Effect of atmospheric plasma treatment on mechanical properties of jute fiber and interface adhesion between fiber and resin

Journal of Chemistry, Vol. 45 (5A), P. 201 - 206, 2007<br /> <br /> <br /> EFFECT OF ATMOSPHERIC PLASMA TREATMENT ON<br /> MECHANICAL PROPERTIES OF JUTE FIBER AND INTERFACE<br /> ADHESION BETWEEN FIBER AND RESIN<br /> Received 16 August 2007<br /> Ta Thi Phuong Hoa, Nguyen Thi Thanh Binh, Nguyen Chau Giang<br /> Polymer Center, Hanoi University of Technology<br /> <br /> <br /> Summary<br /> The surface treatment by physical method of jute fiber using air plasma was investigated.<br /> Fiber was treated by the atmospheric plasma with various conditions of power 50W and different<br /> treatment times (from 1 min to 7 min). After treatment, the characteristics of fiber changed<br /> remarkably and fiber surface observed by SEM analyze showed a better morphology for<br /> adhesion. The result showed that tensile strength and Young’s modulus of jute fiber were slightly<br /> improved, however there was a remarkable improvement interface adhesion between fibers and<br /> polypropylene (PP) resin. Especially, when combine physical method and chemical method, the<br /> interfacial adhesion and mechanical properties of jute fibers were significantly improved.<br /> <br /> <br /> I - Introduction II - Experimental<br /> <br /> Natural fiber reinforced composites have 1. Material<br /> recently increased concerns of scientists and<br /> - Jute fiber: silk jute and roll of jute supplied<br /> technologists because of many advantages. from Hanoi Jute Company.<br /> Natural fibers are abundant with various species,<br /> can be recyclable and biodegradable and - MAPP - Compatibilizer polypropylene -g-<br /> therefore are very potential in manufacturing maleic anhydride with 0.8% of maleic<br /> environmental friendly polymer composite. It is anhydride was synthesised at Polymer Center,<br /> Hanoi University of Technology, Vietnam.<br /> however important to improve interface<br /> adhesion properties between natural fiber and - Technical potassium hydroxide was used<br /> resin. Among several fiber treatment methods, for alkali treatment.<br /> plasma treatment is a new physical method - Acetic acid from China with density and<br /> which is regarded as a dry surface processing concentration of 1.05 g/ml and 99.3%<br /> method for adhesion improvement without respectively.<br /> waste liquid. Moreover, plasma treatment can 2. Fiber preparation<br /> modify surface without obstructing basic<br /> properties of fiber. In this research, atmospheric Raw jute fiber obtained locally was scoured<br /> plasma treatment has been applied to improve by treating with a 1% solution of a detergent at<br /> 70oC for 1 h to remove weaving size (potato<br /> adhesion properties between jute fiber and<br /> starch and waxes), then by washing in distilled<br /> polypropylen (PP) resin.<br /> water and drying.<br /> <br /> <br /> 201<br /> 3. Alkali treatment excess of sodium hydroxide and thoroughly<br /> rinsed with distilled water and dried.<br /> Jute fibers were soaked in beakers<br /> containing potassium hydroxide concentration 4. Plasma treatment<br /> in 0.5N for 2h, 4h, 6h and 8h. The fibers were The plasma experiment system used for this<br /> then washed with dilute acetic acid to neutralize study is shown in figure 1.<br /> <br /> <br /> Dielectric Electrode<br /> <br /> <br /> <br /> <br /> Power supply<br /> 12-20 KHz<br /> 0-200 W<br /> <br /> <br /> <br /> <br /> Gas exhaust Enclosure<br /> <br /> <br /> Vacuum pump<br /> <br /> Figure 1: Experimental system creates plasma<br /> Two Plane-parallel metal electrodes are separated by an atmospheric environment in which<br /> silent discharge environment at the gap. The electrodes are connected to a power supply with high<br /> frequency and power of 12 KHz and 50W. Fiber was treated under conditions as showed in table 1.<br /> <br /> Table 1: Plasma treatment condition<br /> Gas Air<br /> Pressure and temperature Atmospheric pressure, room temperature<br /> Intensity and frequency of power 50W and 12 KHz<br /> Treatment time 1 to 7 min<br /> <br /> 5. Morphology study jute fibers was glued on the sheet of paper<br /> working as an attachment for the specimen.<br /> The morphology was observed by using<br /> Then, the gage positions of the paper were cut<br /> SEM.<br /> after checking it on LLOYD (5000 N)<br /> 6. Tensile test of jute fiber equipment at a crosshead speed of 2 mm/min.<br /> The average diameters of fiber were 7. Microdroplet test<br /> measured in microscope which magnifying<br /> Single fiber composite (SFC) of jute fiber<br /> index comes to 40 times. Figure 2 shows the<br /> and PP was prepared, then the interfacial shear<br /> dimensions of the fiber specimen. One of the<br /> strength (IFSS) was measured by microdroplet<br /> <br /> 202<br /> test on LLOYD (5000 N) at a crosshead speed of 2 mm/min.<br /> <br /> Adhesive agent<br /> Jute fiber<br /> 2 cm<br /> <br /> <br /> <br /> <br /> 2 cm<br /> 0.7 cm<br /> <br /> <br /> <br /> <br /> 5 cm<br /> Paper tab will be cut<br /> <br /> <br /> Figure 2: Tensile test of fiber<br /> <br /> <br /> <br /> Jute fiber PP<br /> Blade<br /> <br /> Adhesive agent<br /> <br /> <br /> <br /> <br /> Paper tab will be cut<br /> <br /> Figure 3: Microdroplet test<br /> <br /> III - Results and Discussion<br /> <br /> 1. Effect of alkali treatment on the tensile properties of Jute fiber<br /> Table 2 presents tensile properties of jute fiber after alkali treatment with various conditions.<br /> <br /> Table 2: Tensile properties of untreated and alkali treated Jute fiber<br /> Alkali treatment Tensile strength, Young’s Modulus,<br /> conditions MPa GPa<br /> Untreated 198 21.920<br /> Jute fiber KOH 0.5 N, 2h 239.15 23.290<br /> KOH 0.5 N, 4h 274.95 24.471<br /> KOH 0.5 N, 6h 287.6 28.432<br /> KOH 0.5 N, 8h 241.95 22.292<br /> <br /> The results show the change of tensile alkali - sensitive bonds existing between the<br /> properties when changing the treatment different components of the fiber as a result<br /> condition. An explanation is that rupture of partial removal of the hemicelluloses, lignin and<br /> <br /> 203<br /> other substances. They have amorphous average value of tensile strength and Young’s<br /> structure, inhomogeneous property and can modulus increased 45.25% and 29.71%.<br /> respond to low stress. Treated fiber becomes<br /> 2. Effect of atmospheric plasma treatment on<br /> more homogeneous and capable of rearranging<br /> themselves along the direction of tensile the tensile properties of jute fiber<br /> deformation. Consequently, tensile properties of Changes of tensile properties of jute fiber<br /> treated fiber increase. Especially, in case the after atmospheric plasma treatment are shown in<br /> alkali treatment of 0.5 N in potassium table 3.<br /> concentration and 6 hours in treatment time, the<br /> <br /> Table 3: Tensile properties of untreated and atmospheric plasma treated jute fiber<br /> Kind of fiber Atmospheric plasma Tensile strength, Young’s Modulus,<br /> treatment condition MPa GPa<br /> Untreated 1 min 227.92 22.436<br /> 3 min 254.60 23.527<br /> 5 min 265.39 25.145<br /> Alkali treated 1 min 308.90 29.774<br /> KOH 0.5N,6h 5 min 335.26 33.720<br /> 7 min 313.30 27.315<br /> <br /> In case the atmospheric plasma treatment, Plasma treatment showed higher effect than<br /> highest tensile properties achieved at treatment alkali treatment. In the case of combination of<br /> time of 5 min. That is suitable treatment atmospheric plasma treatment of 5 min and<br /> condition. Especially, the combination of alkali alkali treatment of 0.5 N KOH in 6 hours, the<br /> treatment and atmospheric plasma treatment interfacial adhesion is 30.96% higher than that<br /> leads to increases of 69.32 % and 53.83 % in the between untreated fiber and MAPP.<br /> average value of tensile strength and Young’s<br /> 3<br /> modulus.<br /> Untreated<br /> Effect of atmospheric plasma treatment on 2.669<br /> Alkali treated,<br /> the tensile properties of fiber is however slight. KOH 0.5N, 6h 2.562<br /> It may be that atmospheric plasma treatment 2.5<br /> strafed on fiber surface caused a partial removal 2.323<br /> IFSS, MPa<br /> <br /> <br /> <br /> <br /> of lignin and hemicelluloses. As known that<br /> plasma treatment can modify only fiber surface 2.061<br /> without obstructing basic properties of fiber.<br /> 2<br /> 3. Effect of atmospheric plasma treatment on<br /> interfacial adhesion between Jute fiber<br /> and MAPP<br /> 1.5<br /> The effect of atmospheric plasma treatment Untreated Plasma treated, 5 min<br /> on interfacial adhesion between jute fiber and Plasm a treatm ent condition<br /> MAPP is indicated in figure 4.<br /> As shows in this figure, the interfacial Figure 4: Effect of atmospheric plasma<br /> adhesion between two phases improved treatment on interfacial adhesion<br /> significantly by atmospheric plasma treatment. between Jute fiber and PP resin<br /> <br /> 204<br /> 4. Effect of plasma treatment and alkali The SEM images of untreated and treated<br /> treatment on the surface morphology fiber surface are shown in figure 5.<br /> <br /> <br /> untreated Plasma, 5min<br /> <br /> <br /> <br /> <br /> KOH 0.5N, 6h + Plasma, 5min<br /> <br /> <br /> <br /> <br /> KOH 0.5N, 6h<br /> <br /> <br /> <br /> Figure 5: SEM images of Jute fiber surface<br /> <br /> It showed that jute fiber consists of many Third International Workshop on Green<br /> individual fibers which are bonds together Composites. March 16-17, Kyoto, Japan<br /> closely by adhesive substances. After alkali (2005).<br /> treatment, individual fiber becomes more 2. Ta Thi Phuong Hoa, Nguyen Thi Thanh<br /> oriented and has cleaner surface. After Mai, Nguyen Hoang An, Nguyen Anh Tuan,<br /> atmospheric plasma treatment of 5 min, fiber Le Thanh Hung, Young Sik Song.<br /> surface became rougher comparing to the Proceeding of the International Conference<br /> surface of untreated fiber. on Engineering Physics, Ha noi, October 9-<br /> 12, P. 397 - 401 (2006).<br /> IV - Conclusion<br /> 3. Dr X. J. Dai, Mr L. Kvi. Study of<br /> atmospheric and low pressure plasma<br /> The atmospheric plasma treatment can be<br /> Modification on the Surface properties of<br /> used as an effective surface treatment method<br /> Synthetic and Nature Fibers. CSIRO textile<br /> for jute fiber in PP composite application which<br /> and fiber technology, p. 1-10.<br /> can not only improve the adhesion between fiber<br /> www.tft.csiro.au (2001).<br /> and PP resin but also the mechanical properties<br /> of the fiber without waste liquid and has higher 4. D. Sun, G. K. Stylios. 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