Enhanced  re retardancy of poly methyl methacrylate

by combination with aluminium hydroxide and

magnesium hydroxide

A. Ebdam

, S. Jameh-Bozorghi

, M. Youse

* and A. Niazi

1Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran

2Department of Chemistry, Hamedan Branch, Islamic Azad University, Hamedan, Iran

3Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran

ABSTRACT

The use of polymeric materials in life, due to their unique properties such as low weight and easy process, signi -

cantly increased. But polymers are relatively high combustibility and most of them produce smoke and toxic and

corrosive gases during burning. As a result of modi cation of the polymer behavior against  re is the main challenge

to make them more useful. Retardant additives reduce the risk of  re and release of it. The performance of this class

of materials is by increase in combustion time, improve in in ammability of polymer, reduce in heat release rate and

prevent of dripping during burning. In this study, it is tried to improve thermal resistance of polymethyl methacrylate

PMMA by synthesis and characterization of nanoparticles of magnesium hydroxide and aluminum hydroxide nano-

particles by SEM and XRD and use it as  llers for polymers, which is highly used in Industry. 4 composite samples

with ratios of 10/90, 20/80, 30/70 and 40/60 of PMMA and Mg(OH)2 and 4 composite samples with ratios of 5/5/90,

10/10/80, 15/15/70 and 2/20/40 of PMMA and Mg(OH)2 and Al(OH)3 were prepared and their thermal behavior was

studied. The results show that increasing the percentage of magnesium hydroxide in the composites, heat resistance

of polymer and the melting temperature and the percentage of residual mass in composite increased. The addition of

aluminum hydroxide to composite increased the thermal resistance and increased the percentage of residual mass in

some of them.

KEY WORDS: FIRE RETARDANCY, NANO ALUMINUM HYDROXIDE, POLY(METHYLMETHACRYLATE), NANO MG(OH)2, NANO COMPOSITE

ARTICLE INFORMATION:

*Corresponding Author: Myouse 50@hotmail.com

Received 27

Nov, 2016

Accepted after revision 31

March, 2017

BBRC Print ISSN: 0974-6455

Online ISSN: 2321-4007

Thomson Reuters ISI ESC and Crossref Indexed Journal

NAAS Journal Score 2017: 4.31 Cosmos IF : 4.006

reserved.

Online Contents Available at: http//www.bbrc.in/

Biosci. Biotech. Res. Comm. Special Issue No 1:54-59 (2017)

Ebdam et al.

INTRODUCTION

The research and developments on new engineering

materials belong to the important  elds of material sci-

ence. One can see the continuous competition between

the traditional inorganic engineering materials and pol-

ymers. Since polymeric materials (including composites)

are promising, due to their economic versatile applica-

bility, they are widely used in many applications, such

as housing materials, transport and electrical engineer-

ing (Almeras et al. 2003; Anna et al. 2002; Bourbigot

et al. 1996a; Bourbigot et al. 1996b). These commercial

polymers are easily  ammable. The  ame retardant can

act in various ways i.e. physically or chemically. Many

types of  ame retardants are used in consumer prod-

ucts (Troitzsch, 1990; Sain, 2004; Zhu, 2003). They are

mainly phosphorus, antimony, chlorides and bromides,

magnesium and boron-containing compounds (Seymour

et al. 1978).

Al(OH)3can act also as a reinforcing agent and smoke

suppressant additive with low or zero emissions of toxic

or hazardous substances. The main advantages of poly-

meric materials over many metal compounds are high

toughness, corrosion resistance, low density and ther-

mal insulation. Improvement of the  ame retardancy

and thermal stability of polymers is a major challenge

for extending their use for most applications. The higher

level of  ame retardancy of nanoparticles is due to their

bigger surface to volume fractions which let them dis-

perse into the polymeric matrix homogeneously, and

hence leads to formation of a compact char during the

combustion (Grigsby et al. 2005; Wang et al. 2007; Kul-

janin et al. 2006).

Poly(methyl methacrylate) (PMMA) isa highly  am-

mable polymer, improving its thermal stability is very

important. There are several  re retardants available in

the market. Although they improve the  re resistance of

PMMA, they have a lot of disadvantages. Many addi-

tives are effective only at high loadings, generally from

10 wt% to 40 wt%, which changes the physical proper-

ties of the polymer. Most  ame retardants additivesare

halogenated compounds (Bundersek et al. 2012a). On

the other hand, metaloxides are halogen-free products,

which can also be used for improving thermal stabil-

ity and  re properties of PMMA. Aluminum hydrox-

ide (Al(OH)3) and magnesium hydroxide (Mg(OH)2) are

environmentally benign, butneed to be added in high

concentrations to be effective (Beyer, 2002). Trans-

parency of PMMA in the visible region is reason that

PMMA is an importantthermoplastic for numerous uses

(Beyer, 2005; Beyer, 2002; Chiang et al. 2009; Bundersek

et al. 2012b).

Inorganic compound magnesium hydroxide [Mg(OH)

2] as a smoking- and toxic-free additive has been exten-

sively used in halogen-free  ame-retardant polymeric

materials. However, its fatal disadvantages are low

 ame-retardant ef ciency and thus very large usage

amount, which lead the mechanical properties of a  ame-

retardant polymeric material to drop down sharply. The

surface modi cation of magnesium hydroxide in order

to increase the compatibility between Mg(OH)2 particles

and polymers can enhance the mechanical strength of

composites (Wang et al. 2001).

Finally, to improve the properties of composites

made of PMMA, some changes in proposed structures

are necessary. Therefore, in this study, Nano-magnesium

hydroxide and aluminum hydroxide nanoparticles as

mineral retardant  llers are synthesized and identi ed

by XRD and SEM. Then, composites of PMMA with dif-

ferent ratios of Mg (OH) 2 were built DSC-TGA and LOI

test were carried out on them. At the end, composites

composed of PMMA with different ratios of Mg(OH)2

and Al(OH)3 were made and the same tests with the

previous composites were done on them and thermal

behavior of composites containing aluminum hydrox-

ide and composites lacking aluminum hydroxide were

compared.

MATERIALS AND METHODS

All materials and solvents used in the synthesis of Nano

magnesium hydroxide and Nano aluminum hydroxide

were purchased from Sigma Aldrich and Merck and used

without any further puri cation. the melting points (ºC)

of the complexes were recorded on a Kruss instrument

and TG/DSC curves were obtained from a Diamond TGA

PerkinElmer 60 Hz. Poly methyl methacrylate (PMMA)

was obtained from I Tech polymer company Iran with

melt mass  ow rate (MFR) of 0.9 – 27 g/10 min at 125ºC

and density 1.15 ‐ 1.19 g/cm3.. Infrared spectra were

recorded as KBr disks on Tensor 27 Bruker spectropho-

tometer. The evaluation of Al(OH)3oxide and synthe-

sized Nano composites were monitored by powder X-ray

diffraction Philips PW 1800 diffractometer with Cu K

radiation. Atomic force microscopy was carried out on

a Denmark Dual scope/Raster scope C26, DME micro-

scope. Scanning electron microscopy measurements was

performed on a VEGA\\TESCAN at an accelerating volt-

age of 15 kV. The LOI values were measured using a ZRY

type instrument (made in China) on the sheets of120 · 60

·3 mm3 according to ASTM D2863-77 standard.

2.1 Synthesis of Nano magnesium hydroxide

To prepare magnesium hydroxide nanoparticles,  rst 5

g (MgSO4.7H2O) was solved in 40 ml of deionized water

and 5 ml of sodium hydroxide was added to it. Then, the

obtained solution was stirred with 1600 rpm for 1 hour

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS ENHANCED FIRE RETARDANCY OF POLY METHYL METHACRYLATE 55

Ebdam et al.

in 60 ºC. The obtained solution was passed from Nano

 lter paper by Buchner funnel and then was rinsed with

deionized water in order to completely rinse the Ammo-

nia. The remaining sediment was put in an oven with

105 ºC for 8 hours and  nally magnesium hydroxide

nanoparticles will be synthesized.

2.2 Synthesis of Nanoaluminum hydroxide

1g Al(NO3)2 9H2O were dissolved 33 ml of water. Then

various precipitation agents ethylenediamine, propylene

diamine, triethylenetetramine, tetraethylenepentamine

were added until the pH of the solution adjust to 8. A

white precipitate is obtained con rming the synthesis

of Al(OH)3. The white precipitate was centrifuged and

washed with distilled water to removing the surfactant,

and later dried at 70°C for 24h in a vacuum dryer.

Preparation of PMs composites

In this study, 4 samples with different percent of mag-

nesium hydroxide and PMMA were prepared to study

thermal properties that were named as follows:

To prepare the composite samples, a two-armed mixer

device was used and its temperature and speed were

adjusted respectively as 110ºC and 60 rpm and then 10

minutes was considered for the formation of composites.

2.4 Preparation of PMAs composites

To study the effect of aluminum hydroxide nanoparti-

cles in retardaning PMs composite samples, 4 samples of

PMAs composite were prepared with different percent of

aluminum hydroxide, magnesium hydroxide and PMMA

and then were named as follows:

To prepare the composite samples, a two-armed mixer

device was used and its temperature and speed were

adjusted respectively as 110ºC and 50 rpm and then 15

minutes was considered for the formation of composites.

Thermal gravimetric

The tests related to differential thermal analysis were

performed by TGA device under ASTM-E1131 standard.

Thermal analysis, changes in the sample weight (los-

ing the weight of the sample that is controlled under

a heating program) is considered as the basis of Ther-

mogravimetry analysis (TG) and test conditions are

similar for all produced composites and the temperature

increases to 10 centigrade per minute and the tempera-

ture range from ambient conditions is to 600 ºC.

Characterization of Mg(OH)2 Nanoparticlesand of

Al(OH)3Nanoparticles

The typical powder XRD pattern of Mg(OH)2 nano-

particlesis given in Fig. 1. All diffraction peaks canbe

indexed as the hexagonal structure of Mg(OH)2 with the

lattice constants comparable to the values of JCPDS7-

239. No XRD peaks arising from impurities such as NaCl

and MgO were detected. Moreover, the peaks of the sam-

ples are signi cantly broadened. This indicates that the

Mg(OH)2 particles have a very small grain size, which

can be calculated from the broadened XRD peaks by

means of Scherrer formula (Staudenmaier, 1898).

XRD pattern of Al(OH)3 nanoparticles is shown in

Fig. 2. The pattern of as prepared Al(OH)3 nanopar-

ticles is indexed as a pure monoclinic phase (space

group:P21/n) which is very close to the literature values

(JCPDS No. 33-0018), the narrow sharp peaks indicate

that Al(OH)3 nanoparticles are well crystallized.

The crystallite size measurements were also carried

out using the Scherrer equation, Dc = K/Cos, Where

b is the width of the observed diffraction peak at its half

maximum intensity (FWHM), K is the so-called shape

factor, which usually takes a value of about 0.9, and  is

the X-ray wavelength (CuK radiation, equals to 0.154

nm). The estimated crystallite size is about 8 nm.

Table 1. The properties of PMs composite samples

Composite Compounds

PM-10PMMA 90% - Mg(OH)210%

PM-20PMMA80% - Mg(OH)220%

PM-30PMMA70% - Mg(OH)230%

PM-40PMMA60% - Mg(OH)240%

Table 2. The properties of the produced composite

samples

Composite Compounds

PMA-10PMMA90% - Mg(OH)25%-Al(OH)35%

PMA-20PMMA80% - Mg(OH)210%-Al(OH)310%

PMA-30PMMA70%- Mg(OH)215%-Al(OH)315%

PMA-40PMMA60% - Mg(OH)220%-Al(OH)320%

FIGURE 1. Effect of vemicompost and azotobacter on

kernel weight

56 ENHANCED FIRE RETARDANCY OF POLY METHYL METHACRYLATE BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

Ebdam et al.

Scanning electron microscopic analysis (SEM) on

magnesium hydroxide nanoparticles was shown in  g-

ure 3.and Scanning electron microscopic analysis (SEM)

on aluminum hydroxide nanoparticles was shown in

 gure 4. As is clear, the magnesium hydroxide nano-

particles like aluminum hydroxide nanoparticles have a

good and uniform distribution.

Thermal analysis

The results of the thermal behavior of composites PMs in

Table 4 and the results of the thermal behavior of PMAs

composites are shown in Table 5. Degradation began in

PMs series of composite with increasing Mg(OH)2 nan-

oparticles in three samples are almost identical an at

the  nal sample due to changes in the physical struc-

ture of PMMA it was decreased. The peak temperature

of degradation and thermal resistance of composites in

Table 4, increases from top to bottom that shows the effect

of Nano-Mg(OH)2 nanoparticles in burning behavior of

composites this series. In Table 5, thermal behavior of

composites of PMAs series is provided and the differ-

ence over PMs series is the nanoparticles of Al(OH)3 in

produced composites structure. It is well shown that the

temperature composites. Degradation temperature in

PMAs series is not much different from PMs compos-

ite series but peak temperature of degradation in PMAs

composite series improved by average of 7 ° C in PMs

series.

Analysis of the residual mass of the composite material

The results of the composite residual mass after thermal

analysis is provided in Table 6 for composites of PMs

Series and in Table 7 it is provided for composites of

PMAs. It is well shown that by increasing the amount of

retardant in the composite structure, a smaller percent-

age of them disappears. By comparing Tables 6 and 7 it

clear that apart from PMA-20 composite that its percent-

age of residual mass compared to composite of PM-20 is

signi cantly improved, the percentage of residual mass

of other composites in Tables 6 and 7 are almost the

same in comparison.

Limited Oxygen Index (LOI) analysis

LOI test results of PMs composites and PMAs compos-

ites series are respectively shown in Figure 5 in Figure

6. It is well shown that by increasing the percentage of

Mg(OH)2, the amount of oxygen required for combus-

tion of samples has increasing trend. LOI of pure PMMA

sample was 17 % and with an increase of Mg(OH)2 in

PMMA it had a rising trend so that LOI of PM-40 that

40% of composite products is Mg(OH)2 is 30. In the case

of Figure 6, the same trend is visible and LOI of PAM-

FIGURE 2. Effect of vemicompost and azotobacter on ker-

nel weight

FIGURE 3. Effect of vemicompost and azotobac-

ter on kernel weight

FIGURE 4. Effect of vemicompost and azoto-

bacter on kernel weight

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS ENHANCED FIRE RETARDANCY OF POLY METHYL METHACRYLATE 57

Ebdam et al.

40 composite is 31.5 that 20% of produced sample is

Mg(OH)2 and 20% is Al(OH)3.

By comparing Figures 5 and 6, the close test results of

LOI between PMAs and PMs series composites is realized

and it is clear that except PMA-20composite, which had

about 22.5 % favorable performance than PM-20 com-

posites, other sample results are almost the same.

RESULTS AND DISCUSSION

Given the importance and high consumption of poly

methyl methacrylate (PMMA) in different industries

including construction, automotive, electronics, etc.

in this project we tried to improved thermal resistance

of PMMA using magnesium hydroxide and aluminum

hydroxide nanoparticles as additives. Although the

addition of  llers weakens the mechanical and physical

properties and behavior of the polymer. According to

Table 3. Thermal behavior of PMs composites Series

Sample

First Temperature of

demolition ºC

Peak Temperature of

demolition ºC

End Temperature of

demolition ºC

PM-10199301425

PM-20198300430

PM-30200330442

PM-40190420490

Table 4. Thermal behavior of PMAs composites Series

Sample

First Temperature

of demolition ºC

Peak Temperature

of demolition ºC

End Temperature of

demolition ºC

PMA-10200298430

PMA-20200301436

PMA-30220331450

PMA-40188410495

Table 5. Amount of residual mass

after the thermal Analysis in PMs

composites Series

Sample

The Remaining

Percentage

PM-103.22

PM-208.70

PM-3024.67

PM-4049.33

Table 6. Amount of residual mass

after the thermal Analysis in

PMAs composites Series

Sample

The Remaining

Percentage

PMA-104.38

PMA-2021.05

PMA-3026.56

PMA-4049.19

FIGURE 5. Effect of vemicompost and azotobacter

on kernel weight

FIGURE 6. Effect of vemicompost and azotobacter on ker-

nel weight

58 ENHANCED FIRE RETARDANCY OF POLY METHYL METHACRYLATE BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

Ebdam et al.

the results, resistance of composite made from magne-

sium hydroxide particles against  re increased and melt

rate increased as well. Increase in the amount of mag-

nesium hydroxide in composite improved the residual

mass of composite. The LOI test results show that com-

posite had achieved a good resistance against  re and

smoke of process of burning is reduced. By comparing

the degradation temperature magnesium hydroxide and

aluminum hydroxide nanoparticles it can be concluded

that the degradation temperature was between 180° C

-200 ° C and given the degradation reaction reduced

the  ammability of polymer and produced Al2O3 pro-

vides a thermal insulation coating and the resulting

water vapor diluted the  ammable gases and provided

a thin protective gas layer. However, due to lower deg-

radation point compared to magnesium hydroxide,

when it was used in PMAs composites it decreased the

peak degradation temperature of the composite com-

pared to degradation temperature of PMs series. It is

because of Magnesium hydroxide nanoparticles degra-

dation temperature, which is about 350° C. The residual

mass percentage of composite and LOI test results indi-

cated an improvement in polymer properties of PMAs

series.

Generally, by comparison of eight composites, aver-

age degradation temperature is more favorable in PMAs

series and according to initial thermal resistance against

the destruction of the best examples of PAM-30 is made

of composite.

REFERENCES

Almeras X, Le Bras M, Hornsby P, Bourbigot S, MarosiGy,Keszei

S. (2003): Effect of  llers on the  re retardancy of intumescent

polypropylene compounds. Polymer Degradation and Stabil-

ity; 82(2):317-23.

Anna P, MarosiGy, Bourbigot S, Le Bras M, Delobel R. (2002):

Intumescent  ame retardant system of modi ed rheology. Pol-

ymer Degradation and Stability; 77:243-7.

Beyer G., (2002): Plast. Additive. Compound, 4, 22.

Beyer G., (2005): Plast. Additive. Compound, 7, 32.

Bourbigot S, Le Bras M, Breant P, Tremillon JM, Delobel R.

(1996): Zeolite new synergistic agents for intumescent  re

retardant thermoplastic formulations criteria for the choice of

the zeolite. Fire and Materials; 20(3).

Bourbigot S, Le Bras M, Delobel R, Decressain R, Amourex JP.

(1996): Synergistic effect of zeolite in an intumescent process

study of the carbonaceous structure usıng solid-state NMR.

Faraday Transactions; 92(1):149-58.

Bundersek A., B. Japelj, B. Music, N. Rajnar, and P. Krajnc,

(2012a): Midem, 48thInternational Conference on Microelec-

tronics, Devices and Materials, Otocec.

Bundersek A., B. Japelj, B. Music, N. Rajnar, and P. Krajnc,

Midem, (2012b): 48th International Conference on Microelec-

tronics, Devices and Materials, Otocec.

Chiang C.L. and Chiu S.L., (2009): J. Polym. Res., 16, 637.

Grigsby W. J., Ferguson C. J., Franich R. A., Russell G.T., Int. J.

(2005): Adhes. Adhes. 25:127–137.

Kuljanin J., M. I. Comor, V. Djokovic, and J. M. Nedeljkovic.

(2006): Mater. Chem. Phys. 95: 67–71.

Sain M, Park SH, Suhara F, Law S. (2004): Flame retardant and

mechanical properties of natural  bre-PP composites contain-

ing magnesium hydroxide. Polymer Degradation and Stability:

83:363-7

Seymour RB. (1978): Additives for plastic. New York: Aca-

demic Press.

Staudenmaier L., (1898): Ber Dtsch Chem Ges. 31:1481.

Troitzsch J. (1990): International plastics  ammability hand-

book. New York: Hanser Pub.

Wang H., Fang P., Chen Z., Wang S., (2007): Appl. Surf. Sci.

Synthesis and characterization of CdS/PVA nanocomposite

 lms. 253:8495–8499.

Wang ZZ, Qu BJ, Fan WC, Huang P. (2001): Combustion char-

acteristics of halogen-free  ame-retarded polyethylene con-

taining magnesium hydroxide and some synergists. J Appl

Polym Sci; 81(1):206–14.

Zhu S, Shi W. (2003): Thermal degradation of a new  ame

retardant phosphate methacrylate polymer. Polymer Degrada-

tion and Stability; 80:217-22.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS ENHANCED FIRE RETARDANCY OF POLY METHYL METHACRYLATE 59