STUDY OF THE SUPERFICIAL COHESION AND CHROMATIC

CHANGES OF MARBLES TRATED WITH POLYMERS AND EXPOSED

TO ARTIFICIAL AGEING

Mara CAMAITI,

Halit CANOL,

CNR–ICVBC, Sesto Fiorentino(Italy),

e-mail: m.camaiti@icvbc.cnr.it

Course of Second Cycle Degree “Science for Conservation-Restoration of Cultural Heritage, University of Bologna (Italy),

e-mail: halitcanol@yahoo.com

2nd International Congress Chemistry for Cultural Heritage

• The selection of the types and evaluation of the efficacy and durability of conservative treatments

• Samples of marble of the quarry of Kozağaçand Lorano Quarry (Carrara Marble) were used to perform tests of treatment with polymers

Aims of the Research

2° International Congress Chemistry for Cultural Heritage

TREATMENT BY POLYMERS TESTS

Evaluation of durability Uv CC (Climatic Chamber)

Evaluation of Treatments- Water Capillary Absorption Tests- Color Determination Test

Yatağan Quarry(Mugla)Lorano Quarry

Application Of PolymersFLUOROELASTOMERSPoly (Hexafluoroprene-co-Vinylidene Fluoride)

N-215 (Low wt)N-935(Medium wt)NH (High wt)

ACRYLIC RESINSPoly (isobutyl methacrylate) -PB 67Poly (ethyl methacrylate-co-methyl acrylate) 30/70- PB72Rabbit glue

2° International Congress Chemistry for Cultural Heritage

Application of Polymers

Polymers Amount (g/cm2) Protective efficacy (%PE)

N935 6.8 23

PB72 5.8 72

NH 6.2 54

Rabbit glue (RG) 2.1 8

N215 3.0 23

PB67 6.8 88

Lorano (Carrara) Marbles

Mugla MarblesPolymers Amount (g/cm2) Protective efficacy (%PE)

N215 5.2 38

PB72 7.2 64

Rabbit glue (RG) 3.7 11

All polymers have applied by brush on all the six faces of the cubic samples. The treatment was carried out wet on wet until saturation has reached.

2° International

Congress

Chemistry for

Cultural Heritage

Thermo

Hygrometric

Ageing

The relative humidity was

maintained at 60% in

Evaluation of Durability

0

4 4

25 25

40 40

25 25

4 4

25 25

40 40

25 25

0

5

10

15

20

25

30

35

40

0 2 2 3 3 5 5 6 6 8 8 10 10 12 12 24TEMP

T (°C

1° Ageing Cycle

20

40 40

10 10

25 25

45 45

25 25

10 10

40

0

5

10

15

20

25

30

35

40

45

50

0 20 100 130 190 205 265 285 345 365 425 485 545 605TEMP

2° Ageing Cycle

The relative humidity was

maintained at 75% in

T(C)

Time (Hour)

Time (min)

2° International Congress

Chemistry for Cultural

Heritage

Evaluation of Durability

Uv Ageing

0

50

100

150

200

250

300

0 200 400 600 800 1000 1200

Wavelight(Nm)

Time (Hours)

2° International

Congress Chemistry

for Cultural Heritage

Water capillary absorption test

PE% = (Ao- A1) / Ao * 100 Where Ao, A1 are the mass of water absorbed

before and after the treatment.

Color determinations

ΔE* = [(ΔL*2+ Δa*2 + Δb*2)] 1/2

Where ΔE, ΔL, Δa, Δb are parameters of colour shifts and expressed in three variables, namely, ΔL (+ =

lighter, – = darker), Δa (+ =shift to red; – = greener), Δb (+ = yellower; – = bluer). The magnitude of the color

change is given by ΔE.

Evaluation of Treatments

Water capillary absorption test

2°

International

Congress

Chemistry

for Cultural

Heritage

-40

-20

0

20

40

60

80

100

N215 N935 NH PB72 PB67 NT

PE%

Treatment

after treatment

1st ageing

2nd ageing

Results of PE % in Lab.Conditions for two marbles

-10

0

10

20

30

40

50

60

70

80

N215PB72

NT

PE%

Treatment

after treatment

1st ageing

2nd ageing

Lorano marble

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

-40

-20

0

20

40

60

80

100

N215 N935 NH PB72 PB67 NT

PE%

Treatment

after treatment

1st ageing

2nd ageing

Lorano marble

-40

-30

-20

-10

0

10

20

30

40

50

60

70

N215 PB72 NT

PE%

Treatment

after treatment

1st ageing

2nd ageing

Muğla marble

Results of PE % after ageing in CC (Climatic cham.) for two marbles

2° International

Congress

Chemistry for

Cultural Heritage

-40

-20

0

20

40

60

80

100

N215 N935 NH PB72 PB67 NT

PE%

Treatment

after treatment

1st ageing

2nd ageing

-20

-10

0

10

20

30

40

50

60

70

80

90

N215PB72

NT

%PE

Treatment

after treatment

1st ageing

2nd ageing

Results of PE % after ageing under UV irradiation for two marbles

Lorano marble

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

0

0.5

1

1.5

2

RGN215

N935NH

PB72PB67

NT

ΔE

Treatment

0

0.5

1

1.5

2

2.5

RGN215

PB72NT

ΔE

Treatment

Results of Color Changes after the treatment on two kinds of marbles

Lorano marble

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

0

0.5

1

1.5

2

RGN215 N935 NH

PB72PB67 NT

ΔE

Treatment

1st ageing

2nd ageing

Lorano marble

0

0.5

1

1.5

2

2.5

RGN215

PB72NT

ΔE

Treatment

1st ageing

2nd ageing

Results of Color Changes after ageing in Lab.conditions on two kinds of marbles

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

0

0.5

1

1.5

2

RG N215 N935 NHPB72 PB67 NT

ΔE

Treatment

1st ageing

2nd ageing

0

0.2

0.4

0.6

0.8

1

1.2

RGN215

PB72NT

ΔE

Treatment

1st ageing

2nd ageing

Results of Color Changes after ageing in CC (Climatic cham.) on two kinds of marbles

Lorano marble

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

0

0.5

1

1.5

2

RG N215 N935 NHPB72 PB67 NT

ΔE

Treatment

1st ageing

2nd ageing

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

RGN215

PB72NT

ΔE

Treatment

1st ageing

2nd ageing

Results of Color Changes after UV irradiation on two kinds of marbles

Lorano marble

Muğla marble

2° International

Congress

Chemistry for

Cultural Heritage

All the treatments performed do not show relevant changes on the color of the

surface both after treatment and after ageing.

Although the ΔE values for all the treatments are below the limit of three

(3), Rabbit glue seems the less suitable for its more sensibility to UV

irradiation.

Must be noticed that a low amount of polymer is applied on the marble

surfaces and the samples are exposed to artificial ageing in a relativity short

time as applied in this study.

CONCLUSIONS

Acrylic resins seem to have better hydrophobic properties than

fluoroelastomers, as well as a good UV irradiation stability. However a longer

ageing is necessary in order to evaluate the possible decay of acrylic resins

THE RESULTS ARE POSITIVE AND CONSTITUTE A FIRST STEP FOR

THE DEVELOPMENT OF THE CONSERVATIVE TREATMENT OF THE

MARBLE SURFACE WITH POLYMERS.

2° International

Congress

Chemistry for

Cultural Heritage

Prof.Rocco Mazzeo and All Members of Bologna University ,Faculty

of Mathematics, Physics and Natural Sciences

ERMAS Marble Company (Mugla /Turkey )for supplied quarry

samples

Prof. Giuseppe Maria Bargossi and Prof.Giorgio Gasparotto

Prof.ssa Mara Camaiti

THANKS TO,

FOR YOUR ATTENTION2° International

Congress

Chemistry for

Cultural Heritage