Studies on interacting Blends of Acrylated Epoxy resin based Poly(Ester-Amide)s and Vinyl EsterResin

doi:10.4236/msa.2011.27106

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Materials Sciences and Applicatio n, 2011, 2, 771-776

doi:10.4236/msa.2011.27106 Published Online July 2011 (http://www.SciRP.org/journal/msa)

Studies on Interacting Blends of Acrylated Epoxy

Resin Based Poly(Ester-Amide)s and Vinyl Ester

Resin

Pragnesh N. Dave1*, Nikul N. Patel2

1Department of Chemistry, KSKV Kachchha University, Gujarat, India; 2Institute of Technology, Nirma University, Ahmedabad,

India.

E-mail: [email protected]

Received January 24th, 2011; revised March 23rd, accepted May 27th, 2011.

ABSTRACT

Epoxy resin based Unsaturated poly(ester-amide) resins (UPEAs) can be prepared by many methods but here these

were prepared by reported method [1]. These UPEAs were then treated with acrylotl chloride to afford acrylated

UPEAs resin (i.e. AUPEAs). Interacting blends of equal proportional AUPEAs and vinyl ester epoxy (VE) resin were

prepared. APEAs and AUPEAs were characterized by elemental analysis, molecular weight determined by vapour

pressure osmometer and by IR spectral study and by thermogravimetry. The curing of interacting blends was monitored

on differential scanning calorimeter (DSC). Based on DSC data in situ glass reinforced composites of the resultant

blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends

were characterized by thermogravimetry (TGA).

Keywords: Unsaturated Bisamic Acid, Epoxy Resin, Unsaturated Poly(Ester-Amide) Resin (Upeas), Acrylation, Vinyl

Ester (VE) Resin, Differential Scanning Calorimetry, Thermogarvimetry, Glass Reinforced Compos ites

1. Introduction

Both the polyesters and polyamides discussed have par-

ticular individual properties and applications. Hence

many researchers have synthesized co-poly (ester-am-

ide)s from different raw materials in order to obtain the

properties and applications of the individual ones into

one segment. Some of the poly (ester-amide)s synthe-

sized by different researchers. The three polymer candi-

dates namely epoxy resin, unsaturated poly ester and

polyamides are most widely versatile industrial materials

and have broad spectrum of characteristics for wide ap-

plications ranging from aerospace to micro electronics.

They are also important as laminating resins, moulding

composites, fibers, films, surface coating resins, fiber

cushion [3,4]. Particularly Polyamides material used in

the form of fibers as especially thermoplastics of par-

ticular used in engineering applications. The glass fiber

reinforced nylon plastics are now of substantial impor-

tance due to rigidity and creep resistance. Polyamides are

also used in fiber application, automotive industries,

valve covers, coatings [5,6].

Merging of all three segments (i.e. epoxy, ester and

amide) into saturated and unsaturated polymer chain has

been recently reported from our Indian scientists [7-10].

Certain properties of resins may also be improved via

interact of with the other unsaturated resin is another

possibility. In order to improve certain properties of such

reported USPEAs their blending with commercial vinyl

ester epoxy resin is possible. While vinyl ester resin is

versatile industrial resin today [11,12] Hence the present

paper comprises studies of interacting blending of re-

ported unsaturated poly(ester-amide) resin with vinyl

ester (VE) resin. The glass fiber reinforced composites of

these blends have been fabricated and characterized by

chemical, mechanical and electrical properties. The

whole work is scanned in Scheme 1.

2. Materials and Methods

2.1. Materials

Commercially available epoxy resin, diglycidyl ether of

bisphenol-A and vinyl ester epoxy resin was obtained

from local market.

The specification of diglycidyl ether of bisphenol-A

(DGEBA) are as follows:

Studies on Interacting Blends of Acrylated Epoxy Resin Based Poly(Ester-Amide)s and Vinyl Ester Resin

772

+H2NNH2

Maleic Anhydride

(2.0 Mole)

0-5 0C

HOOC CH CH

CO HNNH CH

CH COOH

Unsaturated Bisamic Acids(1a-c)

Diglycidylether of Bisphenol-A

CH CH

CO HNNH CH

OOC COO CH2CH2

OR1

Unsaturated Poly(Ester-Amide) Resin (UPEAs 2a-c)

Aromatic Diamines

(1.0 Mole)(a-c)

Acrylol Chloride

CH CH2

Acrylated Unsaturated Poly(Ester-Amide) Resin (AUPEAs 3a-c)

Benzoyl Peroxide

0.05% Hydroquinone

Stirr well forten minutes at 850C

AUPEAs-VE Blends (4a-c)

Glass Fiber Reinforced Composites (5a-c)

Stirrer 50% of AUPEAs and 50% of VE resin atfor 1-hour

Where,

(b) (c)

R1= C

CH3

CH2

CH CH

CO HNNHCH

OOC COO CH2CH2

CH OR1

80 0C

CH2

CH CH2

VE =C

CH3

CH2CH2CH CH2CO CHCH2

CH2

0-5˚C

85˚C

80˚C

CO2

NH2

H2N

4,4'-methylenedianiline

H2NNH2H2NNH2

4,4'-oxydianiline 4,4'-sulfonyldianiline

(a)

Scheme 1. Synthesis Steps.

Studies on Interacting Blends of Acrylated Epoxy Resin Based Poly(Ester-Amide)s and Vinyl Ester Resin 773

1) Epoxy equivalent weight, 190.

2) Viscosity 40 - 100 poise at 25˚C.

3)Density at 25˚C, 1.16 - 1.17 g/cm.

Vinyl ester epoxy.

The aromatic diamines used for the preparation of un-

saturated poly(ester-amide) resin are,

1) 4,4’-methylenedianiline

2) 4,4’-oxydianiline

3) 4,4’-sulfonyldianiline

Plain weave fibers, in the form of E-glass woven fab-

ric (poly (ester-amide) compatible) 0.25 mm thick (Un-

nati Chemicals, India) of a real weight 270 g·m–2 were

used for composite fabrication. All other chemicals used

were of pure grade.

2.2. Synthesis of Unsaturated Bisamic Acids

The unsaturated bisamic acid was prepared by a simple

addition reaction of maleic anhydride and diamines.

These were prepared by using method reported in the

literature [7,8]. The general procedure for the synthesis

of unsaturated bisamic acid is as follows.

To a well-stirred solution of maleic anhydride (2.0

mole) in dry acetone, the solution of diamine (1.0 mole)

in dry acetone was gradually added at 0˚C -5˚C within 30

minutes. After complete addition of the diamine, the re-

action mixture was further stirred for half an hour at

room temperature. The resulting unsaturated bisamic acid

was then filtered, washed with dry acetone and air-dried.

Unsaturated bisamic acid was obtained in the form of

free flowing powder. The reaction scheme for the syn-

thesis of unsaturated bisamic acid is shown in Scheme 1.

2.3. Synthesis of Unsaturated Poly(Ester-Amide)

Resin and Acrylated Poly(Ester-Amide)

Resin

The unsaturated poly(ester-amide) resin (UPEAs) was

prepared by following the same method reported in [7,8]

The general procedure is as follows:

Diglycidylether of Bisphenol-A (DGEBA) (1.0 mole)

and unsaturated bisamic acid (1.0 mole) were charged in

three necked flask equipped with a mechanical stirrer.

The unsaturated bisamic acid was then treated with di-

glycidylether of Bisphenol-A according to method re-

ported for reaction of epoxy resin and carboxylic group

[13]. To this 8.0% of the total weight of above, triethyl-

amine (TEA) was added as a base catalyst. The reaction

mixture was slowly heated up to 85˚C with continuous

stirring till the acid value fell below 60 mg KOH/gm.

The resultant resin was then discharged and called un-

saturated poly(ester-amide) resin (UPEAs) and their de-

tails are furnished in Table 1. Further reaction of all

these unsaturated poly(ester-amide) resin (UPEAs) was

carried out with acryloyl chloride (i.e. acrylation) and the

resultant products called acrylated poly(ester-amide)s

(APEAs) and their details are furnished in Table 2.

2.4. Synthesis of Acrylated Poly(Ester-Amide)

Resin and Vinyl Ester Resin Blend

When the acid value of acrylated poly(ester-amide)s fell

below 55 mg KOH/gm, 0.05% of hydroquinone was

added as an inhibitor. The whole reaction stirred well for

ten minutes maintaining the temperature at 85˚C. Then

add 50% of APEAs and 50% of vinyl ester (VE) resin

was added and stirred well at 80˚C for one hour. The

resultant APEAs-VE blends were obtained in the form of

viscous syrup.

3. Analysis and Thermal Study

3.1. Elemental Analysis

The C, H, N content of unsaturated poly(ester-amide)s

(UPEAs) and acrylated poly(ester-amide)s (APEAs) was

estimated by means of Thermofinagan 1101 flash ele-

Table 1. Characterization of UPEAs (2a-c).

Elemental analysis (Wt%) Calc. / (Found)

UPEAs

%C %H %N

No. of –OH group

per repeating unit Number average molecular

weight (Mn ) ± 60

2a 65.62/64.23 5.72/5.50 6.43/5.83 1.96 3902

2b 64.06/63.83 5.20/4.86 3.64/3.15 1.82 3828

2c 60.29/60.12 4.90/4.63 3.43/3.05 1.81 4206

Table 2. Characterization of AUPEAs (3a-c).

Elemental analysis (Wt%) Calc. / (Found)

AUPEAs

%C %H %N

No. of double bonds per

repeating unit Number average mo-

lecular weight (Mn) ± 60

3a 65.75/65.37 5.74/5.48 3.19/2.63 3.91 4133

3b 64.38/63.87 5.02/4.70 3.19/2.91 3.76 4135

3c 63.22/62.88 4.93/4.62 3.13/2.61 3.81 4428

Studies on Interacting Blends of Acrylated Epoxy Resin Based Poly(Ester-Amide)s and Vinyl Ester Resin

774

mental analyzer (Italy). The IR spectra were recorded in

Kerr pellets on a Nicollet 760 D spectrometer. The num-

ber average weight of unsaturated poly(ester-amide)s

(UPEAs) and acrylated poly(ester-amide)s (APEAs) was

estimated by non-aqueous conductometric titration fol-

lowing by method reported in the literature [14]. Pyridine

was used as a solvent and tetra-n-butyl ammonium hy-

droxide was used as a titrant.

3.2. Thermal Study

Curing of all APEAs-VE blends were carried out on a

differential scanning calorimeter (DSC) by using benzoyl

peroxide as a catalyst. A Du Pont 900 DSC was used for

this study. The instrument was calibrated using standard

indium metal with known heat of fusion (ΔH = 28.45 J/g).

Curing was carried out from 30˚C - 300˚C at 10˚C min–1

heating rate. The sample weight used for this investiga-

tion was in the range of 4 - 5 mg along with an empty

reference cell. The results are furnished in Table 3.

Unreinforced cured samples of APEAs-VE blends

were subjected to thermogravimetric analysis (TGA) on

Du Pont 950 thermo gravimetric analyzer in air at a

heating rate of 10˚C min–1. The sample weight used for

this investigation was in the range of 4 - 5 mg. The re-

sults are furnished in Table 4.

4. Composite Fabrication

The composites were prepared by using E-type of glass

fiber. The glass fiber: APEAs-VE blend ratio is 60:40

(40% APEAs-VE blends). Suspensions of APEAs-VE

blends were prepared in tetrahydrofuran (THF). In the

above polymer suspension, 1% of ethylene dimethy-

lacrylate (as a cross linking agent) with 0.05% benzoyl

peroxide (as an initiator) were added and mixed well.

The mixture was applied with a brush to a 200 mm × 200

mm glass cloth and the solvent was allowed to evaporate.

The ten dried prepregs prepared in this way were then

stacked one on top of another and pressed between steel

plates coated with a “Teflon” film release sheet and

compressed under 70 psi pressure. The prepregs stacks

were cured by heating it in an autoclave oven at around

140˚C for about 6 hour. The composites so obtained were

cooled to 45˚C - 50˚C before the pressure was released.

4.5. Composite Characterizations

4.5.1. Chemical Resistance Test

The resistances against Chemicals of the composites

were measured according to ASTM D 543. The results

are furnished in Table 5.

4.5.2. Mechanical and Electrical Testing

1) The Flexural strength was measured according to

ASTM D 790.

2) The Compressive strength was measured according

to ASTM D 695.

3) The Impact strength was measured according to

ASTM D 256.

4) The Rockwell hardness was measured according to

ASTM D 785.

5) The Electrical strength was measured according to

ASTM D 149.

6) The Tensile elongation was tested according to

Table 3. DSC Curing of UAPEAs-Vinyl ester epoxy resin Blends (4a-c).

Curing Temperature (˚C) UAPEAs-VE resin Blends Ti Tp Tf

4a 130 151 172

4b 116 147 174

4c 126 138 186

Table 4. TGA of Unreinforced Cured Samples of UAPEAs-Vinyl ester epoxy resin Blends (5a-c)-BPO system.

% Weight loss at various temps. (˚C) from TGA

UAPEAs-VE resin

Blends 150˚C 300˚C 450˚C 600˚C 750˚C

5a 2.01 9.34 64.23 77.32 81.34

5b 1.87 9.21 68.56 76.63 79.34

5c 1.71 8.03 65.25 75.87 80.06

Table 5. Chemical, Mechanical and Electrical Properties of Composites Based on APEAs-MMA Blends.

% Change on exposure to 25%

(W/V) NaOH

Composites Thickness Weight

Compressive

strength (MPa)Impact

Strength (MPa)Rockwell

hardness (R)

Electrical

strength

(in air)

(kV/mm)

5a 0.78 1.07 460 424 111 22.65

5b 0.81 1.10 467 456 104 19.45

5c 0.79 1.02 478 447 106 23.35

Studies on Interacting Blends of Acrylated Epoxy Resin Based Poly(Ester-Amide)s and Vinyl Ester Resin 775

ASTM 0638.

All mechanical and electrical tests were performed

using three specimens and their average results are sum-

marized in Table 5.

5. Results and Discussion

The unsaturated bisamic acids were prepared by the reac-

tion of malelic anhydride (2.0 mole) and aliphatic dia-

mines (1.0 mole) by following method reported in litera-

ture [7,8]. Unsaturated poly(ester-amide)s (PEAs) was

prepared by reaction of epoxy resin (DGEBA) with un-

saturated bisamic acids using triethylamine (TEA) as a

base catalyst. The post reactions of all these unsaturated

poly(ester-amide)s (PEAs) were carried out with acryloyl

chloride. The resultant products are called acrylated poly

(ester-amide)s (APEAs). Blending of acrylated poly(es-

ter-amide)s APEAs with vinyl ester (VE) resin was also

carried out. The resultant products are called APEAs-VE

blends.

The C, H, N content of all the unsaturated poly(ester-

amide)s (PEAs) and acrylated poly (ester-amide)s

(APEAs) were estimated by means of Thermofinagan

1101 Flash Elemental Analyzer (Italy). The values of C,

H, N of each of the unsaturated poly(ester-amide)s (PEAs)

and acrylated poly (ester-amide)s (APEAs) were consis-

tent with their predicted structures and are furnished in

Tables 1 and 2. The number average molecular weight of

both unsaturated poly (ester-amide)s (PEAs) and acry-

lated poly (ester-amide)s (APEAs) were estimated by

non-aqueous conductometric titration method [14]. Their

results are furnished in Tables 1 and 2, respectively. The

results indicate that the degree of polymerization of both

unsaturated poly (ester-amide)s (PEAs) and acrylated

poly (ester-amide)s (APEAs) is about 6. The IR spectra

were consistent with the ones expected from the struc-

tures of the PEAs (3a-c) and APEAs (4a-c).

Numbers of hydroxyl group present per repeating unit

in unsaturated poly(ester-amide)s (PEAs) was also ana-

lyzed by employing acetylating method [15]. Also, acry-

lated poly(ester-amide)s (APEAs) were characterized for

the presence of double bonds per repeating unit employ-

ing mercury-catalyzed bromate-bromide method [16].

Satisfactory results were found and the results are fur-

nished in Tables 1 and 2 respectively.

Curing of all these APEAs-VE blends were carried out

on a differential scanning calorimeter (DSC) by using

benzoyl peroxide as a catalyst. The data of DSC thermo-

grams of all APEAs-VE are furnished in Table 3.

The unreinforced cured samples of APEAs-VE blends

were also analyzed by thermo gravimetric analysis

(TGA). The result reveals that the cured sample starts

their degradation at about 150˚C and their initial weight

is about 2% - 3%. This small weight loss may be due to

either in sufficient curing of components used or due to

the catalyst used. A weight loss of about 10% - 11% is

found at 300˚C. However, the rate of decomposition in-

creases very rapidly between 300˚C to 450˚C and the

products are lost completely beyond 750˚C. TGA data of

all the samples are shown in Table 4.

The glass and carbon fiber reinforced composites of all

APEAs-VE blends were prepared based on their DSC

data. The composites were characterized for their chemi-

cal, mechanical and electrical properties. Their results are

furnished in Table 5. The results shows that composites

have good chemical resistant property, good mechanical

and electrical strength.

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