Aliphatic and Aromatic Polyketones – Introduction, Performance Comparison and Applications

 

In this blog post we review the aliphatic and aromatic Polyketones. What are the differences and what makes them special?

Introduction

Let us get started with the structure of Polyketones. The key for understanding Polyketones is the ketone group. In general, a ketone group has the structure of R2R=O, where R stands for a replacement compound.  Also, ketones have a carbon-oxygen double bond (= carbonyl group). The carbonyl group is important since it leads to a high polar behavior. Carbon has a slight positive charge and the oxygen has a negative charge. The strong attraction of the carbonyl groups to one another leads to an increase in melt temperature (255°C), compared to Polyethylene (140°C).  

In the case of aliphatic Polyketones, the ketone group is part of the backbone, together with carbon monoxide (copolymer) or carbon monoxide, ethylene, and propylene (terpolymer).

Figure 1: ketone unit (above) and a monomer unit of Polyketone (below) [1]

.

Figure 2: Polyketone made out of ethylene and carbon monoxide [1]. 

In the case of aromatic Polyketones, the R-rests are constituted out of phenyls, together with the carbonyl group (Figure 3). Additionally, Polyaryletherketone makes use of the diphenyl ether groups too (Figure 4). The role of the aromatic ring structure is another key for understanding the high performance properties. High macromolecule stiffness, high heat and chemical resistance are the result of having ring structures in the polymer backbone [2]. Explanation for this behaviour are the double bonds of benzene which are not statically localized, i.e. electrons move along the carbon cyclic structure, which is expressed by the ring in the structural formula.

Figure 3: diphenyl ketone - basic structure of aromatic Polyketones.

Figure 4: diphenyl ether group.

Depending how the diphenyl ether and diphenyl ketone groups are aligned in the backbone, different glass- and melt temperatures are obtained (Figure 5).

Figure 5: change in glass- and melt temperature based on the amount of ether and ketone groups in the backbone.

Property Comparison and processing

In Table 1 selected physical, thermal, and mechanical properties of aliphatic and aromatic Polyketones are shown. 

Table 1: property comparison of base and reinforced Polyketones. 

Performance strength of POK and PEEK

Aliphatic Polyketones are engineering polymers which compete with aliphatic Polyamides, PBT, and POM (Acetal). They have a high impact strength (impact/fatigue twice of POM), combined with excellent chemical resistance towards Automotive fluids, hydrocarbon solvents, and salts. Wear and friction properties are better than POM and barrier properties towards Gasoline and Diesel are twice better compared to PA 12. For meeting UL V-0 flame retardancy level only half of flame retardant is needed compared to other engineering polymers. Also, due to fast crystallization rate and good flow properties, short cycle times are possible. In terms of material selection, Polyketone can be used for several applications in the Automotive, Electrical/Electronics, Appliances, Industrial, and Medical market. For a deeper look into applications and properties of Polyketone, I recommend checking out our guest interview with Doug Eom from Hyosung.

Aromatic Polyketones are semi-crystalline high performance polymers (definition according UL 746B) and offer exceptional performance over a wide range of temperatures. Polyetheretherketone (PEEK) has excellent chemical resistance, low moisture absorption, and good wear and abrasion resistance. Furthermore it has excellent heat distortion properties, a low coefficient of friction, good radiation resistance, low flammability, and good resistance to hydrolysis. Also, it has a high resistance to thermal aging and it is resilient when exposed to boiling water. In case of burning, it releases very low smoke and toxic gases. Based on the aforementioned excellent properties, PEEK is used for applications in aircraft, marine, automotive medical, food processing, defense, and oil and gas industries.

Apart from the different properties between aliphatic and aromatic Polyketones, cost per kilogram material also differs between aliphatic and aromatic Polyketones with a factor of 10 as a rule of thumb.

Final remarks

Depending on your application requirements, aliphatic or aromatic Polyketones may fit your needs in terms of material selection. Due to the ongoing material shortages in the field of engineering polymers such as Polyamides, PBT and POM, I expect that Polyketones will find their way into more and more applications, and this globally.

Thanks for reading and #Findoutaboutplastics

Herwig Juster

 Interested to talk with me about your plastic selection and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] https://pslc.ws/macrog/level2.htm

[2] https://www.findoutaboutplastics.com/2020/05/the-secret-of-high-performance-polymers.html

[3] https://www.sspseals.com/blog/properties-benefits-peek-material

[4] www.Polysource.net

[5] https://www.findoutaboutplastics.com/2021/05/guest-interview-doug-eom-poketone.html

[6] http://www.poketone.com/en/index.do

Rule of Thumb: Investing and Scaling Up Polymer Production Plants

Hello and welcome to a new rule of thumb post. More rule of thumb posts can be found here.

In this post we discuss two topics: investment decision making based on scaling models and the growth in chemical businesses.

In general, the investment amount in new production capacity can be estimated using the following equation:

Equation 1: estimation of investment amount for new production capacity using the "Lang factor"

The exponent in this equation is called the “Lang Factor”. It can have different values and ranges typically between 0.6 to 0.7 (6/10-rule).

Investment example

In the following, an example of a capacity increase from 1 million tons material per year to two million tons material per years is shown. 

Investment example: doubling the production capacity leads only to a 57% investment increase compared to the original investment. 

Reasons why the costs are lower includes the lower operating costs (spreading the fixed costs over more product), reduced capital investment per unit, and an increased market clout.

Altogether, there is no linear relationship between investing and production output.

A word on growth of chemical businesses

On average, chemical and plastic manufacturers follow the regional Gross Domestic Product (GDP) growth. During crises, stock levels along the supply chain will be consumed and new purchases are decreased. Therefore, in an economic crisis, growth falls below GDP and after the crisis, demand is increasing leading to a growth above GDP level. Chemical businesses are cyclic businesses and similarities to the so-called pig cycle can be found.

More rule of thumb posts can be found here.

Thank you for reading and #findoutaboutplastics,

Greeting Herwig

Interested to talk with me about your plastic selection and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] https://training.nexanteca.com/Global%20Petrochemical%20Industry

Design Properties for Engineers: Hot Runner System Suitability of High Performance Polymers

 Hello and welcome to a new blog post!

Today I present to you the hot runner system suitability data of high performance polymers for injection moulding.

In my comparison I have selected three different hot runner systems:

-Nozzle gate, open with straight outlet  

-Nozzle gate, open with tip ("hot tip")

-Valve gate with needle

For every of the eleven selected high performance polymers the suitability to use the different hot runner systems was checked by literature review.

 Hot Runner System Suitability of High Performance Polymers

Allover, material degradation is more likely to occur when hot runner systems are used due to the longer residence times at higher temperatures and often not completely balanced flow/temperature gradients in the hot runner system itself. Therefore it is essential to lower the temperature of the hot runner whenever moulding is interrupted.

Additionally, it is beneficial to have a hot runner system which allows a separate heating zone by using different control units as well as using an electrical circuit which enables gradual heating (less risk of short circuiting due to moisture present in the heater cartridges).

What are your experiences with hot runner systems and high performance polymers? 

Let me know in the comments below. 

Greetings and #findoutaboutplastics

Herwig

Interested to talk with me about your plastic selection and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] https://docplayer.org/112974799-Heisskanal-systeme-fuer-technische-thermoplaste.html

[2] https://www.picoplast.nl/uploads/Grivory%20HT1V%205%20FWA%20black%209225%20-%20MDS%20-%20DE.pdf

[3] https://www.synventive.com/uploadedFiles/MK-PRM.BRM.DE-P.HRGD01.pdf

[4] https://multimedia.3m.com/mws/media/96718O/injection-molding-guide-for-dyneontm-pfa.pdf

Rule of Thumb for Plastic Part Design: The Rule of 10 in Part Costs

Hello and welcome to a new Rule of Thumb post. Today we discuss the rule of 10 in context of the Polymer Product Pentagram.

Uncovering mistakes during or after the plastic design and production phase leads to high fixing costs in return. The fixing costs are described by Mr. Anderson in his publication as “The Rule of 10” [2]: when costs are discovered in the next design phase, they increase with the factor 10.

Let us now apply the rule of 10 to our Polymer Product Pentagram [1]:

Polymer Product Pentagram 

In case one needs to re-select another polymer, costs will increase by 10. If the part design and polymer selection stage are approved, however a mistake was made in mould design and construction, then costs are up by a factor 100 already.

Altogether, it does not need to be exactly 10. In one's particular case it may be 6 or 8, which is still a high number.

Thank you for reading and #findoutaboutplastics

Greetings

Herwig Juster 

Interested to talk with me about your plastic selection and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

 [1] Polymer Product Pentagram: https://www.findoutaboutplastics.com/2021/01/rule-of-thumb-for-polymer-engineering.html

[2] The Rule of 10: https://articles.bplans.com/the-rule-of-10-for-product-design/