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Novel Uncured Epoxy Resin/CaCO3 NanocompositesHaojie Yu a , Li Wang a , Quan Shi a , Zhenrong Zhao a & Guohua Jiang aa State Key Laboratory of Polymer Reaction Engineering, College of Materials Science andChemical Engineering, Zhejiang University, Hangzhou, China

Available online: 15 Feb 2007

To cite this article: Haojie Yu, Li Wang, Quan Shi, Zhenrong Zhao & Guohua Jiang (2006): Novel Uncured Epoxy Resin/CaCO3

Nanocomposites, Polymer-Plastics Technology and Engineering, 45:7, 809-813

To link to this article: http://dx.doi.org/10.1080/03602550600612097

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Novel Uncured Epoxy Resin/CaCO3 Nanocomposites

Haojie Yu, Li Wang, Quan Shi, Zhenrong Zhao, and Guohua JiangState Key Laboratory of Polymer Reaction Engineering, College of Materials Science and ChemicalEngineering, Zhejiang University, Hangzhou, China

In this paper, we synthesized epoxy resin/CaCO3 nanocompo-sites through in-situ and inclusion polymerization, and the nano-particles were well dispersed in the resin matrix observed bySEM. The effects of the nanoparticles on the properties of epoxyresin are discussed.

Keywords Nanocomposite; Epoxy resin; In-situ and inclusionpolymerization

INTRODUCTION

Epoxy resin is an important polymer material that iswidely used for coatings[1–3], adhesives[4,5], insulation mate-rials[6], and other engineering applications[7]. Nowadays,many studies were performed to introduce nanomaterialsinto epoxy resin matrix in order to improve its propertiesor endow it with novel peculiar properties[8–11]. Magedet al.[12] found that the resistance of gas permeation ofthe epoxy-layered silicate nanocomposites can be enhancedby introducing exfoliated aluminosilicate layers into epoxyresin matrix, which could build a barrier for the permeatinggas molecules. Chenggang et al.[13] found that the diffusioncoefficients of solvent were also reduced in the epoxy-layered silicate nanocomposites. K. H. Chen et al.[14]

synthesized epoxy-montmorillonite nanocomposite, andthe resultant composite showed good heat resistance(Tg), water resistence, and optical properties comparedwith the epoxy resin with no addition of clay or unmodifiedclay. Nanoparticles in the epoxy resin can also consumeenergy during fracture in comparison to the neat epoxymatrix and can result in superior mechanical properties[9].

Most of the reported epoxy nanocomposites wereobtained as cured polymer networks, especially for theepoxy=clay system. Though the resultant nanocompositesshowed excellent properties, reprocess such as extruding

could hardly be performed, and their applications aregreatly limited.

In this paper, we prepared epoxy resin=CaCO3 nano-composites through in-situ and inclusion polymerization.The resultant nanocomposites were uncured and have noinfluence on reprocess. The nanoparticle dispersion in theepoxy matrix and the effect on the thermal properties ofthe epoxy resin were investigated.

EXPERIMENTAL

Materials

Bisphenol A was purchased from Nippon Steel Che-mical Co. Std. Epichlorokydrin (analytical grade) waspurchased from WuLian Chemical Plant in Shanghai.And nanoCaCO3 was purchased from NanomaterialsTechnology Co. Std. All these materials were used asreceived.

Preparation of NanoCaCO3-Modified Epoxy Resin

Epoxy resin=CaCO3 nanocomposites were preparedthrough in-situ and inclusion polymerization according tothe reference[15], and the process is shown in Figure 1.

Epoxy resin=CaCO3 nanocomposites with differentnanoCaCO3 content were prepared as the conditions listedin Table 1.

In order to compare the effect of different preparationmethods on Tg of the resultant composites, some amountof sample 2 was dissolved in acetone. The solution wasfiltrated to remove nanoCaCO3. The obtained epoxy resinsolution was used to prepare sample 6, 7, and 8, as shownin Table 2.

Measurement and Characterization

The nanoCaCO3 in the resultant epoxy nanocompositeswas observed with SEM (S570, Hitachi Co. Std.). Differen-tial scanning calorimetry was performed on a Perkin-ElmerDSC 7 from 30–150 at a heating rate of 20 =min.

Address correspondence to Li Wang, State Key Laboratory ofPolymer Reaction Engineering, College of Materials Science andChemical Engineering, Zhejiang University, Hangzhou 310027,China. E-mail: opl wl@dial.zju.edu.cn

Polymer-Plastics Technology and Engineering, 45: 809–813, 2006

Copyright # Taylor & Francis Group, LLC

ISSN: 0360-2559 print/1525-6111 online

DOI: 10.1080/03602550600612097

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RESULTS AND DISCUSSION

Dispersion of Nanoparticles in the Epoxy Resin Matrix

The resultant epoxy nanocomposites with differentnanoCaCO3 content were fractured, and the fractured sur-faces were observed with SEM. Figure 2 shows the SEMphotos of the epoxy resin=CaCO3 nanocomposites withdifferent nanoCaCO3 content, from which we can see thatmost of nanoparticles were dispersed in the epoxy resinseparately. And the fractured surfaces are smooth sincethey were not cured. With the increase of the nanoCaCO3

content, more nanoparticles appeared in the same area.Different from the method performed to prepare curedepoxy nanocomposites, in the method of in-situ andinclusion polymerization, nanoparticles were directly dis-persed in the monomers of bisphenol A and epichloro-kydrin. Monomers can permeate into the slightlyaggregated nanoparticles, and following polymerization,the aggregated nanoparticles can be separated owing tothe growth of the epoxy resin among the particles.

In order to study the dispersion of the nanoparticles in alarger system, we prepared epoxy resin=CaCO3 nanocom-posites with 10.4% nanoCaCO3 loading in a 100L reactor.Figure 3 is the SEM photo of the fractured surface of theresultant nanocomposites. From the figure, we can see thatmost nanoparticles are uniformly dispersed in the epoxyresin matrix, and some nanoCaCO3 rich area also existedin the scale up system. Because nanoparticles have largespecific surface areas and strong interactions with eachother, many nanoparticles will form aggregated groups.As previously mentioned, the monomers of bisphenol Aand epichlorokydrin can permeate into the aggregatedgroups, and the epoxy resin grown inside them after poly-merization started. From the magnified area of the figure,we can see that nanoparticles were separated by the epoxyresin grown in the interspace of the aggregated groups andformed a nanoCaCO3 rich area. The nanoparticles in thenanoCaCO3 rich area can disperse by further process suchas extruding.

Because nanoparticles have large specific surface areasand many defects in the surface, epoxy resin can forminteractions such as chemical bonding, hydrogen bonding,and van der Waals interaction with them as shown inFigure 4, which can improve cross-linking points whenthe epoxy resin matrix is cured and can improve theproperties of the nanocomposites.

Thermal Properties of the Resultant Nanocomposites

Figure 5 shows DSC curves of samples 2, 6, 7, and 8.There was only a little difference in the DSC cures of thesamples obtained through different methods. The Tg ofsample 2 prepared by in-situ and inclusion polymerizationis 66.7. The Tg of sample 6 with nanoCaCO3 preparedby solution blending is 66.6, and the Tg of sample 7

FIG. 1. Preparation procedure of nanoCaCO3-modified epoxy resin.

TABLE 2Preparation of samples 6, 7, and 8

Sample Preparation methodCaCO3

(%)

6 NanoCaCO3 was addedand dispersed by stirring,followed with vacuumdehydration to remove acetone

10.4

7 Micron-CaCO3 was addedand dispersed by stirring,followed with vacuumdehydration to remove acetone

10.4

8 Acetone was removedby vacuum dehydration

0

TABLE 1Preparation of epoxy resin=CaCO3 nanocomposites

Sample

Epichlorokydrin=Bisphenol A(mol ratio)

NaOH=Bisphenol A(mol ratio)

Nano-CaCO3

(%)

1 1.22 1.35 13.92a 1.22 1.35 10.43 1.22 1.35 7.54 1.22 1.35 3.95 1.22 1.35 0

a Prepared in 100 L reactor and the others were prepared in500 ml reactor.

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with micron-CaCO3 prepared by solution blending is 64.0.The Tg of pure epoxy resin (sample 8) without CaCO3 is62.9.

Many studies[14,16–18] have been performed to investigatethe influence of the introduction of nanomaterials on thethermal properties of the resultant composites. They foundthat the introduction of the nano-material influences the

cross-link density of the obtained nanocomposites andresults in the changes in Tg. As in the epoxy resin=CaCO3

nanocomposites prepared by in-situ and inclusion polymer-ization, nanoCaCO3can form strong interaction with theepoxy resin chain around them; however, the compositeswere not cured, and the movements of most epoxy resinchains in the matrix were not effected by nanoCaCO3 as

FIG. 3. SEM photo of the epoxy resin=CaCO3 nanocomposite with 10.4% nanoCaCO3 prepared in a 100 L reactor.

FIG. 2. SEM photos of the epoxy resin=CaCO3 nanocomposites with different nanoCaCO3 content (pure epoxy resin; 3.9%, 7.5%, and 13.9%).

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shown in Figure 6. As a result, the Tg of the different com-posites only have a little difference.

CONCLUSION

Epoxy resin=CaCO3 nanocomposites were obtainedthrough in-situ and inclusion polymerization, and thenanoparticles were well dispersed in the resin matrix. Thesatisfied dispersion of the nanoparticles also achieved eventhe system scaled up to 100 L reactor. Since the system wasuncured and nanoparticles only have the interaction withthe polymer chain around them, the introduction of thenanoparticles in uncured epoxy resin system only have a

little effect on the Tg of the nanocomposites, which willnot influence the following reprocess.

ACKNOWLEDGMENTS

Financial support by the National Key Technologies R&DProgramme (2001BA310A14) is gratefully acknowledged.

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