NADIC METHYL ANHYDRIDE (NMA) CAS Reg. No. 25134-21-8 · 2020. 3. 27. · levels of NADIC methyl...

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PRODUCT TECHNICAL BULLETIN

NADIC METHYL ANHYDRIDE (NMA)

CAS Reg. No. 25134-21-8 Typical Properties

Characteristic Test Method Typical

Molecular Weight 178.2

NMA, % >97

Specific gravity @ 20° C, g/cc D-102 (ASTM D 4052) 1.20 – 1.25

Color, Pt-Co D-103 (ASTM D 1209) 75 max.

Appearance D-104 (Visual) Pale yellow to tan liquid.

Refractive index, n25/D 1.500-1.506

Viscosity (Brookfield, cps, 25°C)


NADIC METHYL ANHYDRIDE

Page 2 of 16

Vapor Pressure as a Function of Temperature

0

100

200

300

400

500

600

700

800

100 120 140 160 180 200 220 240 260 280 300

Temperature (°C)

Vap

or

Pre

ssu

re (

mm

Hg)

Specific Gravity as a Function of Temperature

1.19

1.20

1.21

1.22

1.23

1.24

1.25

10 20 30 40 50 60 70

Temperature, (°C)

Spe

cifi

c G

ravi

ty



Page 3 of 16

Applications NADIC methyl anhydride (NMA) is a liquid alicyclic anhydride commonly used to cure epoxy resins in many challenging applications, including fiber reinforced composites used in high performance aerospace and military applications, as well as mechanically demanding applications like filament wound bearings. The excellent electrical properties and high temperature performance make NMA-cured epoxies outstanding materials for encapsulating electronic components and circuits. NMA demonstrates many excellent characteristics when used as a curing agent for epoxy resins, including:

Ease of handling

Compatibility with solid and liquid epoxy resins

Long pot life

Low viscosity mixtures

Low volatility

Freedom from odor

Less reactive than amines

Easily catalyzed to match any process requirements

Low exotherm Epoxy resins cured with NMA demonstrate outstanding properties, including:

Light color

Excellent electrical characteristics, including arc resistance

High heat distortion temperature (HDT) and glass transition temperature (Tg)

Thermal stability

Minimal shrinkage when cast

Excellent hardness and impact strength NMA may also be used as a building block for unsaturated polyester resins. Epoxy Curing Agent For more information on the use of anhydrides like NMA as epoxy curing agents, please consult the Technical Bulletin, FORMULATING ANHYDRIDE-CURED EPOXY SYSTEMS, available from Dixie Chemical Company.



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Modifying Other Anhydrides As a liquid, NMA is useful in modifying other anhydrides to lower their freezing points and make them easier to handle. The following plot shows how NMA lowers the freezing point of five other anhydrides.

0

20

40

60

80

100

120

140

0 20 40 60 80 100

Hexahydrophthalic Anhydride

Phthalic Anhydride

Succinic Anhydride

Tetrahydrophthalic Anhydride

Maleic Anhydride

Binary Blends

% NMA

Fre

eze

Po

int

(°C

)

Cure Catalysts The effect of benzyldimethylamine (BDMA) catalyst on mix stability was studied using the following formulations:

System Uncatalyzed Catalyzed

EPON Resin 828 (Momentive) 100 100

NADIC methyl anhydride 67.3* 88.7

Benzyldimethylamine (BDMA) 0 1.0

*Epoxy homopolymerization is a significant side reaction for uncatalyzed systems, so anhydride demand is less.



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Viscosity as a function of time is summarized in the following plot.

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

0 1 2 3 4 5 6 7 8 9 10

Uncatalyzed

Catalyzed

Time (days)

Vis

cosi

ty (

cP)

Anhydride Level Most applications use between 60-90 phr NADIC methyl anhydride with liquid epoxy resins. Most high performance applications utilize 80-90 phr where high levels of heat resistance, chemical resistance, or high strength are required. Examples A study was done to examine the effect of anhydride level on performance. The levels of NADIC methyl anhydride chosen were 75, 85, and 93 phr to cure EPON Resin 828 (Momentive) using 1 phr BDMA catalyst. The cure cycle was 2 hours at 93°C with a post-cure of 2 hours at 204°C. The following results were obtained:

NMA, phr 75 85 93

HDT, °C 129 132 102

Tensile Strength, psi 11,000 11,000 11,600

Elongation, % 3.0 2.7 2.8

Flexural Strength, psi 18,900 20,700 24,500

Flexural Modulus, ksi 520 570 560

Compressive Strength, psi 18,700 19,400 20,500

Dielectric constant, at 25°C 1 MHz

3.6 3.8 3.7

Dissipation factor, at 25°C 1MHz

0.01 0.02 0.02



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These results display a typical response for heat distortion temperature, (and glass transition temperature) where there is an optimum anhydride level for a given formulation (epoxy and catalyst) and cure cycle. This is shown in the following plot:

100

110

120

130

140

75 80 85 90 95

Nadic Methyl Anhydride Level (phr)

HD

T (°

C)

The anhydride level has different impact on other performance properties as shown below for flexural and compressive strength:

18,000

19,000

20,000

21,000

22,000

23,000

24,000

25,000

75 80 85 90 95Nadic Methyl Anhydride Level (phr)

Fle

xura

l Str

en

gth

(psi

)

18,400

18,800

19,200

19,600

20,000

20,400

20,800

75 77 79 81 83 85 87 89 91 93 95

Nadic Methyl Anhydride Level (phr)

Co

mp

ress

ive

Str

en

gth

(psi

)



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The effect of NADIC methyl anhydride level on heat distortion temperature and weight loss after 1000 hours exposure at 200°C for cured bisphenol A epoxy resin (with 1 phr tris(dimethylamino methyl) phenol as accelerator has been reported and is reproduced below. It can be seen that the optimum level of NMA is different depending on which property is more important.

150

152

154

156

158

160

162

164

84 86 88 90 92 94 96 98 100 102 104

Heat Distortion Temp (°C)

Wt Loss (% after 1000 hr @ 200°C)

6

4

2

0

phr Nadic® Methyl Anhydride

% W

eig

ht

Loss

He

at D

isto

rtio

n T

em

p (

°C)

Cure Cycle The cure cycle used has a dramatic effect on system performance. This cure cycle includes the initial time and temperature used to cure the formulation, as well as all post-cure times and temperatures used to improve performance properties. This is important because longer cure times and higher cure temperatures promote increases in crosslinking. Higher crosslinking results in higher levels of mechanical strength and chemical resistance. Examples In one study, 100 parts EPON Resin 828 was combined with 90 parts NMA and one part BDMA to evaluate the impact of cure times from 4 to 200 hours. The cure cycles and performance results are summarized as follows:

Time (hours at 150°C)) 4 24 200

HDT, °C 112 128 144

Tensile Strength, psi 11,600 10,500 12,100

Tensile Modulus, ksi 500 500 400

Elongation, % 3.0 2.7 4.5

Wt. gain after 24 hr water boil 0.98 0.67 0.67

Wt. gain after 4 hr acetone boil 3.2 1.9 0.9



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The HDT results and chemical resistance results are summarized in the following plots.

Samples were then tested at -25°C, at room temperature, and at 100°C. The following charts summarize results for tensile strength and elongation:

0

2

4

6

8

10

12

14

-25 0 25 50 75 100

4 hr at 150°C

24 hr at 150°C

200 hr at 150°C

Test Temperature (°C)

Ten

sile

Str

en

gth

(ks

i)

0

100

200

300

400

500

600

-25 0 25 50 75 100

4 hr at 150°C

24 hr at 150°C

200 hr at 150°C


Ten

sile

Mo

du

lus

(ksi

)

0

2

4

6

8

10

12

14

16

18

20

-25 0 25 50 75 100

4 hr at 150°C

24 hr at 150°C

200 hr at 150°C


Ten

sile

Elo

nga

tio

n(%

)

110

115

120

125

130

135

140

145

1 10 100 1000

Cure Time (hours at 150 C)

He

at D

isto

rtio

n T

em

pe

ratu

re(°

C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 10 100 1000

Water Boil

Acetone Boil

Cure Time at 150°C (hr)

% W

eig

ht

Incr

eas

e



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Two studies were performed to evaluate the effects of post-cure on HDT. The first used 100 parts EPON Resin 828, 83 parts NMA and 1.83 part BDMA. The following cure cycles were used, and HDT results were obtained:

Cure 80°C (hr) 120°C (hr) 150°C (hr) 180°C (hr) HDT (°C)

A 2 0 0 0 44

B 2 2 0 0 131

C 2 2 2 0 143

D 2 2 2 2 149

It is clear that heat history helps to maximize HDT. The second study used 100 parts EPON Resin 828, 80 parts NMA and 2 parts BDMA. The following cure cycles were used, and HDT results were obtained:

Cure Time (hr)

Cure Temp (°C)

Post-Cure Time (hr)

Post-Cure Temp (°C)

HDT (°C)

A 4 80 20 150 144

B 4 100 20 150 142

C 4 100 20 180 145

D 4 120 20 150 140

E 4 120 20 180 144

F 20 150 0 --- 133

G 20 180 0 --- 137

These results reconfirm the importance of cure cycle on system performance

Formulating with Liquid Epoxy Resins Dow Chemical Company conducted an excellent and extensive formulation study in which a variety of liquid epoxy resins were formulated with NADIC methyl anhydride.1 It is worthwhile to review some of these results here. The table below summarizes key formulation and performance data from this study. The following table summarizes chemical and thermal resistance properties. It is noted that all formulations gave high levels of hardness and strength, combined with good toughness and elongation. All formulations demonstrated excellent electrical properties.

1 "Dow Liquid Epoxy Resins," published by Dow Chemical Company, January, 1999



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Properties of Liquid Epoxy Resins Cured with Nadic Methyl Anhydride

Dow Liquid Epoxy Resin1

D.E.R 332 D.E.R 330 D.E.R 383 D.E.R 331 D.E.R 317

Average Epoxy Equivalent Weight 174 180 180 190 197

Average Epoxy Viscosity (P) 50 85 97.5 130 200

Nadic Methyl Anhydride (phr) 87.5 87.5 87.5 87.5 87.5

Formulation Viscosity at 80°C (cP) 30 35 36 38 45

Gel Time (min.)2

97 158 160 129 80

Gel Temperature (°C)2

93 113 112 99 100

Peak Exotherm Time (min.)2

152 132 130 146 155

Peak Exotherm (°C)2

125 180 182 153 100

Heat Distortion Temperature (°C)3

135 148 144 156 147

Flexural Strength (psi)4

21,200 19,200 18,500 14,000 15,000

Flexural Modulus (ksi)4

472 470 480 440 441

Compressive Strength (psi)5

20,190 16,900 17,100 18,300 15,000

Compressive Modulus (ksi)5

340 384 380 440 441

Tensile Strength (psi)6

6260 6340 7000 10,000 7000

Elongation (%)6

1.6 1.4 1.7 2.5 1.8

Izod Impact (ft-lb/in. notch)7

0.21 0.30 0.30 0.48 0.48

Hardness (Rockwell M)8

114 111 112 111 109

Dielectric Constant (Condition A)9

at 60 Hz 3.14 3.15 --- 3.15 3.12

at 1 KHz 3.12 3.13 3.54 3.14 3.09

at 1 Mhz 2.99 3.01 --- 2.97 2.89

Dielectric Constant (Condition D)9

at 60 Hz 3.30 3.39 --- 3.34 3.22

at 1 KHz 3.28 3.35 --- 3.32 3.19

at 1 Mhz 3.13 3.14 --- 3.11 3.01

Dissipation Factor (Condition A)9

at 60 Hz 0.0049 0.0030 --- 0.0020 0.0024

at 1 KHz 0.0045 0.0054 0.0038 0.0054 0.0053

at 1 Mhz 0.015 0.016 --- 0.017 0.018

Dissipation Factor (Condition D)9

at 60 Hz 0.0030 0.0079 --- 0.0023 0.0038

at 1 KHz 0.004 0.0063 --- 0.0059 0.0059

at 1 Mhz 0.018 0.020 0.021 0.020

Volume Resistivity (ohm-cm)10

Condition A 7.2 x 1015

6.11 x 1015

6.15 x 1015

6.1 x 1015

0.90 x 1015

Condition C 1.01 x 1015

3.67 x 1015

--- 1.17 x 1015

0.474 x 1015

Surface Resistivity (ohm-cm)10

Condition A 6.28 x 1015

4.71 x 1015

4.95 x 1015

3.93 x 1015

>7.85 x 1015

Condition C 1.1 x 1015

3.93 x 1015

--- 3.93 x 1015

3.93 x 1015

1Data adapted from "Dow Liquid Epoxy Resins"

6ASTM D638

published by Dow Chemical Company, January, 19997ASTM D256

2500 g samples held at 80°C.

8ASTM D785

3ASTM D648

9ASTM D150

4ASTM D790

10ASTM D257

5ASTM D695



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Chemical and Thermal Resistance Properties Of Liquid Epoxy Resins Cured with

NADIC Methyl Anhydride

Dow Liquid Epoxy Resin* D.E.R. 331

Chemical Immersions 120 days (% weight change)

30% Sulfuric acid 0.55

3% Sulfuric acid 0.96

36% Hydrochloric acid 1.36

10% Hydrochloric acid 0.78

40% Nitric acid 1.7

10% Nitric acid 0.94

28% Ammonium hydroxide 1.84

10% Ammonium hydroxide 1.36

25% Acetic acid 0.90

95% Ethyl alcohol 0.59

Acetone 22.3

Toluene 0.28

50% Sodium hydroxide -0.16

10% Sodium hydroxide 0.5

JP4 Fuel 0.16

10% Citric acid 0.94

40% Chromic acid -2.14

Distilled water 0.87

Thermal Degradation 500 hr (% weight change)

160°C -0.1

210°C -1.8 *Data adapted from "Dow Liquid Epoxy Resins" published by Dow Chemical Company, January, 1999

With the exception of the acetone immersion, excellent chemical resistance was observed after 120 days of immersion. Excellent thermal resistance was also observed with minimal weight loss after 500 hours at 210°C. As seen above, system performance depends on many factors involving formulation and cure cycle. An experimental program was pursued to identify the factors that have the most effect on maximizing performance properties. The formulation and process factors studied are summarized below:



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Formulation Factors

EPON Resin 828 (Momentive)

100

NADIC Methyl Anhydride 80 85 90

Benzyldimethylamine 2.5 3.0 3.5

Process Factors

Cure Temperature (°C) 90 110 130

Cure Time (hr) 1 2 3

Post-cure Temperature (°C) 183 205 227

Post-cure Time (hr) 20

Results were obtained for HDT, flexural strength, and tensile strength, and are summarized below:

Physical Property Maximum

HDT

Maximum Flexural Strength

Maximum Tensile

Strength

Cure Temperature (°C) 107 115 90

Cure Time (hr) 2.8 2.2 3.0

NADIC methyl anhydride(phr)

89 90 90

Benzyldimethylamine (phr) 2.2 2.5 2.5

Post-cure for 20 hr at (°C) 256 188 161

Property Optimum Value 218°C 22,980 psi 13,070 psi

It will be noted that all three properties cannot be optimized with the same formulation and cure conditions. Therefore, the formulator must design the formulation and process to achieve the most critical performance criteria. Formulating with Epoxy Phenol Novolac Resins NMA gives excellent high temperature performance, and has been formulated with multifunctional resins such as epoxy phenol novolacs to get high levels of crosslink density and maximum performance properties at high temperature. Dow Chemical Company conducted an excellent and extensive formulation study in which a variety of epoxy phenol novolac resins were formulated with NADIC methyl anhydride.2 It is worthwhile to review some of these results here. The epoxy resins were formulated with 85 phr NMA and 1 phr 1-(2-hydroxypropyl)

2 "Dow Epoxy Novolac Resins," published by Dow Chemical Company, October, 1998



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imidazole. The cure cycle employed was 2 hours at 85° C, plus 2 hours at 150° C, plus 2 hours at 230° C. Glass transition temperatures (Tg) were measured, and appear to follow the functionality of the novolac in a linear manner, as seen in the following plot:

150

160

170

180

190

200

210

220

230

2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0

Approximate Novolac Epoxy Functionality

Gla

ss T

ran

siti

on

Te

mp

era

ture

(Tg,

°C

)

These glass transition results can be explained by the fact that increasing epoxy functionality leads to increasing crosslink density, which in turn leads to increasing Tg. Samples were immersed in various chemicals for 120 days, and the weight increase was measured. D.E.R. 331 is a bisphenol A liquid epoxy resin, and was used as a control. Except for the acetone immersions, all systems gave good results.

D.E.N. 438 D.E.N. 439 D.E.R 331

30% Sulfuric Acid 0.77 0.8 0.55

36% Hydrochloric Acid 1.5 1.09 1.36

25% Acetic Acid 1.12 1.28 0.9 28% Ammonium Hydroxide 1.92 2.4 1.84

10% Sodium Hydroxide 0.64 1.13 0.5

Distilled Water 1.13 1.38 0.87

Toluene 0.32 0.28 0.28

JP4 Fuel 0.12 0.15 0.16

40% Nitric Acid 3.11 2.05 1.7

Acetone 5.07 3.43 22.3



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The system based on the epoxy phenol novolac (D.E.N. 438) and the system based on the bisphenol A liquid resin (D.E.R. 331) were exposed to steam at 15 psi for 500 hours. The percentage weight increase was measured. Flexural strength, flexural modulus, and glass transition temperature were also measured before and after exposure. The results are summarized below:

% Wt. Increase Dow D.E.R. 331 (liquid resin) 3.68

Dow D.E.N. 438 (novolac) 2.21

Flexural Strength (MPa) Before After % Retention

Dow D.E.R. 331 (liquid resin) 159 48 30

Dow D.E.N. 438 (novolac) 143 95 66

Flexural Modulus (MPa) Before After % Retention


Dow D.E.N. 438 (novolac) 3738 3386 91

Glass Transition Temperature (°C) Before After % Retention


Dow D.E.N. 438 (novolac) 195 161 82

Clearly, the epoxy phenol novolac cured with NMA outperformed the system based on the liquid bisphenol A resin in terms of these properties. Formulating with Epoxy Bisphenol A Novolac Resin Momentive Specialty Chemicals has an epoxy bisphenol A Novolac Resin, with the trade name EPON™ Resin SU-3. It is another multifunctional epoxy resin which gives very high performance in fiber reinforced composites. Momentive has published a formulation for a resin system based on this bisphenol A novolac and NADIC methyl anhydride.3 This system is designed to be a “High Temperature FRP Matrix for Wet Lay-Up, Filament Winding and Prepreg.” It is suitable for electrical applications, aerospace applications, and other high performance composite applications. It is useful to review some features of this formulation here. However, one should also consult the original reference for more process details on laminating, filament winding, and prepreg fabrication, and for laminate performance characteristics. 3 "Starting Formulation 8011," published by Momentive Specialty Chemicals, July, 2007.



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The formulation consists of 100 parts EPON Resin SU-3, 88 parts NMA, and 0.5 parts 2-ethyl-4-methyl imidazole. Formulation viscosity and working life as a function of temperature are summarized as follows:

Temperature (°C)

Initial Viscosity

(cP)

Working Life (hr)

25 8500 >24

49 1020 12

71 200 8

82 300 2

The cure cycle is 2 hours at 93°C, 6 hours at 175C., and 8 hours at 260°C. Performance characteristics include:

Heat Distortion Temperature (°C) 276

Tensile Strength (psi) 8500

Tensile Modulus (ksi) 570

Elongation (%) 1.5

Flexural Strength (psi)

at 25°C 10,700

at 175°C 7000

at 230°C 4300

Flexural Modulus (ksi)

at 25°C 510

at 175°C 330

at 230°C 230

Weight Loss on Heat Aging (%)

1000 hr at 150°C nil

350 hr at 200°C 0.9

700 hr at 200°C 1.6

350 hr at 260°C 10.5

700 hr at 260°C 16.3

The high temperature performance is clearly excellent.



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Handling & Storage It is recommended that NADIC methyl anhydride is stored between the temperatures of 18° C (85° F) and 40° C (104° F) to avoid freezing, although the material is not affected by freezing. If material does freeze, thaw at a temperature below 40° C and mix well before using. Store in a dry place and keep container tightly closed to prevent absorption of atmospheric moisture or contamination. The presence of moisture could cause free acid to form in the anhydride. NMA will react with water to form diacids. This is normally undesirable, so NMA should be stored in such a way that it is carefully protected from moisture contamination. For more details on the design of bulk storage for NMA, consult the Dixie Chemical Company brochure “Epoxy Curing Agent Storage Requirements.” Health Hazards Read and understand the relevant Material Safety Data Sheets (MSDS) for all products before use. These anhydrides are primary skin and eye irritants. Avoid contact with skin, eyes, and clothing. Use only with adequate ventilation. In case of contact, follow the procedures outlined in the MSDS. Generally, these procedures include immediately flushing the affected skin or eyes with copious amounts of water for at least 15 minutes. In the case of eye contact, get medical attention. Wash contaminated clothing before reuse. Follow the recommendations in the MSDS for personal protective equipment when handling these materials. At a minimum, these procedures typically include protective chemical goggles, impenetrable gloves, and measures to avoid breathing chemical vapors.

Availability Nadic Methyl Anhydride is available from Dixie Chemical Company in Pasadena, Texas. Contact your Dixie representative for details.

Typical PropertiesAnhydride LevelThe effect of NADIC methyl anhydride level on heat distortion temperature and weight loss after 1000 hours exposure at 200 C for cured bisphenol A epoxy resin (with 1 phr tris(dimethylamino methyl) phenol as accelerator has been reported and is repro...The HDT results and chemical resistance results are summarized in the following plots.

Health HazardsAvailability

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NADIC METHYL ANHYDRIDE (NMA) CAS Reg. No. 25134-21-8 · 2020. 3. 27. · levels of NADIC methyl...

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