The development of thermal insulation materials from the beginnings to the appearance of plastic foams

Abstract

The history of thermal insulation materials is not as long as that of other materials but the necessity of insulation is as old as the building activity. Prehistoric human beings built shelters to protect themselves from the elements. Originally they used organic materials for insulation and later durable ones. Earth-sheltered houses and cave dwellings were also popular because of their benefits (thermal lag of earth covering). However people used not only materials that were found in the nature, but discovered others which were suitable for insulating. Processing organic materials, people produced the first insulated plates of cork, reed, flax, and eelgrass in the 19th century. Meanwhile lots of synthetic materials were invented (slag wool, rock wool, fiberglass, foam glass). In addition insulated bricklaying elements (hollow bricks, AAC) were developed too. Expanded perlite and clay have also been used since the 1930s as loose insulation or aggregate in lightweight concrete. The appearance of plastic foams caused huge revolution. Plastic production was well-known in the 19th century but the first plastic foam was made of XPS in 1941. Nowadays the most popular insulation materials are plastic foams and mineral wool. Only a small amount of natural materials are built in. Their growth is substantial because of many reasons.

Full text

XXXVII IAHS
World Congress on Housing
October 26 – 29, 2010, Santander, Spain
The development of thermal insulation materials from the
beginnings to the appearance of plastic foams
David BOZSAKY
Department of Architecture and Building Construction
Szechenyi Istvan University, Faculty of Engineering Sciences, GYOR, Hungary
H-9026 GYOR, Egyetem ter 1. (D504), Tel.: +36(96)-503-454, Fax: +36(96)-613-595
e-mail: bozsaky@gmail.com
Key words: thermal insulation, building material, plastic foam, development
Abstract
The history of thermal insulation materials is not as long as that of other materials but the necessity of
insulation is as old as the building activity.
Prehistoric human beings built shelters to protect themselves from the elements. Originally they used
organic materials for insulation and later durable ones. Earth-sheltered houses and cave dwellings were
also popular because of their benefits (thermal lag of earth covering).
However people used not only materials that were found in the nature, but discovered others which
were suitable for insulating. Processing organic materials, people produced the first insulated plates of
cork, reed, flax, and eelgrass in the 19th century.
Meanwhile lots of synthetic materials were invented (slag wool, rock wool, fiberglass, foam glass). In
addition insulated bricklaying elements (hollow bricks, AAC) were developed too. Expanded perlite
and clay have also been used since the 1930s as loose insulation or aggregate in lightweight concrete.
The appearance of plastic foams caused huge revolution. Plastic production was well-known in the
19th century but the first plastic foam was made of XPS in 1941.
Nowadays the most popular insulation materials are plastic foams and mineral wool. Only a small
amount of natural materials are built in. Their growth is substantial because of many reasons.
1 Introduction
The history of thermal insulation is not as long as that of other building constructions. Long ago
thermal insulation did not form a separated layer in the building construction because there was no
need to build in extra materials to assure the insulating function.
The process of building activity appeared when prehistoric human beings first created shelters
themselves. The root cause of this activity was the protection against some effects, or in another way

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain)
the insulation from the surroundings. So from the beginnings buildings had to defend the resident from
the cold of the winter and the heat of the summer, consequently from the elements.
Accordingly we can reveal that one of the most important requirements about building constructions is
the necessity of adequate thermal insulation which is as old as building activity and has existed since
the ancient times.
2 The beginnings of the history
Prehistoric people built temporary dwellings from materials that they used for clothing. The most
sufficient materials were animal skins, fur, wool and vegetable matters (reed, flax, straw) but their
lifetime was not very long. Later because of the settled lifestyle and the development of agriculture
they needed durable materials for housing, like stone, wood and earth.
Both earth-sheltered houses and cave dwellings were built at the same time and they were very popular
because of their benefits. Their implementation was cheap and earth covering assured excellent
protection against wild animals and fire. Accordingly they were hard to burn down during wartime. In
addition earth houses use soil as a magnificent insulating blanket. Because of the high density of earth
the inside temperature changes very slowly. This phenomena is called thermal lag and that is why
earth covering keeps the interior warm in winter and cool in the summer.
The houses in the Neolithic village of Skara Brae (Orkney Island, Scotland) are known as the oldest –
nearly 5000 years old – earth-sheltered, green roofed dwellings in the world but we can come across
similar buildings in cold climate areas like Scandinavia, Iceland, Russia, Greenland and Alaska.
3 Natural materials
Vegetable fibres were wide-spread long ago. Native inhabitants of tropical areas built their lodges
from dried eelgrass or reed. In cold climates reed and long-stemmed wheat straw was particularly used
for thatching roofs. In the 12th and 13th centuries the ancient north Europeans built thatched houses
with 60-80cm thick straw roof construction and walls were often built of clay and straw. The dry,
hollow fibre of straw and reed provided excellent degree of thermal resistance, so thatched houses
quickly spread especially in the northern parts of Europe and America. [3]
Processing these materials people produced the first insulated panels in the late 19th century. They
were cheap but at the same time they had several disadvantages. The main problem was their good
hygroscopic ability and this is why they needed extra damp-course.
Reed panels were also used in the 19th century as thermal insulation mainly in ancillary buildings.
They were popular because they were disinclined to rot and they had bad hygroscopic ability. At the
beginning of the 20th century reed plates appeared with bituminous coating. [4]
In 1920 the American Celotex Company introduced insulating plates made of bagasse. Owing to their
flammability they were not secure therefore later one or both of their sides were coated with asbestos
cement. The first attempts to produce insulating panels from flax were made in the USA and
eventually in the 1910s the first products (Flaxlinium, Fibroleft) were put on the market. [3]
Indigenous people in the region of the Caribbean Sea built their huts from dried eelgrass (Zostera
marina) which had as good insulating abilities as reed or straw. Resuscitating this technology in 1893
the American industrialist, Samuel Cabot (1850-1906) developed a new insulating panel called Cabot-
Quilt. This product consisted of dried eelgrass which was sandwiched between two layers of paper.
Because of its popularity Cabot-Quilt stayed on the market until the 1940s. [3]
Cork was firstly applied as insulation in the Mediterraneum. The ancient Romans used it in shoes to
keep their feet warm, but as we know it from Caius Plinius Secundus the Elder (23 AD – 79 AD), the
Romans used it for insulating roofs. Inhabitants of the Iberian Peninsula made wall insulations from

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain
cork. In the Middle Ages monks in Spain and Portugal sheathed the inner side of the walls in their
monasteries with cork. Some native tribes in North Africa used a special mixture of clay and cork bark
to construct the walls of their dwellings. [3]
Cork had been a well-known insulating material since the ancient times so the first insulating panels
were made of cork too in the 1870s. People used them for sheathing the inner side of facade walls.
Nevertheless, they had serious problems. Under the plates condensation arose, which caused
unpleasant atmosphere. Moreover, various kinds of parasites (fungus, insects) settled down inside. In
the 1880s some products appeared which were made from pulped cork, lime, clay and water. [4]
For thousands of years straw have been in use but the real straw bale construction was born when the
first machine-manufactured modular bales were created. The first buildings of straw bale were built in
1904 in Nebraska (USA). Housing was an urgent necessity and among the sand hills the only available
building material was the straw bale. To make familiar surroundings in their straw bale huts people
plastered the inside and outside walls. These houses existed for decades and straw bale construction –
because of its ecological advantages – is very popular nowadays as well. [3]
Straw is an agricultural waste product and, in addition, it is plentiful and cheap. This is why several
attempts were made to manufacture structural insulated panels of compressed straw. This technology
was patented by Theodor Dieden in Sweden in 1935. The method developed and in the late 1940s
Torsten Mossesson started the production of compressed agricultural fibre under the name of Stramit.
Since then this product has spread all around the world as core insulation in frame structures. [6]
In the early 20th century wood shavings and sawdust were very popular insulation products because
their costs were very low and the raw material was easily available. These materials were often mixed
up with some chemicals to increase their resistance to water absorption, fire and mouldiness. [6]
The history of wood wool insulations dates back to 1842 when Herr von Pannewich in Breslau (today
Wrocław, Poland) produced counterpanes by processing the needle of pine.
As the first slivering machines were put in operation in the USA in 1876 the mass production of wood
wool was possible. Because of its good hygroscopic ability towels and diapers were made of it.
Only in the early 20th century came the idea to make insulation plates of it. The first insulation panel of
wood wool was made in 1908 by Heraklith Company in Ferndorf (Austria) using magnesite and
cement as adhesive. For the 1930s this product spread worldwide. [6]
Cellulose basis thermal insulations appeared in the 1920s in Scandinavia and they were prepared
from forestry by-products. Originally they were employed as core insulation in traditional half-
timbered houses and sometimes as insulation of attic spaces. Today the environmentally friendly loose
cellulose insulation is applied in a widely because of its rapid accomplishment. [6]
Materials of animal origins are the most ancient thermal insulation materials. Prehistoric human
beings made their warm clothes and shoes from animal skins, fur and wool to protect themselves
against the cold winter. These materials were suitable for insulating their dwellings, huts and tents but
in the second half of the 20th century several types of insulating blankets made of sheep wool appeared
on the market. They are also applied nowadays because of their ecological and economical benefits.
Dried manure had acceptable insulation properties and it was widely used by elementary architecture.
Even to the present day we can come across it in some underdeveloped territories. [6]
4 Synthetic materials
4.1 Mineral wool products
Natural asbestos is a fibrous mineral and its beneficial properties (fire resistance, high tensile strength)
were already identified in the ancient times. Archaeologists found 3000-year-old log homes in Finland,
in which asbestos was used for chinking. The ancient Egyptians also applied asbestos to strengthen

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain)
their clothes, but only the ancient Greeks used it intensively. After they had realized its security
against fire, they named this material “asbestos”, which means inextinguishable. To take advantage of
its flame-resistance asbestos was used in spaces that were exposed to intensive heat.
The ancient Romans also used asbestos and fabricated clothes, towels, tablecloths and napkins.
Because of their flame-resistance they were easy to clean by throwing them into the fire, where
pollution was burnt out.
Asbestos became a popular insulating material during the industrial revolution. The manufacturing
industry used it for insulating pipes, steam engines, boilers, chimneys, and other high-temperature
machines. Later it broke into the vehicle industry (brakes, clutches) and the manufacture of household
devices (refrigerator, iron, hairdryer). Lots of insulating and packing materials also contained asbestos.
Already in the 1st century the Greek geographer, Strabo (64 BC – 23 AD), diagnosed that those people,
who were wearing clothes containing asbestos fibre often suffered from lung sickness. Plinius also
noted down that slaves who worked in asbestos mines often died of respiration disorders.
Unfortunately the harmful effects of asbestos were forgotten until the beginning of the 20th century. In
1897 an Austrian doctor documented the first ailment by reason of asbestos. The first proved case of
asbestos-related death occurred in 1906. As the dangers of asbestos turned out the use of asbestos
became forbidden in several countries of the world. [3]
Natural mineral wool could de formed from effusive rocks when the escaping steam breaks the
molten lava into fluffy fibre. Native inhabitants living near volcanoes (Hawaiian Islands) could use
this material to blanket their huts. [3]
The first commercially produced mineral wool insulation was invented in Wales by Edward Perry in
1840. He insulated pipes and machines to reduce their heat loss and the risk of accidents, but the
production was abandoned because of its harmful effects on workers.
The first manufacturing of slag wool began in 1885 in Manchester (United Kingdom). Rock wool was
first prepared from limestone by the American chemical engineer, Charles Corydon Hall in 1897. He
started the commercial production of rock wool in Alexandria (Indiana, USA) in his factory called
Chrystal Chemical Works. [3] [6]
The row material of rock wool (limestone, basalt) is melted in a gas-heated smelting furnace at a
temperature of 1500-1600°C through which stream or air is blown. Then with a help of high speed
spinning wheels fine and intertwined fibres are generated with a diameter of 6-10µm. During this
action some binder material (phenol-formaldehyde resin, oil emulsion) is added.
The ancient Egyptians and Venetian glassware makers already discovered that they could make
threads from hot glass with which they decorated their vessels but the mass production of fibreglass
was made possible by the invention of fine set machines. In 1893 Edward Drummond Libbey (1854-
1925) experimented with glass fibres with the diameter as fine as the silk fibres but the first fibreglass
which was suitable for insulation was invented in 1938 by Russel Games Slayter (1896-1964), a
researcher of the Owens-Corning Company. [3] [6]
Fibreglass contains quartz sand, limestone, dolomite and 50-60% recycled glass which is melted at a
temperature of 1400-1500°C. The molten glass is jetted through tiny heated holes into high-speed air
streams. The result of this procedure is very thin and long fibres. Their surface is filmed with binder
materials (phenol-formaldehyde resin) to form insulating blankets.
4.2 Foam glass [6] [8]
In the 1930s there were three similar patents to produce foam glass and it is hard to consider the first.
The American Albert L. Kern patented a method in 1931 using silica with 20% combustible material
(lignite, coal, wood) and foaming agents (hydrochloric acid, sodium hydroxide solution). He heated
this mixture to 1500°C which resulted in a porous product. The laboratory engineer of the Mendeleev
Institute of Moscow, I. I. Kitaigorodsky developed another method to create foamed glass in 1932. He

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain
took a mixture of finely powdered glass and calcium-carbonate (CaCO3) as a foaming agent and
heated it up to 850°C and cooled it down in steel moulds.
Another sort of process was developed in 1934 using a mixture of finely powdered silica, borax and
zinc oxide. Heating it up the entrapped gases evolved leaving back a multitude of bubbles with cellular
body. This technology was further developed by William O. Lytle, who was a laboratory technician of
Pittsburgh Plate Glass & Corning Glass Works (Pennsylvania, USA). In 1940 he patented a procedure
using additional foaming agents (air, water vapour) to create extra pores. From that time there was a
possibility for mass production and it started up in 1943 in Port Allegany (Pennsylvania, USA).
4.3 Brick elements
In the 1870s and 1880s there were projects to lighten the weight and to upgrade the thermal insulation
ability of ceramic brick elements. The first attempt was Bischweiler’s brick. This ceramic element
consisted of two parts, a hollow ash-filled lower and a solid upper one. Unfortunately the insulating
power of it was not as strong as expected, moreover it had wrong mechanical strength. [4]
The first not really successful tasks inspired the manufacturers to make innovations so came up at the
very begging of the 20th century the first hollow bricks elements came up. The first products were
also not very heartening – bad mechanical strength, bad insulating power – but the quality of them
progressively got better and they are produced in huge quantities nowadays. [4]
At the same time porous bricks were also manufactured; they were baked together with coal-dust or
tuff. These additives having burnt out in the fire leave small pores in the bricks resulting in
homogeneity and better mechanical quality, too. This technology uses sawdust or plastic granulate
today. At the beginning of the 20th century there were hollow bricks filled with diatomaceous earth.
In 1918 the Swedish architect, Johan Axel Eriksson (1888-1961), working together with Henrik
Kreüger (1882-1953) started a research in Royal Institute of Technology to get a new rot-, mould- and
fire-proof building material and finally in 1923 they patented a method for creating aerated
autoclaved concrete joint blocks made from lime, metal powder and crumbled oil shale. In 1929 Karl
August Carlén (1876-1960) the owner of the Yxhults Stenhuggeri AB (today Ytong AG) started the
production of this new material under the name Ytong (Yxhult Angherdede Lättbetong). [6]
Today the technology needs crumbled calcined lime, gypsum and quartz sand, scale, water and
aluminium powder as gas-forming agent. Lime reacts with the water, creating slaked lime (Ca(OH)2).
The aluminium powder reacts with calcium hydroxide and with water and form hydrogen that foams
the mixture creating pores inside with a diameter of 2mm.
After this procedure the blocks are placed into an autoclave chamber (10-12 hours, 8-12 bars, 170-
190°C) to create solid blocks. Since then lots of other technologies have been developed to prepare
porous, lightweight concrete joint blocks and they are worldwide manufactured nowadays.
4.4 Loose insulations
Dross was used first as insulation of flat roofs and other ferroconcrete slab structures at the end of the
19th century. Because of its low price it was very attractive. However its worst disadvantage was the
extraordinarily heavy curb weight that was enlarged by the condensed water vapour accumulated in
the structure owing to the good hygroscopic ability of dross. From the 1930s dross was allowed to be
used only with the assurance of water vapour ventilation. [4]
Perlite is actually a sort of natural volcanic glass (riolite) with relatively high water content and it had
had various names until the official name “perlie” was given to it in 1822.
There were experiments in 1929 in Japan about perlite but the real breakthrough came in the 1930s
when the expanded perlite was invented in 1938. L. Lee Boyer in his assay office in Superior
(Arizona) wanted to fuse a mixture of silicates to create a new insulation material. One day he strewed
a sack of crumbled perlite into his furnace that was heated up to 850-900°C and saw that suddenly the

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain)
grains of perlite began to pop. Boyer examined the final product curiously and made a discovery.
When this material is heated the surface of the grains softens and in the pores the sealed water changes
into stream that causes a 7-16-fold increase of perlite.[1]
The cellular structure of the expanded perlite results in resistance to the conduction of heat. Moreover
it is fireproof and extremely lightweight so by the 1950s it spread worldwide. It could be used as loose
insulation in slab structures and also as aggregate in mortars and lightweight concrete.
The technology of manufacturing expanded clay was invented in 1917 by the owner of the brick
factory, Stephen John Hayde in Kansas City (Missouri). Burning out the bricks he noticed abnormal
expansion of some bricks made of a certain raw material. This observation gave him the idea for
making expanded clay and in 1918 he patented his process.
Hayde used crumbled shale that was heated up to 1000-1200°C in a rotary kiln. Because of the high
temperature the surface of the grains softens and the sealed organic peaces are burnt. The arising gases
cause a 4-5-fold increase of the grains leaving pores inside that give valuable thermal insulating power
to this product. These grains with the diameter of 4mm are used generally as an aggregate in
lightweight concrete. [1]
From the 1920s the technology of expanded clay spread in the USA but it came to Europe only in the
1940s in spite of the invention of the Danish Oskar Olsen who patented a similar technology in 1919.[1]
5 Plastic foams [2]
The appearance of plastic foams caused huge revolution on the market of insulation materials in the
1940s and 1950s. The most popular materials are polystyrene and polyurethane foams.
There are three methods for producing plastics today (polymerization, polycondensation and
polyaddition) from which the first two were well known in the 19th century. Polymerisation in natural
circumstances was first observed in 1838 by Henri Victor Regnault (1810-1878). He experimentally
produced vinyl-chloride gas and when he left it exposed to intensive sunlight Regnault noticed that it
changed into a white powder inside a vessel forming polyvinyl-chloride.
The first human-made polymerization – supposedly by accident – was presented by the American
chemist Charles Nelson Goodyear (1800-1860). In 1839 he tried to vulcanize rubber gum in a hot
stove and discovered that it changed into a durable and flexible material.
Another technology for producing plastics – the polycondensation – was invented by Johann Friedrich
Wilhelm Adolf von Baeyer (1835-1917). In 1871 he prepared phenolphthalein (C20H14O4) with the
condensation of phthalic anhydride (C8H4O3 ) and phenol (C6H5OH) under acidic conditions. [2]
5.1 Polystyrene foam [2] [5] [6] [7]
Polystyrene was known long before but it was not in use until the 20th century. Its original monomer
was the natural styrene that was named after a genus of tropical and Mediterranean trees called Styrax.
These plants generate a special resin (storax) that was used as a fumigant and medicine long ago.
In 1839 Eduard Simon distilled an oily, colourless, fragrant and refractive substance from storax and
named it styrene. A few days later Simon observed that this material had changed into a thick, jelly
mass. He presumed that it happened from oxidation so he named this compound styrene-oxide.
Nevertheless in 1845 John Blyth (1815-1892) and August Wilhelm von Hoffmann (1818-1892)
showed that this reaction could also take place in the absence of oxygen and they called this substance
metastyrene. The later experiments demonstrated the chemical correspondence of it with styrene-oxide
and in 1866 Marcellin Pierre Eugène Berthelot (1827-1907) identified the formation of metastyrene
from styrene as a polymerization process. In 1922 the German organic chemist Hermann Staudinger
(1881-1965) realized that heating styrene up to a high temperature actuates a chain reaction that
produces macromolecules.

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain
The monomer of polystyrene could be commercially manufactured from petroleum which is a mixture
of around 500 various substances. The industrial oil extraction started in the 1850s but the first plastic
made of petroleum – the Bakelite – was created only in 1907 by Leo Hendrik Baekeland (1863-1944).
Therefore it is no wonder that we had to wait for the invention of synthetic polystyrene until the 20th
century even though the natural styrene was actually known in the ancient times. In 1929 in
Ludwigshafen (Germany) the researcher of the IG Farbenindustrie AG (today Badishe Anilin und
Sodafabrik) Hermann Franz Mark (1895-1992) produced synthetic styrene with catalytic
dehydrogenation of ethyl-benzene in a temperature of 500-600°C. In 1930 two scientists of this
company, Karl Wulff and Eugen Dörrer, carried out a successful polymerisation with styrene creating
polystyrene. Thereafter the industrial production of polystyrene began and the utilization of it as
plastic foam raised soon.
The theory of creating polystyrene foam was born in 1931 in the USA. The Swedish inventor Carl
Georg Munters (1897-1989) cooperating with John Tandberg (1896-1968) patented the method of
foaming polystyrene. Applying their technology the first polystyrene foam was produced in 1941 by
Otis Ray McIntire (1918-1996), the engineer of Dow Chemical Company. He heated the milk-white
polystyrene granulate up to 200°C in an extruder using chlorinated hydrocarbon (chloromethane) as a
foaming agent. He led the polystyrene foam through a narrow aperture which resulted in polystyrene
plates with 98% closed cellular structure. The first polystyrene insulating product was put on the
market by the company in 1943 under the name of Styrofoam®.
Another technology for producing foamed polystyrene – the expanded one – was invented in Europe
by the engineers of the IG Farbenindustrie AG (today BASF) in 1950. Using pentane as a foaming
agent the polystyrene granulate is supplied with water vapour. As the temperature is rising the grains
of the raw material grow soft and the pentane 20-50-fold increase of the pearls. During this action
plenty of small closed cells arise inside. Owing to them the expanded polystyrene foam has excellent
thermal insulating power so it is evident to use it in building insulation.
To create a useable and saleable product the technology of making blocks was needed. Researchers
noticed that after the foaming procedure the surface of the cooled polystyrene pearls becomes solid,
the foaming agent contracts so the air can infiltrate into the cells. When the blocks are rested for a few
days during the steaming added water vapour evaporates. If these pearls are steamed again in a closed
mould they form a regular block without a binding material. The first product made with the help of
this technology was put on the market in 1951 under the name of Styropor®.
5.2 Polyurethane foam [5] [6]
To manufacture polyurethane foam firstly the invention of the third method of producing plastics was
necessary. Polyaddition was invented accidentally in the United Kingdom in 1933 by laboratory
engineers of the Imperial Chemical Industries (ICI), Reginald Gibson and Eric Fawcett.
They researched the chemical reactions of various organic compounds at high temperature and under
high pressure. One day they reacted ethylene (C2H4) with benzaldehyde (C6H5CHO) in expectation of
creating a new kind of ketone. They left the reactor vessel switched on all night long and in the
morning they found a small amount of a white waxy solid that is known as polyethylene today.
Applying their technology in 1937 Otto Bayer (1902-1982) in Leverkusen (Germany) prepared
polyurethane in the research laboratory of IG Farbenindustrie AG (today Bayer AG) with a reaction of
glycol and polyisocyanate. During World War II polyurethane foam was applied as aircraft coating but
the final breakthrough came in the 1950s when the commercial production of polyisocyanates was
available. The first commercial insulating panel made of polyurethane foam was produced in 1954. In
those days these panels were badly workable and they were disposed to deflections but the
development of the mounted polyurethane panels has made it possible to use them as a common
building insulation material today.

XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain)
6 Epilogue
We can not imagine our buildings without thermal insulation nowadays. The global warming, climate
change, environmental pollution and high energy prices make us to use them in huge numbers.
If we take a look at the reports about the market of thermal insulation materials we can consider that
the most popular material is mineral wool with about 50-55% of the total production. According to the
available information it can be also detected that plastic foams represent around 40%. Because of this
significant amount we can consider that the appearance of plastic foams has caused a radical change
on the market.
It is also distinct that only a small amount (about 5%) of organic materials (straw bale, cork, sheep
wool) is built in. Their growth would be substantial because of many reasons (sustainable
development, environmental pollution) but it is not easy to realize. They spread very slowly in spite of
the intensive propagation because people are wary of these materials. They have several disadvantages
in relation to synthetic materials (flammability, low durability, often wrong dimension stability, hazard
of rodents, insects) and their advantages (environmentally friendly, economical, inexpensive) are often
relegated to the background.
Reference
[1] Ballenger, C. and Dunlop, R.: That wonderful volcanic popcorn. Popular Mechanics Magazine
Vol. 102/6 (1954) pp.136-139.
[2] BASF AG: 75 Jahre Polystyrol: Ein seltsames Öl und eine kreative Explosion. Plastics Vol. 7/2
(2005) pp. 2-8.
[3] Bynum, R. T.: Insulation Handbook. The McGraw-Hill Companies, New York (USA), 2001
[4] Dery, A.: Torteneti anyagtan. Terc Kft, Budapest (H), 2000, pp. 167-172.
[5] Fisher, I. and Krauser, J. and Kleinrath T.: Die Geschichte der EPC Platte - Austrotherm EPS®
vom Mikroorganismus zum umweltfreundlichen Dämmstoff. Austrotherm GmbH, Pinkafeld, 2007
[6] Plundstein, M.: Dämmstoffarten. Detail Praxis – Dämmstoffe (Grundlagen, Materialen,
Anwendungen), Institut für internationale Architektur-Dokumentation GmbH & Co. KG, München
(D), 2007, pp. 17-57.
[7] Pontiff, T.: Foam Agents for Foam Extrusion. Foam Extrusion Chapter 10, CRC Press LLC, Boca
Raton (Florida, USA), 2000, pp. 251-254
[8] Scheffler, M. and Colombo, P.: Cellular Ceramics: Structure, Manufacturing, Properties and
Applications. Wiley-WCH Verlag GmbH & Co.KGaA, Weinheim (D), 2003, pp. 158-160.