Saturday, October 25, 2014

Caucasian Rugs[1]
Art Essay

Marie-Therese Wisniowski

Preamble
For your convenience, I have listed posts below that also focus on rugs.
Navajo Rugs
Persian Rugs
Turkish Rugs


Introduction
The term "Caucasian race" was coined by the German philosophe Christoph Meiners, who defined the term in his The Outline of History of Mankind (1785). Meiners's unique racial classification, contained only two racial divisions (Rassen): Caucasians and Mongolians.

The Caucasus range (the Great Caucasus in Russian terminology) is about 1,100 km long, extending from the vicinity of the Taman (or Anapa) peninsula to the Apsheron peninsula, on an axis- oriented West-NorthWest to East-SouthEast. Its total area is about 145,000 km2, and it is 180 km wide in the region of Mount Elbrus. A dozen or so peaks surpass an elevation of 5,000 m. On its north side the range, which is generally interpreted as an enormous complex of anticlines, rises gradually in a series of parallel chains above the Kuban and Terek plains, which are separated by the Stavropol sill; on the South side it towers over the basins of the Transcaucasia, two opposing triangles that open toward the Black Sea (the Colchian lowlands) and the Caspian Sea (the Kura and Araxes basins) respectively with their apexes meeting in the Surami sill. In addition to this dissymmetry between the Northern and Southern faces, the range is divided by Mounts Elbrus and Kazbek into three distinct regions on its Southern side: the Western, Central, and Eastern Caucasus.

Location of the Caucasus Range.

The population within the boundaries of the Caucasus range has been estimated at 1.25 million in an area of 103,000 km2; that is, an average density of more than twelve per km2. In fact, a large part of the western Caucasus is almost uninhabited, as are several valleys in the central Caucasus, whereas in the eastern Caucasus the population density is often extremely high.

Between 1942 and 1945 many inhabitants of the Caucasus were evacuated or deported; Balkars, Chechens, Ingush, and Karachai even lost their national rights for a time. Although a number of them returned to their lands after 1956, the population density never reached its pre-war level.

Ramzan Kadyrov celebrates Chechen Language Day in style.

The post today will not deal with how to create needlework miniature rugs, but rather with the design of Caucasian rugs themselves. The images of most designs are those reproduced by Frank M. Cooper using his needlepoint techniques [1].


Caucasian Rugs
Caucasian rugs were woven in the mountainous area between the Caspian Sea on the East and the Black Sea on the West. Over the course of time, many different ethnic groups – Turks, Persians, Armenians and Turkomen tribes from Central Asia - occupied this region. Some of these groups have remained, and so the area now features many different tribes and tongues.

The miniature rug below was reproduced by Frank Cooper [1] from a rug that is held in the McMullin Collection in the Metropolitan Museum of Art in New York. The rug is unmistakably Kazak, recognizable by its widely spacer decoration on a plain-colored field. The wide white border is filled with highly stylized Kufic script, separated by Mystic knots, which are symbolic of God.

Kazak (A).

The Kazak rug shown below was adapted from a rug that is in The Nelson-Atkins Museum of Art, Kansas City, Missouri, USA. The bright colors and bold designs are typical of rugs from this area. In the center of each of the two medallions, which almost cover the entire field, is a gold square containing what appears to be a swastika. This, in turn, is surrounded by eight cloud bands and thus the rug is sometimes called the “cloud band” Kazaks. The wide, light-colored border, with its stylized “eagle beaks” design is often used in this region.

Kazak (B).

Rugs often decorate the floor of Mosques. As devout Muslims kneel upon their prayer rug fives times each day to pray, they intone:

In the name of God, the Compassionate, the Merciful
Praise be to God, Lord of the Worlds!
The compassionate, the merciful!
King on the day of reckoning!
Thee only do we worship, and to Thee do we cry for help.
Guide Thou us on the straight path,
The path of those to whom Thou hast been gracious;
With whom Thou art not angry, and who do not go astray.


The rug below is in the McMullan Collection in the Metropolitan Museum of Art, New York, USA. It has also been identified as a Moghan rug. The Moghan area is in Southern Azerbaijan, right on the Iranian border. The area is a melting pot of many ethnic groups. For hundreds of years before it became a part of Russia, it was a battleground for Arabs, Mongols, Turks, Persian and Russians, all striving to dominate this region. Naturally these various cultures left their imprints on the inhabitants of the area, which was then reflected in the designs of their rugs.

The design of the rug below is very similar to rugs seen in Early European paintings and in Timurid miniatures of the late 14th Century. At first glance the rug seems to have little color other than red, dark blue, white and some green in the triangles and border. On closer inspection, there is a lighter shade of blue and gold. The stars within the octagons are the same design but the colors vary in hue.

Caucasian (A).

One of the most pleasing rug patterns that comes from this area is the Kuba rug shown below. It contains five reddish Lesghi stars named for the Lesghian tribes with whom the design originated. These stars, with brown centers, are placed on a dark blue, almost black background. The field is further ornamented with squares containing different designs. The light brown main border, with characteristic S-shaped design, is centered between two narrow borders with identically shaped rosettes.

Kuba.

In Caucasian homes, pile carpets were used on the floors for warmth. Flat-woven rugs called Kilims, were used when a more flexible material was needed. Kilims were also made into bags for storing food, household utensils, clothing etc. Nomads also used them to make saddle bags.

The rug below is a Kilim, which Cooper adapted from a rug that is now in the Mustafayev Museum in Baku. The colors of this Azerbaijan rug are much more restrained than those of the nearby Kazak rugs. The decorative figures in the rug may reflect the everyday environment of the weaver. Note how the dark brown of the main border is carried across the center portion of the rug.

Caucasian (B).

The “eagle-head” border in the rug below is very similar to the main border of a Kazak rug in the collection of the Nelson-Atkins Museum of Art in Kansas City, Missouri, USA. However this is a Shirvan rug, the colors in the main border are much more subtle, due to the shading from dark to light.

Shirvan (A).

The cottage industry has played an important role in rug weaving in Turkey, Persia (now Iran) and the Caucasus. In the 17th and 18th Centuries, many of the rugs exported to Europe from Western Turkey had been produced by cottage industries. Some were made under contract, with the contractor sometimes furnishing all the materials needed for making rugs, even looms.

The contract system was introduced into the Caucasus by the Persians in the latter part of the 19th Century. The Persians brought with them some of the designs from the court rugs.

The design of the rug below dates from the 19th Century. The rug is described as a product of the cottage industry in Shirvan, a district in the Southern part of the Caucasus.

Shirvan (B).


Reference:
[1] F.M. Cooper, Oriental Carpets in Miniature, Interweave Press, Colorado (1994).

Saturday, October 18, 2014

Batiks From Warlpiri (Yuendumu)1
Australian Aboriginal ArtCloth

Marie-Therese Wisniowski

Preamble
This blog spot is a great supporter of Aboriginal ArtCloth and prints on paper since it is simply great! The posts below are in this genre.
Stanley and Tapaya – Ernabella Arts
ArtCloth from Tiwi Islands
Aboriginal Batik From Central Australia
ArtCloth from Utopia
ArtCloth from the Women of Ernabella
ArtCloth from Kaltjiti
Australian Aboriginal Silk Paintings
Contemporary Aboriginal Prints on Paper
Batiks from Kintore
Aboriginal Batiks from Northern Queensland
ArtWorks from Remote Aboriginal Communities
Urban Aboriginal ArtCloths


Introduction
There are approximately 5000 - 6000 indigenous Australians who speak the Warlpiri language. Most of the Warlpiri people live in a few towns and settlements scattered through their traditional land, which is north and west of Alice Springs (Northern Territory, Australia).

Of these settlements and townships, the town of Yuendumu is by far the largest (population 897). It lies 290 kilometers north west of Alice Springs on the Tanami track. The township was established in 1946 by the Native Affairs Department of the Australian Government in order to deliver rations and welfare services to the Warlpiri people. In 1947 a Baptist mission was established there. Today, some of the services and facilities available in Yuendumu include three community stores, school, airstrip, swimming pool, the Warlukurlangu art center, an Aboriginal media organization (PAW Media), a church, an old people's program, women's center and safe house. Yuendumu retains links with other Warlpiri communities within the region.

Location of Yuendumu with respect to other Aboriginal settlements in Central Australia.

The high content of UV light that descends through a dry atmosphere in the Tanami desert give objects stark and sharp definitions. There is no haziness or soft images in this land, and so their images on cloth are similarly defined.

Batik ArtCloth by the Warlpiri people began in 1984, when Peter Toyne an adult educator, facilitated workshops where the Anangu women from Ernabella came to Yuendumu to demonstrate Batik techniques and to share their skills with the Warlpiri women.

Most of the Warlpiri Batik ArtCloths were on cotton, with a few of the early Warlpiri Batiks on silk. The first Warlpiri Batik ArtCloths included pictorial motifs, ranging from bush plants to goannas, while the latter Batiks appeared to be abstract in design they were nevertheless grounded in the practice of body painting for women’s ceremonies. The Batik ArtCloths of the Warlpiri offer strong linear symbols and circle-path configurations, either in secular or sacred contexts.

In the late 1980s the international art market for aboriginal artwork began to accelerate. It was far easier to market and sell art using traditional media – such as canvas paintings – rather than art using non-traditional media – such as cloth. Hence more aboriginal artists gravitated to traditional media and so by 1987 the output of Batik ArtCloth at Yuendumu rapidly declined. See - Warlukurlangu Artists

The National Gallery of Victoria has the largest collection of Aboriginal ArtCloth in Australia. Below are some examples of the Batik ArtCloth of the women artists of Yuendumu.

Raelene Napurrurla Kennedy, Pamapardu Jukurrpa (Flying Ant Dreaming) (1986).
Technique: Batik on cotton.
Size: 83.8 cm (width) x 110.1 cm (length).
Courtesy of reference[1].

Raelene Napurrurla Kennedy, Yumurrpa (1986).
Technique: Batik on silk.
Size: 115.5 cm (width) x 158.5 cm (length).
Courtesy of reference[1].

Neville Japangardi Poulson, Janganpa Jukurrpa (Marsupial Mouse Dreaming) (1986).
Technique: Batik on cotton.
Size: 85 cm (width) x 259.5 cm (length).
Courtesy of reference[1].

Peggy Napurrurla Poulson, Yarla Jukurrpa (Bush Yam Dreaming) (1986).
Technique: Batik on cotton.
Size: 84.8 cm (width) x 257.3 cm (length).
Courtesy of reference[1].

Peggy Napurrurla Poulson, Parrakelia Dreaming (1986).
Technique: Batik on cotton.
Size: 85 cm (width) x 266.5 cm (length).
Courtesy of reference[1].

Beryl Napangardi Robertson, Ngalyipi Manu Karnta Jukurrpa (Snake Vine And Women’s Dreaming) (1986).
Technique: Batik on silk.
Size: 88 cm (width) x 224 cm (length).
Courtesy of reference[1].

Beryl Napangardi Robertson, Karntakurlangu (Women’s Dreaming) (1986).
Technique: Batik on cotton.
Size: 87 cm (width) x 223.8 cm (length).
Courtesy of reference[1].

Beryl Napangardi Robertson, Janyinki (1986).
Technique: Batik on cotton.
Size: 84.8 cm (width) x 199.1 cm (length).
Courtesy of reference[1].

Unknown (1986).
Technique: Batik on cotton.
Size: 88.5 cm (width) x 161 cm (length).
Courtesy of reference[1].

Lottie Napangardi Robertson, Wardapi Manu Wanakiji Jukurrpa (Goanna And Bush Tomato Dreaming) (1986).
Technique: Batik on silk.
Size: 92 cm (width) x 179.5 cm (length).
Courtesy of reference[1].

Jorna Napurrurla Nelson, Ngurlu Manu Yarla Jukurrpa (Little Seed And Bush Yam Dreaming) (1986).
Technique: Batik on cotton.
Size: 86 cm (width) x 188.2 cm (length).
Courtesy of reference[1].


Reference:
[1] J. Ryan et al., Across The Desert – Aboriginal Batik from Central Australia, Council of Trustees of the National Gallery of Victoria, Melbourne (2008).

Saturday, October 11, 2014

Traditional Japanese Arabesque Patterns (Part I)
Art Review

Marie-Therese Wisniowski

Preamble
There have been two other posts on this blogspot that have entered on Arabesque Patterns and for your convenience I have listed them below.
Traditional Japanese Arabesque Patterns (Part II)
Sarasa Arabesque Patterns (Part III)


Introduction
Arabesque is a complex, ornate design of intertwined floral, foliage, and geometric figures. In Japanese it known as Karakusa. In general the Japanese variant consists of patterns of circular and elliptical shapes of stems and leaves drawn by an unlimited number of diagonal lines of simple and defined patterns, thereby creating an image of endlessly linked forms.

The simple type of Karakusa pattern can still be seen today in Japan on fabrics for items such as Furoshiki, ticks and various types of bags, which are an integral part of Japanese daily life. Hence it has become one of the most commonly used patterns in Japan.

An example of original cloth with medium-sized motifs used for everyday clothing of the common people.

The tome – “Textile Design In Japan: Traditional Arabesque”, Kamon Yoshimoto, Graphic-sha Publishing Co. Ltd., Tokyo (1977) - presents 550 stunning patterns. The book contains five categories, with today’s post concentrating on Indigo arabesque patterns (stencil dyed). This category contains 108 patterns. The overview below gives you just a glimpse of some of the Indigo arabesque patterns (stencil dyed) in this book - a must buy!


Brief History of Karakusa Patterns
The popularity of Karakusa patterns dates from the second half of the Edo period (1604-1867). The patterns were first introduced into Japan during the Asuka (592 – 710) and the Nara (711 – 794) periods via trade with the Chinese mainland. While the original pattern was called Karakusa, it was followed by more decorative patterns of Renge and Ungyo, the latter of which was worn by court nobles, aristocrats and priests.

With the advent of the Kamakura period (1192-1333) and with the samurai class gaining more and more power, the samurai began to use these patterned fabrics both for their everyday clothing as well as for their amour. When the tea ceremony began to flourish, the import of luxurious materials and Sarasa cloth dyed with Karakusa and Soka patterns were greatly supported by feudal lords, samurai and people of sophisticated taste. Even some of the rich merchants who were on good terms with feudal lords and samurai wore luxurious apparel, which eventually spread to the common people as a new fashion.

As peace reigned, the shogunate during the second half of the Edo period, issued a proclamation to the public from time-to-time warning them against indulging in luxury. As a consequence, the public began wearing cotton instead of silk garments. This caused a dilemma that needed to be resolved – how could cotton fabrics be made to look beautiful and how do you wear cotton garments with refinement? The Karakusa patterns were taken up in order to resolve this dilemma and so these patterns gained popularity in Edo (Tokyo), Kyoto and then finally swept the country. The Karakusa patterns were adopted for fabrics used for making articles such as mattresses, ticks, clothing, Furoshiki etc. and so infiltrate all aspects of daily life.

Since the end of the second world war, the use of traditional Karakusa patterns have been in a slow decline in Japan.


Indigo Japanese Arabesque Patterns (Stencil Dyed)

Indigo Arabesque Pattern Number 1.

Indigo Arabesque Pattern Number 6.

Indigo Arabesque Pattern Number 26.

Indigo Arabesque Pattern Number 32.

Indigo Arabesque Pattern Number 38.

Indigo Arabesque Pattern Number 40.

Indigo Arabesque Pattern Number 46.

Indigo Arabesque Pattern Number 47.

Indigo Arabesque Pattern Number 51.

Indigo Arabesque Pattern Number 62.

Indigo Arabesque Pattern Number 82.

Indigo Arabesque Pattern Number 91.

Indigo Arabesque Pattern Number 94.

Indigo Arabesque Pattern Number 103.

Saturday, October 4, 2014

Man-Made Synthetic Fibers - Acrylic and Modacrylic[1-2]
Art Resource

Marie-Therese Wisniowski

Preamble
This is the thirty-second post in the "Art Resource" series, specifically aimed to construct an appropriate knowledge base in order to develop an artistic voice in ArtCloth.

Other posts in this series are:
Glossary of Terms
Units Used in Dyeing and Printing of Fabrics
Occupational, Health & Safety
A Brief History of Color
The Nature of Color
Psychology of Color
Color Schemes
The Naming of Colors
The Munsell Color Classification System
Methuen Color Index and Classification System
The CIE System
Pantone - A Modern Color Classification System
Optical Properties of Fiber Materials
General Properties of Fiber Polymers and Fibers - Part I
General Properties of Fiber Polymers and Fibers - Part II
General Properties of Fiber Polymers and Fibers - Part III
General Properties of Fiber Polymers and Fibers - Part IV
General Properties of Fiber Polymers and Fibers - Part V
Protein Fibers - Wool
Protein Fibers - Speciality Hair Fibers
Protein Fibers - Silk
Protein Fibers - Wool versus Silk
Timelines of Fabrics, Dyes and Other Stuff
Cellulosic Fibers (Natural) - Cotton
Cellulosic Fibers (Natural) - Linen
Other Natural Cellulosic Fibers
General Overview of Man-Made Fibers
Man-Made Cellulosic Fibers - Viscose
Man-Made Cellulosic Fibers - Esters
Man-Made Synthetic Fibers - Nylon
Man-Made Synthetic Fibers - Polyester
Man-Made Synthetic Fibers - Olefins
Man-Made Synthetic Fibers - Elastomers
Man-Made Synthetic Fibers - Mineral Fibers
Man Made Fibers - Other Textile Fibers
Fiber Blends
From Fiber To Yarn: Overview - Part I
From Fiber to Yarn: Overview - Part II
Melt-Spun Fibers
Characteristics of Filament Yarn
Yarn Classification
Direct Spun Yarns
Textured Filament Yarns
Fabric Construction - Felt
Fabric Construction - Nonwoven Fabrics
A Fashion Data Base
Fiber Construction - Leather
Fabric Construction - Films
Glossary of Colors, Dyes, Inks, Pigments and Resins
Fabric Construction – Foams and Poromeric Material
Knitting
Hosiery
Glossary of Fabrics, Fibers, Finishes, Garments and Yarns
Weaving and the Loom
Similarities and Differences in Woven Fabrics
The Three Basic Weaves - Plain Weave (Part I)
The Three Basic Weaves - Plain Weave (Part II)
The Three Basic Weaves - Twill Weave
The Three Basic Weaves - Satin Weave
Figured Weaves - Leno Weave
Figured Weaves – Piqué Weave
Figured Fabrics
Glossary of Art, Artists, Art Motifs and Art Movements
Crêpe Fabrics
Crêpe Effect Fabrics

The Glossary of Terms, Timelines of Fabrics, Dyes and Other Stuff, A Fashion Data Base, Glossary of Colors, Dyes, Inks, Pigments and Resins, Glossary of Fabrics, Fibers, Finishes, Garments and Yarns and Glossary of Art, Artists, Art Motifs and Art Movements have been updated in order to better inform your art practice.

If you find any post on this blog site useful, you can save it or copy and paste it into your own "Word" document etc. for your future reference. For example, Safari allows you to save a post (e.g. click on "File", click on "Print" and release, click on "PDF" and then click on "Save As" and release - and a PDF should appear where you have stored it). Safari also allows you to mail a post to a friend (click on "File", and then point cursor to "Mail Contents On This Page" and release). Either way, this or other posts on this site may be a useful Art Resource for you.

The Art Resource series will be the first post in each calendar month. Remember - these Art Resource posts span information that will be useful for a home hobbyist to that required by a final year University Fine-Art student and so undoubtedly, some parts of any Art Resource post may appear far too technical for your needs (skip over those mind boggling parts) and in other parts, it may be too simplistic with respect to your level of knowledge (ditto the skip). The trade-off between these two extremes will mean that Art Resource posts will hopefully be useful in parts to most, but unfortunately may not be satisfying to all!


Introduction
The first acrylic finer, trade-name Orlon, was developed by Du Pont in 1950. Since then others have been produced by different companies: Orlon, Acrilan, Creslan and Zefran are trade names of acrylic fibers.

The term "acrylic" is derived from the Latin word aryl, which means bitter, irritating or pungent and is descriptive of the properties of acrylic acid. Acrylonitrile is chemically related to acrylic acid and the term “acrylic” is a layperson's shortened version of polyacrylonitrile.

Early acrylic fibers were difficult to dye and so often appeared in pastel colors or blended with other fibers that were more easily dyed. Today acrylics come in most colors.

This post will focus on acrylics and modacrylics.


General Overview of Acrylics and Modacrylics
Acrylic fibers are man-made, synthetic polymer based on polyacrylonitrile filaments or staple fibers. They are divided into two camps:
(i) Polyacrylonitrile fibers - generally referred to as the acrylic fibers.
(ii) Modified polyacrylonitrile fibers generally referred to modacrylic fibers. Verel and Dynel are trade names of two modacrylic fibers. These fibers are similar to acrylics but have been modified so that they possess special characteristics that make them suitable for long pile garments, as they look and feel like fur. Wigs, other than those composed from human hair, are made from Dynel.

By definition, acrylic fibers are composed of at least 85% by weight of acrylonitrile units, whereas the modacrylic fibers must be composed of at least 35% but more than 85% by weight of acrylonitrile units. The remaining percentage is made from other polymer(s), which makes the dyeing and printing of these fibers easier.

Acrylic Fibers.

The fiber density of both these fibers averages 1.16 g cm-3, which makes these fibers relatively lightweight, and so makes possible the production of bulky knitwear that is lighter in weight than wool equivalents.

Electron Micrograph Of Arcylic Fibers.

The acrylic fibers appear as regular, translucent, slightly wavy filaments or staple fibers. Hence, in general, acrylics are produced as delustered fibers. The reasons for texturizing, and also crimpling acrylic staple fibers are similar to those give to viscose rayon (see earlier post).

World Wide Production Of Acrylics in 2007.

The diameter of acrylic fibers ranges from about 15 to 25 microns, depending on the end-use requirements. The fiber length to breadth ratio is usually in excess of 2000:1. This ensures that even the shortest staple fibers will satisfactorily spin into yarn.

Manufacture of Acrylics.

The main component of the acrylic polymer is the acrylonitrile monomer.

Formation Of Acrylonitrile.
Note: The repeating units; the nitrile (CN) and methylene(CH2)groups.

Polyacrylonitrile or as its commonly known acrylic polymer is a linear polymer with a length of about 500 nm and a thickness ranging from 0.3 nm at the methylene (CH2) group to 0.53 nm at the nitrile (CN) group.

This fiber must be composed of 15% of other polymers, called comonomers (or copolymers). Two such copolymers are acrylic acid and sodium vinylbenzene sulfonate, both of which have anionic groups that attracts the cation of basic dyes.

By definition the modacrylics must contain at least 35%, but not more than 65% of a monomer, other than acrylonitrile. The copolymers for these fibers vary significantly depending on the types of dyes used. For basic dyes, the copolymers all possess anionic groups (see above paragraph). Nevertheless, the copolymers in modacrylics are changed in order that the modacrylics fibers can be dyed with azoic, direct, metal complex, sulfur, vat, chrome and reactive dyes.


Macro Polymer Structure
It is generally accepted due to the non-polar nature of the acrylic polymer system that van der Waals forces are the dominant force that holds the polymer system intact. Furthermore, for van der Waals force to be the main attractive force, excellent alignment or orientation of the long polymer chains are necessary. This indicates a crystalline polymer system, which has been estimated to be about 70 – 80% crystalline and 30 - 20% amorphous. This tends to make the acrylic polymer system very crystalline.

The acrylic fibers show a longitudinal instability when subjected to hot, wet conditions such as immersion in boiling water (conditions used for dyeing). It is believed that during fiber manufacture, the polymer system becomes highly ordered in the lateral direction (i.e. across the fiber width). It further appears that the polymer system does not assume any particular order along the longitudinal direction of the fiber. The difference between the order in the lateral and the disorder in the longitudinal directions permits overstretching during manufacture and so places the polymer system under stress, due to the polymers being forced to adopt unnatural configurations. The intra-polymer forces (i.e. forces within the polymer) are strained in these unnatural configurations and will, if circumstances permit, return the polymers to their natural or relaxed configurations. This relaxation occurs in the presence of wet heat (i.e. during dyeing in boiling water), whereby van der Waals forces of attraction (that is responsible for the polymer to polymer cohesion) are severed, which allows the intra-polymer forces to return the polymer system configurations to their natural state. This is consistent with the observation that the fibers contract in length but increase in bulk under wet heat conditions.

Acrylic fibers hot-stretched.
Note: During a hot wet process, the stretched fibers relax and shrink, pulling the other fibers into loops.


Physical Properties
Tenacity
The fair to strong tenacity of acrylic fibers is due to the crystalline nature of the polymer system because their polymers are extremely long. These two characteristics enable a very efficient and effective environment for van der Waals forces to hold the polymer system intact.

The loss of tenacity that occurs when acrylic fibers are wet is due to the few water molecules that enter the amorphous region of the polymer system, thereby severing van der Waals forces of attraction between the polymer units.

Elastic-Plastic Nature
Acrylics have a soft handle, even though they are crystalline in nature. This is because the polymer system is only weakly held together and so if the acrylic filament or fiber is being crushed or bent, this has sufficient energy to overcome the forces of attraction and so enable the polymers to slide over each other. This slippage is evident on the ease of wrinkling the textile material in response to bending, stretching and/or crushing. The weakness of the forces of attraction, within the polymer system, is exemplified by the low temperature that is required in order to iron out wrinkles and creases etc.

Hygroscopic Nature
Acrylic fibers are hydrophobic (water hating) because the polymer system is highly crystalline, and so because the crystalline regions have too small voids, water molecules are prevented to enter this region, thereby restricting their entry into only the amorphous regions (which by definition is comparatively small). Furthermore, the slight polarity of the of the nitrile groups in the acrylic polymer and the stronger polarity of the anionic groups as copolymers, is not as dominant as its crystalline properties.

The lack of water uptake of the acrylic polymer system results in the lack of dissipation of static electricity build up in dry atmospheric conditions.

Thermal Properties
Acrylics are the most heat sensitive of the commonly used synthetic fibers. The weaker forces of attraction, which are the cohesive force between polymers units, is primarily responsible for their heat sensitivity. Body heat in conjunction with the stresses and strains of day-to-day wear, can provide sufficient energy to reduce cohesive effectiveness of the van der Waals forces of attraction in the acrylic polymer system. This causes the ease of wrinkling and/or distortions of acrylic fabrics under such conditions.

When near a naked flame, acrylic fibers tend to ignite immediately with a smoky luminous flame, rather than melt and then burn - as do nylon and polyester fibers. Acrylic fibers are the most flammable fibers in common use.

The ease at which acrylics burn is not applicable to modacrylic fibers, which have been copolymerized with chlorine containing monomers. Modacrylics will not burn, but will melt, char and disintegrate. Generally, polymer systems that contain chlorine-carbon bonds yield a two fold effect: (i) the chlorine-carbon bond severing process requires heat to be absorbed, thereby lowering the temperature of the flame; (ii) the liberation of chlorine radicals captures other radicals in the flame and so renders these as non-combustible materials, starving the flame of its “feedstock”. Countering this effect is the severing of carbon-oxygen and carbon-hydrogen bonds, which provides heat and “feedstock” for the flame to intensify. In general, the former processes out weigh the latter, since there are more carbon-chlorine bonds than carbon-hydrogen and carbon–oxygen bonds in these fabrics. Hence, in chlorine containing modacrylics, such as Teklan, contact with a flame will not readily produce combustion.

Chlorine-containing modacrylics, however, are more sensitive than other modacrylics or acrylics, since they have weaker van der Waals forces holding their polymer system intact, and so will soften and distort, at lower temperatures than conventional acrylic fibers.


Chemical Properties
Effect Of Acids
The acrylic fibers are resistant to acids, because their polymer systems do not contain any chemical groups, which will attract or react with acidic ions. Hence they are used for clothing of people who work with common chemicals.

Effect Of Alkalis
The very crystalline nature of the acrylic polymer system provides too small gaps for entry of alkali substances. However, surface alkaline hydrolysis (or surface saponification) will occur. Thus any nitrile group (CN) and/or anionic or basic group on the surface of the fiber will react with sodium or the cation of the alkali. It should be noted that the anionic or basic groups were introduced via the copolymerization process, while sodium is a major constituent of such common alkalis as soap, laundry detergent powder or liquids, washing soda etc. This fiber saponification is gradual; it will eventually lead to surface discoloration, yellowing, and/or dulling of the acrylic textile.

Effect of Bleaches
Bleaches in general have the same effect on acetate fibers as they do on cotton fibers (see earlier post).

Effect of Sunlight and Weather
Acrylic fibers are the most sunlight and weather-resistant fibers in common use. Hence they are used for awnings. Their resistance to atmosphere, which is slightly acidic, is due to their innate resistance to acids in general.

Acrylic textiles, when subjected to sunlight, will initially suffer a small loss of tenacity, which then levels off. The levelling off is due to a slight internal polymer arrangement that causes particular sections of the polymer system to form stable ring structures, which is fuelled energy-wise, by the continual exposure to sunlight. This enables the polymer system to resist the influence of UV light and other degrading agents.

Color-Fastness
The acrylic and modacrylic fibers are mostly dyed and printed with basic and disperse dyes. Hence, their color-fastness will be discussed below.

Basic Dyes
When dyes were originally developed for acrylic fibers, they were referred to as “modified” basic dyes. Since the original basic dyes that were used on cellulose fibers were no longer in use, these altered basic dyes have had the descriptor “modified” dropped and so they were labeled as the “basic dyes”.

Basic dyes are also known as cationic dyes, since the colored portion of the basic dye is cationic or the positively charged part of the dye molecule. The cationic (or basic) radical is attracted to the anionic (or acidic) radical on the acrylic or modacrylic copolymers.

The very good wash-fastness of basic dyed and/or printed acrylic textile materials is due to the hydrophobic and very crystalline nature of the acrylic polymer system. These properties minimize the entry of water molecules into the amorphous regions, which are water hating, and by far the largest region. The voids in this region are too small for entry of water molecules, and so there is little opportunity for water up-take in both the crystalline and amorphous region of the acrylic polymer system. Hence there is little tendency for the dye molecule to be rinsed from the fabric.

Basic dyed and/or printed acrylic textile have also very good light-fastness. The crystalline structure produces very efficient and effective van der Waals forces, which hold the polymer system intact. The chromophores in the basic dye molecule resist degradation from UV light.

Basic Dyed Acrylics.

Disperse Dyes
Acrylic fibers, which are hydrophobic, are readily dyed with non-ionic disperse dyes. The fair to good light-fastness of disperse dyed and/or printed acrylic textile materials is attributed to the dyed molecule’s non-ionic nature, which tends to indicate that its chromophores are resistant to UV light. Nevertheless, prolonged exposure to UV light will adversely affect coloration.

Disperse dyed and/or printed acrylic textile materials have good wash-fastness for the same reasons attributed to basic dyes


References:
[1] A Fritz and J. Cant, Consumer Textiles, Oxford University Press, Melbourne (1986).

[2] E.P.G. Gohl and L.D. Vilensky, Textile Science, Longman Cheshire, Melbourne (1989).