Zeitschrift Kunststofftechnik Journal of Plastics ...

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Wissenschaftlicher Arbeitskreis der UniversitätsProfessoren der Kunststofftechnik

Zeitschrift Kunststofftechnik Journal of Plastics Technology

archivierte, rezensierte Internetzeitschrift des Wissenschaftlichen Arbeitskreises Kunststofftechnik (WAK) archival, reviewed online Journal of the Scientific Alliance of Polymer Technology www.kunststofftech.com; www.plasticseng.com eingereicht/handed in: 24.07.2006 angenommen/accepted: 11.10.2006

Prof. Dr.-Ing. Alois K. Schlarb, Dipl.-Ing. Martin Floeck, Institut für Verbundwerkstoffe GmbH, University of Kaiserslautern Dr.-Ing. Patrick Rosso, Centre for Advanced Materials Technology (CAMT), University of Sydney

Steel Fiber Reinforced Polypropylene. Part 1: On the Influence of Maleic Anhydride on the Fiber/Matrix-Adhesion The objective of the presented study was to investigate the adhesion and bonding quality between steel fibers and a polypropylene (PP) matrix. In order to improve the fiber matrix adhesion, neat PP had been modified with various proportions of maleic anhydride grafted polypropylene (MAHgPP). Fiber pull-out tests had been conducted to determine the apparent interfacial shear strength app. It could be proven that the grafted PP grades exhibit up to 40 % better app values than the unmodified PP matrix, while the major mechanical properties of the matrix were kept constant. Furthermore, scanning electron microscope pictures confirmed an excellent bonding quality between steel and PP grafted with 0.1% MAH. Autor/author Prof. Dr.-Ing. Alois K. Schlarb, Dipl.-Ing. Martin Floeck, Univesität Kaiserslautern Institut für Verbundwerkstoffe Erwin-Schrödinger-Straße, Gebäude 58 67663 Kaiserslautern E-Mail-Adresse: [email protected] Webseite: www.ivw.uni-kl.de Dr.-Ing. Patrick Rosso Centre for Advanced Materials Technology (CAMT), Building No. J07, University of Sydney, NSW 2006, Australia Herausgeber/Editor: Europa/Europe Prof. em. Dr.-Ing. Dr. h.c. G. W. Ehrenstein, verantwortlich Lehrstuhl für Kunststofftechnik Universität Erlangen-Nürnberg Am Weichselgarten 9 D-91058 Erlangen Deutschland Phone: +49/(0)9131/85-29703 Fax.: +49/(0)9131/85-29709 E-Mail-Adresse: [email protected]

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Amerika/The Americas Prof. Dr. Tim A. Osswald, responsible Polymer Engineering Center, Director University of Wisconsin-Madison 1513 University Avenue Madison, WI 53706 USA Phone: +1/608 263 9538 Fax.: +1/608 265 2316 E-Mail-Adresse: [email protected]

Beirat/Editorial Board: Professoren des Wissenschaftlichen Arbeitskreises Kunststofftechnik/ Professors of the Scientific Alliance of Polymer Technology

Carl Hanser Verlag

Zeitschrift Kunststofftechnik/Journal of Plastics Technology 2 (2006) 6

© 2006 Carl Hanser Verlag, München

www.kunststofftech.com

Nicht zur Verwendung in Intranet- und Internet-Angeboten sowie elektronischen Verteilern.

A.K. Schlarb, M. Floeck, P. Rosso

Steel Fiber Reinforced Polypropylene

Steel Fiber Reinforced Polypropylene. Part 1: On the Influence of Maleic Anhydride on the Fiber/Matrix-Adhesion A.K. Schlarb, M. Floeck, Institut für Verbundwerkstoffe GmbH, University of Kaiserslautern P. Rosso, Centre for Advanced Materials Technology (CAMT), University of Sydney This article is dedicated to Prof. Dr.-Ing Dr.-Ing. E.h. Walter Michaeli, on his 60th birthday. The objective of the presented study was to investigate the adhesion and bonding quality between steel fibers and a polypropylene (PP) matrix. In order to improve the fiber matrix adhesion, neat PP had been modified with various proportions of maleic anhydride grafted polypropylene (MAHgPP). Fiber pull-out tests had been conducted to determine the apparent interfacial shear strength app. It could be proven that the grafted PP grades exhibit up to 40 % better app values than the unmodified PP matrix, while the major mechanical properties of the matrix were kept constant. Furthermore, scanning electron microscope pictures confirmed an excellent bonding quality between steel and PP grafted with 0.1 % MAH.

1

INTRODUCTION

In times of limited resources cost efficient light-weight construction plays a continually more prominent role. This not only applies to energy, which is increasingly running short and necessitates constantly lighter constructions in order to satisfy the requirement for mobility, but also to a reduction in funds, which results in a demand for cost efficient solutions. Fiber reinforced polymer composites (FRPC) are remarkably suited for lightweight construction. With regard to cost, this material class is tied to disadvantages compared with the classical construction material steel, in particular when high component stiffness is required. Steel, however, presents an excellent stiffness at low cost, but is due to its comparably high density steel only conditionally suited for light-weight applications. In automotive applications the ability of energy absorption by the materials used plays a particular role. Classical FRPC is known to have great weight specific energy absorption properties. This is basically a result of the high strength and

Zeitschrift Kunststofftechnik 2 (2006) 6

1






toughness of these materials. However, steel is also well suited for energy absorption applications due to its ductile deformation ability. With regard to cost and weight the use of composites and steels is tied to the above mentioned disadvantage.

2

STATE OF THE ART

Since glass fiber-reinforced composites have been in use for more than five decades, it is well known how to process raw glass fibers and thermoplastic matrices in order to obtain a satisfactory fiber-matrix-interphase. Many works have been published on the improvement of fiber-matrix-adhesion employing bonding agents. In the framework of this paper, only a few of them can be cited as examples. Amongst them are CHEN et al. [1]. The authors have found that the addition of maleic anhydride grafted PP (MAHgPP) led to an improved interfacial adhesion between the glass fibers and the PP matrix. MOUZAKIS et al. [2] have come to the conclusion that the incorporation of maleic acid anhydride into a polypropylene-styrene/ethylene-butylene/styrene composite reinforced with glass beads leads to a significantly improved adhesion between the matrix and the glass beads, compared to the ungrafted matrix. CHOU et al. [3] proved that the bonding between glass fibers and a PP matrix can be ameliorated by adding a MAHgPP emulsion to the composite. They call two reasons to account for this improvement: first, MAHgPP can form chemical bonds with the glass fibers, and secondly, due to the good compatibility of MAHgPP and PP, a better interphase can develop between fibers and matrix. ABACHA et al. [4] found that grafting PP with maleic anhydride not only results in an enhanced compatibility with Nylon 6, but also leads to improved mechanical properties (tensile strength and modulus as well as Izod impact resistance) when reinforced with glass fibers. The last reference to be cited in this context – as a monograph on polypropylene and its composites, and to show that grafting PP with maleic anhydride in order to improve the fiber-matrix-adhesion is state of the art – is the “Handbook of Polypropylene and Polypropylene Composites” [5]. The author explains that maleated PP is used for both sizing the glass fibers and as an additive for the neat PP matrix. As a result, depending on the type of maleated PP being used, 50-60 % increases in tensile strength and up to 100 % in impact strength of the fiber-reinforced composite can be observed. However, although much effort has been directed to the optimization of the bonding and interphase quality of glass fibers and thermoplastics – as set forth in the previous paragraph –, very few researchers have worked on the bonding mechanisms of steel fibers and thermoplastics. The papers known to the authors of this study are outlined below. PAKDEMIRLI et al. [6] did not chemically modify the polymers used (PP and PE) but incorporated different metal fibers (bronze, aluminum, steel, copper, and iron) in the composites investigated. The main result is that compared to the pristine polymers a deterioration of the impact strength for the fiber reinforced composites could be observed. Since the matrix was not modified in any way, this finding underlines the necessity to research the bonding mechanisms of metal fibers with polyolefins and how they


2






can be improved. In 1979, D. M. BIGG published two papers on the mechanical properties of metal fiber-filled polymer composites [7, 8]. He pointed out that in an aluminum fiber-PP-composite, the interfacial bonding capability between fibers and matrix is the dominant factor for the physical properties of the composite. He found that general purpose PP and Al fibers showed the poorest properties, whereas chemical modification of the PP, which is not described in detail, led to significantly improved properties. Another work was published by KATSURA et al. [9] in 1985. He studied composites comprising steel fibers and PP. The authors showed that the incorporation of either maleated PP (MPP) or maleated PP wax (MPPW) led to an increase in tensile strength (up to 125 %) and impact strength (up to 250 %) compared to unmodified PP. In the course of their study, it turned out that MPPW is much more effective than MPP. TAN et al. [10, 11] investigated steel fiber-PP-composites regarding their suitability for electromagnetic interference shielding. However, they also determined the interfacial interaction of steel-PP-composites. They concluded that the interfacial adhesion between steel fibers and maleated PP is much higher than that of not grafted PP. A substantial increase in impact strength, flexural strength as well as flexural modulus could be observed in case of the maleated PP. Finally, numerical and analytical evaluations of metal fiber-reinforced thermoplastic composites have been performed by SAYMAN et al. [12], ARSLAN et al. [13], and CLYNE et al. [14]. For the above reasons, it is crucial for the development and successful manufacturing of advanced hybrid steel-glass fiber-reinforced composites to have reliable, repeatable, easy-to-use manufacturing techniques. Such techniques have been developed for glass and carbon fiber reinforced composites. However, in case of metal fiber reinforced polymers, only basic research has been done up to now. Thus, the present paper focuses on the improvement of the interphase between steel fibers and PP, since this is the key to successful manufacturing of such hybrid metal-glass-composites. Since it has been shown in the technical literature that maleic anhydride leads to a better compatibility of steel fibers and polypropylene, two grades of grafted PP have been used in addition to not grafted PP. Being able to use the same coupling agent for steel and glass fibers in hybrid composites will be a big step towards excellent new materials.

3

EXPERIMENTAL

3.1

Materials and Characterization

Novolen 1100VC polypropylene (formerly provided by Targor GmbH, Germany, now available from Basell Polyolefins as Moplen HP 500 V) has been used as base material for the matrix. This homopolymer is normally used for items with long flow paths as well as for long glass fiber reinforced recipes (GMT/LFT). It contains neither nucleation agents nor antistaticums or slip/antiblock agents. The MAHgPP compatibiliser used in this study was Scona TPPP 8012 FA (po-


3






lypropylene master batch powder with 1wt.% MaH), obtained from Kometra GmbH, Germany. Three compositions of these two components have been investigated in this study: PP, PP + 5% compatibiliser and PP + 10% compatibiliser. All of them were compounded in a twin-screw extruder and extruded to thin films in a single step. They will be referred to as PP, PP5, and PP10 in the following. The thickness of the films was 0.125 mm. The notation PP5 and PP10 refers to the content of MaH in the PP materials (PP5 = 0.05%; PP10 = 0.1%). Tensile yield strength was measured according to DIN EN ISO 527–3 at a speed of 5 mm/min and the dynamic elastic moduli by dynamic mechanical thermal analysis (DMTA, values at room temperature). In addition to the mechanical and DMTA tests carried out on the polymer materials, the surface tension of the three materials has been determined as well, because surface tension is the decisive factor for the wetting and thus the formation of the interphase. The surface tension has been measured by contact angle measurements (Goniometer, Remé–Hart Inc., Mountain Lakes) using four different fluids (bromonaphtalene, glycerin, distilled water, formamide). Based on these measurements the surface tension was calculated using the data reduction method of ZISMAN [15]. The steel fibers used in this study were made of spring steel (0.2 mm diameter). The trade name of this steel type is “REMANIT”, an austenitic stainless steel containing approximately 18% Cr and 8% Ni (according to EN 10088).

3.2

Fiber Pull-Out Test

The specimens for the fiber pull-out tests were prepared using four PP films with an embedded spring steel fiber. The dimension of each film was approximately 0.125 5 10 mm. Two films were placed on a hot plate. The steel fiber was then positioned on top of these two films. Finally, the fiber was covered with another two layers of PP film. This structure has subsequently been heated to a temperature of 180 °C. The temperature was kept constant for 5 minutes to allow for the complete melting of the PP matrix. After the matrix material had wetted the fibers, the heating of the hot plate was switched of and the now embedded fibers were cooled down to 100 °C at a cooling rate of 15 °C/min before being removed from the hot plate. The difference in the coefficient of thermal expansion of PP and steel (steel 10 10-6 1/K; PP 100 10-6 1/K) is beneficial for the sample preparation to such an extent that the matrix shrinks onto the fiber. A light-optical microscopic picture of the resulting samples is shown in Figure 1. The top and bottom of each specimen was analyzed microscopically in order to determine the embedded length of the fiber. The embedded length used for the calculation of the apparent interfacial shear strength app was defined as the average value of the embedded lengths visible from the two sides of the sample. In addition to the specimens made to determine the apparent interfacial shear strength app, a small number of samples were manufactured for the purpose of visualizing the fiber-matrix-debonding. These samples were specifically de-


4






signed to allow observing the fiber pull-out using a light-optical microscope. In order to prepare the samples for these experiments, two PP films together with the steel fiber were placed between two microscope glass slides (i.e. object holders) and inserted into a lab kiln. After the polymer matrix had melted and wetted the fiber, the specimen was removed from the kiln and cooled to room temperature.

Figure 1:

Spring steel fiber embedded into four layers of PP10 film

The pull-out tests have been performed using a Zwick universal testing machine (model Zwick 1445) equipped with a 1 kN load cell. The test rig used for performing the fiber pull-out tests is shown in Figure 2. This type of test is referred to as “microbond test” in some of the available technical literature [16]. The suitability of this test for the determination of the fiber-matrix bond strength is discussed by various authors [16, 17]. The experimental set-up used in the present study consisted of two steel plates that were mounted to the upper and lower clamping jaw of the testing machine. The diameter of the holes in the steel plates was 0.3 and 1.2 mm in case of the lower and upper plate. The steel fiber with the PP matrix on one end was threaded through the lower and upper retaining plate. In order to firmly fix the sample, a wire end sleeve was carefully clamped onto the loose end of the fiber, inducing the tensile force into the fiber. While the lower retainer was kept in place, the upper retainer traveled up as the crosshead of the testing machine moved upward at a speed of 1 mm/min. The force required to pull the fiber out of the PP matrix was recorded continuously as a function of the displacement of the crosshead. The tests were conducted at an ambient temperature of approximately 23 °C (room temperature). Afterwards the value of apparent interfacial shear strength app was calculated by applying the following relationship:


5





app =


Fmax d le

where Fmax is the maximum tensile load at the debonding point, d is the diameter of the fiber, and le is the embedded fiber length, as measured using a lightoptical microscope and adequate analysis software. In order to inspect the failure mechanisms, scanning electron microscopy was carried out on already tested specimens.

Figure 2:

Test rig used for the fiber pull-out experiments

4

RESULTS AND DISCUSSION

4.1

Characterization of the Polypropylene Matrix Materials

The DMTA plots recorded during the material characterization are illustrated in Figure 3. Compared to the non-grafted PP the materials with MAH show an increase in modulus. Caused by the DMTA-frequency of 10 Hz the glass transition temperature in a range of 15 - 20 °C for the three matrices seems to be comparably high.


6




4000

0,12

0,1 3000 0,08

2000

0,06

PP5

tan

E complex [MPa]



PP PP10

0,04

1000 0,02

0

0 -50

0

50

100

150

Temperature [°C]

Figure 3:

DMTA plots of the three PP grades

The properties of the matrix materials including the results regarding the different tests such as tensile tests, DMTA, and contact angle measurements (surface tension) are listed in Table 1. Dynamic Elastic Modulus [MPa] 1,540

Melting Temperature [°C]

Crystallinity [%]

Surface Tension [mN/m]

164.9

41.6

31.3

PP

20.8 ± 1.3

Tensile Strain at Break [%] 15.0 ± 1.4

PP5

26.3 ± 1.2

14.0 ± 0.6

1,690

163.7

41.1

36.0

PP10

24.8 ± 1.1

14.1 ± 0.5

1,700

164.4

41.3

39.0

Tensile Strength [MPa]

Table 1:

Mechanical properties of the three PP grades used in this study

According to the data sheet of the manufacturer (Basell) the tensile strength T of the pristine polypropylene is about T = 35 MPa. At a speed of 5 mm/min it can be seen that the PP exhibits a tensile strength of T = 20.8 MPa. In comparison to the PP5 the PP10 shows slightly higher tensile strengths and dynamic elastic moduli by adding an MAHgPP to the neat PP. It is, however, a well known-fact that the addition of MAH causes a loss in ductility [2]. Additionally the melting temperature and crystallinity only change marginally. The surface tension was calculated to 31.3, 36, and 39 mN/m for PP, PP5, and PP10, respectively. Apparently, the addition of MAH is responsible for the increase in surface tension of the PP materials. Generally, metals exhibit very high surface energies compared to polymers. The wetting behavior is, however, dependent on more factors than only the absolute surface tension value. The polar and disperse fractions play an important role as well. Since metals tend to form an oxidized layer on the surface, it is more


7


likely that the surfaces possess a polar character. PP, in contrast, normally provides a larger disperse fraction. At this stage, it is not clear to what extent the increase in total surface energy due to the addition of MAH to the PP contributes to the final wetability of the steel fiber. In general, the higher the surface tension, the worse the wetting behavior. However, it is shown that the addition of maleic anhydride leads to better mechanical properties of the matrix material.

4.2

Fiber Pull-Out Test

Representative results of the pull-out tests are shown in Figure 4. This figure illustrates the apparent shear stress-displacement curve of the three PP grades considering three single specimens (one sample per PP type). PP10 features the highest apparent interfacial shear strength app values (maximum force value divided by the embedded fiber length), whereas neat PP exhibits the lowest app values. At first, in each case the apparent shear stress applied in the pull-out test rises to a maximum value before dropping to about 60–70 % of the maximum value. It is reasonable to assume that in the first stage of the experiment – i.e. before reaching the maximum stress level – the steel fiber is loaded continuously as the crosshead travels up. In contrast to other reports [16, 17] published, the stress-displacement curve does not show a change in its slope that could be attributed to a partial failure of the fiber-matrix-interphase. Instead, the stress increases up to a maximum value, at which an abrupt and complete failure of the interphase seems to occur. The almost constant stress level after the failure of the interphase can be explained by the sliding frictional force caused by the steel fiber being pulled through the matrix. The remaining interfacial frictional stresses are not the same for the different PP grades. Instead, even after the failure of the interphase, the greatest stress is observed in case of PP10, which also featured the best app values. Accordingly, in case of neat PP, which exhibited the lowest app values, the lowest frictional stress was recorded. 3,5 3,0 Apparent Shear Stress [MPa]





2,5 2,0 1,5 1,0 0,5 neat PP

PP5

PP10

0,0 0,0

0,2

0,4

0,6

0,8

1,0

1,2

Displacement of Crosshead [mm]

Figure 4:

Stress-displacement plot of the three PP grades


8




The average results of all pull-out tests conducted in this study are illustrated in Figure 5. It can clearly be seen that the addition of maleic anhydride leads to an improved fiber-matrix-adhesion. While an apparent interfacial shear strength app of 2.34 MPa could be observed in case of the neat PP, the shear strength of PP5 and PP10 was 2.84 MPa and 3.26 MPa, respectively. 4,0 3,5 Apparent Shear Strenght [MPa]



3,0 2,5 2,0 1,5 1,0 0,5 0,0 PP

Figure 5:

PP5

PP10

Apparent interfacial shear strength app values of the three different PP grades, measured in fiber pull-out tests

The PP10 exhibits a app, which is approximately 40 % higher than that of neat PP and about 15 % higher than the one of PP5. The app of PP5, compared to neat PP, is about 20 % higher. The data can be fitted by a straight line: app = 2,36 + 9,3 wMAH, where wMAH is the content by weight of MAH in the specimen. These results match in principle the findings published by [7 -11] in that MAH leads to a much improved fiber-matrix-adhesion. The observed app values are rather low compared to the shear stress that can be sustained by glass fibers or natural fibers in a thermoplastic matrix. Unfortunately, a comparison of the app values displayed in Figure 5 with results reported in the literature cannot be made because no papers, in which appropriate data is published, are known to the authors. Although not investigating metal fibers, CHOU et al. [3] report shear strengths of 3.5–11.5 MPa in case of glass fibers embedded into PP. DOAN et al. [18] reported a shear strength of 16.3 -19.8 in the case of jute fibers, depending on the type and amount of compatibiliser used for grafting the neat PP. The same authors [18] additionally calculated for Polypropylene a shear yield strength of about 19 – 20 MPa from the Von Mises criterion. However, the results displayed above indicate – although yet to be improved – that maleic anhydride is not only suitable as a coupling agent for glass fibers but also for steel fibers. Another result is that an optimum bonding quality was not


9






yet realized, but that significant improvements may be achieved by optimizing the manufacturing process of the samples. These samples were made without exerting any pressure. As a result, the polypropylene portion of the specimens contained a considerable number of pores, impairing the fiber-matrix-adhesion. Thus, developing a manufacturing process for pull-out specimens, and applying pressure to the molten polypropylene in order to reduce the number and size of the pores will most likely lead to an improved interphase and – as a consequence – to an enhanced shear strength.

4.3

Visualization of the Fiber-Matrix-Debonding

The favorable effect of the compatibiliser on the formation of the fiber-matrixinterphase can be called to account for the superior apparent interfacial shear strength of the highly grafted PP10 with 0.1 % MaH. The enhanced fiber-matrixadhesion is responsible for that significant increase in app when having a look at the pulled-out region in Figure 6 and Figure 7. While the neat PP peels off the steel fiber completely without leaving traces, the bonding of PP10 and the steel fiber is much stronger. The pulled-out fibers clearly show residues of the matrix material on them, i.e. no adhesive failure occurred but rather a partly cohesive failure of the fiber-matrix-interphase. However, the achieved bond strength is not yet sufficient to result in interlaminar shear strengths greater than 3.3 MPa, since there are still portions of fiber displayed in Figure 7 suggesting an inferior adhesion, although no complete exfoliation occurred. This finding suggests that one approach towards enhancing the app is modifying the manufacturing process of the specimens in such a way that a satisfactory wetting of the fiber can be ensured, which in turn results in a good interphase.

Figure 6: SEM micrograph of PP


Figure 7: SEM micrograph of PP10

10





5


CONCLUSIONS

The need for new, hybrid composites made of both glass and steel fibers is a result of the fact that the present, commercially available carbon composites are rather expensive. Steel/glass hybrid composites offer a high stiffness and strength at reasonable costs. However, producing and using such hybrid composites necessitates manufacturing processes resulting in excellent material properties. One of the crucial factors for achieving good mechanical material properties is the fiber-matrix-adhesion, i.e. the interphase. The present study shows that the incorporation of maleic anhydride in PP leads to an increase in interfacial shear strength of about 40 % compared to neat PP when using a steel fiber. Furthermore, SEM observations showed the superb bonding quality between steel and PP10, whereas neat PP/steel adhesion seemed to be very poor. The major mechanical properties of the PP were affected only marginally by the addition of the maleic anhydride. The addition of maleic anhydride to PP leads to a considerably improved fibermatrix-adhesion. Further studies should address the influence of different processing conditions, the combination of glass and steel fibers in one hybrid composite, and the influence of maleic anhydride grafted polypropylene on the mechanical properties.

6

REFERENCES

[1]

Chen, M. J.; Wan, C. Y.; Zhang, Y.; Zhang, Y. X.

Fibre orientation and mechanical properties of short glass fibre reinforced PP composites POLYM POLYM COMPOS 13 (2005) 3, 253–262

[2]

Mouzakis, D. E.; Stricker, F.; Mülhaupt, R.; Karger-Kocsis, J.

Fracture behaviour of polypropylene/glass bead elastomer composites by using the essential work-offracture method J MATER SCI 33 (1998), 2551–2562

[3]

Chou, S.; Lin., L. S.; Yeh, J. T.

Effect of surface treatment of glass fibers on adhesion to polypropylene resin POLYM POLYM COMPOS 8 (2000) 2, 131–138

[4]

Abacha, N.; Fellahi, S.

Synthesis of polypropylene-graft-maleic anhydride compatibilizer and evaluation of nylon 6/polypropylene blend properties POLYM INT 54 (2005) 6, 909–916

[5]

Constable, R. C.

Chemical Coupling Agents for Filled and GlassReinforced Polypropylene Composites in: Karian, H. G. (editor): Handbook of Polypropylene and Polypropylene Composites. New York: Marcel Dekker, Inc., 1999, 39–80


11






[6]

Pakdemirli, E.; Williams, J. G.

Metal Fibre reinforced Thermoplastics and the Role of Adhesion Efficiency J MECH ENG SCI 11 (1969) 1, 68–75

[7]

Bigg, D. M.

Mechanical, Thermal, and Electrical Properties of Metal Fibre-Filled Polymer Composites POLYM ENG SCI 19 (1979) 16, 1188–1192

[8]

Bigg, D.M.

Mechanical and conductive properties of metal fibrefilled polymer composites COMPOSITES 10 (1979) 2, 95–100

[9]

Katsura, T.; Kamal, M. R.; Utracki, L. A.

Some Properties of Polypropylene Filled with Metal Fibres POLYM COMPOS 6 (1985) 4, 282–295

[10] Tan, S. T.; Zhang, M. Q.; Rong, M. Z.; Zeng, H. M.; Zhao, F. M.

Interfacial Interaction in Stainless Steel Fibre-Filled Polypropylene Composites J APPL POLYM SCI 78 (2000), 2174–2179

[11] Tan, S. T.; Zhang, M. Q.; Rong, M. Z.; Zeng, H. M.; Zhao, F. M.

Properties of Metal Fiber Filled Thermoplastics as Candidates for Electromagnetic Interference Shielding POLYM POLYM COMPOS 9 (2001) 4, 257–262

[12] Sayman, O.; Yanginci, S.; Sayer, M.

Thermoplastic-Plastic Stress Analysis in a Thermoplastic Composite Disc. J REINF PLAST COMP 24 (2005) 1, 21–33

[13] Arslan, N.; Özben, T.

An Elastic-Plastic Stress Analysis of a Woven Reinforced Steel Fiber Thermoplastic Composite Cantilever Beam Subjected to Transverse Uniform Loads on the Upper Surface J REINF PLAST COMP 24 (2005) 14, 1493–1508

[14] Clyne, T. W.; Markaki, A. E.: Tan, J. C.

Mechanical and magnetic properties of metal fibre networks, with and without a polymeric matrix COMPOS SCI TECHNOL 65 (2005), 2492–2499

[15] Sell, P.-J.; Neumann, A.W.

Die Oberfächenspannung fester Körper ANGEWANDTE CHEMIE, 78 (1966) 6, 321-331

[16] Zhandarov, S.; Mäder, E.

Characterization of fiber/matrix interface strength: applicability of different tests, approaches and parameters COMPOS SCI TECHNOL 65 (2005), 149–160


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[17] Pisanova, E.; Zhandarov, S.; Mäder, E.; Ahmad, I.; Young, R. J.

Three techniques of interfacial bond strength estimation from direct observation of crack initiation and propagation in polymer–fiber systems COMPOS A: APPL SCI MANUF 32 (2001), 435–443

[18] Doan, T.-T.-L.; Gao, S.-L.; Mäder, E.

Jute/polypropylene composites I. Effect of matrix modification COMPOSITES SCIENCE and TECHNOLOGY 66 (2006), 952-963

Keywords: Polymer-matrix composites; Steel-fiber mechanical tests; Chemical coupling

reinforcement;

Interface;

Micro-

Kontakt: Autoren:

Prof. Dr.-Ing. Alois K. Schlarb Dipl.-Ing. Martin Floeck Dr.-Ing. Patrick Rosso

Herausgeber:

Prof. em. Dr.-Ing. Dr. h.c. Gottfried W. Ehrenstein, Prof. Dr. Tim Osswald

Erscheinungsdatum:

November/Dezember 2006






13

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