A Comparative Study of the Effectiveness

of Stearic Acid in Preventing Iron

Against Rusting

In partial fulfillment of the requirements in Technical Research

Presented to:

Ms. Divina Paulette

Proponents:

Vibandor, Mark Angelo

Pulintan, Aubrey Marie

Martin, Kristine Jane

Dianito, Ivan Rennel

Ramos, Luzviminda

Robles, Ian Carlos

Paala, Darrel John

Dean, Ma. Isabel

Co, Charlene

Abstract

Philippines is considered as the ‘Gateway of Typhoons’ in the Pacific. Because of the

continuous climate change, this condition greatly affects the country’s stability especially when

most of our infrastructures and equipments were damaged due to bad weather. When our

equipments especially those which are made in metal are exposed to changing environment’s

condition, their quality will soon deteriorate because of rusts caused by abnormal climate

change. The researchers therefore thought of a solution to that problem which is more

affordable than buying more paints then coat them again, which is obviously time consuming

and impractical. There are many types of paint available in the market today which came from

different manufacturers but of the same purpose and of the same effect. We all know that

paint’s resistance of rust is affected by our environment and of the climate change we are

experiencing making the resistance of the paint be effective in such a short time. In our

experiment we made an enamel paint which could resist the oxidation of metal in such a longer

time compared to any other available enamel paint in the market by mixing Stearic acid in the

enamel paint itself. We conducted experiments and gathered in formations based on the set-ups

we made wherein we made four samples of it- one with only enamel paint itself, second is of

constant amount of paint but changing amount of Stearic acid, third is of constant Stearic acid

and changing enamel paint and the fourth of equal amount of Stearic acid and enamel paint.

Based on the data we’ve gathered we were able to prove the effectiveness of Stearic acid in the

prevention of oxidation of such metal. And as the amount of Stearic acid increase the more the

effective the enamel paint would be.

1

Acknowledgement

The researchers would like to express their deepest gratitude to the following people:

Our classmates for the enjoyment they gave us during ups and downs, our class adviser for

being supportive and reminding us about our responsibilities, our teachers for giving us their

time to finish this research project, our research adviser for her persistence and sympathy, our

parents for providing us our needs, enduring support and assistance which made us what we

are today. And above all, we thank God for His guidance wherever we are and for He endowed

us such knowledge and strength to accomplish this project.

2

Table of Contents

Chapter1: Introduction…………………………………………………………………………………4

Background of the study………………………………………………………………………4

Statement of the problem ……………………………………………………………………..5

Significance of the problem……………………………………………………………………5

Scope and limitation…………………………………………………………………...............6Chapter II: Review of Related Literature and Studies……………………………………………7

Related Literature……………………………………………………………………………7-10

Related Studies……………………………………………………………………………..11-12

Chapter III: Methodology……………………………………………………………………………..13

Materials………………………………………………………………………………………….13

Research paradigm…………………………………………………………………………….14

Procedural Diagram……………………………………………………………………………15

Chapter IV: Results and discussion………………………………………………………………..16

Table 1: The Iron Plates after Experimentation…………………………….………….16-17

Table 2: Region of Rust in Iron Metal Plates accumulated per Day……………………18

Graph 1: Region of Rust in Iron Metal Plates accumulated per Day…………………..19

Analysis of data………………………………………………………………………………20-21

Chapter V: Conclusions & Recommendation…………………………………………………….22

Bibliography………………………………………………………………………………………….…23

3

Chapter I

Introduction

Paints are quite causing too much expenses just to prevent rust from the objects they

were being consumed. And it is quite hard to find a paint that could last for a longer period of

time when it is exposed to different environments. Environments that could damage its

performance and leads to another paint coating again to protect our properties being used

everyday.

Paints have preventive measure for combustion because it contains gas which is a fine

source of fire. It is widely used in the world today to prevent rust. Rusting occurs when oxygen

and moisture come into contact with exposed to metal. It can be control using metal coating. It

takes place when metal is isolated from the rest environment such as paint.

Stearic Acid is an effective preventive measure against oxidation and combustion that

leads to rusting of iron metals. This study will enhance the features of paints against rust, a type

of paint that will prevent composition against rusting for a longer period of time by using the

property of Stearic Acid against oxidation and combustion.

I. Background of the Study

The Stearic Acid allows metal powders such as aluminum and iron to be stored for a

longer period of time because of its property against combustion and oxidation11. The study

now will determine if the property of Stearic Acid to prevent oxidation and combustion can even

prevent iron from rusting by enhancing the property of commercially available enamel paints.

One interesting fact about Stearic Acid is that it is available in the market. Stearic acid

occurs in many animal and vegetable fats and oils but it is more abundant in animal fat than

1 The statements were according to Giselle Diamond, an eHow contributor that shows the instruction and effectiveness of Stearic acid in the removal of rust.

4

vegetable fat. It is usually used in making candles, plastics, dietary supplements, oil pastels and

cosmetics, and for softening rubber.

II. Statement of the Problem

General Objective

Is enamel paint with Stearic Acid an effective agent for the prevention of rust than

commercially available paints?

Specific Objective

Is enamel paint with Stearic Acid lasts longer than commercially

available paints to protect iron metal from rusting?

Is enamel paint with Stearic Acid accumulates lesser rust than

commercially available paints?

III. Significance of the Study

The enamel paint’s performance to stay longer is one of the most important qualities that

consumers take into consideration. Using the properties of Stearic Acid, we can establish the

enamel paint maintenance for longer period of time, simply by combining the major properties of

Stearic Acid and enamel paint against rust. This can help us to minimize our expenses, efforts

and time for enamel paint coating for our properties to last longer with or without any damage.

The study can economically help our society in solving one of its minor problems, such as

iron rusting. It can also offer better services to various consumers from different fields that use

paints for iron metal coatings. It will be easier for all of us to use our properties, equipments and

other objects coated with paint whatever that may occur, whether the weather may rain or shine.

5

IV. Scope and Limitation

The study will be on chemical property of Stearic Acid against oxidation and combustion used to

enhance enamel paint performance against iron rusting as well as the reactions that may occur

to the Stearic Acid, enamel paint, iron, and the iron rust. It will only focus on the iron metals that

are commercially available as well as the enamel paint specifically white enamel paint and

Stearic Acid. The study will only determine the effectiveness of paint with Stearic Acid on iron

metal against rusting for a longer period of time than commercially available enamel paint.

6

Chapter II

Review of Related Literature and Studies

Related Literature

Stearic Acid

Stearic acid is a saturated fatty acid with an 18 carbon chain and has the

IUPAC name octadecanoic acid. It is a waxy solid, and it is a weak acid with a

chemical formula C18H36O2, or CH3(CH2)16COOH, come from the Greek word

stéar (genitive: stéatos), which means tallow. The salts and esters of stearic acid

are called stearates.2

It is extracted from any type of animal fats, vegetable fats and some oil s.

It is also often use d to change the consistency and melting temperature of a

product, as a lubricant, or to prevent oxidation.2

It is commonly used to coat metal powders such as iron and aluminium

that are used in fireworks, allowing them to be stored for longer period. It also

used tin some metal polishes to help prevent the oxidation and rust that can

occur on metal parts of tools.

Enamel Paint

Enamel paint is a paint that dries with air which is usually glossy and

hard. It is usually used in coating metal to prevent rust3. Typically, enamel paint is

an oil-based covering product with significant amount of gloss. These have been

used in varnishing oil-based paint. Enamel paint is also used on wood to make it

2 Susan Budavari, ed (1989). Merck Index (11th ed.). Rahway, New Jersey: Merck & Co., Inc. p. 8761. ISBN 9780911910285.3 www.wikipedia.org/Enamel_paint

7

resistant to the elements via the waterproofing and rotproofing properties of

enamel. Generally, treated surfaces last much longer and are much more

resistant to wear than untreated surfaces.

Composition of white enamel paint

Pigment

Enamel paint manufacturers began replacing white lead pigments with the less

toxic substitute, titanium white (titanium dioxide).The titanium dioxide used in

most paints today is often coated with silica or alumina for various reasons such

as better exterior durability, or better hiding performance (opacity) via better

efficiency promoted by more optimal spacing within the paint film.4

Binder

The binder imparts adhesion, binds the pigments together, and strongly

influences such properties as gloss potential, exterior durability, flexibility, and

toughness4. Binders include synthetic or natural resins such as alkyds, acrylics,

vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes, polyesters, melamine

resins, epoxy, or oils. Binders can be categorized according to drying, or curing

mechanism. The four most common are simple solvent evaporation, oxidative

crosslinking, catalyzed or cross linked polymerization, and coalescence.

Solvent

The solvent are to adjust the curing properties and viscosity of the paint. It is

volatile and does not become part of the paint film4. It also controls flow and

application properties, and affects the stability of the paint while in liquid state. Its

4 Berendsen, A. M., & Berendsen, A. M. (1989). Marine painting manual. London: Graham & Trotman. ISBN 1853332860

8

main function is as the carrier for the non volatile components. In order to spread

heavier oils (i.e. linseed) as in oil-based interior housepaint, a thinner oil is

required. These volatile substances impart their properties temporarily, once the

solvent has evaporated or disintegrated, the remaining paint is fixed to the

surface.

Iron Metal Rusting

Iron rusts when it is in contact with water and oxygen or other strong oxidants

and acids. Iron metal is relatively unaffected by pure water or by dry oxygen. As

with other metals, like aluminium, a tightly adhering oxide coating, a passivation

layer, protects the bulk iron from further oxidation. Thus, the conversion of the

passivating iron oxide layer to rust results from the combined action of two

agents, usually oxygen and water. Other degrading solutions are sulfur dioxide in

water and carbon dioxide in water. Under these corrosive conditions, iron

hydroxide species are formed. Unlike iron oxides, the hydroxides do not adhere

to the bulk metal. As they form and flake off from the surface, fresh iron is

exposed, and the corrosion process continues until all of the iron is either

consumed or all of the oxygen, water, carbon dioxide, or sulfur dioxide in the

system are removed or consumed.5

The rusting of iron is an electrochemical process that begins with the

transfer of electrons from iron to oxygen6. The rate of corrosion is affected

by water and accelerated by electrolytes, as illustrated by the effects of

55 Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-56 Gräfen, H.; Horn, E. M.; Schlecker, H.; Schindler, H. (2000). "Corrosion". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.b01_08

9

road salt on the corrosion of automobiles. The key reaction is the

reduction of oxygen:

O2 + 4 e- + 2 H2O → 4 OH-

Because it forms hydroxide ions, this process is strongly affected by the

presence of acid. Indeed, the corrosion of most metals by oxygen is

accelerated at low pH. Providing the electrons for the above reaction is the

oxidation of iron that may be described as follows:

Fe → Fe2+ + 2 e−

The following redox reaction also occurs in the presence of water and is crucial

to the formation of rust:

4 Fe2+ + O2 → 4 Fe3+ + 2 O2−

Additionally, the following multistep acid-base reactions affect the course of rust

formation:

Fe2+ + 2 H2O ⇌ Fe(OH)2 + 2 H+

Fe3+ + 3 H2O ⇌ Fe(OH)3 + 3 H+

as do the following dehydration equilibrium:

Fe(OH)2 ⇌ FeO + H2O

Fe(OH)3 ⇌ FeO(OH) + H2O

2 FeO(OH) ⇌ Fe2O3 + H2O

10

Related Studies

Stearic acid prevents oxidation that can result in rusting of metals. It is best

shown in the manufacturing of fireworks where stearic acid is coated on iron to prevent

oxidation. Aside from this, it is also proven that stearic acid is a best removal of rust.

Stearic acid acts as a to sealant over metal object prevent them from oxidizing, which

causes rust7. It is very easy to apply stearic acid to any metal object, and it only takes a

few minutes. Stearic acid can be found in the candle-making section of most craft stores,

as it is often used to improve the appearance of candles and soap.

In this experiment they have used the following materials Rag, Rust remover, Towel,

Rubber gloves. First there is a need to examine the rusty object that you want to

recover. Find the worst rust spots. It is important that the rust did not cause any holes to

form in the object. If it has, then you probably will not be able to reuse the item even

after the rust has been removed. If the rusty object is still intact, use the rust remover

and a rag to rub the biggest rust spots first. Second, remove the rust from the rest of the

object by rubbing the rust remover into the rusty areas. However, if the rust is really bad,

then it may be necessary to soak the object in a container of rust remover. This was

done for a few hours, depending on how bad the rust is. Remove the object when the

rust was completely gone then dried it with a towel. Then open the stearic acid

container. Stearic acid is generally used as an emulsifier, so it will be thick or oily in

appearance. Do not get the acid in your eyes or near your face. Wear rubber gloves

when handling the stearic acid.Dip a rag into the stearic acid. Put enough on the rag so it

is damp, but don't soak the rag. Smear the stearic acid onto the item that you want to

protect from rust. Use a large amount at first to completely cover the object.Rub the

stearic acid into the object. Use circular motions. You need to do this for several

7 The statements below were according to Giselle Diamond, an eHow contributor that shows the instruction and effectiveness of stearic acid in the removal of rust.

11

minutes. Try to absorb as much of the stearic acid into the object as possible. The

stearic acid acts as a protector for the metal, so it is important to cover the entire metal

object. Lastly, wipe away the excess stearic acid with another dry rag. Set the metal

object on a table or other surface to completely dry. Once the object is completely dry,

you can use it for whatever task you had in mind. The object will now be protected from

collecting future rust.

In this study we saw that stearic acid is an effective measure in preventing rust.

Rust-Lubricant compositions

This invention relates to rust-proof lubricant compositions8 of the solid film type

for use with metals which are applied on the surfaces of hot rolled steel plates, cold

rolled steel plates and surface treated steel plates to effect temporary rust proofness of

steel plates or an improvement in lubrication at the time of forming. More particularly, the

present invention is directed to rust proof lubricant composition comprising partial esters

of pentaerythritol with fatty acid, as a chief constituent, rust preventives lubrication

improving agents surface active agents etc. having melting points of 30-60 degrees

Celsius, which can be applied on steel plates without the necessity of any solvent or

heat dry, and which maybe adapted for the continuous coating of steel plates.

The present invention resides in a coating composition which possesses not only a very

excellent rust proof action and lubricity as compared with conventional composition

which have been used to give steel plates some rust-prevention and working lubrication,

but also no danger of fire, explosion or poisoning.

8 Lubricating Oil Composition For Food Processing Machines by Royji Ohgake, Chiba; Mitsuo Okada, Yokohama; Hiroyuki Takashima, Yokohama

12

Chapter III

Methodology

Method of Research Used

In our study we used Experimental Research to test if Stearic Acid can enhance

the preventive measure of enamel paints against iron metal rusting. There will be two

paints being tested first the Enamel paint with Stearic Acid and the commercially

available paints. Each of the paints had four set-ups of iron metals being observed to

test the enamel paint performance.

The study used experimental research to determine if the enamel paint with

Stearic Acid would last longer than commercially available paint and would accumulate

lesser rusts than ordinary enamel paints. The samples would undergo controlled

condition and environment to accurately get the results of the experimentation.

Materials/Equipment

First, we need commercially available Stearic acid melted at 343F which will be

mixed in the paint to enhance the paint’s rust preventing ability. Second, eight iron plates

of same sizes which will be coated by the paint with stearic acid and paint without stearic

acid. Third, 1L of white enamel paint which will serve as coating for the iron plates, one

will be mixed with Stearic acid and other set-up will use paint alone. Last, use muriatic

acid to shorten the time it will take for the iron plates to rust, it will cause the iron plates

to rust easily

Treatment/General Procedure

The iron metal was cut into the desired size, producing eight iron metal plates.

Next, in order to liquefy our Stearic acid from its pellet form, we heated it at 343

13

Fahrenheit. Label the container according to the ratio of the amount of paint and Stearic

Acid. We let it cool until the temperature is tolerable for us to incorporate the enamel

paint in the mixture. After that we measured the amount of Stearic acid that is

incorporated with the enamel paint. Mixed it properly until we achieved the desired

consistency. With our pre-cut metal plates, we applied each mixture to its corresponding

plate. Let it dry.

Method of Collecting Data

In the study, the data are collected after the enamel paints have dried and ready

for observation. The samples undergone controlled condition and were exposed to

certain environment for two weeks. Everyday, observations were taken to determine if

there is any occurrence of rusts in the samples being experimented. At the moment

when the rusts appeared, the rusts were being measured by getting the area of the

samples affected by rusts.

Research Paradigm

Inputs Process Output

Enamel Paint

Stearic Acid

Iron Metal Plate

Time*

Environment*

Rust

Melting Stearic Acid Pellets Hypotheses:

Null: Stearic acid is not really

effective in the prevention of

rust.

Alternative: Stearic acid is

really effective in the

prevention of rust.

Incorporate Stearic acid to

paint

Drying of enamel paints

coatings

Exposed to controlled

environment

Soaked in Muriatic Acid

14

Procedural Diagram

Chapter IV

Results and Discussion

15

Cut Iron Metal Plates into equal sizes

Melt Steatic Acid Pellets

Measure the volume of liquefied Stearic Acid according to the ratio in mililiters

Measure the volume of enamel paint according to the ratio in mililiters

Cool the Stearic Acid until the temperature is tolerable for us to incorporate the enamel paint in the mixture

Mix the enamel paint with Stearic Acid and stir thouroughly

Cover the iron metal plates with the enamel paint with Stearic Acid and with the ordinary enamel paint

Let the metal iron plates coated with different enamel paints to dry

Place and expose the metal iron plates in the area of controlled condition and environment, if necessary use a rusting agent to test

the paints’ performances

The Iron Plates After Experimentation

Set ups

Amount in mlIron Metal PlateEname

l PaintStearic Acid

Set up 1

10 ml 0 ml

Set up 2

50 ml 40 ml

50 ml 30 ml

50 ml 20 ml

16

Set up 3

50 ml 50 ml

Set up 4

40 ml 50 ml

30 ml 50 ml

20 ml 50 ml

17

Region of Rust in Iron Metal Plates accumulated per Day

Set ups

Amount in ml Exposed to Controlled Environment

Soaked in Muriatic Acid

Enamel Paint

Stearic Acid

1-9 10 11 12 13 14 15 16 17

Set up 1

10 ml 0 ml

0%

0% 2% 6% 11% 14% 16% 90% 100%

Set up 2

50 ml 40 ml 0% 0% 0% 1% 5% 10% 55% 65%

50 ml 30 ml 0% 0% 0% 0% 0% 4% 19% 22%

50 ml 20 ml 0% 0% 0% 0% 0% 0% 2% 3%

Set up 3

50 ml 50 ml 0% 0% 0% 0% 0% 2% 10% 12%

Set up 4

40 ml 50 ml 0% 0% 0% 0% 0% 3% 17% 19%

30 ml 50 ml 0% 0% 0% 0% 1% 6% 35% 92%

20 ml 50 ml 0% 0% 0% 0% 2% 9% 40% 97%

Collected Data

18

In the table above, the metal iron plates coated with different mixture of enamel paint is first treated with controlled environment (moisture and the presence of water) from day 1 to day 14, and there are no rust occurrences from set up 2 (5:3),(5:40) until set up 4 (4:5). As the presence of muriatic acid in the experiment is used, all of the metal iron plate rust but still the set ups that is mentioned in the first sentence of this, there is slow rate of iron rusting

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 9

Day 10

Day 11

Day 12

Day 13

Day 14

Day 15

Day 16

Day 17

Exposed to Controlled Environment Soaked in Muriatic Acid

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Set up 1 10 ml 0 mlSet up 2 50 ml 30 ml

Set up 3 50 ml 50 mlSet up 4 30 ml 50 ml

Region of Rust in Iron Metal Plates accumulated per DaySet up 1 10 ml 0 ml

Set up 2 50 ml 40 ml

Set up 2 50 ml 30 ml

Set up 2 50 ml 20 ml

Set up 3 50 ml 50 ml

Set up 4 40 ml 50 ml

Set up 4 30 ml 50 ml

Set up 4 20 ml 50 ml

19

In the graph above, there is rapid rusting of metal iron plate in first set up, as the presence of Stearic Acid in the mixture increases with constant amount of enamel paint (set up 2), rusting of iron metal plate is lowered, as the amount of Stearic Acid reaches the same amount of enamel paint (set up 3) and as it overcomes the amount of enamel paint, there is a rapid rusting of metal iron plate.

Analysis of Data

The collected data is used to prove if the presence of Stearic Acid in Enamel Paint is

more effective than the Enamel paint in preventing. In order to determine the answer, there is a

need to take data of rust occurrences for a certain period of time and the rust that an iron metal

had accumulated.

The second table showed the occurrences of rust in iron metal plates for a certain period

of time. It is proven that the changing amount of enamel paint and Stearic Acid has a significant

relevance to the rusting of iron metal plates. It also showed that in any condition the iron metal

plates rust according to the amount of mixtures of enamel paint and Stearic Acid.

The graph showed the amount of rusts that the iron metal plates had accumulated. The

researchers found out that the amount of enamel paint and Stearic Acid has a great effect to

rusts that a certain iron metal plate had accumulated.

Conclusion

Based on the results gathered after the experimentation, the researchers found out that

enamel paint itself greatly inhibits rust than the enamel paint with Stearic Acid. It is clearly

showed that in the first condition that it has undergone (controlled environment) and second

condition (soaked in muriatic acid), the iron metal plate coated with paint only is the first to rust

among all of the iron metal plates coated with different mixture of enamel paint and Stearic Acid

and it had also accumulated the greatest amount of rusts

In the experiment, it is also found out that the amount of Stearic Acid in enamel paint has

a significant to rusts that a certain iron metal plate had accumulated after a certain time. It only

shows that amount of Stearic Acid in enamel paint should be higher than 80% but lesser than

100% of the amount of enamel paint because in the experiment it is clearly showed that as the

20

amount of Stearic Acid exceeds below 80% of the enamel paint the rusts the iron metal plate

increases faster through certain time and as well as it exceeds above 99% of the enamel paint.

These data only suggest that Stearic Acid is effective as it reaches 80% of the enamel

paint but as it reaches and exceeds 100%, the adhesiveness of paint to the iron metal plate

decreases that leads to easy breakage of enamel paint when dried which accumulates more

rusts.

21

Chapter V

Conclusion and Recommendation

Conclusion

After all the experiments that the researchers made and gathered data, the researchers

were able to prove that Stearic acid in enamel was really effective in the preventing rust in iron

metal plates. It was also prove that as the amount of Stearic acid in enamel paint has a certain

point in integrating with enamel paint because as amount of Stearic Acid exceeds below 80%

and above 99% of the amount of enamel paint, the ability of the mixture to prevent rusting of

iron metal plate decreases. The researchers therefore conclude that Stearic Acid is an effective

preventive measure against rusting of iron metal plates.

Recommendation

Based on the study, it is proven that paint with Stearic Acid is more effective in

preventing rust, than commer cially available paint, that’s why the study suggests for further

researches about paints’ reaction with Stearic Acid to enhance its special characteristics in

preventing iron from rusting. This study also recommends the readers and researchers to study

Stearic Acid’s preventive property against rusting for future use in manufacturing metals.

22

Bibliography

Giselle Diamond, an eHow contributor, ”The Instruction and Effectiveness of Stearic Acid

in the Removal of Rust”.

Susan Budavari, ed (1989). Merck Index (11th ed.). Rahway, New Jersey: Merck & Co.,

Inc. p. 8761. ISBN 9780911910285

www.wikipedia.org/Enamel_paint

Berendsen, A. M., & Berendsen, A. M. (1989). Marine painting manual. London: Graham

& Trotman. ISBN 1853332860

Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001.

ISBN 0-12-352651-5

Gräfen, H.; Horn, E. M.; Schlecker, H.; Schindler, H. (2000). "Corrosion". Ullmann's

Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.b01_08

Lubricating Oil Composition For Food Processing Machines by Royji Ohgake, Chiba;

Mitsuo Okada, Yokohama; Hiroyuki Takashima, Yokohama

23