There is a widespread assumption that plastic is among the hardiest of materials, but that is far from true, as conservators in museums and galleries know only too well.

The Victoria & Albert Museum is now collaborating with Imperial College and University College London to find ways of saving 20th-century works of art and design featuring plastics, including polyester and polyurethane.

Sculptures, along with landmark pieces of design including furniture, fashion and even toys are among museum exhibits that are suffering decay, ranging from discolouration to a disintegration to powder, shrinkage and stress cracking.

In the V&A, the Blow chair – designed with layers of PVC in 1969 as the first inflatable chair to be mass produced – has become completely rigid. The foam in an early 1970s Larry the Lamb toy – within the V&A’s Museum of Childhood holdings – has deteriorated and can no longer even be handled; while once-slinky 1960s PVC dress has become “very sticky” because plasticers are coming to the surface, attracting dust that attacks it still further.

The Tate boasts the world’s largest collection of early sculptures by Naum Gabo, the 20th-century artist who pioneered the use of plastic in art. Construction in Space Crystal, 1937, and Spiral Theme, 1941 – both cellulose acetate sculptures – are among 43 Gabo works made wholly or partly from various types of plastic. Despite storage in controlled conditions and regular monitoring, many are showing signs of degradation, including warping and cracks, due to the inherent instability of the plastics.

Stephen Willats Mini dress: this is a 1960s PVC dress which is very sticky because the plasticers within the PVC are coming to the surface. Photograph: V&A

The materials that he used have an in-built suspectibility to shrinkage and Tate conservators have developed replicas of these works as a visual record of the artist’s original concept.

Ahead of a panel discussion on the subject on Tuesday at the Royal Institution in London, organised in collaboration with Hiscox, the specialist art insurers, Sandra Smith, the V&A’s head of conservation, said: “It’s something that museums all over the world are trying to find a solution to. We’re doing a lot of work collectively to try and find answers … Plastics are such a relatatively modern material in terms of mankind, we’re on that learning curve.”

She said that people wrongly assume that plastic is “stable”. It is, in fact, a “brittle” material, she added: “People don’t recognise that, when something’s a modern material, it takes time to understand [it].”

Some plastics have become too delicate even to be exposed to too much light or have developed a sensitivity to cleaning, even with water. Like the most delicate of works on paper, they have to be put in dark storage between displays.

Smith said that they are trying “to understand how modern materials deteriorate and how we’re going to preserve them for the future”, finding techniques to slow down the ageing process: “Plastic material is used in all kinds of design and the V&A is a museum of art and design … In many of our modern and contemporary collections … it’s remarkable how much plastic [is involved]. So we’re undertaking research at the moment … to understand how light affects plastics and, I know this sounds strange, but how we can clean plastics.

“We have lots of techniques that we’ve used traditionally on wood, glass and other materials that we understand. Plastics are really quite sensitive. So Imperial College are working with us to understand at a really microscropic level what’s happening to plastic.”

The Issues Surrounding the Conservation of Contemporary Art panel discussion will explore the permanence and future value of contemporary art. Speakers include Sir Christopher Frayling, former head of the Royal College of Art.

Smith, one of the debate’s speakers, said that it is a common problem for plasticides to seep to the surface: “Plastic itself is a material that is very rigid. The plasticides are put in there to allow it to be foldable and malleable.”

The V&A collection includes some furniture with polyurethane foam, which replaced traditional upholstery in the 1960s, but which has since been reduced to “just powder”, Smith said. Such examples include The Globe Chair, a polyester shell also known as the Ball chair, created by Finnish designer Eero Aarnio.

Robert Read, head of art and private clients at Hiscox, said that so much contemporary art is “tricky” to restore, raising questions about its longevity and “whether that’s going to affect the market” for such works.

He added: “There’s a lot of contemporary art being sold now. That’s why [this] is an interesting topic. A lot of the work is made out of innovative material, and a lot is being sold for very high prices. That’s what prompted this debate.”

He believes that delicate, sensitive materials like plastic, with such inherent problems, could have an impact on values eventually.