Melt rheology of maleic anhydride polypropylene
blended with EMAA-ionomer
Takumi Koizumi, Hideyuki Uematu, Akihiro Nishioka
Masataka sugimoto,Takashi Taniguchi, Kiyohito Koyama
Department of Polymer Science and Engineering, Yamagata University, JapanAbstract
The purpose of this study is to clarify the rheological properties of maleic anhydride
Polypropylene (MAPP) / ionomer blends.
We measured dynamic viscoelasticity and uniaxial elongational viscosity of the blends and researched
the influence of ionomer blends on strain-hardening of MAPP.

1 Introduction
Ionomer is polymer that has a few mole percent of ionic groups into polymer chains.
The ionomer has excellent toughness, transparency and wear resistance by aggregates of ionicgroups 1). The properties of ionomer depends on amount of ionic groups (neutralization degree)
and the kind of metallic ion. EMAA-Na ionomer is copolymer of ethylene-methacrylic acid inwhich a part of methacrylic acid is neutralized by metallic ion Na+. Nishioka et al. reported thata strain-hardening of copolymer of styrene and methacrylic acid (StMAA) became larger by
blending with EMAA-Na ionomer 2). They reported that strain-hardening of StMAA became
largerby the interaction of Na+ of EMAA-Na ionomer with COOH of StMAA. We consideredthat this phenomenon can be applied to control of strain-hardening of polymer with COOH
group. In this study, we intended to control the strain-hardening of maleic anhydride
polypropyrene (MAPP) by blending with EMAA-Na. MAPP just shows weak strain-hardening.
We considerd that the grafted maleic anhydride group changes to maleic acid easily. It is
expected that strain-hardening of MAPP is influenced by the interaction between COOH inMAPP and Na+ of EMAA-Na. Our purpose of this study is to examine the effect of ionomer
blending on the strain-hardening of maleic anhydride polypropylene (MAPP).

2 Experimental
Material

Table 1：Sample composition and code

MAPP has grafted anhydride
Code
MAPP E20Na E54Na
species onto the polypropylene(wt%)
chain. Neutralization degrees ofMAPP
10000EMAA-Na ionomer were 20% and
MAPP/E20Na(90/10)
9010054%, these were designated as
MAPP/E54Na(90/10)
90010
E20Na and E54Na. MAPP wasprovided by Mitsui Chemicals.
EMAA-Na was provided by DU PONT-MITSUI POLYCHEMICALS CO.,LTD. Thesesamples were mixed by co-rotating twin screw extruder (KZW-30, L/D=45). The rotating speed
was 100rpm and barrel temperature was 200oC. The details of blends are shown in table1.

Experiments
Uniaxial elongational viscosity measurements and dynamic viscoelasticity measurements
were performed with an ARES (TA Instruments) under nitrogen atmosphere.

4 Results and discussion
Figure1(a) showed the uniaxial elongational viscosity of MAPP. The solid line indicates linearelongational viscosity (3ηS (t)) that is calculated from the result of dynamic viscoelasticity

5 Conclusion

106(a)MAPP
5104

η E(Pa・・ s)

10oη E(Pa・・ s)(b)MAPP/E20Na(90/10)
10105.
ε1.0(1/s)
0.5(1/s)0.1(1/s)
3η
η (t)

4o

106S

170 C

η E(Pa・・ s)(c)MAPP/E54Na(90/10)
105.
ε10

1.0(1/s)0.5(1/s)0.1(1/s)
3η
ηS(t)

4o

170 C
310-110100t(s)10110

2

Figure1:Uniaxal elongational viscosity at
170oC for (a)MAPP, (b)MAPP/E20Na(90/10),(c)MAPP/E54Na(90/10)
10510

410

310

210

1170oC

MAPP
MAPP/E20Na(90/10)
MAPP/E54Na(90/10)

010 -210

The strain-hardening and linear elongational viscosity ofMAPP become larger by blending with EMAA-Na. The
strain-hardening of MAPP/E20Na(90/10) was larger than
MAPP/E54Na(90/10). The linear elongational viscosityof MAPP/E54Na(90/10)was larger than
MAPP/E20Na(90/10).

1.0(1/s)0.5(1/s)0.3(1/s)3ηη E(t)170 CG'(Pa)measurement. The data showed weak strain-hardening at
the higher strain rates regions (ε& ≥ 0.5(1 / s )) . On theother hand, at the lower strain rates
regions (ε& < 0.5(1 / s )) , the data did not show strainhardening. Figure1(b) and (c) showed the uniaxial
elongational viscosity of MAPP/E20Na(90/10) andMAPP/E54Na(90/10), respectively. Both of the data
showed strain-hardening at not only higher strain rates
regions, but also lower strain rates regions. Furthermore,
linear elongational viscosity of MAPP/E20Na(90/10) andMAPP/E54Na(90/10) were larger than that of MAPP.
Figure 2 showed the storage modulus G’ obtained fromdynamic viscoelasticity measurements. These data
showed same behaviour at the higher frequencies regions
except for MAPP. At lower frequencies regions, the slopeof G’ became smaller and G’ increased by loading
EMAA-Na ionomer. Though this figure does not show
the loss modulus G”, in particular, the value of G’ ofMAPP/E54Na(90/10) was nearly equal to G”. Such abehaviour resembles the data of dynamic viscoelasticityof physical gels.
We considered that MAPP/E54Na(90/10) acted like thegels by the interaction between COOH in MAPP and Na+of EMAA-Na. Accordingly, linear elongational
viscosity of MAPP/E54Na(90/10) wasthe largest infigure1. However, the strain-hardening ofMAPP/E20Na(90/10) was larger than
MAPP/E54Na(90/10). Both blends are inhomogeneous
system with domains of ethylene ionomer. It has beenreported that rigid particles reduce the intensity of strainhardening. We considered that deformation of dispersed
particles of E20Na was larger than E54Na in the matrix ofMAPP because viscosity of E20Na was lower than E54Na.
As a result, the strain-hardening of MAPP/E20Na(90/10)
was larger thanMAPP/E54Na(90/10).

10-1010ω(rad/s)

11010

2

Figure2：G’ curves plotted against
angular frequencies at 170oC for MAPP,
MAPP/E20Na(90/10), MAPP/E54Na(90/10)

References
1) Vanhoorne P and Register RA, Low-Shear Melt Rheology of Partially-Neutralized
Ethylene-Methacrylic Acid Ionomers,Macromolecules, 29(2), PP.598-604(1996)
2) Nishioka A, Nishio M, Sugimoto M, Takahashi T, Koda T, Ikeda S and koyama K,Uniaxial
Elongationl Viscosities of Ethylene Ionomer / Styrene-co-Methacrylic Acid Blends, J. Soc.
Rheol.Jpn., 32(1), PP.49~53(2004)