A Comparative Study of Bisphenol-A, Hydantoin and Cyanuric Acid Based Epoxy Resins Using XRD

doi:10.4236/msa.2011.210204

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Materials Sciences and Applications, 2011, 2, 1516-1519

doi:10.4236/msa.2011.210204 Published Online October 2011 (http://www.SciRP.org/journal/msa)

A Comparative Study of Bisphenol-A, Hydantoin

and Cyanuric Acid Based Epoxy Resins

Using XRD

Sanjay Swarup

Coaching Institute, Agra, India.

Email: [email protected]

Received July 12th, 2011; revised August 4th, 2011; accepted September 4th, 2011.

ABSTRACT

To evaluate the efficiency of modified epoxy resins using bisphenol-A, hydantoin & cyanuric acid & to investigate the

structural change due to the presence of Nitrogen atoms in polymeric chain for improved insulating properties,

weatherability etc. The samples of epoxy resin bisphenol-A, hydantoin and Cyanuric acid based was taken for X-ray

diffraction analysis. The diffraction patterns were Fourier analysed to get an exact idea about the change in the poly-

mer structure. From X-ray diffraction analysis it was found that all physical parameters like area of cross section,

number of carbon atoms per entanglement, stiffness parameter, particle size, percentage crystallinity & electron density

fluctuation, in case of bisphenol-A based epoxy resin is more than other epoxy resins; that is; as the number of nitrogen

atoms increased, all the physical parameters were reduced. In the present study only X-ray diffraction patterns of

bisphenol-A, hydantoin and cyanuric acid based epoxy resins were studied. However their dielectric and ultrasonic

properties could also be studied to get more information about the structure. With the help of X-ray diffraction patterns,

one can easily check the synthesized samples of epoxy resins. The method to investigate the structural analysis of epoxy

resin was novel and could find numerous applications in surface coatings.

Keywords: X-Ray Diffraction, Epoxy Resins, Fourier Analysis, Crystallinity

1. Introduction

Polymers are usually amorphous in nature and it is diffi-

cult to interpret their detailed structure by methods like

U.V. and I.R. spectroscopy.

X-ray Diffraction has been successfully used in the

study of various structural aspects of amorphous poly-

mers [1], as carried out in the present research paper.

Recently Liang et al. [2] did XRD studies on polyacryl-

ics. Using XRD, the curing kinetics of epoxy resin was

studied by Wei-Bing et al. [3]. Epoxy resins are com-

pounds which contain the molecule more than one 1,2-

epoxy group capable of undergoing polyreaction referred

to as curing reactions [4]. Today epoxy resins are the

versatile and widely used polymers essential for the

various end uses of human civilization. The most widely

used epoxy resins are diglycidyl ethers of bisphenol-A

(DGEBA) derived from bisphenol-A and epichlorohydrin.

Recently, epoxy resins derived from heterocyclic com-

pounds have played a significant role showing good high

temperature performance, outdoor WEATHERABILITY

and insulating properties. A successful interpretation on

X-ray DIFFRACTION studies regarding the structure of

different resins was published earlier [5,6].

A constant search to get improved properties laid the

foundation of a new generation of epoxy resins based on

heterocyclic compounds consisting of hydantoin and

triazine nuclei. Hydantoin based epoxy resins have been

reported to provide increased pot life, chemical and sol-

vent resistance and low smoke generation during com-

bustion. Heat deflection temperature is significantly

higher than that for comparably cured conventional ep-

oxy resin [7]. Though conventionally used epoxy resins

provide good properties for electrical insulation, hydan-

toin based epoxy compositions have also been reported

as superior electrical insulators. In this series cyanuric

acid based epoxy resins have also been reported as good

electrical insulators due to their superior adhesion, ther-

mal, electrical and mechanical properties. Researchers

have developed many suitable formulations based on

A Comparative Study of Bisphenol-A, Hydantoin and Cyanuric Acid Based Epoxy Resins Using XRD1517

Figure 1. Hydantoin, showing the presence of 2N atoms in

its structure.

Figure 2. Cyanuric acid, showing the presence of 3N atoms

in its structure.

triazine epoxies in order to get good electrical insulation

properties.

It is known that hydantoin based epoxy resin contains

two nitrogen atoms in its structure as shown in Figure 1,

whereas cyanuric acid based epoxy resin contains three

nitrogen atoms as shown in Figure 2. The nitrogen con-

taining heterocycle provides the resin extensive variation

in polarity, melting point, viscosity and hydrophobicity

by the choice of alkyl group. It was therefore decided to

take the X-ray DIFFRACTION patterns of bisphenol-A,

hydantoin and cyanuric acid based epoxy resins for their

more detailed structural investigations.

The epoxide equivalent of all the three was found to be

200. The second section describes the theory used to

study these resins, the third section describes the experi-

mental set up. The fourth section presents the results and

discussions, and the fifth section gives the conclusion

made from the above study.

2. Theory

The X-ray diffraction patterns of bisphenol-A based,

hydantoin and Cyanuric acid based epoxy resins consist

of halos which confirm that these samples are amor-

phous. The definitions of different physical parameters

like, area of cross section, the stiffness parameter etc

are given in our earlier papers [5,6], where the use of

Boyer miller curves in estimating the different physical

parameters is also described. For obtaining more de-

tailed information about the structure of these resins,

the X-ray diffraction halo was Fourier analysed [8].The

theoretical derivation of correlation function is given in

our earlier paper [5,6]. However the experimental scat-

tering curve is given by

  



cos 2πd

Sl SxSS

Sl SS









where, γ(x) is the correlation function S is sin θ/λ, λ is the

wavelength of X-rays and θ is the angle of diffraction.

I(S) is the measured intensity.

The interchain separation (R) can be measured by [9]

the value of 2θ at which the intensity of the diffused halo

is maximum using the equation:





58 sinR





 (1)

3. Experimental

The X-ray diffractometre of West German make was

employed to record the diffraction pattern from an X-ray

source emitting CuKα radiation. The pattern was ob-

tained on a strip chart recorder running at 30 mm/min

speed. The range of diffractometers recording angle lay

from five degree to 20 degree (2θ). This pattern was

symmetrised about the peak on the high angle side. The

different values of I & θ were subjected to a Fourier

analysis using a program written for this purpose. The

computer PDP 11/23 was used for this purpose. Figure 3

shows the diffraction patterns of bisphenol-A & Cyanuric

acid based epoxy resins. Figure 4 shows the position

correlation curves for these resins.

4. Results and Discussions

In Table 2 summarises the results of applying Boyer

miller method [10-12] to the X-ray diffraction halos of

bisphenol-A, hydantoin and Cyanuric acid based epoxy

resins. The method of determining the particle size and

electron density fluctuations for these resins (from the

position correlation curve) is given in our earlier paper

[5,6].

On comparing Tables 2 and 3 it was found that the

bisphenol-A based epoxy resin (Epon 1) has largest area

of cross-section, Nc, σ, particle size and electron density

fluctuations as compared to other resins (Epon 2 and

Epon 3). It is due to the absence of N atoms in bisphenol-

A based resin. As the number of N atoms increases, the

area of cross-section, the number of carbon atoms, stiff-

ness parameter, the particle size and finally the electron

density fluctuations decreases.

The presence of N atoms in the polymeric chain effects

the interchain separation (Table 4). As the number of Na-

toms increase, the interchain separation decreases.

In hydantoin based epoxy resin (Epon 2), there are 2N

atoms and hence, its physical parameters have lower

values as compared to Epon 1.

In cyanuric acid based epoxy resin (Epon 3), there are

3N atoms, reduces these physical parameters more as

A Comparative Study of Bisphenol-A, Hydantoin and Cyanuric Acid Based Epoxy Resins Using XRD

1518

Figure 3. It shows the XRD patterns of Epoxy resin & Cy-

anuric acid based Epoxy resin.

Figure 4. It shows the Fourier analysis of Epoxy resin &

Cyanuric acid based Epoxy resin.

Table 1. Epoxy resins & their code names; the present pa-

per reports the results of three epoxy resins shown in Table

S.No. Epoxy resin Code name

1 Bisphenol-A based Epon 1

2 Hydantoin based Epon 2

3 Cyanuric acid based Epon 3

Table 2. Value of deff determined from the X-ray diffrac-

tions halo, and the corresponding cross-sectional area, the

number of carbon atoms per entanglement (Nc) & the stiff-

ness parameter (σ).

RESIN deff (nm)Area of cross-section(nm2) Nc σ

Epon 10.44 0.21 315 1.69

Epon 20.43 0.20 300 1.64

Epon 30.40 0.17 266 1.61

It is clear from this table that area of cross-section number of carbon atoms

per entanglement & stiffness parameter decreases as N-atoms increases in

epoxy resins.

Table 3. It collects the results obtained from the curves re-

lating position correlation with distance for different resins

studied in the present work.

Resin Particle size Electron density fluctuation

Epon 1 42 1.87

Epon 2 39 1.80

Epon 3 35 1.78

This table clearly indicates that as number of N-atoms increases, the particle

size & electron density fluctuation becomes minimum in epoxy resins.

Table 4. It collects the results of interchain separation (R)

(using Equation (1)) for different resins studied in the pre-

sent work.

Resin Interchain separation (R) (In A.U.)

Epon 1 0.55

Epon 2 0.53

Epon 3 0.50

This is clear from the table that interchain separation in case of cyanuric acid

based epoxy resin is msinimum as it has maximum number of N-atoms.

compared to Epon 1 and Epon 2. From above observa-

tions, it is thus clear that the increase of N atoms in ep-

oxy resins (studied in present paper) reduces its physical

parameters (obtained from X-ray diffraction analysis).

5. Conclusions

The different conclusions arising from the above study

are summarised below:

It is clear from our X-ray diffraction analysis that to

increase the polarity in an epoxy resin, it is essential to

reduce its area of cross-section, number of carbon atoms,

the stiffness parameter, the particle size and the electron

density fluctuations. The presence of N atoms plays an

important role for making an epoxy resin to be more in-

sulators. This increases also the other chemical properties

like outdoor weatherability etc. in epoxy resins. This also

A Comparative Study of Bisphenol-A, Hydantoin and Cyanuric Acid Based Epoxy Resins Using XRD

1519

concludes that the application of X-ray diffraction meas-

urements leads to the successful interpretation of the

structure of bisphenol-A, hydantoin and cyanuric acid

based epoxy resins in terms of the presence of N atoms in

their structure.

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