Thursday, 28 March 2019

Reviewing Key Engineering Plastics – Polyamide 6 and Polyamide 6.6 [incl. Video]

Hello and welcome to this post on reviewing key engineering plastics. Today, we have a closer look at polyamide 6 and polyamide 6.6.
Similarly to the last time with ABS, we review the chemistry including the simplified petrochemical flowchart, discuss the properties and applications of polyamides and look at their global demand and producers. I will provide you some price indications as well.

Here you can find the youtube video of the review:




Before we start with the chemistry I would like to spend some words on the history of polyamide. Wallace Carothers, working 1930 at DuPont Company, developed together with his assistants the two most widely used synthetic polymers of the 20th century: nylon or polyamide and neoprene (synthetic rubber). We will focus in this review on polyamide 6 (PA 6) and polyamide 6.6 (PA 6.6). Although they may seem quite alike they are different e.g. in terms of glass transition and melting temperature as well as water uptake. The latter is higher for PA 6.

Polyamide chemistry


PA chemistry and simplified flow chart: Where do PA 6 and PA 6.6 have their roots?
PA 6 is made by ring-opening polymerization of e-amino caprolactam which is obtained over the benzene route (from benzene over cyclohexane to caprolactam). Cyclohexane is first converted to its oxime. An oxime is a chemical compound with a carbon-nitrogen double bond. The word oxime is a combination of the words oxygen and imine. Treating the oxime with acid initiates the so-called Beckmann rearrangement to obtain caprolactam. The global demand on caprolactam are 5 milllion tons. PA 6.6 can be polymerized using hexamethylenediamine and adipidic acid. Both have 6 carbon atoms leading to the nomenclature of 6.6. HMDA can be obtained over three routes: from adipidic acid route, from hydrogenation of acrylonitrile, and from hydrocyanation of butadiene.
Polyamide - Simplified Flow Chart


Poylamide properties
PA 6 shows good toughness at relatively high (80°C) and low temperatures as well as resistance to repeated impacts. This is rounded up with good resistance to abrasion and wear. Chemically, PA 6 exhibits resistance to many organic solvents, oils and gasolines. In comparison, Polyamide 6.6 can be used at higher continuous service temperatures (100°C – 120°C) combined with a better retention of stiffness, tensile properties, and shape at high temperatures.
Polyamide - Properties

PA Capacity and Global demand
The total consumption of Polyamides in 2016 was around 7.5 Million Tons. PA 6.6 has a consumption of 2.4 million tons and PA 6 of 5.1 million tons. 70% of the global PA 6.6 consumption was used in the automotive market. Half of the consumption of PA 6 is used for producing fibers.
Polyamide - Capacity and Global Demand
 
Geographically you can state that Asia is the largest market for PA 6 and it is preferred when flexibility and barrier properties are important. North America is the largest market for PA 6.6 and is mainly selected for engineering thermoplastic applications due to a higher melting point. Important to note is that both Nylons are interchangeable for most applications.
Polyamide - Capacity and Global Demand

PA Price to performance
Polyamides are forming the base of engineering thermoplastics and have a price range of 2.5€/ kg for base grades and high heat Nylons can reach up to 6.5€/kg.
Polyamide - Price to Performance

PA End uses
As previously shown, PA 6 is more selected for fiber applications such as tire cords, and filaments for fishing lines. PA 6.6 with a glass fiber reinforcement of 30% is used in many automotive applications where the combination of elevated temperature, toughness and long life time is needed. However, there are many other industry fields, where the properties of Nylon 6.6 can play a key role. Important to note is the water uptake of PA 6.6 which can be 2.5% at 50% relative humidity. PA6 has with 2.8% a bit higher water uptake. The water uptake results in dimensional changes, reduces the yield stress 29% of its original value. Elongation will be increased with the factor of 5 and toughness will be doubled. Overall stiffness can decrease almost 60%.

Typical polyamide applications Just to name a few of the typical applications: belts, guitar strings, car engine upper intake manifold and engine support mounts.

This was a review on polyamide, an important engineering thermoplastic used in many applications.


Thanks for reading & till next time!
Greetings,
Herwig Juster


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Interested in my monthly blog posts – then subscribe here.
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Literature:
1. https://www.nexant.com/
2. W. Kaiser: Kunststoffchemie für Ingenieure, Carl Hanser Verlag, München 2016
3. http://www.polymerdatabase.com/

Sunday, 10 March 2019

Plastics Part Design: The Continuous Use Temperature of 124 Most Used Plastics



Hello and welcome to this blog post on the topic of continuous use temperature (CUT) of thermoplastics.

The maximum acceptable temperature for thermoplastics is one of the most critical requirements to be handled during your material selection. Above the maximum use temperature, mechanical properties (mainly tensile strength and impact strength) or electrical properties (dielectric strength) will drop significantly. On the other hand, long term retention of mechanical and other required properties over the product lifetime is crucial. Therefore, you need to be able to estimate your continuous use temperature.
Don’t worry; there are already methods out there which can assist you. There is the UL 746 which is used to calculate the Relative Temperature Index (RTI; measured in °C).

What is RTI?
Citation UL: “RTI is the temperature in °C, at which properties have decreased to 50% of their initial value after a long-term exposure to this temperature (100,000 hours)”.


The table below shows the maximum use temperature of 124 most used plastics and can assist you in your daily material selection.

Thank you for reading and till next time!
Herwig Juster


If you liked this post, share and like!
Interested in my monthly blog posts – then subscribe here.
New to my Find Out About Plastics Blog – check out the start here section
Check out also my personal webpage.


Table: Continuous Use / Service Temperature of 124 most used Plastics


Polymer Name
Max Value (°C)
 according
UL 746 (RTI)
ABS - Acrylonitrile Butadiene Styrene
89.0
ABS Flame Retardant
95.0
ABS High Heat
110.0
ABS High Impact
100.0
ABS/PC Blend –
Acrylonitrile Butadiene Styrene/Polycarbonate Blend
110.0
ABS/PC Blend 20% Glass Fiber
110.0
ABS/PC Flame Retardant
110.0
ASA - Acrylonitrile Styrene Acrylate
90.0
ASA/PC Blend –
Acrylonitrile Styrene Acrylate/Polycarbonate Blend
110.0
ASA/PC Flame Retardant
110.0
ASA/PVC Blend –
Acrylonitrile Styrene Acrylate/Polyvinyl Chloride Blend
90.0
CA - Cellulose Acetate
95.0
CAB - Cellulose Acetate Butyrate
105.0
CP - Cellulose Proprionate
105.0
CPVC - Chlorinated Polyvinyl Chloride
100.0
ECTFE - Ethylene Chlorotrifluoroethylene
150.0
ETFE - Ethylene Tetrafluoroethylene
155.0
EVA - Ethylene Vinyl Acetate
70.0
EVOH - Ethylene Vinyl Alcohol
100.0
FEP - Fluorinated Ethylene Propylene
205.0
HDPE - High Density Polyethylene
120.0
HIPS - High Impact Polystyrene
80.0
HIPS Flame Retardant V0
80.0
Ionomer (Ethylene-Methyl Acrylate Copolymer)
48.0
LCP - Liquid Crystal Polymer
240.0
LCP Carbon Fiber-reinforced
240.0
LCP Glass Fiber-reinforced
240.0
LCP Mineral-filled
240.0
LDPE - Low Density Polyethylene
100.0
LLDPE - Linear Low Density Polyethylene
110.0
MABS - Transparent Acrylonitrile Butadiene Styrene
80.0
PA 46 - Polyamide 46
150.0
PA 46, 30% Glass Fiber
160.0
PA 6 - Polyamide 6
120.0
PA 6-10 - Polyamide 6-10
150.0
PA 66 - Polyamide 6-6
140.0
PA 66, 30% Glass Fiber
150.0
PA 66, 30% Mineral filled
140.0
PA 66, Impact Modified, 15-30% Glass Fiber
140.0
PA 66, Impact Modified
130.0
Polyamide semi-aromatic
135.0
PAI - Polyamide-Imide
280.0
PAI, 30% Glass Fiber
220.0
PAI, Low Friction
220.0
PAR - Polyarylate
130.0
PBT - Polybutylene Terephthalate
140.0
PBT, 30% Glass Fiber
140.0
PC (Polycarbonate) 20-40% Glass Fiber
125.0
PC (Polycarbonate) 20-40% Glass Fiber Flame Retardant
125.0
PC - Polycarbonate, high heat
140.0
PC/PBT Blend –
Polycarbonate/Polybutylene Terephthalate Blend
121.0
PC/PBT blend, Glass Filled
193.0
PCL - Polycaprolactone
45.0
PCTFE - Polymonochlorotrifluoroethylene
175.0
PE - Polyethylene 30% Glass Fiber
130.0
PEEK - Polyetheretherketone
260.0
PEEK 30% Carbon Fiber-reinforced
240.0
PEEK 30% Glass Fiber-reinforced
240.0
PEI - Polyetherimide
170.0
PEI, 30% Glass Fiber-reinforced
170.0
PEI, Mineral Filled
170.0
PESU - Polyethersulfone
180.0
PESU 10-30% glass fiber
180.0
PET - Polyethylene Terephtalate
140.0
PET, 30% Glass Fiber-reinforced
140.0
PET, 30/35% Glass Fiber-reinforced, Impact Modified
140.0
PETG - Polyethylene Terephtalate Glycol
63.0
PFA - Perfluoroalkoxy
260.0
PHB-V(5% valerate)
95.0
PI - Polyimide
360.0
PMMA - Polymethylmethacrylate/Acrylic
90.0
PMMA (Acrylic) High Heat
150.0
PMMA (Acrylic) Impact Modified
90.0
PMP - Polymethylpentene
110.0
PMP 30% Glass Fiber-reinforced
110.0
PMP Mineral Filled
110.0
POM - Polyoxymethylene (Acetal)
105.0
POM (Acetal) Impact Modified
100.0
POM (Acetal) Low Friction
105.0
POM (Acetal) Mineral Filled
105.0
PP - Polypropylene 10-20% Glass Fiber
130.0
PP, 10-40% Mineral Filled
130.0
PP, 10-40% Talc Filled
130.0
PP, 30-40% Glass Fiber-reinforced
130.0
PP (Polypropylene) Copolymer
130.0
PP (Polypropylene) Homopolymer
130.0
PP, Impact Modified
115.0
PPA - Polyphthalamide
140.0
PPA, 30% Mineral-filled
156.0
PPA, 33% Glass Fiber-reinforced
186.0
PPA, 45% Glass Fiber-reinforced
186.0
PPE - Polyphenylene Ether
110.0
PPE, 30% Glass Fiber-reinforced
110.0
PPE, Flame Retardant
110.0
PPE, Impact Modified
110.0
PPE, Mineral Filled
110.0
PPS - Polyphenylene Sulfide
220.0
PPS, 20-30% Glass Fiber-reinforced
220.0
PPS, 40% Glass Fiber-reinforced
220.0
PPS, Conductive
220.0
PPS, Glass fiber & Mineral-filled
220.0
PPSU - Polyphenylene Sulfone
210.0
PS (Polystyrene) 30% glass fiber
122.0
PS (Polystyrene) Crystal
80.0
PS, High Heat
90.0
PSU - Polysulfone
180.0
PSU, 30% Glass finer-reinforced
180.0
PSU Mineral Filled
150.0
PTFE - Polytetrafluoroethylene
290.0
PTFE, 25% Glass Fiber-reinforced
260.0
PVC (Polyvinyl Chloride), 20% Glass Fiber-reinforced
80.0
PVC, Plasticized
80.0
PVC, Plasticized Filled
80.0
PVC Rigid
80.0
PVDC - Polyvinylidene Chloride
90.0
PVDF - Polyvinylidene Fluoride
150.0
SAN - Styrene Acrylonitrile
95.0
SAN, 20% Glass Fiber-reinforced
95.0
SMA - Styrene Maleic Anhydride
100.0
SMA, 20% Glass Fiber-reinforced
100.0
SMA, Flame Retardant V0
100.0
SMMA - Styrene Methyl Methacrylate
100.0
UHMWPE - Ultra High Molecular Weight Polyethylene
130.0
XLPE - Crosslinked Polyethylene
82.0



Source:
1. https://omnexus.specialchem.com/
2. Saechtling Kunststoff Taschenbuch by Erwin Baur