Monday, April 30, 2012

New Acquisition - Prada Car-Inspired Shoes

We were very excited to add three new contemporary acquisitions to our collection in April.  We appreciate the generosity of the team at Prada in Milan who donated to us three pairs of the most talked about shoes from their Spring/Summer 2012 Collection.  This collection is described by Prada as being "...based on he juxtaposition between 'sweet' femininity and the motoring universe.  This collection's footwear is also inspired by 1950s luxury cars".



The Prada catalogue describes the design inspiration for these unique shoes:

"Very traditional and feminine styles, such as mules, T-shaped and slingbacks, all symbols of elegance, are reviewed in an ironic light by means of introducing ironic, pop details such as car wings, lights, extra-large bows, flames and chrome plates that look like the American Cadillac cars.

Heels are high and thin, mainly stilettos, but some decorated wedges also show, for a very dynamic effect."

The Bata Shoe Museum is very excited to have these innovative shoes as part of our permanent collection and they can be seen in our B1 foyer between now and May 8th, 2012.

This pair of patent leather sling-back, wedge-heeled shoes features throat decorations of yellow roses framed by blue rhinestones.  The wedge heel is accented by novelty tail-lights and is reminiscent of the rear fins of cars from the 1950s.
These sling-back, wedge-heeled, T-strap sandals show to great effect the bold contrast of red and black which further embellishes the flame motif that is seen in many of the shoes designed by Prada for this season.

This pair of green, black and beige stiletto-heeled shoes features a series of Prada's design elements from this season; the flame motif and novelty tail-lights combine to create an unmistakable automotive reference.


Tuesday, April 24, 2012

Plastics Blog - Chapter 2 - When Good Plastics Go Bad

When Good Plastics Go Bad
By Samantha Conover
In my last blog I discussed the surprising prevalence of plastics within the Bata Shoe Museum. Today I would like to talk about why it’s important to identify and care for plastics. Plastics are often misconstrued as indestructible. In fact, plastics can degrade spectacularly, sometimes causing damage to materials nearby. This degradation can be unpredictable because of differing makeups in plastic composition (such as additives used in manufacture) and exposure to light, heat and moisture prior to museum storage. 

Extreme environmental weathering

Like most other materials, plastics are vulnerable to environmental weathering. Exposure to light, heat, oxygen and water can cause chemical reactions which alter the arrangement and type of chemical bonds present in a plastic. So when plastics break down visibly, they are also breaking down on a molecular level. The breakdown of a plastic can reveal itself in many ways including crumbling, cracking, stickiness, stiffness, yellowing, blooming and sweating.  Because the chemical makeup of a plastic will determine how a plastic breaks down, each type of plastic tends to degrade in its own particular ways. This is why it is so important to identify plastics, as it allows conservators to strategize ways to prevent this degradation. 

Rubber is most susceptible to damage caused by exposure to oxygen.  Exposure to oxygen can cause crosslinking, a process that creates links between  linear polymer chains.  Rubber is often crosslinked intentionally in order to add strength and stability to the material. But when crosslinking happens unintentionally it can lead to brittleness.  Exposure to oxygen can also cause chain scission. This is when the long polymer chains of a plastic break off to form shorter chains. Chain scission can cause cracking and crumbling or softening and oozing.  Below are some images of shoes who have suffered due to oxidation.


The rubber sole of this boot used to be flexible. 



































































Now it's cracked and brittle.  This is likely due to crosslinking






























The rubber sole of this shoe has become soft and sticky.  This is likely due to chain scission.  In order to prevent it from adhering to other surfaces, the conservator has attached a Mylar barrier.

 Exposure to UV radiation and light can cause the development of chromophoric groups.  This development causes a formerly white or transparent plastic to become yellow.  This is very common with objects made of nylon and PVC.  Below are images of shoes with nylon and PVC straps that used to be transparent, but turned opaque and yellow due to light exposure.

Yellowed nylon (above) and PVC straps (below).  I've photographed the nylon besides a roll of new nylon monofilament to show how yellowed the straps have become with age.



Another factor involved in plastics deterioration is the use of additives in manufacture. These additives are incorporated in the polymer matrix to change physical and chemical characteristics such as colour, strength and flexibility. As plastics age, the additives can become incompatible. When this happens, the additives will separate from the plastic and leech out. For example, flexible PVC is made by adding a plasticizer during manufacture. As PVC ages, the plasticizer escapes to the surface to form droplets or a sticky film. The vinyl strap of the shoe below is covered in small dots, which are likely dried droplets of plasticizer. 

Plasticizer drops that have dried on the surface of flexiable PVC


Some plastics are more problematic than others.  Most plastics only damage themselves as they degrade. So-called “malignant plastics” are a danger in the museum as they can harm nearby materials as they deteriorate.[1] Plasticized PVC, polyurethane, cellulose acetate, cellulose nitrate and rubber (usually highly vulcanized hard rubber) are the bad guys of the plastics world. Cellulose nitrate is the most notorious of these villains. With exposure to moisture, cellulose nitrate eventually breaks down and releases nitric oxides, which quickly become nitric acid. Nitric acid is highly corrosive, and can damage nearby objects and materials. The 1920s shoe below is decorated with two types of beads. The small beads are brass, the larger beads are of an unknown material. The brass beads that are in contact with the unknown beads are starting to corrode. I suspect that the unknown beads may be cellulose nitrate!


The small brass beads that are in contact with the larger beads are starting to corrode.  It's possible the larger beads are cellulose nitrate

Most modern plastics are designed to withstand environmental pressures and remain in good condition throughout their “service lifetime.” However, this period of regular use will always be much shorter than the time an artifact is expected to remain viable in a museum. The best way to deal with deterioration is to try to stop it before it starts. Since different plastic types have different degradation paths, identifying what kind of plastic was used to create an object or part is crucial. In my next blog I hope to discuss some methods of identification and to solve plastic mysteries. Plastics conservation is a relatively youthful field and much of the work being done right now is groundbreaking research. If you want to learn more, I suggest you check out the work of the POPART project at http://popart.mnhn.fr/!




[1] I prefer to the phrase “bad neighbors” a term coined by John Morgan of the Plastics Historical Society. I think “malignant” sounds a little too harsh. These plastics may do wrong, but they know not what they do… it’s not their fault!

Thursday, April 12, 2012

BSM New Acquisition

Always interested in adding to the Museum's internationally renowned collection of North American Footwear, we recently obtained two pair - one pair is of the Seminole tradition, and the other is Penobscot in origin.

 
Seminole Moccasin
Penobscot Moccasin

The Seminole pair of finely constructed tanned deerskin, is a one-piece moccasin.  The moccasin is cut from the one piece of deerskin in a pattern that allows for the top and bottom of the foot to be encased by way of a back seam, a front seam and lacing at the centre front.  All of the seams are sewn with a leather thong and a thin strip of deerskin.  Free of applied embellishment, this pair's but and construction is its only decoration.  Note the carefully styled gathering at the toe and at the heel that is punctuated by the circular tab at the end of the thong.



The Penobscot artefact is a two-piece moccasin, meaning it is constructed from two pieces that are then sewn together.  This moccasin has the addition of the cuff piece, which is embellished with applique and beading.  The apron piece, at the top front of the shoe is decorated with beading in a style typical of the Penobscot.  It is sewn together by way of strips of sinew that are as thin as thread and cannot be seen easily.