New Ideas with Recyclable Composites

New Ideas with Recyclable Composites

New materials and processes usually take time to catch on, at least in the construction industry. But as the small base of early adopters grows, and more people become interested in using a material, there are more and more brains focused on improving it, extending its capabilities, and resolving its issues.

One of the issues with composites has always been their recyclability, or lack thereof. If the process that hardens the resin is irreversible, then the composite is going to stay composited.

Twintex is a recyclable composite developed by Owens Corning. They described it as “co-mingled glass and thermoplastic reinforcement.” Glass fibers and polypropylene filiments – or alternatively PET – are co-mingled.  When baked under low pressure, the composite becomes rigid.  The heat-setting process of these resins is reversible, making the composite product recyclable.

Owens-Corning sales literature said Twintex was available in single-end roving, fabric, plates, and long glass fiber concentrated pellets. Their suggested list of applications included bumper beams, kayak seats, truck panel skins, under engine protection, small boat hulls, and inside door panels.

In 2011, students at the Rhode Island School of Design (RISD), apparently at the instigation of Lothar Windels, Assistant Professor, and with support from Owens Corning, explored what else you could do with Twintex if you wanted to make furniture.

The students made tables, chairs, and lighting fixtures using Twintex single strand roving that they wound, or in some cases knitted, over wooden molds, and then baked under low pressure to ‘freeze’ the shape. The windings include many examples of fanciful randomization, which tends to emphasize the structure being made up of many very thin strands.

There were 12 projects in all – more than we can show here – but you can see them all on RISD’s website.

Just to focus on a couple to whet your appetite…

Elizabeth Moran’s Practical Table is a sharply defined little hollow polygon made of thin strands of Twintex. They were wound on a wooden mold in a method she describes as “purposefully haphazard” to create an intriguing pattern, but still allow space to remove the mold after the composite had hardened. The strands that support the structure vertically all emanate from one of four points around the sides, fanning out to support the tabletop, and then changing direction to become the tabletop.

Eun Sang Ernie Lee’s Perm Chair takes a very different approach to the material. He knit a fabric of Twintex (there’s a video about the making of this chair that shows this: the needles appear to be about 30 inches long and probably 3 inches across) and formed it over a model to made a pillowy armchair. Then he permed the fiber to make it look like his Grandmother’s hair, and baked it in shape.

The more people there are thinking about a material, the further it can go.

(In 2012, Owens Corning sold its Twintex rights to Fiber Glass Industries (FGI). FGI closed its two plants in 2014, and its website no longer appears to be online, so this particular material may no longer be available. Alas.)

Images via RISD except as noted.