the use of cellulosic fibers wastes to increase the ...

2nd INTERNATIONAL CONFERENCE ON NATURAL FIBERS

THE USE OF CELLULOSIC FIBERS WASTES TO INCREASE THE MECHANICAL BEHAVIOUR ON BIODEGRADABLE COMPOSITES FOR AUTOMOTIVE INTERIOR PARTS N.C. Loureiro1,2(*), J.L. Esteves1,3 and J.C. Viana4 1 Institute of Mechanical Engineering and Industrial Management (INEGI), Porto, Portugal 2 Superior Institute of Douro and Vouga (ISVOUGA), Santa Maria da Feira, Portugal 3 Department of Mechanical Engineering, Faculty of Engineering of University of Porto (FEUP), Porto, Portugal 4 Institute for Polymers and Composites (IPC/I3N), Polymer Engineering Department, University of Minho (UMinho), Guimarães, Portugal (*) Email: [email protected]

ABSTRACT The best way to obtain cellulosic fibers is to use the pulp wastes from the paper plants. The pre-processing of the fibers is a very complex and chemically heavy set of operations. At the end a small part of the fibers will be rejected and removed from the production system. Actually these rejected fibers are being incinerated at the furnace that dries the raw-wood. This means that after a set of chemical treatments, that ends with a bleach, the fibers will be incinerated driving to a waste of money, once that all the effort applied to the treatment are not useful, and by other side, the incineration can release some non-healthy emissions. Is possible to use these rejected fibers on composite applications where there mechanical properties can improve the matrix. We will present the study of the incorporation of these rejected fibers into a biodegradable PLA and PHA blended matrix to replace, in some applications, the petrol-based polymers used into the automotive interior trims. The mechanical, and thermal properties will be assess and compared, with the properties of the petrol-polymers used normally in this type of applications. At the end it will be presented some concrete applications studied during this work. INTRODUCTION In the north of Portugal and in the Galiza region (Spain) is possible to count 824.000 ha of Pine trees and 468.000 ha of Eucalyptus trees. [1] To process and transform the wood in paper this euro-region counts with nine industrial plants. From these nine plants, two are thermochemical paper pulp plants. The other seven can be divided in five plants to produce MDF and two to produce fiberboard. (fig.1) The process to extract fibers from the wood is a chemically heavy and requires a parallel system to purify the produced wastes to decrease the environmental impact. The process is quite similar if we are extracting pine fibers or eucalyptus fibers. The main differences are at the chemical compounds used. In fig.2 it’s presented a simplified diagram of a typical pulp and paper process. At the end of this process the rejected fibers are segregated and used into the cooking stage as a boiler combustible. These rejected fibers will be used in this work. 2nd ICNF – From Nature to Market

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Azores/Portugal, 27-29 April 2015

Fig. 1 –Northern Iberian Peninsula Wood Transformation Plants Geo-localization [1]

Fig.2– Pulp process scheme [2]

MATERIALS AND METHODS Materials The polymers used in this work were: PHA, under the trade name PHI002, manufactured by Natureplast, France PLA, under the trade name Ingeo Biopolymer 3251D, manufactured by NatureWorks LLC, USA The material suppliers provided the data properties presented in Table 1.

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Editor: R. Fangueiro


Table 1 - Raw-material manufacturer’s datasheet properties values. Melt Temperature (ºC) Degradation temperature (ºC) Tensile Strength at break (MPa) Tensile elongationat break (%) TensileModulus (MPa) HDT A (1.8 MPa) (ºC) Density MFI (190 ºC/2.16 kg) (g/600 s)

PLA 188 - 210 200 48 2.5 2700 60 1.24 30-40

PHA 145 – 155 200 35 2 2950 72.5 1.25 15-30

The cellulosic fibers are from Portuguese eucalyptus globulus trees, and becomes from a Portuguese paper pulp plant. The eucalyptus fibres are made of pure cellulose from the bleached kraft pulping process. The main properties of these fibers are presented in Table 2. Table 2–Eucalyptus Globulus properties [3-4] Average fiber diameter (μm) Average fiber length (mm) Tensile Strength at break (MPa) Tensile elongation at break (%) Tensile Modulus (GPa) Flexural Modulus (GPa) Flexural Strength at break (MPa) Density

10.9 0.66 160 5.2 17.4 16 130 1.6

Preparation of the Composites The materials were dried at 60ºC for 24 hours before processing and kept into separate Ziploc bags. The composites were compounded in Compound Injection Moulding Machine. The different ratios were adjusted by setting the feed throat of each hopper. The mould temperature was set at 20 ºC, and the injection temperature profile is presented in Fig. 3.

Fig. 3 – Injection moulding temperature profile.

This temperature profile was established by combining the melting temperature of the polymers, the degradation temperature and the injection molding conditions suggested by the supplier´s datasheets. A constant injection velocity of 20 mm/s (corresponding to an injection flow rate of 6.3 cm3/s) was used. The several composite were injection molded in the form of specimens with the following geometries and dimensions (according to the respective standard): • Flexural and HDT specimens: 12 x 150 x6 [mm] parallelepipedic bars • Impact specimens: central gated discs of Ø60x2 [mm]

2nd ICNF – From Nature to Market

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• Tensile specimens (type II): dog-bone geometry with a narrow section of 57x10x4 [mm], and an overall dimensions of 183x19x4 [mm]. MECHANICAL CHARACTERIZATION

Tensile properties measurements The tensile properties were tested in a universal mechanical testing machine Shamidzu AG-X 100kN, equipped with a 50 mm Shamidzu extensometer, according to ASTM D638 test procedures. The crosshead velocity used was of 5 mm/min, and the tests were performed in a standard laboratory atmosphere of 23±2ºC and 50±5% relative humidity. A grip distance of 150 mm was used. The envisaged tensile properties were the initial modulus, the maximum/yield stress and the strain at break. At least 11 specimens were tested for each reinforced blend composition. Flexural properties measurements A Universal Tiratest 2705 5kN Machine was used to measure the flexural properties according to ASTM D790 standard. It has been used a 3-point flexural test, with a crosshead velocity of 2.56 mm/min and a spam of 96 mm. Tests were performed in a standard laboratory atmosphere of 23±2ºC and 50±5% relative humidity. The envisaged flexural properties were the initial modulus, the maximum stress and the strain at maximum stress. At least 11 specimens were tested for each reinforced blend composition. Instrumented Impact properties measurements Instrumented impact tests are performed according ISO 6603-2 standard in a CEAST Fractovis plus Impact machine (velocity of 1 m/s). All tests were carried out in standard laboratory atmosphere of 23±2ºC and 50±5% relative humidity. From the force-displacement curve, the impact toughness was calculated as the area below the force-displacement graph. The impact data presented are the average of 7 measurements. Heat Deflection Temperature (HDT) measurements The Heat Deflection Temperature (HDT) was measured according to ISO 75-2, in a RAYRAN HDT apparatus. This test used the method HDT A with an applied stress state of 1.8 MPa and an increasing temperature rate of 120 ºC/h. Presented HDT results are the average values of three measurements. EXPERIMENTAL RESULTS AND REMARKS The mechanical properties obtained experimentally are expressed in table 3. Table 3 –Experimental results Matrix [70:30][PLA:PHA] Tensile Modulus [GPa] Maximum Tensile Stress [MPa] Maximum Flexural Stress (MPa] Absorved Energy [J] Heat Deflection Temperature [ºC]

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3,4 46,02 62,30 6,4 62,1

Biocomposite (10% fiber) 4,8 86,20 68,86 10,5 63,0

Biocomposite (20% fiber) 6,1 91,78 76,33 10,5 71,7



The interior door trims are mainly injection molded into ABS or PP-copolymer, that’s why is obligatory to compare the obtain results with the general ABS and PP properties. Using online databases (www.matweb.com) it was possible to resume the main properties of ABS and PP. The results are expressed into table 4. Table 4 – ABS and PP General Properties [5] ABS (injection grade) Tensile Modulus [GPa] Maximum Tensile Stress [MPa] Maximum Flexural Stress (MPa] Absorved Energy [J] Heat Deflection Temperature [ºC]

2,33 38,4 68,6 22,7 96

PP (injection grade) 1,72 31,3 48,1 10,8 63

Based in tables 3 and 4 is possible to compare (fig.4) the properties of the raw-materials. The graphic presented in fig1 will emphasize the relation of all these parameters.

Fig. 4 – Raw-materials properties comparison

Regarding the HDT, is possible to see that the ABS presents the highest value. However the value presented is an average of all ABS grades actually in the market. It’s possible to have an ABS with a HDT lower than the studied composites. Using the figure is possible to choose the best solution since that for producing automotive parts it’s going to be used the composite that presents the equal or better properties in all dimensions.


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By analyzing the graphic is possible to conclude that the composite with 20% fiber (gray shadow) is the one that fulfill the previous statement.

FINAL REMARKS The properties of biodegradable composites can be tailored to achieve a given performance. Composites with a [30:70] [PHA:PLA] matrix and with a fiber content of 10% and 20% (wf) were compared with the most used petrol-based polymers for automotive interior parts (PP and ABS) The incorporation of 20% wf fiber leads to an eco-composite that presents the best properties of all biopolymer blends and biocomposites studied. When compared with ABS and PP, this eco-composite, normally, presents equal or better properties, excluding the impact absorbed energy. The feasibility of producing interior parts on the studied eco-composites has been investigated. Is possible to conclude that this composite can reveal himself an option for replace the petrolbased polymers in some cabin interior parts applications has demonstrated in this part casestudy. Once that the composites are from renewable sources this work gives an indication of the potential use of these composites replacing the petrol-based matrix composites with synthetic reinforced fibers. It also proved that is possible to give an added-value to rejected fibers into the pulp plants.

ACKNOWLEDGMENTS The authors acknowledge the Portuguese Science and Technology Foundation (FCT) for the financial support provided by the project MIT-Pt/EDAM-SMS/0030/2008 – Assessment and Development of integrated Systems for Electric Vehicles. N.C. Loureiro acknowledges also the Portuguese Science and Technology Foundation (FCT) for the financial support provided by the Ph.D. grant SFRH/BD/42978/2008.

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J.C. Viana also acknowledges the project PEst-C/CTM/LA0025/2011 (Strategic Project - LA 25 - 2011-2012).

REFERENCES [1]

A.R. Campos, GreenMotion – Transfer of Ecological Materials for the Automotive Industry, 2nd Journeys of GreenMotion Project, Guimarães, Portugal (2012)

[2]

J.M. Patino, M.P. Nunez, Retrofit Approach for the Reduction of Water and Energy Consumption in Pulp and Paper Production Processes, Environmental Management in Practice, Dr. Elzbieta Broniewicz (Ed.), InTech, (2011)

[3]

H. Savastano Jr., P.G. Warden, R.S.P. Coutts, Brazilian waste fibres as reinforcement for cemente-based composites, Cement & Concrete Composites, vol.22, pp. 379-384 (2000)

[4]

V. Agopyan, H. Savastano Jr., V.M. John, M.A. Cincotto, Developments on vegetable fibre-cement based materials in São Paulo, Brazil: an overview, Cement & Concrete Composites, vol.27 , pp. 527-536 (2005)

[5]

Information on: http://matweb.com (consulted at 24th February 2013)


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