Plastic frames

ademort

Given that bike frames are made from steel,aluminium,titanium and carbon does anyone feel that in the not to distance future there may be a frame made purely from plastic. All comments, views welcome greetings Ademort

redddraggon

ademort wrote:

Given that bike frames are made from steel,aluminium,titanium and carbon does anyone feel that in the not to distance future there may be a frame made purely from plastic.

Carbon fibre is effectively a plastic.

EDIT: Carbon fibres are carbon fibre, but bike frames are made out of CFRP - Carbon Fibre Reinforced Plastic

synchronicity

It's only a matter of time. There are continuing developments in the field of polymer science. And polymer chemists hate the term 'plastic' by the way...

You only have to look at the current proprties of aramid & poly-ether-ether ketone (PEEK).



Interestingly enough, polyethylene fibres are extremely strong -but the difficulty in forming a composite is that nothing sticks to them!

Here's a few science abstracts on just one new polymer:

The properties of PIPD-fibre/epoxy composites
Abstract
In this paper we describe measurements of the properties of composites based on a new organic fibre, poly {2,6 dimidazo [4,5-6: 4′5′-e] pyridinylene – 1,4 (2,5-dihidroxy) phenylene} (PIPD). The properties of unidirectional PIPD-fibre/epoxy composites were measured using a range of standard ASTM tests, and the measured values were compared with other fibre-reinforced materials. This comparison showed that the most outstanding property of the PIPD composites was a very high compressive strength. Measurements of the elastic properties of the PIPD fibre, using the ultrasonic velocity technique and an inverse modelling procedure, showed that, as expected, the high compressive strength of the PIPD fibre-based composites was linked to the high shear modulus of the PIPD fibre.

Abstract
The development of the new high-modulus and high-strength fibre M5, made of poly{2,6-diimidazo[4,5-b:4,5-e]-pyridinylene-1,4(2,5-dihydroxy)phenylene} or PIPD, has resulted in an organic polymer fibre with exceptional fire protection properties when compared with PBO, Twaron, Kevlar and Nomex fibres. The PIPD as-spun fibre with a modulus of 150 GPa and a tensile strength of 2.5 GPa is a crystal hydrate containing 21 wt% water. Cone calorimeter measurements yielded a fire performance index (FPI) 20 times higher than Nomex, with extremely low value for the specific extinction area (SEA) characterizing the smoke formation. The PIPD-HT fibre (recrystallized in an after treatment into the anhydrous crystalline structure) with a modulus >300 GPa and a strength >5 GPa has a FPI value similar to PBO but shows much less smoke formation than this fibre.

Abstract In this work, the flammability properties of a new rigid rod polymer fibre are examined. This new fibre was called M5 and is formally poly[2,6-diimidazo[4,5-b:4,5-e]- pyridinylene–1,4(2,5-dihydroxy)phenylene or PIPD. In a first step, characterisation of PIPD (M5) by solid state NMR confirms the chemical composition of the fibre. The investigation of the fire performance of M5 fibers using the cone calorimeter has shown the excellent behaviour of M5 in comparison with poly-p-phenylenediamine-terephtalamide (PPTA). M5 fibre does not burn even in very severe conditions (flashover conditions). It can then be used where high level of safety is required. The investigation of its heat resistance shows that M5 degrades via exothermic reactions of 30% lower energy than PPTA and have a strong pyrolysis resistance which can explain, in part, its unique fire properties.

dennisn

I'm not sure what you call them over there, but they are called "Big Wheels"
over here and they are all plastic. I know. I'm an a#shole.

Dennis Noward

vbc

I'll give it a couple of years and you'll be seeing Bakelite frames...very retro.

geoff_ss

There was an almost all plastic bike sold about 20 years ago IIRC. Can't remember the name but there's one on display at the Manchester Velodrome. Dreadful things - someone borrowed one from Mercians and rode an evening'10' on it. Can't remember the exact times but I know it put well over 5 minutes on his usual time.

Were they made in Sweden? Itera? Don't know.

Geoff

synchronicity

Yes, the swedish? Itera Bike. I read about it in The Ultimate bike book if I recall

redddraggon

My bike is mainly polymer - what else is the matrix in the composite?

I think you're looking for a discovery that is already here.

(Materials Scientist BTW, although do more ceramic stuff ATM)