natural); the same value is printed for Amodel AFA-6133V0Z (33 % glass, black)test ISO 11357-3—
7Heat deflection temperature, 1.8 MPa, unannealed, Zytel HTN 51G35HSL—grade Zytel HTN 51G35HSL NC010stress 264 psi (1.8 MPa)state unannealedtest ASTM D648—
8Heat deflection temperature, 1.8 MPa, unannealed (ISO), Zytel HTN 51G35HSL—grade Zytel HTN 51G35HSL NC010stress 264 psi (1.8 MPa)state unannealedtest ISO 75-2/A—
9Heat deflection temperature, 1.8 MPa, unannealed, Amodel A-6135HS—grade Amodel A-6135HS, 35 % glass fibrestress 1.8 MPastate no annealingtest ISO 75-2/A—
10Heat deflection temperature, 1.8 MPa, annealed, Amodel A-6135HS—grade Amodel A-6135HS, 35 % glass fibrestress 1.8 MPastate annealed, 3.20 mmtest ASTM D648—
11Heat deflection temperature, 0.45 MPa, unannealed, Amodel A-6135HS—grade Amodel A-6135HS, 35 % glass fibrestress 0.45 MPastate no annealingtest ISO 75-2/B—
12Heat deflection temperature, 1.8 MPa, no annealing, Amodel AFA-6133V0Z—grade Amodel AFA-6133V0Z, 33 % glass fibre, blackstress 1.8 MPastate no annealingtest ISO 75-2/Af—
13Linear expansion coefficient, flow, 23 to 55 degC, Zytel HTN 51G35HSLValue printed on the IDES copy in cm/cm/degC; the datasheet prints it in in/in/degF firstgrade Zytel HTN 51G35HSL NC010direction flowrange 23 to 55 °Cprinted as 8.3E-6 in/in/degF (0.000015 cm/cm/°C)—
14Linear expansion coefficient, flow, 0 to 100 degC, Amodel A-6135HSValue printed on the plastic database page as 2.2 with unit x10^-5/degC (so 2.2 x 10^-5 per degC)grade Amodel A-6135HS, 35 % glass fibredirection flowrange 0 to 100 °Ctest ASTM E831—
15Tensile stress at break, 23 degC, dry, Zytel HTN 51G35HSLValue printed on the IDES copy as 31900 psi (220 MPa)grade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate drytemperature 23 °Ctest ISO 527-2—
16Tensile stress at break, 23 degC, conditioned, Zytel HTN 51G35HSLValue printed on the IDES copy as 30500 psi (210 MPa)grade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate conditioned (procedure not stated on the copy)temperature 23 °Ctest ISO 527-2—
17Tensile breaking stress, 23 degC, Amodel A-6135HSValue printed on the plastic database page (ASTM D638 gives 203 MPa for tensile strength on the same page)grade Amodel A-6135HS, 35 % glass fibretemperature 23 °Ctest ISO 527-2—
18Tensile breaking stress, 175 degC, Amodel A-6135HSValue printed on the plastic database page, measured at 175 degCgrade Amodel A-6135HS, 35 % glass fibretemperature 175 °Ctest ISO 527-2—
19Tensile modulus, 23 degC, dry, Zytel HTN 51G35HSLValue printed on the IDES copy as 1.75E+6 psi (12100 MPa)grade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate drytemperature 23 °Ctest ASTM D638—
20Tensile modulus, 23 degC, dry and conditioned (ISO), Zytel HTN 51G35HSLValue printed on the IDES copy as 1.74E+6 psi (12000 MPa) in both columnsgrade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate dry and conditioned both printed as 12000 MPatemperature 23 °Ctest ISO 527-2—
21Tensile modulus, 23 degC, Amodel A-6135HSValue printed on the plastic database page (ASTM D638 gives 13800 MPa on the same page)grade Amodel A-6135HS, 35 % glass fibretemperature 23 °Ctest ISO 527-2—
22Tensile modulus, 175 degC, Amodel A-6135HS—grade Amodel A-6135HS, 35 % glass fibretemperature 175 °Ctest ISO 527-2—
23Tensile strain at break, 23 degC, Amodel A-6135HS—grade Amodel A-6135HS, 35 % glass fibretemperature 23 °Ctest ISO 527-2—
24Flexural modulus, 23 degC, dry, Zytel HTN 51G35HSLValue printed on the IDES copy as 1.49E+6 psi (10300 MPa)grade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate drytemperature 23 °Ctest ASTM D790—
25Flexural modulus, 23 degC, Amodel A-6135HSValue printed on the plastic database page (ASTM D790 also prints 11400 MPa)grade Amodel A-6135HS, 35 % glass fibretemperature 23 °Ctest ISO 178—
26Flexural strength, 23 degC, dry, Zytel HTN 51G35HSLValue printed on the IDES copy as 44100 psi (304 MPa)grade Zytel HTN 51G35HSL NC010, 35 % glass fibrestate drytemperature 23 °Ctest ASTM D790—
27Dielectric constant, 1 kHz, Zytel HTN 51G35HSL—grade Zytel HTN 51G35HSL NC010frequency 1 kHztemperature 23 °Ctest ASTM D150—
28Dielectric constant, 1 MHz, Amodel AFA-6133V0Z—grade Amodel AFA-6133V0Z, 33 % glass fibre, blackfrequency 1 MHztest ASTM D150—
29Dielectric tangent, 1 MHz, Amodel AFA-6133V0ZValue printed on the plastic database page (named dielectric tangent on the page)grade Amodel AFA-6133V0Z, 33 % glass fibre, blackfrequency 1 MHztest ASTM D150—
30Dielectric strength, 23 degC, 1.60 mm, Zytel HTN 51G35HSLValue printed on the IDES copy as 690 V/mil (27 kV/mm)grade Zytel HTN 51G35HSL NC010thickness 0.0630 in (1.60 mm)temperature 23 °Ctest ASTM D149—
31Dielectric strength, 3.18 mm, Amodel AFA-6133V0Z—grade Amodel AFA-6133V0Z, 33 % glass fibre, blackthickness 3.18 mmtest ASTM D149—
32Relative thermal index, impact, Zytel HTN 51G35HSL, 0.85 mmValue printed on the IDES copy as 257 degF (125 degC); this is a UL 746 rating, not a single maximum temperaturegrade Zytel HTN 51G35HSL NC010thickness 0.0335 in (0.850 mm)test UL 746Non-canonical property name (not in spores/property-canon.yaml).
33Relative thermal index, electrical, Zytel HTN 51G35HSL, 0.85 mmValue printed on the IDES copy as 302 degF (150 degC)grade Zytel HTN 51G35HSL NC010thickness 0.0335 in (0.850 mm)test UL 746Non-canonical property name (not in spores/property-canon.yaml). Electrical RTI is higher than the impact RTI for the same grade.

Corrosion and compatibility

What happens when it meets other materials and environments.

Corrosion and compatibility
EnvironmentConcernWhat happens
Continuous heat in air, 35 % glass Zytel HTN 51G35HSL (UL 746 relative thermal index) moderate Relative thermal index is 125 degC for impact and 150 degC for electrical use, so long-life parts need a lower limit than the heat deflection temperature.1
Continuous heat, tensile strength at 175 degC, Amodel A-6135HS moderate Tensile breaking stress falls from 211 MPa at 23 degC to 82 MPa at 175 degC.2
Humidity and water, Zytel HTN 51G35HSL (23 degC, saturation) low Saturation uptake is 3.5 %, but the printed tensile stress at break falls only from 220 to 210 MPa when conditioned.3
Synthetic lubricant base oils at 100 degC for 30 days (polar esters and PAO), compared with air at 100 degC moderate Oil-immersed PPA formed carbonyl groups on its surface and was more affected than PEEK.4
Corrosion details
#EnvironmentDetailsTest conditions
1 Continuous heat in air, 35 % glass Zytel HTN 51G35HSL (UL 746 relative thermal index) The IDES copy of the datasheet prints a relative thermal index (UL 746) of 125 degC for impact and 150 degC for electrical use at 0.85 mm. These are life-based ratings. The heat deflection temperature of the same grade is 260 degC at 1.8 MPa, so the thermal index sets the lower limit for long-term use. grade Zytel HTN 51G35HSL NC010thickness 0.85 mmbasis UL 746 relative thermal index as printed
2 Continuous heat, tensile strength at 175 degC, Amodel A-6135HS The database page prints a tensile breaking stress of 211 MPa at 23 degC and 82 MPa at 175 degC (ISO 527-2), and a tensile modulus of 11500 MPa at 23 degC against 5310 MPa at 175 degC. Strength and stiffness both fall at temperature; the data are short tests, not ageing data. grade Amodel A-6135HS, 35 % glass fibretest ISO 527-2, short-term tensile test at each temperatureexposure not an ageing test
3 Humidity and water, Zytel HTN 51G35HSL (23 degC, saturation) The datasheet prints a water saturation of 3.5 % at 23 degC (ASTM D570) and 4.5 % by ISO 62 on a 2.00 mm specimen. Tensile stress at break is 220 MPa dry and 210 MPa conditioned (ISO 527-2), and tensile modulus is 12000 MPa in both states. The conditioning procedure is not printed on the copy read, and no long-term hydrolysis or humid-ageing test for PPA was found. grade Zytel HTN 51G35HSL NC010, 35 % glass fibreexposure saturation at 23 °C as printed; conditioning procedure not statedtest ASTM D570 and ISO 527-2
4 Synthetic lubricant base oils at 100 degC for 30 days (polar esters and PAO), compared with air at 100 degC The abstract of the Ljubljana study reports carbonyl groups on the surfaces of PEEK and PPA after 30 days at 100 degC in the oils, changes in surface free energy, and higher crystallinity and microhardness. It states that PEEK was less affected by aging than PPA, and that the propylene glycol ester had the strongest effect. No numeric values were read from the full text, so the rating is qualitative. exposure polymer discs immersed in polar synthetic esters (propylene glycol and trimethylolpropane) and non-polar PAO, 30 days at 100 °C; air-only control at 100 °Creference Polymer Testing 131 (2024) 108342

Risks and side effects

Hazards to people, what happens when a cell overheats, and how the material is handled and stored.

For people

The finished resin was not checked against a safety data sheet in this run. The monomer hazard data are the strongest hazard information available.

Monomer
Hexamethylenediamine causes severe skin burns and eye damage (PubChem, 100 % of reports for H314). Terephthalic acid is irritant in the minority of reports that give a hazard.
Processing
The Zytel datasheet sets melt temperatures of 320 to 330 degC for injection moulding. No dust or fume data for the resin were read.

If a part overheats

These are design limits from the datasheets, not field incidents.

Strength with heat
Amodel A-6135HS drops from 211 MPa tensile breaking stress at 23 degC to 82 MPa at 175 degC.
Thermal index
Zytel HTN 51G35HSL has a UL 746 relative thermal index of 125 degC for impact and 150 degC for electrical use, at 0.85 mm.

Handling and storage

Drying
Dry at 100 degC for 6 to 8 h before moulding, to below 0.10 % moisture (Zytel datasheet).
Moisture
The Zytel grade reaches 3.5 % water at saturation at 23 degC, and the datasheet sets a moisture limit of below 0.10 % before moulding.

Test details
The original wording and numbers from the sources, for readers who want them.

Failure risks

Failure risks
FailureTrigger and consequence
Loss of strength and stiffness in continuous heatmoderate severityContinuous operation at 175 degCTensile breaking stress of Amodel A-6135HS falls from 211 MPa at 23 degC to 82 MPa at 175 degC, and tensile modulus from 11500 MPa to 5310 MPa (ISO 527-2).
Heat-ageing life limit for impact-loaded partsmoderate severityLong-term use above the UL 746 relative thermal index for impactThe Zytel HTN 51G35HSL relative thermal index for impact is 125 degC at 0.85 mm, lower than its electrical index of 150 degC, so impact-loaded parts need the lower value as the long-life limit.
Moisture uptakelow severityExposure to humid air or water until saturation at 23 degCSaturation uptake of 3.5 % for the 35 % glass grade; conditioned tensile stress at break is 210 MPa against 220 MPa dry.
Surface oxidation in hot lubricant oilmoderate severityImmersion in synthetic ester or PAO oils at 100 degC for 30 daysCarbonyl groups formed on the PPA surface, with changes in surface energy and crystallinity; PPA was more affected than PEEK (abstract, qualitative).

Handling and storage

  • Dry the resin before moulding: the Zytel datasheet gives a drying temperature of 100 degC for 6.0 to 8.0 h and a suggested maximum moisture content below 0.10 %.
  • Melt temperature for injection moulding is 320 to 330 degC for the Zytel grade, with mould temperature 140 to 160 degC. Amodel A-6135HS is printed with a resin temperature of 316 to 335 degC and mould temperature 66 to 93 degC.
  • Monomer handling: hexamethylenediamine is corrosive (PubChem GHS H314). Handle the monomer with eye and skin protection; the cured polymer was not checked against an SDS in this run.

Mitigations

  • Keep the resin dry before moulding (below 0.10 % moisture per the Zytel datasheet) and design impact-loaded parts to the lower relative thermal index of 125 degC.

Supply and geography

How common the raw materials are and where they come from.

Polyphthalamide resin