Polymer Issues in Conservation and

Preservation of Cultural HeritageBy Mary F. Striegel,

National Center for Preservation Technology and Training

The objects that

make up a

portion of our

cultural heritage

have physical

lives.

Over time, they

respond to their

environments and

break down from

natural or manmade

causes.

NCPTT was created to develop or transfer

new technologies to the world of historic

preservation.

NCPTT works with a variety of partners to

advance preservation techniques.

Without the ability to

develop new

improved coatings for

use with cultural

materials, many of

these treasures will

be lost.

New technologies hold the promise of new

ways to study and conserve our cultural

heritage.

We must engage interdisciplinary teams to

apply new polymer systems can help

preserve cultural objects for future

generations.

What is Cultural Heritage?

KellyMullaney, “Cultural Exhibits during Hispanic Heritage Family Day,” October 21,

2008, online image, flickr.

Architectural

buildings

and structures. . .

Archeological

sites and

collections. . .

Art or historical collections. . .

Parks, gardens and other landscapes can

all be considered cultural heritage.

Cultural Heritage can be internationally

significant or highly personal.

Cultural resources are subjected to many

agents of deterioration.

Natural decay goes

unchecked from

lack of

understanding of

chemical/physical

properties.

Decay is a result of complex factors

that lead to loss of integrity.

Air pollution interacts with stone to produce

weathering products and accelerates decay.

Subsequent rains

wash away the

stone resulting in

a “melting” of

outdoor sculpture.

Metal Corrosion

Moisture and Water

Moisture and Water

Biological Organisms

Grow in an amazing

variety of environments

Micro-organisms can:

– produce corrosive

compounds

– consume compounds

that inhibit corrosion

The presence of biological

organisms almost

always increases

corrosion rates in

metals and deterioration

rates in stone.

Inherent vice

Ethical Considerations

• Do no harm

• Respect and retain

original material

• Minimize impact

• Understand

treatments and

materials used

• Choose stable

materials

Polymers Used in

Conservation

Anti-Corrosion Coatings

Chemical Types

Oils5 Lemon Oil

Paraffin Oil

Castor Oil

Shellac15 Copal Shellac in methylated

spirits

Natural Waxes16 Beeswax

Carnuba Wax

Lacquers5 Cellulose acetate

Agateen (nitrocellulose)

Microcrystalline Waxes17, 18 Synthetic waxes

Polyethylene wax

Brush

Application of a

microcrystalline

wax coating

Chemical Types

Acrylics5, 6, 19-23 Incralac (a methylmethacrylate)

Nikolas 11565 Acrylic Lacquer

Bedacryl 221X

Polyvinyl chloride

Waterborne Acrylic Urethanes6 Nikolas 11650 Eco-borne Brass

Lacquer

StanChem one-part acrylic

urethane

Cape Cod Research, Inc.

polyurethane (2-part system)

Solvent-based urethanes6, 24 Nikolas 9778 Exterior Uralac

PPG’s DelClear® DAU75

Acrylic Urethane

Siloxanes25 Ormacer (an organic-inorganic

copolymer sol-gel)

Spray

Application of

an Incralac

Coating

Stone Consolidants

Types of Stone

Consolidants

Inorganic materials

Organic polymers

Alkoxysilanes

Conversion treatments

Inorganic Materials

Alkali silicates

Calcium hydroxide

Barium hydroxide

Silicofluorides

Organic Polymers

Acrylic

Epoxy

Polyurethane

AlkoxysilanesEthyl silicate (TEOS)

Methyl trimethoxy silane

Methyl triethoxy silane

HCT is a conversion

treatment recently

developed for calcareous

substrates. Treatment

converts calcium

carbonate to a more

stable mineral.

Adhesives

Surface Integrity

Visual Appearance

Retreatability or Reversibility

Viqi French, “Intense,” from Meeting of the Waters,

St. Louis, Mo. February 23, 2011,online image, flickr.

Water Vapor

Permeability

VOC Regulations

Calcareous Stone

Indiana Limestone Vermont Marble

Ideal Polymers…

• Transparent color

• Adds no gloss or sheen

• Applies as a waterborne system

• Stable under a variety of environmental

conditions, including temperature cycling,

and UV exposure and

• Reversible or Retreatable

Current

polymeric

treatments are

inadequate to

protect our

cultural heritage

from decay.

“…the need to build broad based partnerships

between conservation scientists and scientists

from universities, national laboratories, industry

and other institutions...”

CHEMISTRY AND MATERIALS

RESEARCH AT THE INTERFACE

BETWEEN SCIENCE AND ART

Report of a Workshop Cosponsored by the

National Science Foundation and the Andrew W. Mellon Foundation, July 6-7, 2009

Engage interdisciplinary teams to

apply new polymer systems that

can help preserve cultural objects

for future generations.

Create collaboration

and outreach

through

conferences,

publications, and

social media to bring

together new teams

and unique

approaches.

Create Sustained Funding efforts ...

• NSF program

solicitation 11-528

• Full proposals due by

May 11, 2011

• Three year awards

with funding up to

$140,000 per year

• Must have a

recognized

conservation scientist

as part of the team

Act III, Scene 4 – The Resolution

2012

Preservation Technology and Training Grants

• Annual Call for Proposals:

September 2011

• Deadline for Submission

October 15, 2011

• One Year Award Up to

$25,000

• Requires a 1 to 1 match

• Simple online process

• http://www.ncptt.nps.gov/grants

/call-for-proposals-2011/

Polymer scientists can play a crucial role in

preserving our nation’s treasures.