Plastic check: Material with potential

In the last few months, the proportion of plastic bicycle parts has increased sharply. But this is not a new development. Some of you maybe know the tuff-Wheels from the brand Skyway, who are still producing and selling their parts. Also the UNI Seat for BMX Racers is not unknown. Not surprisingly, because the saddle + Seat posts combination out of plastic had been sold millions in the 80’s and became the best-selling BMX saddle of his time. To give you a short glimpse about this interesting material, I have written down this few lines.

Basics:

Ripping, crackling shopping bags, plastic garbage… no question the image is bad. But the negative reputation of this versatile material is not correct. Often the wrong plastic was chosen for the wrong application. In addition, the product sometimes was insufficient or unloving designed. So it is understandable that the displeasure of customers was big which gave the fault to the material.

As an example, the differ of plastic pedals from used material as well as the dimensions and design is as big as the opinion of the buyer on the suitability of the pedals.

Development:

The request to build an "artificial material" had been early, so there is no exact date to call for the beginning of plastic development.

The poverty and lack of food during the First World War, which was very strong, pushed the research for cheap substitutes for food as well as for textiles. This strong urge coupled with some luck and coincidence, spurred chemists, biologists and other researchers alike into the development of the material, which potential is not fully exploited yet.

Classification:

The plastic we know today can be split into 3 major groups.

Models particles under a microscope (simplified)

1.) Thermoplastics:
The name derives from "thermos" = "warm" and "plasso" = "form".
Plastics in that category (such as PE, PVC…) deform at a certain temperature and keep their form after cooling down.
They usually consist of thread-shaped, only low-branched molecule chains, among only very weak forces act.

2.) Duromere or Duroplastics:
The name comes from "durus" = "hard".
In contrast to the thermoplastics, Duromere (such as epoxy resins…) can be only once heated and deformed. Once cured, they are hard and not solvable. The macromolecules are strongly interconnected in all directions.

3.) Elastomere:
From "elastic" = "expandable" and "meros" = "piece" this plastics group has its name. The macromolecules have only a few links in lateral direction, leading to high elasticity. Plastics from this group would be, for example, natural rubber (NR) or silicone rubber (SIR).

Polarized or polymerized – that’s the question:

From oil that just shot out of the ground and through the nearest pipeline and transform to the finished plastic product, it is a long way. Too long for me to explain in this article fast and easy. Just that: From the entire annual flow of oil are currently estimated only 4%! for the chemical industry, which includes the plastics.

Only a very small proportion of oil will be plastic

The large proportion of oil like gasoline or fuel gets irretrievably burned.

Nomenclature - a name is needed:

Scientifically, plastics are known as polymers. The term comes from Greek and is derived from "poly" = "a lot" and "meros" = "piece". So Plastic is a material consisting out of "many parts" (mainly carbon).

Chemists just as mathematicians are a bit lazy about writing much, so they have invented short cuts and although I personally didn’t give the chemistry lessons the due attention, even I understood the simple principles. The short cuts are uppercase letters which describe the plastic-based polymers that are contained in the material (usually the first letter of the chemical name).

The effective chemical name of plastics are made in accordance with the IUPAC rules (International Union of Pure and Applied Chemistry), but you might know some plastics better under the trivial- or brand name from a company.
For example, Aramid (aromatic polyamide) is often called Kevlar™
(Brand name of the company DuPont).

Other examples:

Stability factor:

Only in the rarest cases, plastic is processed in its pure form.
Stabilizers / antistatic agents / flame retardants / Masterbatches (pigments) / filling and reinforcing materials are often into the plastic melt admixed additives.
Thanks to the excellent properties of many plastics, as well the possibility of the material to be matched for the purpose, plastic is interesting for many applications.

In some areas on the bicycle, plastic can’t be replaced by other materials (tires, grips, tubes…). Other plastic parts like pedals have already proven their eligibility, where the plastic causes low weight and provides to save money. Hardly any other material makes this possible.

But I am also against displacing every part of the bike by one made out of plastic. A good steel frame, fork or handlebar, will continue his permission. However, there are parts where the use of plastic still has the potential to reduce weight, increase stability or achieve other benefits.

Weight factor:

Also the weight differs a lot by the various types of plastic.
However, in general, the density of plastic is much lower compared to usual metals used in cycling.

Examples:

Price factor:
13 euro for very suitable pedals. At this price few people may assume a typing error. But the price is right and the pedals are also good. The usually low costs for plastic bicycle components can be explained by the low cost for the material and the simple manufacturing. However, plastic not only save your account balance…

Environmental factor:
Because of plastic compared to metals, production and processing consumes less energy, so the environment and our valuable resources are saved. Furthermore, could this versatile material even reduce the weight of cars so drastically that the lower fuel consumption saved more oil than was needed for the plastic in cars. Plastics are also recyclable.

Style factor:
The appearance of bicycle components plays a not unimportant role when buying the parts. Tastes are different, but with the big range of styling like different colours, transparent or translucent, matte or glossy, there is something for everyone’s flavour.

Another advantage is that the material is dyed completely and not like a paint colour only on the surface liable. Thus, the beautiful appearance is permanently. The colour takes place during the processing of the raw granules, so there are no additional high labour costs.

Technology from the future - now!
Not only bicycle components use the advantages of plastics. Just think of the “InMold” technology by helmets which weld the hard shell and the foam together. The result is a complete connection, a very stable structure and a helmet by up to half of the weight then those helmets of conventional design.

Are we arrived talking about protectors, there is still a second notable great development.

is a specially engineered material made with intelligent molecules. They flow with you as you move but on shock lock together to absorb the impact energy.

The British company™ d3o lab engineered a special plastic with intelligent molecules. They flow with you as you move but on shock lock together to absorb the impact energy. The flexible rubbery material thus transforms within a hundredth of a second too a hard resistant absorber to protect the carrier. This is possible if the property of the plastic is "dilatant".

Incidentally, the name of the company as a search term entered in the Internet, there are a bunch of some very interesting videos about them.

Knowledge is power
The topic around the plastic material is enormous and it is not always easy to explain something for the layman so he understands but without too many details thus to bore others. However, I hope that this was not the case and I could give you an interesting insight on this material. For more open questions I am on-hand (mostly). :D

best regards from our guestwriter from Vienna

Matthias aka mountainlion