Research On Fabrication And Mechanical Properties Of Jute Fiber Reinforced Polypropylene Composite

The development of composite reinforced by natural fiber can promote the progress of related industry, environment protection and resource recycling. In the field of natural fiber reinforced composite, bast fiber reinforced material promised a great future. The fabrication and mechanical properties of jute/PP composite were studied. The main content of this study includes the following five aspects: jute fiber surface modification, composite fabrication. study on mechanical properties of composite and moisture effects on material properties.(1) Jute fiber surface modificationIn this study jute fiber was pretreated by sodium hydroxide solution, silane coupling agent (KH550) and acetic anhydride respectively. Moisture absorption, linear density, mechanical properties, FTIR analysis and SEM morphology observation of jute fibers were tested after different pretreatments, to identify the optimum methods of each treatment for fiber suface modification. The results showed that (a) the best pretreatment parameters of sodium hydroxide solution was: 5wt% NaOH, 60min; (b) for KH550: 5wt% NaOH, 60min followed by 3wt% KH550, 30min; (c) and for acetic anhydride: 5wt% NaOH, 60min followed by acetic anhydride marination for 60 min, with bath ratio of 30:1. All the experiments were carried out under room temperature.(2) Jute/PP composite fabricationRaw and treated jute fibers (jute fiber pretreated by three best methods as mentioned above) were used for jute/PP and jute/Mah-g-PP/PP composites fabrication. Two different fabrication processes were applied: (a) laminating composite: firstly, jute fibers were processed to form fiber felts, then insert fiber felts into pp or PP/MAH-g-PP films (made in the lab) respectively to form the sandwich structure, so as to fabricate 8 different composites under thermal pressure; (b) blending composite: firstly, cut fibers into 2mm long, then mix fiber and PP or PP/MAH-g-PP grains by twin-screw exturer to fabricate composite under thermal pressure fabricate 8 different composites. The optimum parameters of thermal pressure formation for both methods are as follows: preheating-180℃. 10min; thermal pressing-12.5MPa, 180℃, 20min; cooling-4MPa, 30min.(3) Mechanical properties of jute fiber/PP compositesTensile and bending propeties of the fabricated 16 different composite as stated above were tested, as well as the cross section SEM morphology observation, to disscuss the effects of fiber surface modification, matrix modification and fabrication process on composite properties. The KH550 treated jute fiber reinforced PP composite showed better tensile, bending and interfacial properties. The composite with MAH-g-PP modified matrix exhibited improved tensile property. while the bending tests results showed no obvious change. Due to different fabricating processes, composites have different inner structures which results in reinforcing mechanism diversity. Even with the same fiber surface modification and fiber content, it was difficult the compare the properties of composites with different structure.(4) The moisture effects on composite propertiesSoaking composite in fresh water for 240 h and 480 h respectively, weight, tensile and bending properties changing were analysed, to discuss the moisture effects on composite properties. According to the testing results, after 240 h and 480 h water soaking, properties changing of composite could hardly be observed. To determine the moisture effects, advanced experimenting period and mehod shoud be researched.